1. Pre-Design
A. Appraisal
B. Design Brief
1.1. Obtain design brief
1.1.1. CIBSE guidance and tools
The building services engineer should be able to influence the design brief at an early stage in terms of energy efficiency, system options, sustainability, climate change, regulations etc. There are various ways to influence the brief and the following suggested guidance provides information towards some of the issues related to building design.
CIBSE Guide F “Energy Efficiency in Buildings” provides information on energy efficiency issues at various design stages, including information to be used at early design stages, such as the drivers for energy efficiency (chapter 1), setting energy objectives, criteria and targets, equipment and system selection (chapter 2) and developing a design strategy (chapter 3 and 4). Furthermore, Guide F provides general information on LZC technologies (chapter 5), control strategies (chapter 6) and ventilation system design considerations (chapter 7). Part C of Guide F provides benchmarks of energy performance for various building applications and a series of CIBSE policy statements that reinforce the drivers for energy efficiency.
CIBSE Guide L “Sustainability” provides information on sustainability issues to help towards influencing the design brief (chapter 2), forming a sustainability strategy (chapter 3), including energy and low carbon strategy with reference to LZC technologies (§3.1), and adaptation to the impacts of climate change (§3.3).
CIBSE publications related to renewable technologies are the AM12 “Small-Scale Combined Heat and Power for Buildings”, TM25 “Understanding Building Integrated Photovoltaics and TM38 “Renewable Energy Sources for Buildings” with an accompanied simple tool to assist in initial identification of the most promising renewable sources for a given project.
The CIBSE Knowledge Series publication KS8 ”Sustainable Low Energy Cooling: an Overview” explains the principles of using ventilation for passive cooling (chapter 3).
CIBSE TM36 “Climate Change and the Indoor Environment: Impacts and Adaptation” presents case studies where ventilation strategies were used as adaptation measures to future overheating risks and higher energy demand for cooling, caused by climate change, for a variety of building applications (domestic and non-domestic, new and existing).
A more holistic approach of how to influence the design brief that combines energy efficiency, sustainability, cost, regulations, future performance; how certain design decisions could affect the above choices and their interrelations e.g. sustainability against capital, and whole life cost against building regulations requirements etc.
1.1.2. Weather data available for present climate conditions
At this pre-design stage of consulting with the client some general weather statistics based on location could be used towards influencing the design brief in terms of energy efficiency and system option.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
The user should be looking for present day statistics of occurrence of coincident wind speed and temperature, and coincident wind speed and direction, based on location.
The weather data available in the CIBSE guides are location specific but not site specific. The user should take under consideration that locality and microclimate can considerably affect design decisions. Local information could be acquired from city councils, local planning authorities, environment agency, met office etc.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
1.1.3. Weather data available for future climate conditions
At this pre-design stage of consulting with the client some general climate change statistics based on location could be used towards influencing the design brief in terms of climate change; possible impacts on building and building site and designing for future conditions.
CIBSE Guide A “Environmental Design”, chapter 2, §2.9 and CIBSE Guide J “Weather, Solar and Illuminance Data”, chapter 3, §3.2 and chapter 4, §4.4 provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for future statistics of occurrence of coincident wind speed and temperature, and coincident wind speed and direction, based on location.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The CIBSE climate change data (Guides A, J, L and TM34) are available for three locations only (London, Manchester and Edinburgh).
TM34 presents temperature statistics but there are no wind data available due to the lack of suitable algorithm to produce hourly wind speed data from the available UKCIP02 daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty is higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
1.1.4. Other useful references
Environment Agency’s Flood Map resource at: http://www.environment-agency.gov.uk/subjects/flood/826674/829803/
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
1.1.5. Input from members
1.2. Identify client and building user needs and requirements
1.2.1. CIBSE guidance and tools
The building services engineers should be able to identify and acquire client requirements to be used while putting together the brief, so as to optimise design in terms of sustainability, energy efficiency, regulations, future needs etc. Such requirements could include budget, required performance, attitude to risk, health and safety requirements, etc.
An example of listing client and user needs and requirements is presented in CIBSE Knowledge Series publication KS8 “How to Design a Heating System”. A similar list could be developed and expanded to accommodate the design of ventilation systems. Potentially such a list could be composed by designers by using a series of CIBSE publications such as Guide A “Environmental Design” for internal environment requirements, Guide F “Energy Efficiency in Buildings” for energy efficiency requirements, Guide L “Sustainability”, Guide H “Building Control Systems” for control requirements, etc.
CIBSE could offer a checklist of all relevant needs and requirements that the engineer could advise towards reaching objectives described in task 1.1.
1.2.2. Other useful references
1.2.3. Input from members
1.3. Refer to feedback and lessons learned from previous projects
1.3.1. CIBSE guidance and tools
The building services engineers should be able to keep in touch with previous projects in order to learn from them and improve their design methods. Some guidance on energy audits and surveys is included in Guide F, chapter 18.
Facilities managers (FMs) are usually responsible for the management of the building services and energy use in a building and have access to performance and energy use data. Liaising with the FMs during design process could provide useful information about the future operation and maintenance needs of a building and its services. Limited information on facilities and energy management is provided in Guide F, chapter 15.
Further guidance could include advice on possible channels and actions through which the design team could revisit or keep in touch with previous projects. Perhaps some research could be done in current practices.
Could CIBSE influence client perception of the value of monitoring and feedback? For example in some current projects monitoring and feedback is used as an educational process.
Further guidance could concentrate on encouraging integration with Facilities Management (FM), e.g. FM participation during design stages.
1.3.2. Other useful references
1.3.3. Input from members
1.4. Gather information about site, including utilities provision and fuel options
1.4.1. CIBSE guidance and tools
The building services engineers should make sure that they acquire all site specific information that could influence the design decisions. A comprehensive list of all relevant site specific information could assist towards the above.
CIBSE Guide F “Energy Efficiency in Buildings” provides some general site considerations (chapter 4, §4.1) and explains the principles of the various ventilation strategies (natural, mixed mode and mechanical) (chapter 4, §4.2.5).
CIBSE Guide L “Sustainability”, chapter 3, provides information on site analysis, in relation to energy use (§3.1), assessment of flood risk (§3.4), site accessibility (§3.6) and impacts on local environment and community (§3.11). Climate changes are summarised in Guide L for three locations in order to assist in forming adaptation solutions to climate change.
CIBSE TM36 “Climate Change and the Indoor Environment: Impacts and Adaptation” presents case studies where ventilation strategies were used as adaptation measures to future overheating risks and higher energy demand for cooling, caused by climate change, for a variety of building applications (domestic and non-domestic, new and existing).
Fuel choices (mostly presented for heating) are included in CIBSE Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapter 1, §1.6, and in Guide F, chapter 5, §5.2.
A comprehensive checklist of all relevant site specific information and their possible sources e.g. city councils, local planning authorities, environment agency, met office, site visits etc., could be useful.
1.4.2. Weather data available for present climate conditions
At this pre-design stage of gathering site information, statistics on summer and winter events based on location could influence decisions on building form and orientation.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
The user should be looking for site specific climate/weather trends/extremes of occurrence of coincident wind speed and temperature, and coincident wind speed and direction. Furthermore, the user should be looking for site specific flooding/drought occurrences as they might affect the access to the building, e.g. for fuels, or the ventilation based passive cooling strategies that depend on external plants.
The weather data available at the CIBSE guides are location specific but not site specific. The user should take under consideration that locality and microclimate can considerably affect design decisions. Local information could be acquired from city councils, local planning authorities, environment agency, met office etc.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
1.4.3. Weather data available for future climate conditions
At this pre-design stage of gathering site information, trends of future summer and winter events based on location could assist in understanding the changes that the site might undergo over the lifetime of the building. Such information could help in forming a flexible ventilation strategy that could inspire future low/zero energy use for ventilation and be able to respond to future climate change events.
CIBSE Guide A “Environmental Design”, chapter 2, §2.9 and CIBSE Guide J “Weather, Solar and Illuminance Data”, chapter 3, §3.2 and chapter 4, §4.4 provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for future site specific climate/weather trends/extremes of occurrence of coincident wind speed and temperature, and coincident wind speed and direction.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The CIBSE climate change data are available for three locations only (London, Manchester and Edinburgh).
TM34 presents temperature statistics but there are no wind data available due to the lack of suitable algorithm to produce hourly wind speed data from the available UKCIP02 daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty is higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
1.4.4. Other useful references
Environment Agency’s Flood Map resource at: http://www.environment-agency.gov.uk/subjects/flood/826674/829803/
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
BRE (1990) ‘Climate and Site Development. Part 2: Influence of Microclimate’
BRE (2000) “Environmental Site Layout Planning: Solar Access, Microclimate and Passive cooling in Urban Areas”
1.4.5. Input from members
1.5. Obtain information on use of building, occupancy hours and on possible building form, fabric, etc
1.5.1. CIBSE guidance and tools
The building services engineers should be able to acquire all building related information such as form and fabric details, building use and occupancy patterns, etc. An example of listing building specific information is presented in the CIBSE Knowledge Series publication KS8 “How to Design a Heating System” (§ 3.2).
CIBSE could further develop a checklist list and guidance on where/how to acquire the relevant information for the design of the ventilation system e.g. client’s brief, by further questioning the client, design plans and details, etc.
1.5.2. Other useful references
1.5.3. Input from members
1.6. Establish and confirm design requirements from Regulations, Codes of Practice etc.
1.6.1. CIBSE guidance and tools
The building services engineers should be able to refer to all regulations, codes and standards that relate to the individual project. The most up-to-date references and links to specific regulations and codes are included in CIBSE Guide L “Sustainability”. Legislation regarding health issues associated with the building services could also be found in CIBSE TM40 “Health Issues in Building Services”.
