The design reference year – a new approach to testing a building in more extreme weather using UKCP09 projections

Abstract

Current practice in building design is to assess a building’s performance using average or typical weather, a test reference year (TRY), and then to see how it performs when ‘stressed’, using a design summer year (DSY). The DSY is an actual year of hourly data which has the third warmest summer in 20 years’ summers. One of the problems with the DSY method is that it does not explicitly take into account solar radiation, or humidity, nor when more extreme weather occurs – it is selected solely on the mean six monthly temperature from April to September. A DSY may actually be cloudier than the average weather of a TRY. This article proposes an alternative approach using a new type of design reference year (DRY) consisting of a year formed from individual more extreme weather months. The DRY is used in simulating the performance of a building and to identify a single critical month for over-heating, or maximum cooling load. This article compares the characteristics of the DSY and proposed DRY using future projected weather data from UKCIP.

Practical applications : Building designers are increasingly required by their clients to demonstrate how a proposed building will perform under a future rather than historical climate. This article describes a method of processing the latest future climate projections (UK Climate Impacts Programme’s (UKCIP’s) CP09 data released in June 2009) and generating a design reference year (DRY) for use in building simulation programmes. The DRY is proposed as a replacement for the design summer year (DSY), which has a number of limitations.

Get full access to this article

View all access options for this article.

References

Climate Change. IPCC third assessment report. Available at: www.ipcc.ch/ipccreports/tar/ 2001, accessed November 2011.

CIBSE Guides in general. London: Chartered Institution of Building Services Engineers various dates since 2000.

Mylona A (2007). UKCIP, KTP associate. Review of CIBSE Guidance on the use of weather/climate data. Final Draft. For consultation with CIBSE.

Levermore G and Chow DCH. Solar irradiation and coincident dry bulb temperature selection for load calculations, an initial investigation. ASHRAE Transactions, Vol 112 Part B, pp. 690–696, 2006.

CIBSE Guide A Environmental design. CIBSE admittance method. London: Chartered Institution of Building Services Engineers, 2006.

CIBSE Guide

. Weather, solar and illuminance, London: Chartered Institution of Building Services Engineers, 2002.

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

Watkins R, Levermore GJ and Parkinson JB. Constructing a future weather file for use in building simulation using UKCP09 projections. Building Services Engineering Research & Technology, Vol 32(3), August 2011.

Lund H (February 1995). The design reference year users manual. Thermal Insulation Laboratory Report 274, Technical University of Denmark.

10.

BS EN ISO 15927 Part 4. Hygrothermal performance of buildings — calculation and presentation of climatic data – part 4: hourly data for assessing the annual energy use for heating and cooling, 2005, CEN (Comité Européen de Normalisation).

11.

Levermore

Parkinson

. Analyses and algorithms for new test reference years and design summer years for the UK. Building Services Engineering Research and Technology 2006; 27: 311–311.