Quantifying the effects of climate change and risk level on peak load design in buildings

Abstract

Good building design aims to balance providing a comfortable internal environment for as much of the time as possible within a variety of constraints. An important factor is the expected weather, but in a changing climate this poses additional challenges to engineers and architects. This paper examines the effects of increased external temperature on the size of the central air conditioning and heating plant for an example building. It is found that for each 1°C rise in external temperatures, the peak cooling load increases approximately by 10%, the chiller power by 14% and fan power for distribution by 30-50%. These are relatively large increases in power needed to counteract rising external temperature and the paper considers the choice of risk level for sizing building plant. From HadRM3 data, the future frequency distribution of higher external temperatures is examined to evaluate the effects on plant size of designing to a fixed percentile of risk. Projected changes in absolute humidity are also discussed.

Practical applications: Climate change is an important topic for building services engineers, resulting in the UK in the new, performance-based Building Regulations Part L. New, future weather data will also become available with different climate change scenarios. This paper examines the implications of both climate change and the risk level on the peak load for natural ventilation or air conditioning and heating that is used in the design of systems.

Get full access to this article

View all access options for this article.

References

Wright AJ Evidence for climate change relevant to building design in the UK, 1976-2000 . Building Services Engineering Research Technology 2002; 23(4): 205-206.

Pretlove SEC , Oreszczyn T. Climate change: Impact on the environmental design of buildings. Building Services Engineering Research Technology 1998; 19(1): 55-58.

Cibse Guide A. - Environmental design. London: The Chartered Institution of Building Services Engineers, 2006.

HadRM3 data available from the British Atmospheric Data Centre (BADC) . Available at: http://badc.nerc.ac.uk/home/(accessed 15 December 2009).

Murphy JM , et al. UK climate projections science report: Climate change projections, Met Office Hadley Centre, Exeter , 2009.

Hulme M. , Jenkins GJ , Lu X. , Turnpenny JR , Mitchell TD , Jones RG , Lowe J. , Murphy JM , Hassell D. , Boorman P. , McDonald R. , Hill S. Climate Change Scenarios for the UK: The UKCIP02 Scientific Report , Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia , Norwich, UK, 2002.

Levermore G. Building energy management systems: Application to low-energy HVAC and natural ventilation control, 2nd edn, London: E & FN Spon, Taylor & Francis Group, 2000.

Levermore G. , Chow D. , Jones P. , Lister D. Accuracy of modelled extremes of temperature and climate change and its implications for the built environment in the UK . Technical Report 14, Tyndall Centre for Climate Change, 2004.

COPSE: Coincident probabilistic weather data for a sustainable climate, a project supported by the EPSRC Ref: EP/F038100/1.

10.

Cibse TM35, Weather data with climate change scenarios. London : The Chartered Institution of Building Services Engineers , 2004.

11.

Cullen NJ Climate change - designing buildings with a future: Proceedings of the CIBSE National Conference. New York : Plenum Press, 2001.