CIBSE could further develop a comprehensive and dynamic list of all necessary documents and where to find them, download them etc, as well as possible future developments and updates.
1.6.2. Other useful references
1.6.3. Input from members
1.7. Establish requirements for use of on-site renewables
1.7.1. CIBSE guidance and tools
The building services engineers should be able to establish requirements for the use of LZC technologies e.g. check infrastructure, financing, environmental impact, planning requirements etc. CIBSE Guide L “Sustainability” provides guidance on LZC technologies options, environmental impact, current government targets and cost. Further guidance on the requirements for the installation and operation of LZC technologies could also be found in AM12 “Small-Scale Combined Heat and Power for Buildings”, TM25 “Understanding Building Integrated Photovoltaics”, TM45 “Groundwater Cooling Systems” and TM38 “Renewable Energy Sources for Buildings”.
Guidance on potential impact of future developments of the surrounding area that could affect the effectiveness of the LZC technologies, e.g. future high buildings will affect solar & daylight availability, change in land use could improve performance, etc. CIBSE could further develop a comprehensive and dynamic list of all relevant documents and/or where to find them e.g. county councils, building regulations, application documents, etc.
1.7.2. Other useful references
Grants available for installing renewables: http://www.clear-skies.org/
‘Integrating renewable energy into new developments: Toolkit for planners, developers and consultants’: http://www.london.gov.uk/mayor/environment/energy/london_renew.jsp
Energy Saving Trust: http://www.energysavingtrust.org.uk/generate_your_own_energy
1.7.3. Input from members
2. Preliminary Design
C. Concept
D. Design development
2.1. Establish the key design data and parameters that relate to the design of the ventilation strategy, including building air tightness data, air quality and the potential use of renewables
2.1.1. CIBSE guidance and tools
The building services engineer should be looking for guidance on how to establish internal and external design conditions in order to inform the design and sizing of the ventilation system e.g. air quality and comfort requirements, weather data etc. Renewable energy sources could be considered here to contribute towards generating electricity to operate low power fans for mechanically assisted ventilation. Furthermore, ground source systems could be used for the heating and/or cooling of the incoming air.
CIBSE Guide A “Environmental Design” provides comfort criteria for design (chapter 1), surface condensation and mould growth design criteria (chapter 7, §7.6 and §7.7) and other health issues associated with building services (chapter 8).
CIBSE TM40 “Health Issues in Building Services “ also provides comprehensive guidance on health issues associated with the operation and maintenance of building services.
The CIBSE Knowledge Series publication KS6 “Comfort” explains internal comfort criteria.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” provides guidance on the issues related to the choice of ventilation strategy (chapter 2, §2.2) and detailed analysis of the indoor air quality requirements for various applications (chapter 2, §2.3).
CIBSE TM23 “Testing Buildings for Air Leakage” provides guidance on air leakage tests.
CIBSE Guide F “Energy Efficiency in Buildings” (chapter 5) and Guide L “Sustainability” (chapter 3, §3.1 and chapter 5, §5.1) provide general information on LZC technologies and design requirements.
Other CIBSE publications related to renewable technologies are the AM12 “Small-Scale Combined Heat and Power for Buildings”, TM25 “Understanding Building Integrated Photovoltaics” and TM38 “Renewable Energy Sources for Buildings” with an accompanied simple tool to assist in initial identification of the most promising renewable sources for a given project.
There is some concern that the existing overheating criteria suggested by CIBSE do not take under consideration people’s ability to adapt to extended periods of high temperatures and that encourages the use of mechanical cooling and ventilation. The CIBSE Overheating Group is reviewing the existing overheating criteria with a view to create a new set that would take under consideration the adaptive comfort model.
Even though TM23 covers air leakage testing methods (post construction) further guidance on methods to minimise air leakage at design stage could also be beneficial.
2.1.2. Weather data available for present climate conditions
Weather data at this preliminary design stage should be used to decide the external conditions for designing the ventilation system. Data gathered at pre-design stage (task 1.4) could be analysed based on risk, building form and with client involvement in order to establish external design conditions.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
Solar and wind data in Guide A (chapter 2, §2.7 and §2.8) and Guide J (chapter 5 and chapter 6) as well as the maps of average wind speed in the UKCIP08 recent trends report could be used for assessing potential use of renewables.
The user should be looking for percentage of certain conditions exceeded, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
Site specific information should be acquired for assessing potential use of renewables e.g. local wind, sunshine availability and elements blocking the sun around the site etc. Local information could be acquired from city councils, local planning authorities, environment agency, met office etc. and by site visits and discussions with client.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
2.1.3. Weather data available for future climate conditions
Climate change information at this preliminary design stage should be used to decide the external design conditions, to help inform the ventilation strategy over the lifetime of the building. Data gathered at pre-design stage (task 1.4) could be analysed based on risk, building form and with client involvement in order to establish external design conditions that would take under consideration climate change.
Climate change information could also be used here to inform future potential use of renewables; for example, examining the potential of LZC technologies for meeting future demand for ventilation.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for probability of certain conditions exceeded in the future, such as coincident wind speed and temperature, and coincident wind speed and direction based on location.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
CIBSE climate change data are available for three locations only (London, Manchester and Edinburgh).
The data available in TM34 can be used towards establishing future external design conditions, but there are no wind data available due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty is higher than for example for the temperature and rainfall changes. Furthermore, daily average wind speed and cloud cover changes provided in the UKCIP02 scientific report could be used to assess potential use of renewables in the future.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
2.1.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
The Building Regulations second tier document “Low or Zero Carbon Energy Sources: Strategic Guide” provides a simplified calculation tool for assessing the reduction in carbon emissions through the use of LZC technology: http://www.planningportal.gov.uk/uploads/br/BR_PDF_PTL_ZEROCARBONfinal.pdf
Geological surveys at the British Geological Survey: http://www.bgs.ac.uk/
Grants available for installing renewables: http://www.clear-skies.org/
“Integrating renewable energy into new developments: Toolkit for planners, developers and consultants”:
http://www.london.gov.uk/mayor/environment/energy/london_renew.jsp
Energy Saving Trust: http://www.energysavingtrust.org.uk/generate_your_own_energy
BRE (2001) “Cooling Buildings in London: Overcoming the Heat Island”
BRE (2006) “Achieving Airtightness”, three part set
BRE (1994) “Minimising Air Infiltration in Office Buildings”
2.1.5. Input from members
2.2. Develop room design data sheets
2.2.1. CIBSE guidance and tools
The use of room data sheets (RDS) to define detailed performance requirements during design and specification of new build or refurbishment of buildings is common practice.
Such room data sheets were developed for the Carbon Trust’s Low Carbon Design Initiative (LCDI) to provide support to clients of the construction industry and their consultants/advisers, in developing design specifications for new building designs that will achieve a low carbon impact. Copies of the existing peer reviewed room data sheets, overarching technical briefing and other LCDI documents could be acquired from http://www.carbontrust.co.uk/about/reports/lcdi.
It should be noted that the above documents were originally intended to deal with school buildings, and their application to other building types should be undertaken with caution and additional client input.
Furthermore, the building services aspects of the LCDI room data sheets were mainly composed using the information in CIBSE guidance, e.g. Guides A and B, and similarly the same guidance could be used to produce room data sheets for other building applications.
CIBSE could customise the above data sheets for use specifically by the building services engineers and for various types of buildings.
2.2.2. Other useful references
2.2.3. Input from members
2.3. Check that design parameters comply with legislation, energy targets etc.
2.3.1. CIBSE guidance and tools
Design parameters should be reviewed here to check that they comply with legislation and energy targets. A checklist of regulations, codes, standards etc, a sub category derived from the comprehensive list of task 1.6, could be used here that give specifications on design parameters and energy targets.
Guidance on ways to check the design is included in CIBSE Guide F “Energy Efficiency in Buildings”, chapter 13.
CIBSE could develop a dynamic list of possible documents to be used at this stage.
2.3.2. Other useful references
2.3.3. Input from members
2.4. Analyse building ventilation and infiltration performance
2.4.1. CIBSE guidance and tools
The building services engineer should be looking for guidance, rules of thumb and tools to develop an understanding of the various ventilation strategies and infiltration rates. Site and building data gathered during pre-design stage as well as external and internal design conditions from task 2.1 should also be used here.
CIBSE Guide A “Environmental Design” provides guidance, rules of thumb and calculation tools for the analysis of ventilation and infiltration patterns (chapter 4). Further guidance on ventilation and infiltration rates and flow patterns could be found in CIBSE AM10 “Natural Ventilation in Non-Domestic Buildings”. The flow chart (figure 2.8) in AM10 could be used at early design stage to explore ventilation options.
CIBSE AM13 ‘Mixed Mode Ventilation’ provides guidance on the design of a mixed mode ventilation strategy, including rules of thumb to assess whether mixed mode ventilation is a possibility and the various options available.
CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provide guidance on mechanical ventilation options in heated/cooled spaced.
CIBSE Guide F “Energy Efficiency in Buildings” provides information on the energy efficiency of various ventilation systems (chapter 7).
CIBSE TM21 “Minimising Pollution at Air Intakes” could also be used here to assess whether air pollution is going to affect the internal air quality of the building.
Some guidance in relation to building air tightness could be found in CIBSE Technical Manual TM23 “Testing Buildings for Air-Tightness”.
Guidance could further explore ways to achieve air-tightness through material, construction and operation of buildings.
2.4.2. Weather data available for present climate conditions
External design conditions established at task 2.1 should be used here to analyse ventilation and infiltration patterns based on openings and building form and construction.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends, including summer temperatures, cloud cover and wind speeds, based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
The user should be looking for percentage of certain conditions exceeded, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
2.4.3. Weather data available for future climate conditions
Future external design conditions established at task 2.1 should be used here to analyse ventilation and infiltration patterns based on building application, openings, form and fabric.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for probability of certain conditions exceeded in the future, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The data available in the CIBSE Guides A, J and L are general climate change trends that can inform towards future conditions, but can not be used readily in calculations.
The data available in TM34 can generally be used in manual calculations but there are no wind data available for infiltration/ventilation calculations due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty is higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
2.4.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
BRE (2006) “Achieving Airtightness”, three part set
BRE (1994) “Minimising Air Infiltration in Office Buildings”
2.4.5. Input from members
2.5. Assess heating and/or cooling requirements and provision
2.5.1. CIBSE guidance and tools
An assessment of the heating and cooling requirements of the building is necessary at this stage in order to inform the ventilation strategy. The building services engineer should be looking for guidance, rules of thumb and tools to assess heat losses and heat gains of the building to inform the heating and/or cooling requirements.
CIBSE Guide A “Environmental Design” provides manual calculation tools for calculating room and building heat losses i.e. thermal responses of building structure and heat losses through structure and fabric (chapter 3), heat losses due to infiltration and ventilation (chapter 4, §4.6 and §4.7) and the CIBSE Simple Model for calculating total heat losses (chapter 5, §5.6.2). Also available in Guide A (Appendix 5.A3) are the Reference Model and the Basic Model. Appendix 5.A4 offers a quantitative comparison between the three models.
Furthermore, Guide A provides guidance, benchmark values and calculation tools for estimating the heat gains of a building. Chapter 5 (§5.8.1 – CIBSE Cyclic Model) provides a model for the calculation of the solar, fabric and internal heat gains, a calculation method for the solar gain factors is presented in appendix 5.A7, while chapter 6 provides benchmark values for internal heat gains for a variety of building applications.
The heating and cooling design frameworks of the “Design Compass” deal more analytically with the design issues of respective services.
The guidance and tools for estimating heat losses and heat gains are sufficient at this design stage.
2.5.2. Weather data available for present climate conditions
In order to estimate the heat losses and heat gains in a building a good knowledge of frequency and duration of average and extreme winter and summer conditions is important.
CIBSE Guide A “Environmental Design” (chapter 2, §2.3) and CIBSE Guide J “Weather, Solar and Illuminance Data’” (chapter 4, §4.1) provide cold weather data for various UK locations. The binned frequencies of occurrence of low 24-hout and 48-hour average temperatures and the coincidence of low temperatures and high wind speeds could be used for the estimation of heat losses due to ventilation, infiltration and through fabric.
Guide A also provides warm weather data for various UK locations (chapter 2, §2.4) as well as solar data (§2.7) and wind data (§2.8) to inform the cooling requirements. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides warm weather data (chapter 4, §4.2), solar data (chapter 5) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends, including winter temperatures and wind speeds, based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk).
The user should be looking for frequency and duration of average and extreme events of low and high temperatures, coincidence of high temperatures and solar radiation (direct and diffuse) and frequencies of hourly wind speeds by direction and temperature, based on location.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
In both Guides A and J the summer temperatures and solar radiation data are presented separately. A good understanding of frequency and duration of coincident high temperatures and high solar radiation is essential for assessing solar gains, especially in highly glazed buildings. The use of joint probabilities of weather variables could help to better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to include joint probabilities of weather variables, such as temperature and cloud cover, based on observed data (http://www.ukcip08.net).
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures than the ones currently occurring.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects examine the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities, decision will be made upon revising and further updating Guides A and J.
2.5.3. Weather data available for future climate conditions
Heat losses and heat gains should be estimated over the lifetime of the building and for future climate change conditions. A good knowledge of frequency and duration of future winter and summer events is important at this stage.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for probability of occurrence of future events such as low and high temperatures, coincidence of high temperatures and solar radiation (direct and diffuse) and frequencies of hourly wind speeds by direction and temperature, based on location.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The data available in the CIBSE Guides A, J and L are general climate change trends that can inform of future climate conditions, but can not be used readily in calculations.
The data available in TM34 can be used in manual calculations, but there are no data available for infiltration/ventilation calculations due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408 provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty in higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
2.5.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK:
http://eca.knmi.nl
The British Wind Energy Association gives access to wind speeds in the UK:
http://www.bwea.com
2.5.5. Input from members
2.6. Identify possible ventilation strategies in order to achieve ventilation requirements
2.6.1. CIBSE guidance and tools
At this stage the building services engineer should have developed an understanding of the ventilation requirements of the spaces for air quality, thermal comfort and for other processes such as exhaust contaminants, humidity control etc. Guidance, rules of thumb and tools to assist in developing a ventilation strategy should be used here along with the data from tasks 2.1 and 2.4.
CIBSE Guide A “Environmental Design” provides guidance, rules of thumb and calculation tools for the assessment of ventilation air flows (chapter 4). Further guidance on ventilation rates and flow patterns could be found in CIBSE AM10 “Natural Ventilation in Non-Domestic Buildings”.
CIBSE AM13 “Mixed Mode Ventilation” provides guidance on various mixed mode ventilation strategies, including rules of thumb to assess whether mixed mode ventilation is possible.
CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provide guidance on mechanical ventilation strategies in heated/cooled spaced, and analyses air flow movements by the use of computer based tools.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” provides guidance on ventilation strategies for various building applications such as assembly halls, catering, computer rooms etc. Based on the space specific ventilation requirements the strategies address air quality, comfort cooling, humidity control to avoid condensation, exhaust of contaminants etc. (chapter 2, §2.3). In the same guide there is an analysis of various ventilation systems from window positioning and sizing to achieve natural ventilation to fully mechanical systems for close temperature and humidity control (chapter 2, §2.4).
If air pollution around the building is an issue the CIBSE TM21 “Minimising pollution at air intakes” could also be used here to assist in minimising the effect of external air pollution to the indoor environment.
Further guidance could explore cases where the choice between ventilation strategies is not as clear. In cases where more than one ventilation option is possible how does one assess the various options, e.g. through a risk analysis, based on system efficiency, through a life cycle analysis etc.
2.6.2. Weather data available for present climate conditions
External design conditions established at task 2.1 should be used here to analyse ventilation flow rates based on building application, openings, form and fabric.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends, including summer temperatures, cloud cover and wind speeds, based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
The user should be looking for percentage of certain conditions exceeded, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
2.6.3. Weather data available for future climate conditions
Future external design conditions established at task 2.1 could be used here to assess whether the possible ventilation strategy will be able to achieve the air quality requirements over the lifetime of the building.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for probability of certain conditions exceeded in the future, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The data available in the CIBSE Guides A, J and L are general climate change trends that can inform towards future conditions, but can not be used readily in calculations.
The data available in TM34 can generally be used in manual calculations but there are no wind data available for infiltration/ventilation calculations due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty is higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
2.6.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
2.6.5. Input from members
2.7. Assess process requirements of the incoming air
2.7.1. CIBSE guidance and tools
Based on space application sometimes the incoming air will need to go through filtration, heating, cooling, humidification/dehumidification etc. At this stage the building services engineer should have identified a possible ventilation as well as heating and cooling strategy to meet the internal requirements of the space for air quality, thermal comfort and for other processes such as exhaust contaminants, humidity control etc. This task will assist the designer to assess the specific requirements of the incoming air to achieve internal comfort conditions. Guidance, rules of thumb and tools to assist in developing requirements of the incoming air should be used here along with the data from tasks 2.1 and 2.4.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” provides guidance on ventilation requirements and strategies to achieve them, for various building applications such as assembly halls, catering, computer rooms etc. Based on the space application certain processes of the incoming air are suggested (chapter 2, §2.3) as well as systems and equipment for achieving them (chapter 2, §2.4 and §2.5).
CIBSE Guide F “Energy Efficiency in Buildings” provides energy efficient ways to achieve the requirements of the incoming air by the use of controls, low carbon systems etc. (chapter 7).
If air pollution around the building is an issue the CIBSE TM21 “Minimising Pollution at Air Intakes” could also be used here to assist in minimising the effect of external air pollution to the indoor environment.
CIBSE TM26 “Hygienic Maintenance of Office Ventilation Ductwork” informs of the health and safety regulations and requirements associated with the operation and maintenance of the ventilation ductwork and could be used here for establishing process requirements of the incoming air.
Guidance at this design stage is comprehensive.
2.7.2. Weather data available for present climate conditions
External design conditions established at task 2.1 should be used here to assess whether heating, cooling or humidity control of the incoming air is required. Site specific wind patterns could be useful to assess whether external pollution could be affecting the internal environment.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends, including summer temperatures, cloud cover and wind speeds, based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
The user should be looking for percentage of certain conditions exceeded, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
2.7.3. Weather data available for future climate conditions
Future trends of external conditions could be used here to assess whether the ventilation strategy will be able to achieve the internal environment requirements over the lifetime of the building.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for probability of certain conditions exceeded in the future, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The data available in the CIBSE Guides A, J and L are general climate change trends that can inform towards future conditions, but can not be used readily in calculations.
The data available in TM34 can generally be used in manual calculations but there are no wind data available for infiltration/ventilation calculations due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty is higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
2.7.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
2.7.5. Input from members
2.8. Estimate approximate building ventilation rates to inform system selection process
2.8.1. CIBSE guidance and tools
At this stage the building services engineer should have developed the ventilation strategy of the building and the process requirements of the incoming air. Calculation tools to assess ventilation rates should be used here.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” provides guidance, rules of thumb and tools for the estimation of the natural and mechanical ventilation rates (chapter 2, §2.4).
CIBSE Guide A “Environmental Design” provides guidance and calculation methods for assessing room and building ventilation options including natural, mechanical and mixed-mode ventilation (chapter 4) and infiltration rates. Furthermore, paragraph 4.6.3.6 provides an equation for assessing the cooling potential of ventilation.
CIBSE AM10 “Natural Ventilation in Non-Domestic Buildings” provides extensive guidance and calculation methods to assist in the assessment of the natural ventilation rates.
Guidance at this design stage is comprehensive.
2.8.2. Weather data available for present climate conditions
External design conditions established at task 2.1 should be used here to estimate ventilation flow rates based on building application, form and position. Site specific wind patterns could be used here to assess natural ventilation rates.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends, including summer temperatures, cloud cover and wind speeds, based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
The user should be looking for percentage of certain conditions exceeded, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
2.8.3. Weather data available for future climate conditions
Future trends of external conditions could be used here to assess whether the ventilation strategy will be able to achieve the internal air requirements over the lifetime of the building.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for probability of certain conditions exceeded in the future, such as coincident wind speed and temperature, and coincident wind speed and direction, based on location.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The data available in the CIBSE Guides A, J and L are general climate change trends that can inform towards future conditions, but can not be used readily in calculations.
The data available in TM34 can generally be used in manual calculations but there are no wind data available for infiltration/ventilation calculations due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty is higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
2.8.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
2.8.5. Input from members
2.9. Consider zoning requirements
2.9.1. CIBSE guidance and tools
Appropriate zoning of spaces based on air quality requirements, temperature variation, hours of operation, glazing levels and other material, etc. could help in maximising the efficiency of the ventilation system. The building services engineers should be able to identify zoning requirements and integrate them into the design of the systems.
CIBSE Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, §2.4 refers to zoning requirements for the design of systems, e.g. mixed mode ventilation systems (§2.4.5), comfort cooling and air-conditioning systems (§2.4.6) etc., while chapter 3 (§3.2.9) explains zoning when designing the ductwork system.
More in-depth guidance is needed to inform effective zoning that could optimize the efficiency of the ventilation strategy.
2.9.2. Other useful references
2.9.3. Input from members
2.10. Consider alternative sources of heating/cooling the incoming air and ventilation system options
2.10.1. CIBSE guidance and tools
The building services engineers should investigate alternative sources of heating and/or cooling the incoming air available, based on ventilation requirements, environmental impact, cost, efficiency etc. A combination of LZC solutions that keep the temperature of the incoming air at acceptable levels could improve efficiency of the ventilation strategy and minimise environmental impact.
Several ventilation options are available based on air quality and ventilation space requirements. The building services engineers should be able to identify the options available and more suited to their individual project.
Comprehensive guidance on ventilation system options could be found in CIBSE Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapter 2 and Guide F “Energy Efficiency of Buildings”, chapter 5 and 7.
The Knowledge Series publication KS3 “Sustainable Low Energy Cooling: an Overview”, TM45 “Groundwater Cooling Systems” and TM38 “Renewable Energy Sources for Buildings” provide guidance on LZC technologies that could be used for cooling/heating the incoming air.
Existing CIBSE guidance seems sufficient at this design stage.
2.10.2. Other useful references
2.10.3. Input from members
2.11. Establish contribution from renewable sources
2.11.1. CIBSE guidance and tools
Renewable energy sources can contribute towards generating electricity to operate low power fans for mechanically assisted ventilation. Furthermore, ground source systems could be used for the heating and/or cooling of the incoming air.
The building services engineer should be looking for guidance and calculation tools to assess the potential use of renewable energy sources based on the building form, application and location. Cost and benefit analysis is essential at this point as well as assessing potential sources of financing the technologies, environmental impact and alternatives. Site and building data gathered during pre-design stage as well as key design parameters, such as external design conditions, from task 2.1 should also be used here.
CIBSE Guide F “Energy Efficiency in Buildings” (chapter 5) and Guide L “Sustainability” (chapter 3, §3.1 and chapter 5, §5.1) provide general information on LZC technologies and design requirements.
CIBSE TM45 “Groundwater Cooling Systems” explains the principals and issues associated with the installation and operation of such systems.
Other CIBSE publications related to renewable technologies are the AM12 “Small-Scale Combined Heat and Power for Buildings”, TM25 “Understanding Building Integrated Photovoltaics and TM38 “Renewable Energy Sources for Buildings” with an accompanied simple tool to assist in initial identification of the most promising renewable sources for a given project.
CIBSE is not offering at the moment a calculation tool for the analysis of contribution from renewable energy sources and LZC technologies. It is an opportunity for CIBSE to develop a calculation tool that would provide a quantitative analysis of the potential use of such technologies as well as a cost and benefit analysis, for specific projects.
2.11.2. Weather data available for present climate conditions
At this preliminary design stage a good knowledge of the site and the microclimate is essential towards analysing the potential of various renewable resources and LZC technologies.
CIBSE Guide A “Environmental Design” (chapter 2, §2.7 and §2.8) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapters 5 and 6) provide solar and wind data, for various UK locations, that could be used for assessing potential use of renewables.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides wind speed trends based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of maps. The publication is freely available by UKCIP (http://www.ukcip.org.uk/).
The user should be looking for site specific weather data and local elements that could potentially affect the microclimate and/or the performance of renewable technologies.
The data in Guides A and J are not at the moment consistent. Wind data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of unlike external design conditions than those currently occurring.
The CIBSE weather data are location specific but not site specific. Site specific information should be acquired for assessing potential use of renewables e.g. local wind, sunshine availability and elements blocking the sun around the site etc. Local information could be acquired from city councils, local planning authorities, environment agency, Met office etc. and by site visits and discussions with client.
Guidance is required on the type of weather information needed for assessing potential of renewables and how to obtain such site specific information, e.g. Met Office, local weather station, city council archives etc.
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
2.11.3. Weather data available for future climate conditions
At this preliminary design stage a good understanding of the future weather trends and the microclimate of the site could help towards forming a strategy for improving the building’s carbon emissions by improving or incorporating LZC technologies and renewables.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
The user should be looking for site specific weather data and local elements that could potentially affect the microclimate and/or the performance of renewable technologies.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
Changes in sunshine hours included in TM34 could be used towards assessing future use of renewables, but there are no wind data available for wind technologies due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed and cloud cover changes, but extra caution should be taken when using these data since the associated uncertainty in higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
2.11.4. Other useful references
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
The Building Regulations second tier document “Low or Zero Carbon Energy Sources: Strategic Guide” provides a simplified calculation tool for assessing the reduction in carbon emissions through the use of LZC technology: http://www.planningportal.gov.uk/uploads/br/BR_PDF_PTL_ZEROCARBONfinal.pdf
Geological surveys at the British Geological Survey: http://www.bgs.ac.uk/
Grants available for installing renewables: http://www.clear-skies.org/
‘Integrating renewable energy into new developments: Toolkit for planners, developers and consultants’:
http://www.london.gov.uk/mayor/environment/energy/london_renew.jsp
Energy Saving Trust: http://www.energysavingtrust.org.uk/generate_your_own_energy
2.11.5. Input from members
2.12. Consider operating and control strategies, and building usage and layout data
2.12.1. CIBSE guidance and tools
The building services engineers should investigate the various control and operation strategy options based on the ventilation strategy under consideration. A checklist of information required, e.g. building plans, space usage, comfort requirements etc, could be used here to inform the process.
CIBSE guidance on controls exists in Guide H “Building Control Systems”, Knowledge Series KS4 “Understanding Controls”, Guide F “Energy Efficiency in Buildings” (chapter 6). Guidance on noise and vibration controls for HVAC can be found in Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapter 5.
Guidance on system maintenance and operation exists in CIBSE “Guide to Ownership, Operation and Maintenance of Building Services. Guide M “Maintenance Engineering and Management” also provides comprehensive guidance in the management, operation, maintenance and control of building services. Guide F, Part B, refers to management (chapter 15) and maintenance of building services (chapter 17), while the principles of building services management are also analysed in the Knowledge Series publication KS5 “Making Buildings Work”.
Furthermore, CIBSE Guide B, chapter 2 , and Guide F “Energy Efficiency of Buildings”, chapters 5 and 7, contain considerations on control, maintenance and operation options for a variety of ventilation systems.
CIBSE could provide a checklist of all requirements necessary for designing the control and operation strategy of the ventilation strategy.
2.12.2. Other useful references
2.12.3. Input from members
2.13. Assess options against client requirements, performance, risk, energy use etc.
2.13.1. CIBSE guidance and tools
The building services engineers should be able to follow a methodology for assessing the various options against a series of criteria set by the client, building regulations, standards etc. The assessment methods could include a series of consultations with the design team and the client, a prioritising strategy based on client’s brief etc. Assessing the various options identified could become critical when choosing between similar options.
CIBSE could provide a methodology for assessing options.
2.13.2. Other useful references
2.13.3. Input from members
2.14. Select proposed system
2.14.1. CIBSE guidance and tools
Based on the assessment of various options during task 2.13 the building services engineers should be able to identify the optimum solution based on client brief.
See task 2.13
2.14.2. Other useful references
2.14.3. Input from members
3. Design Development
E. Technical design
3.1. Check natural ventilation achieved for air quality and cooling needs – calculate space ventilation rates and assess airflows, optimise openings for natural ventilation, assess summer and winter performance of natural ventilation
3.1.1. CIBSE guidance and tools
At this stage the building services engineer should be looking for the appropriate tools to allow them to analyse the potential of natural ventilation to achieve air quality and thermal comfort requirements. Manual and computer based calculation tools could be used to assess natural ventilation rates and optimise opening sizes and positions.
CIBSE Guide A “Environmental Design” provides estimation methods for calculating room and building natural ventilation and infiltration airflow rates (chapter 4, §4.7). Furthermore, paragraph 4.6.3.6 provides an equation for assessing the cooling potential of natural ventilation.
CIBSE AM10 “Natural Ventilation in Non-Domestic Buildings” provides extensive guidance and calculation methods to assist in the assessment of the natural ventilation rates.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” provides calculation tools for the design of openings, for various natural ventilation strategies, and the estimation of airflow rates (chapter 2, §2.4.3). Furthermore, Appendix 2.A1 summarises the various techniques for assessing ventilation rates including the use of CFD and physical models.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to assess building ventilation strategy based on hourly external data and corresponding building performance.
AM10 (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of computer models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine space temperature variation (model output) by varying the opening size (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.1.2. Weather data available for present climate conditions
Detailed calculations should be part of this design stage using either manual or computer based calculation tools. Depending on the approach, mean and maximum figures or hourly weather data that would best describe the average and extreme weather conditions should be used to assess natural ventilation airflow rates. Site specific wind patterns could be useful to assess natural ventilation rates.
CIBSE Guide A “Environmental Design” provides cold and warm weather data for various UK locations (chapter 2, §2.3 and §2.4) as well as wind data (chapter 2, §2.8) to inform the ventilation strategy. CIBSE Guide J “Weather, Solar and Illuminance Data” also provides summary statistics (§3.5), cold and warm weather data (chapter 4, §4.1 and §4.2) and wind data (chapter 6), for the same UK locations.
The UKCIP08 publication “The Climate of the United Kingdom and Recent Trends” provides climate trends, including summer temperatures, cloud cover and wind speeds, based on observed data (two baselines 1961-1990 and 1971-2000) presented at a 5km x 5km resolution, in a form of graphs and maps. The publication is freely available by UKCIP (whttp://www.ukcip.org.uk/).
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For manual calculations the user should be looking for frequency distributions of average and extreme wind speeds by both direction and external temperature, based on location.
The data in Guides A and J are not at the moment consistent. Weather data in Guide A have been updated to a more recent baseline (1983-2002), while data in Guide J are based on an earlier baseline (1976-1995). The most up-to-date weather data currently available by CIBSE is located in Guide A, chapter 2. Although the weather data in Guide A have been recently updated, Guide J provides the background information on their production and selection processes that could enhance the understanding of the uncertainty associated with their use and as a result lead to more robust design decisions.
The baselines used for the production of weather data in Guides A and J do not include current manifestations of climate change, which could arguably lead to the choice of lower external design temperatures and wind speeds than the ones currently occurring.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
Depending on the outputs of the above activities decisions will be made upon revising and further updating the data in Guides A and J.
3.1.3. Weather data available for future climate conditions
Future trends of external conditions could be used here to assess whether natural ventilation would be able to achieve the internal air requirements over the lifetime of the building.
CIBSE Guide A “Environmental Design” (chapter 2, §2.9) and CIBSE Guide J “Weather, Solar and Illuminance Data” (chapter 3, §3.2 and chapter 4, §4.4) provide climate change trends for various emissions scenarios, for three UK locations (London, Manchester and Edinburgh); changes are based on a 1961-1990 baseline.
CIBSE Guide L “Sustainability” summarises climate changes for one emissions scenario and for the same three locations.
CIBSE TM34 “Weather Data with Climate Change Scenarios” provide climate change data in the same format as in Guide J for use in manual calculations to assess future system and building performance.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For manual calculations the user should be looking for frequency distributions with attached probability of wind speed by direction and external temperature, based on location.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The data available in the CIBSE Guides A, J and L are general climate change trends that can inform towards future conditions, but can not be used readily in calculation tools.
The data available in TM34 can be readily used in manual calculations, but there are no wind data available for calculating infiltration/ventilation heat gains due to the lack of suitable algorithm to produce hourly wind speed data from the available daily averages (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291).
The UKCIP02 scientific report (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=353&Itemid=408) provides daily average wind speed changes, but extra caution should be taken when using these data since the associated uncertainty in higher than for example for the temperature and rainfall changes.
The data in Guides A and J are not at the moment consistent. Climate change data in Guide A is in accordance with UKCIP02 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291), while Guide J data is in accordance with the previous version of UKCIP98 climate change scenarios (http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=255).
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.1.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
BRE (2001) “Cooling Buildings in London: Overcoming the Heat Island”
BRE (2000) “Environmental Site Layout Planning: Solar Access, Microclimate and Passive Cooling in Urban Areas”
3.1.5. Input from members
3.2. Check mechanical ventilation required, including heating, cooling and humidity control of the incoming air and air conditioning
3.2.1. CIBSE guidance and tools
Where the need for mechanical ventilation has been identified the building services engineers should be able to further explore the ventilation system that would provide the required air quality and internal comfort conditions.
Guidance on mechanical ventilation exists in CIBSE Guide B, “Heating, Ventilation, Air Conditioning and Refrigeration”, chapter 2, and in TM30 “Improved Life Cycle Performance of M/V Systems”. Guidance on energy efficiency of mechanical ventilation systems exists in Guide F, chapter 7, while guidance on the use of Computational Fluid Dynamics (CFD) for air flow analysis, including recommendations, how and when to use them and possible sources of error could be found in AM11 “Building Energy and Environmental Modelling”, Guide A “Environmental Design”, Appendix 5.A2, and AM10 “Natural Ventilation in Non-Domestic Buildings”.
Existing CIBSE guidance seems sufficient.
3.2.2. Other useful references
3.2.3. Input from members
3.3. Check whether mixed mode ventilation is possible
3.3.1. CIBSE guidance and tools
The building services engineers should be looking for guidance and tools to allow them to analyse the potential of mixed mode ventilation to achieve air quality and thermal comfort requirements. Computer based calculation tools could be used to establish the mixed mode ventilation strategy, as well as the results from tasks 3.1 and 3.2.
CIBSE AM13 “Mixed Mode Ventilation” provides guidance on various mixed mode ventilation strategies, including rules of thumb to assess whether mixed mode ventilation is possible.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to assess building mixed mode ventilation strategy based on hourly external data and corresponding building performance.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the airflows in a building. AM13 (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine space temperature variation (model output) by varying the ventilation strategy (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.3.2. Weather data available for present climate conditions
Detailed calculations should be part of this design stage using computer based calculation tools. Hourly weather data that would best describe the average and extreme weather conditions should be used to establish mixed mode ventilation strategy.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.3.3. Weather data available for future climate conditions
Future trends of external conditions could be used here to assess whether the mixed mode ventilation strategy would be able to achieve the internal air requirements over the lifetime of the building.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.3.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.3.5. Input from members
3.4. Check ventilation strategy provision still appropriate
3.4.1. CIBSE guidance and tools
The building services engineers should be using assessment methods to evaluate the system selected at task 2.14. The evaluation should be based on results from detailed calculations performed in the previous tasks of stage 3.
CIBSE could provide a checklist of criteria for the evaluation of selected systems.
3.4.2. Other useful references
3.4.3. Input from members
3.5. Consider suitable air distribution system positions and connections
3.5.1. CIBSE guidance and tools
The building services engineers should be using guidance on air distribution and ductwork systems, and optimum positions and connections, for the various choices available.
Guidance exists in CIBSE Guide F “Energy Efficiency in Buildings”, chapter 7 and Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapters 2 and 3.
Extensive guidance on fans and fan coil units could be found in TM42 “Fan Application Guide” and TM43 “Fan Coil Units”.
CIBSE guidance on designing distribution networks is mostly in the form of general recommendations but there is not much practical advice. For example guidance in the form of schematics could be useful.
3.5.2. Other useful references
3.5.3. Input from members
3.6. Check ventilation system layout considering balancing and regulating requirements
3.6.1. CIBSE guidance and tools
The building services engineers should be using guidance on air distribution and ductwork systems and layout requirements.
Guidance exists in CIBSE Guide F “Energy Efficiency in Buildings”, chapter 7, and Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapter 3, and the Knowledge Series publications KS7 “Variable Flow Pipework Systems” and KS9 “Commissioning Variable Flow Pipework Systems”. Guidance on fans could be found in TM42 “Fan Application Guide”.
CIBSE guidance seems sufficient.
3.6.2. Other useful references
3.6.3. Input from members
3.7. Consider circuit layouts and connections and choice of air distribution equipment
3.7.1. CIBSE guidance and tools
The building services engineers should be using guidance on circuit design and various fan and ductwork system choices.
Guidance exists in CIBSE Guide F “Energy Efficiency in Buildings”, chapter 7, and Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapter 3, and the Knowledge Series publications KS7 “Variable Flow Pipework Systems” and KS9 “Commissioning Variable Flow Pipework Systems”.
Extensive guidance on fans could be found in TM42 “Fan Application Guide”.
CIBSE guidance seems sufficient.
3.7.2. Other useful references
3.7.3. Input from members
3.8. Develop control requirements
3.8.1. CIBSE guidance and tools
The building services engineers should be using guidance on controls and control strategies for the ventilation strategy selected.
Guidance exists in CIBSE Guide H “Building Control Systems”, Knowledge Series KS4 “Understanding Controls” and Guide F “Energy Efficiency in Buildings”, chapter 6). Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapters 2 and 3, and Guide F, chapter 7, also present control requirements relative to the system options presented. Guidance on noise and vibration controls for HVAC can be found in Guide B, chapter 5.
CIBSE guidance seems sufficient.
3.8.2. Other useful references
3.8.3. Input from members
3.9. Size and select air distribution systems, equipment and distribution network and determine any distribution losses
3.9.1. CIBSE guidance and tools
The building services engineers should be using guidance and tools for selecting and sizing air distribution network and for estimating distribution losses.
Guidance on air distribution network system and equipment selection and sizing is included in CIBSE Guide B “Heating, Ventilation, Air Conditioning and Refrigeration”, chapters 2 and 3, and Guide F “Energy Efficiency in Buildings”, chapter 7.
For the estimation of distribution losses, guidance and calculation tools could be found in Guide B, chapter 3 and Guide C “Reference Data”, chapter 3.
CIBSE guidance on designing distribution networks is mostly in the form of general recommendations but there is not much practical advice. For example guidance in the form of schematics could be useful.
3.9.2. Other useful references
3.9.3. Input from members
3.10. Calculate building airflow rates
3.10.1. CIBSE guidance and tools
At this advanced stage the building services engineer should be looking for the appropriate tools to allow them to calculate the building airflow rates achieved through the identified ventilation strategy. Computer based calculation tools could be used here to calculate the ventilation rates achieved in the building.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to assess building ventilation strategy based on hourly external data and corresponding building performance.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” Appendix 2.A1 summarises the various techniques for assessing ventilation rates including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” TM29 provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
CIBSE TM33 ‘Tests for Software Accreditation and Verification’, provides ways to check the validity of dynamic models. CIBSE AM11 ‘Building Energy and Environmental Modelling’ provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine space temperature variation (model output) by varying the air changes (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.10.2. Weather data available for present climate conditions
Detailed calculations should be part of this advanced design stage using computer based calculation tools. Hourly weather data that would best describe the average and extreme weather conditions should be used to analyse building airflow rates though the year.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.10.3. Weather data available for future climate conditions
Future trends of external conditions could be used here to analyse building airflow rates and the ability of ventilation strategy to provide air quality and thermal comfort requirements over the lifetime of the building.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.10.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.10.5. Input from members
3.11. Analyse airflow diversity and determine the overall ventilation strategy
3.11.1. CIBSE guidance and tools
At this advanced stage the building services engineer should be looking for the appropriate tools to allow them to analyse the building airflow rates achieved through the identified ventilation strategy. Computer based calculation tools could be used here to provide an analysis of the air movement, temperature distribution and air quality achieved through the building.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to assess building ventilation strategy based on hourly external data and corresponding building performance.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” Appendix 2.A1 summarises the various techniques for assessing ventilation rates and airflow movement including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine space temperature variation (model output) by varying the window operation pattern (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.11.2. Weather data available for present climate conditions
Detailed calculations should be part of this advanced design stage using computer based calculation tools. Hourly weather data that would best describe the average and extreme weather conditions should be used to analyse building airflow rates though the year.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip.org.uk/scenarios/ukcip08/).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.11.3. Weather data available for future climate conditions
Future trends of external conditions could be used here to analyse building airflow rates and the ability of ventilation strategy to provide air quality and thermal comfort requirements over the lifetime of the building.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.11.4. Other useful references
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.11.5. Input from members
.
3.12. Consider any standby and future requirement
3.12.1. CIBSE guidance and tools
The building services engineers should be using guidance on issues related to assessing standby capacity, e.g. risk assessment, risk of oversizing etc.
Guidance is needed on taking under consideration future need for ventilation, while avoiding oversizing.
3.12.2. Other useful references
3.12.3. Input from members
3.13. Determine number of air distribution systems required and size and select main plant
3.13.1. CIBSE guidance and tools
The building services engineer should be looking for guidance on the various ventilation system options based on the ventilation rates and airflow analysis previously undertaken. Guidance should inform of all possible options from openings for natural ventilation to air-conditioning for close temperature and humidity control, and energy efficiency issues related to their operation. Dynamic simulation tools could be used for system and plant sizing based on hourly building thermal and airflow performance. Outcomes from tasks 3.10, 3.11 and 3.12 could be used here. Alternatively, in case dynamic simulations were used to complete tasks 3.10 and 3.11, the results (based on the computer model used) could also incorporate output from plant sizing calculation.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” provides guidance on ventilation and air conditioning system options. Chapter 2 gives information on ventilation and cooling system integration, such as night cooling and thermal mass §2.4.7, chilled surfaces §2.4.8 etc.
CIBSE Guide F “Energy Efficiency in Buildings” provides guidance on the energy efficiency issues related to the selection of ventilation systems (chapter 7). Guide F, chapter 5, also provides guidance on renewable and LZC technologies such as ground and water cooling of the incoming air (§5.1.13).
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to finalise the control strategy of the building based on hourly external data and corresponding building performance.
Guide B, Appendix 2.A1, summarises the various techniques for assessing ventilation rates and airflow movement including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
Computer based simulation tools, such as thermal models could be used to size local and centralised systems, based on hourly external data. CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
Further guidance on integrated solutions could be useful, for example covering base load, peak load and contingency load with a combination of LZC technologies and AC units.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine internal temperature variation, during long periods of hot and sunny weather, (model output) for variable occupancy (model input); is the cooling capacity of the incoming air still sufficient. Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.13.2. Weather data available for present climate conditions
Computer based calculations could be used at this advanced design stage. Hourly weather data that would best describe the average and extreme weather conditions could help in positioning and sizing of the air distribution systems.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.13.3. Weather data available for future climate conditions
Future trends of external conditions could be used here to analyse building airflow rates and the ability of ventilation strategy to provide air quality and thermal comfort requirements over the lifetime of the building.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.13.4. Other useful references
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.13.5. Input from members
3.14. Finalise controls
3.14.1. CIBSE guidance and tools
Guidance and outcomes from tasks 2.12 and 3.8 could be used here in order to finalise the control strategy of the building. Dynamic simulation tools could also be used for more complex building form and ventilation strategy design in order to finalise control requirements, for example when mixed mode ventilation is in operation.
CIBSE Knowledge Series KS4 “Understanding Controls” provides an introduction and overview of control systems and related issues. Chapter 6 of CIBSE Guide F “Energy Efficiency in Buildings” and CIBSE Guide H “Building Control Systems” provide comprehensive guidance on control selection and operation.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating” provides guidance on controls for various ventilation systems and strategies (chapters 2), while Guide F provides guidance on controls for improving the energy efficiency of various ventilation options (chapters 7, §7.4).
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to finalise the control strategy of the building based on hourly external data and corresponding building performance.
CIBSE Guide B, Appendix 2.A1, summarises the various techniques for assessing ventilation rates and airflow movement including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine internal humidity levels (model output) for variable occupancy (model input); are the controls responding sufficiently. Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.14.2. Weather data available for present climate conditions
Based on the complexity of building form and services the control strategy could be fine tuned with the use of computer tools. Hourly weather series often used by the computer tools provide knowledge of the dynamic performance of a building in response to external conditions. Control requirements for air quality, thermal comfort and temperature and humidity to avoid condensation could be established based on simulation outcomes.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.14.3. Weather data available for future climate conditions
Based on the complexity of building form and services the control strategy could be fine tuned with the used of computer tools. Hourly weather series often used by the computer tools provide knowledge of the dynamic performance of a building in response to external conditions. Future weather events could be used towards a flexible control strategy that could respond to future requirements of air quality and thermal comfort.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.14.4. Other useful references
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.14.5. Input from members
3.15. Check layouts and services co-ordination for clashes and ease of commissioning and maintenance
3.15.1. CIBSE guidance and tools
Guidance and outcomes from tasks 3.5 – 3.9 could be used here in order to check systems layout. Dynamic simulation tools could also be used for more complex building form and ventilation strategy design in order to check coordination of systems and avoid conflict of services e.g. AC and open windows at the same time, heating and open windows at the same time etc.
Comprehensive guidance on commissioning and maintenance can be found in CIBSE “Guide to Ownership, Operation and maintenance of Building Services” and Guide M “Maintenance Engineering and Management”. CIBSE Commissioning Codes R “Refrigerating Systems” and C “Automatic Controls”, A “Air Distribution Systems” and W “Water Distribution Systems”, as well as Knowledge Series KS9 “Commissioning Variable Flow Pipework Systems” concentrate on comissioning issues relative to the respective systems.
CIBSE Guide F “Energy Efficiency in Buildings” provides guidance on the commissioning process (chapter 14) and maintenance issues (chapter 17) in order to achieve expected efficiency.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to finalise the control strategy of the building based on hourly external data and corresponding building performance.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating”, Appendix 2.A1, summarises the various techniques for assessing ventilation rates and airflow movement including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine whether high solar gains through a south facing window (model output) could trigger AC, while natural ventilation is in operation (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.15.2. Weather data available for present climate conditions
Co-ordination of building services is important for energy efficiency and cutting carbon emissions, and for cost effectiveness of systems operation. A detailed analysis of the systems’ operation based on the thermal performance of the building can point out the areas where possible clashes of services could exist. Computer tools could be used at this design stage to explore possible clashes of systems. Hourly weather series often used by computer tools provide knowledge of the dynamic performance of a building in response to external conditions. Systems’ clashes could be examined under certain weather events e.g. wind speed and direction difference between various facade orientations could encourage opening of windows and mechanical ventilation at the same time.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly weather series with attached probability of certain events happening, in order to check for possible clashes of services, e.g. once in x observed years event of high wind speed and solar radiation to examine temperature gradient in spaces of different orientation, in a mixed mode ventilated building.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.15.3. Weather data available for future climate conditions
Future climate change conditions could alter the relationships between services and the maintenance strategy of the systems. A detailed analysis of the future operation of the systems could help identifying changes in operation and maintenance and incorporate solutions in the long term operational strategy of the building.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly weather series with attached probability of certain events happening in the future, in order to check for possible clashes of services, e.g. probability of high wind speed and solar radiation happening in the next x years in order to examine temperature gradient in spaces of different orientation, in a mixed mode ventilated building.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.15.4. Other useful references
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.15.5. Input from members
3.16. Review system design and check predicted system performance
3.16.1. CIBSE guidance and tools
At this advanced design stage a review of the overall system design against targets and client requirements could concentrate on various aspects of the design intent such as achieving required performance, energy efficiency at part load and control performance. This task will concentrate on confirming that the energy targets and the internal comfort requirements are met.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to review system design and check system performance based on hourly external data and corresponding building performance.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating”, Appendix 2.A1, summarises the various techniques for assessing ventilation rates and airflow movement including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example confirm that the expected energy use meets targets (model output) for variable system efficiency (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.16.2. Weather data available for present climate conditions
At this advanced design stage a detailed analysis of system performance and building thermal response is essential for the fine tuning of the design. This is possible by the use of computer based tools that use hourly weather series to provide a dynamic performance of the building in response to external conditions. Extreme and average weather conditions should be used to examine the system performance and associated energy use.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.16.3. Weather data available for future climate conditions
At this advanced design stage the designer should make sure that the systems would be able to cope with future conditions and extreme events and that there is scope for their further development towards lower energy use and carbon emissions. A detailed analysis of system future performance is possible by the use of computer based tools that use hourly weather series to provide a dynamic performance of the building in response to external conditions. Extreme and average weather conditions should be used to examine the system performance and associated energy use.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.16.4. Other useful references
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.16.5. Input from members
3.17. Check part load performance
3.17.1. CIBSE guidance and tools
At this advanced design stage a review of the overall system design against targets and client requirements could concentrate on various aspects of the design intent such as achieving required performance, energy efficiency at part load and performance of controls. This task will concentrate on confirming that the system efficiency targets and system performance requirements are met at part load.
Often systems operate at high efficiency at peak load and low efficiency at part load. The load diversity analysis in task 3.11 could identify integrated solutions for ventilation for example covering base load, peak load and contingency load with a combination of LZC technologies and AC units.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to check part load performance of the systems based on hourly external data and corresponding building performance.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating”, Appendix 2.A1, summarises the various techniques for assessing ventilation rates and airflow movement including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine AC load variation (model output) for variable solar gain (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.17.2. Weather data available for present climate conditions
The systems’ performance will be often directly associated with external conditions. It is important that the designer is able to check that the ventilation strategy will cover low and high demand without compromising its efficiency. This is possible by the use of computer based tools that use hourly weather series to provide a dynamic performance of the building in response to external conditions. Certain weather events (e.g. cool summer period) could be identified in order to check the integrated system performance and associated energy use.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data of certain weather events, e.g. days of variable temperature and wind speed. Attached probability to the occurrence of weather events could assist in better understand the overall efficiency of the systems.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.17.3. Weather data available for future climate conditions
Conclusions on the variable load performance of the system based on future conditions could help identify the potential of improving energy use for ventilation. It is increasingly part of the client’s brief to present options for a future zero or neutral carbon building, so it is important that the designer is able to examine further options. This is possible by the use of computer based tools that use hourly weather series to provide a dynamic performance of the building in response to external conditions. The system variable load performance could be examined for future weather events in order to identify future options e.g. cover ventilation requirements with a combination of LZC technologies.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of weather events, e.g. probability of certain coincidence of temperature and wind speed happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.17.4. Other useful references
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.17.5. Input from members
3.18. Check that the selected controls are capable of achieving the required level of control, response and energy efficiency, particularly at part load
3.18.1. CIBSE guidance and tools
At this advanced design stage a review of the overall system design against targets and client requirements could concentrate on various aspects of the design intent such as achieving required performance, energy efficiency at part load and performance of controls. This task will concentrate on confirming that the controls are able to respond effectively to the changes in the internal environment without compromising energy efficiency.
Often systems operate at variable efficiency based on demand. The load diversity analysis in task 3.11 could identify integrated solutions for ventilation, for example covering base load, peak load and contingency load with a combination of LZC technologies and AC units. Integrated solutions will require the fine tuning of their controls to make sure that variable load is covered without compromising the systems’ efficiency.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), could be used to check performance of controls based on hourly external data and corresponding building performance.
CIBSE Guide B “Heating, Ventilating, Air Conditioning and Refrigerating”, Appendix 2.A1, summarises the various techniques for assessing ventilation rates and airflow movement including the use of CFD and physical models.
CIBSE AM10 “Natural Ventilation in Non-domestic Buildings” (chapter 4) provides guidance on the use of CFD (§4.2.5), combination of thermal models and CFD (§4.2.6) and physical models (§4.3.7) for the analysis of the natural ventilation performance in a building. CIBSE AM13 “Mixed Mode Ventilation” (chapter 10) suggests the combination of thermal modelling and CFD in order to better understand the performance of a mixed mode approach, while CIBSE TM29 “HVAC Strategies for Well-Insulated Airtight Buildings” provides case studies where dynamic simulations were used in order to analyse the performance of a mechanical HVAC approach.
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
In relation to computer based tools further guidance could explore the input and output stages of the simulation process by providing directions on sensitivity analysis of model output, based on model input. For example examine space temperatures and humidity levels (model output) for variable occupancy (model input). Suggested sensitivity analysis could vary based on building/space application and construction/fabric, e.g. different for lightweight and heavyweight buildings, naturally and mechanically ventilated etc.
3.18.2. Weather data available for present climate conditions
The ability of the controls to respond effectively to internal conditions and part load performance of the systems is essential for the efficient operation of the system. It is important that the designer is able to check that the system will respond effectively to variable demand without compromising its efficiency. This is possible by the use of computer based tools that use hourly weather series to provide a dynamic performance of the building in response to external conditions. Certain weather events (e.g. cool summer period) could be identified in order to check the integrated system performance and associated energy use.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data of certain weather events, e.g. days of variable temperature and wind speed. Attached probability to the occurrence of weather events could assist in better understand the overall efficiency of the systems.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.18.3. Weather data available for future climate conditions
Conclusions on the ability of the controls to respond effectively to variable load, based on future conditions, could help identify future requirements for the fine tuning of controls. This is possible by the use of computer based tools that use hourly weather series to provide a dynamic performance of the building in response to external conditions. The response of the controls to the system’s variable performance could be examined for future weather events in order to identify future control requirements.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of weather events, e.g. probability of certain coincidence of temperature and wind speed happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.18.4. Other useful references
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.18.5. Input from members
3.19. Check that final system and components meet client requirements for performance, quality, reliability, etc at acceptable cost; and also meet required energy targets and comply with regulations, such as meeting the seasonal efficiency requirements
3.19.1. CIBSE guidance and tools
This task confirms that the final solution does meet original design objectives. Actions could include value engineering and confirming compliance with the building regulations.
Building services engineers should be looking for guidance on value engineering and building regulations compliance tools. They should also make sure that there are no major alterations in the building’s envelope that have been done by the design team to affect building performance.
Computer based simulation tools, such as thermal models and Computer Fluid Dynamics (CFD), should be used here to check overall building performance and compliance with the building regulations, based on hourly external data. Results from simulations completed during previous tasks could also be used here.
CIBSE TM33 “Tests for Software Accreditation and Verification”, provides ways to check the validity of dynamic models. CIBSE AM11 “Building Energy and Environmental Modelling” provides comprehensive guidance on the use of computer models, including the various options available and associated uncertainty and risk.
CIBSE could provide guidance on how to complete a value engineering assessment and issues associated. Guidance on SBEM and the other accredited compliance tools could inform the designers of the ‘problem areas’ related to the use of each of the tools. Finally, checklists of possible areas where last minute changes e.g. by completing a value engineering assessment, could affect the building performance, could be beneficial towards maintaining performance of design intent.
3.19.2. Weather data available for present climate conditions
Building Regulations require the use of certified computer tools in order to prove compliance. The above requirement is also part of the European Energy Performance of Buildings Directive. Such tools use hourly weather data to provide information on the energy use and associated carbon emissions of the building and as a result provide evidence of the building’s design intent compliance with the building regulations.
The CIBSE Test Reference Years (TRY) are often used for building simulation and energy assessments. These are hourly weather series over a year and for 14 different UK locations.
The CIBSE Design Summer Years (DSY) are often used for the simulation of the summer thermal performance and overheating risk assessment of buildings. These are hourly weather series over a year and for the same 14 UK locations.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of certain weather events, e.g. once in x observed years event of wind speed and direction.
The TRYs were specifically composed for the calculation of energy use in buildings over a year and so they express average conditions, while they exclude any extreme events. Furthermore, the TRYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The DSYs are selected based on summer (April – September) means of dry-bulb temperatures (Guide J, §8.4). Based on the above selection criterion the third hottest year was selected of the 1983-2002 baseline. The above selection process raises concerns on whether the DSYs are able to express extreme events and allow the assessment of natural ventilation. Furthermore, the DSYs are based on the 1983-2002 baseline, which almost certainly will not represent the external conditions through the lifetime of the building.
The use of probabilities in weather data used for simulations could help in better understand the risk associated with the design of the building and its services. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to present past events based on observed data in a probabilistic way (http://www.ukcip08.net).
The DSYs and TRYs are available for 14 locations only which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy. The next generation of UKCIP climate change scenarios (UKCIP08) is expected to provide information, at a resolution of 25km x 25km, based on observed data (http://www.ukcip08.net).
The next generation of UKCIP climate change scenarios (UKCIP08), produced by the Met Office’s Hadley Centre, is expected to include weather information based on observed data as well as climate change model output. A variety of weather information based on observed data will be freely available through the UKCIP08 user interface (http://www.ukcip08.net).
There are currently discussions that explore the ways to use future weather data, rather than present data based on past baselines, in building design. CIBSE’s Climate Task Force is examining the short and long term options (including the use of the forthcoming UKCIP08 information) of providing the industry with the best available weather information. Furthermore, a group of EPSRC funded projects are examining the use of UKCIP08 climate change information in building design.
3.19.3. Weather data available for future climate conditions
Even though not formally required by the Building Regulations it is increasingly the client’s brief requirement to show that the building will be able to maintain predicted energy performance over its lifetime. This is possible by the use of computer based tools that use hourly weather series to provide a dynamic energy performance of the building in response to external conditions. Such tools use hourly weather data to provide information on the energy use and associated carbon emissions of the building and as a result provide evidence of the building’s long term energy performance based on design intent.
CIBSE in collaboration with UK Climate Impacts Programme (UKCIP) and ARUP has produced future hourly weather years, based on the existing Design Summer Years (DSYs) and Test Reference Years (TRYs), which incorporate the UKCIP02 climate change scenarios. The above future weather years are available for the same 14 sites, for three timeslices (‘2020s’ 2011-2040, ‘2040s’ 2041-2070 and ‘2080s’ 2071-2100) and for four emissions scenarios (Low, Medium-Low, Medium- High and High) (the future weather years could be ordered from http://www.cibse.org/index.cfm?go=page.view&item=1300). The data may also be provided ready-formatted for certain simulation packages (contact Ken Butcher on 020 8772 3628 or email kbutcher@cibse.org for details). Purchasers of any of the above packages will also receive CIBSE’s TM48: “Climate Change Data for Building Simulation”. TM48 serves as a valuable companion to the future DSYs and TRYs with information and guidance on their production and use.
CCWeatherGen – A Climate Change Weather File Generator: A climate change weather file generator (CCWeatherGen) has been developed by the Sustainable Urban Environment (SUE) programme at the School of Civil Engineering and the Environment, University of Southampton. The tool is Microsoft® Excel-based and uses the UKCIP02 climate change scenarios to transform CIBSE / Met Office TRY/DSY weather files into climate change TMY2 or EPW weather files which are compatible with the majority of building performance simulation programs. The CCWeatherGen and the accompanying documentation are available without charge from http://www.energy.soton.ac.uk/ccweathergen. This tool can be used to generate morphed versions of the DSY and TRY files similar to those provided by CIBSE. However, use of this tool does require some specialist expertise. Consequently, CIBSE is not responsible for any errors associated with its use or any other software to reproduce the morphed files provided by CIBSE. The objective of providing the ready made files is to provide a standardised data set for the industry providing a common platform for climate change impact assessments.
All current climate change data in CIBSE guidance originate from the Met Office’s Hadley Centre model outputs. Four UKCIP02 climate change scenarios are presented at a 50km x 50km resolution based on outputs from the Hadley Centre’s global and regional climate models (Had CM3 and HadRM3, respectively). For each of the four UKCIP02 climate change scenarios (H, M-H, M-L, L), changes are described for three future thirty-year time-slices: 2011 to 2040 (the 2020s), 2041 to 2070 (the 2050s) and 2071 to 2100 (the 2080s). All changes in climate are given relative to the baseline period of 1961 to 1990. For more information on emissions scenarios and the products freely available look at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=161&Itemid=291.
The next generation of climate change information (UKCP09) is currently available and presented in a probabilistic way ( http://ukclimateprojections.defra.gov.uk/). The UKCP09 provide information in various formats such as maps, graphs, plots, etc, available in printed reports and in customisable outputs. Changes in weather variables such as temperatures, rainfall, cloud cover etc are presented in a probabilistic way and are available for 25km grid squares, three emissions scenarios (Low, Medium and High) and seven future overlapping 30 year time periods. The provision of probabilistic projections is the major change from the previous UKCIP02 projections. Probabilistic projections assign a probability to different possible climate change outcomes, recognising the uncertainty involved in their production and inherent of our global climate, and as such help with making more robust adaptation decisions. A User Interface portal (http://ukclimateprojections.defra.gov.uk) has been specifically designed to guide the user to the information more appropriate to them and to explain the underlying science and outputs along the way. One of the resources provided through the User Interface is a Weather Generator which is a type of statistical model that uses relationships between climate variables to generate daily and hourly time series. The produced time series are comprised of set of climate variables at a 5 km resolution that are consistent with the underlying 25 km resolution climate projections. Customisable outputs, including the Weather Generator, are accessible after registration.
For the dynamic computer simulations the user should be looking for hourly data with attached probability of occurrence of certain weather events, e.g. probability of certain coincidence of wind speed and temperature happening in the next x years.
All currently available climate change data and weather series for building design are based on UKCIP02 scenarios and are presented in a deterministic way which means that a single number is used to express future changes in weather variables. A good understanding of the uncertainty related to the development of climate change data is essential in order to assist in robust design decisions. Information on the uncertainty associated with climate change information could be found at http://www.ukcip.org.uk/index.php?option=com_content&task=view&id=232&Itemid=326.
The future weather years are available only for 14 locations, which, in some cases, will not include either the locality or the microclimate. Local wind patterns could significantly affect the ventilation airflows in the building and as a result the ventilation strategy.
Although the new climate projections UKCP09 offer an opportunity for the building professionals to better understand and apply climate change information in the future proofing of buildings, their complexity and existing format can hinder their immediate implementation in building design. One of the issues associated with the data is the lack of correlation between weather variables presented as maps and graphs (Cumulative Distribution Function – CDF and Probability Density Function – PDF). For example for overheating calculations there is no correlation between the temperature and solar radiation figures for a given probability. Other issues include the weakness of the Weather Generator to represent extreme events, as well as the lack of projections on wind speed and direction.
The climate change trends (in both UKCIP and CIBSE guidance) are based on a different baseline (1961-1990) than the present day statistics (Guide A 1983-2002, Guide J 1976-1995, TRYs and DSYs 1983-2004) and so they are not directly comparable.
A group of EPSRC funded projects “Adaptation and Resilience in a Changing Climate” – ARCC are examining the use of probabilistic data and climate change information in building design. CIBSE is representing its members as a key stakeholder, technically co-ordinating the outputs of the projects. For more information and to get involved visit: http://www.ukcip-arcc.org.uk/
The outcomes from the above EPSRC funded projects will be integrated into the “Design Compass” as they emerge.
CIBSE’s suggestion of suitable external design conditions based on climate change data for use towards future proofing of buildings and their services should be made available and be incorporated in the weather related CIBSE guidance. Furthermore, CIBSE could further develop guidance on possible design options for adapting buildings to climate change, for both new built and refurbishments.
3.19.4. Other useful references
South East Climate Change Partnership “Adapting to Climate Change: a checklist for Developers”, November 2005
European Climate Assessment & Dataset (ECA&D) project for indices of extremes and daily information based on observations, for various European locations including UK: http://eca.knmi.nl/
The British Wind Energy Association gives access to wind speeds in the UK: http://www.bwea.com/
3.19.5. Input from members
4. Pre-Construction
F. Production information
G. Tender documentation
H. Tender action
4.1. Information from Design Development to be used here
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4.2. CIBSE members’ involvement at this stage depends on the individual contract with the client
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5. Construction
J. Mobilisation
K. Construction to practical completion
5.1. CIBSE members’ involvement at this stage depends on the individual contract with the client
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6. Post Completion
L. Post practical completion
6.1. Commissioning, management and maintenance of the ventilation system
6.1.1. CIBSE guidance and tools
Guidance on the commissioning, management and maintenance of the building services, after the completion of the project, could be used here by facilities and energy managers in order to meet the design specifications.
The CIBSE Commissioning Codes such as Code A “Air Distribution Systems” and Code C “Automatic Controls” could be used here to inform the commissioning process of the ventilation system. CIBSE Guide M “Maintenance Engineering and Management” provide guidance on the management and maintenance of the building services.
CIBSE guidance seems sufficient.
6.1.2. Other useful references
6.1.3. Input from members
6.2. Design review – Refer to feedback and lessons learned
6.2.1. CIBSE guidance and tools
The building services engineers should be able to keep in touch with previous projects in order to learn from them and improve their design methods.
For post occupancy reviews see energy audits and surveys in Guide F “Energy Efficiency in Buildings”, chapter 18.
CIBSE could offer guidance on reviews at design stage (project team meetings, reviews with other design teams etc) and reviewing system performance at post occupancy.
Further guidance could include advice on possible channels and actions through which the design team could revisit or keep in touch with previous projects. Perhaps some research could be done in current practices.
Could CIBSE influence client perception of the value of monitoring and feedback? In some current projects monitoring and feedback is used as educational process.
Encourage integration with Facilities Management (FM), e.g. develop processes of reporting to the design team.
6.2.2. Other useful references
6.2.3. Input from members
6.3. End of life
6.3.1. CIBSE guidance and tools
Guidance on the building demolition and the recycling of materials is relevant here.
CIBSE Guide L “Sustainability”, chapter 8, provides some guidance on this last stage of the building’s life.
Further guidance is needed on end of life stage.
6.3.2. Other useful references
6.3.3. Input from members