The effects of future climate change on heating and cooling demands in office buildings in the UK

Abstract

As climate change predicts hotter summers and warmer winters in the next 100 years, buildings designed now as well as many existing buildings will need to cope with the future climate. The aim for building designers should be to provide buildings with comfortable environments for occupants without using excessive heating or cooling energy, which will exacerbate carbon emissions. This is particularly important for office buildings, as these are more susceptible to the effects of warmer temperatures, with their relatively high levels of internal heat gains. The productivity of occupants can also be affected if conditions of the workplace are not ideal. Using climate change data from UKCIP02 based on HadRM3 for three main sites in the UK (London, Manchester and Edinburgh), test reference years were selected for 2020s, 2050s and 2080s under various scenarios.1 Using a second-order room model, future energy usage for heating and cooling were estimated for office buildings complying with various editions of the UK Building Regulation, as a test of the buildings’ age against the effects of climate change. The findings show that the fall in heating energy demand is approximately equalled to the rise in cooling demand as a result of climate change up to the 2080s in Heathrow, Manchester and Edinburgh. Natural ventilation alone would not be able to provide enough summer cooling in the UK in the near future. New office buildings, complying with 2002 Building Regulations, perform significantly better than older ones, and their energy and CO2 emissions remain relatively constant with climate change. However, most of the existing office buildings in the UK are older buildings with lower standards of specification, and the challenge is to make these perform more efficiently. Retrofitting them to have similar properties to the 2002 Building Regulations will be sufficient to cope until 2080s, and increasing the ‘weight’ of the building enclosure will reduce the amount of cooling required. This paper also demonstrates that for all-air systems, it will be essential for fans to be sized correctly for the increasing cooling load with future climate. Practical application: This paper aims to provide a comprehensive study and understanding to how various different office buildings in the UK will cope with climate change, especially how climate change will affect the heating and cooling loads, as well as the associated CO2 emissions as a result of meeting the thermal demands. Using a second-order model, this study simulates an office room for three main UK locations, Heathrow (London), Manchester and Edinburgh, under respective climate change data for 2020s, 2050s and 2080s, comparing their thermal energy consumptions with current weather data. Apart from testing the office room with different orientations, construction thermal ‘weight’ and different future climate scenarios, the office room was also made to comply with various Building Regulations, which determine the permitted maximum U-values and glazing area of the external envelope, and the type of glazing used. This represents the office buildings currently in the building stock in the UK, and the analyses conducted are to examine how each will perform in the 21st century. The results from this study would be useful for building designers to know which aspects will affect energy consumption and thus CO2 emissions most in the future, and what should be done with the existing building stock, where most buildings were built to with higher U-values and single glazing, to make them perform efficiently in the face of a warmer climate. Would retro-fitting be adequate, or would they need to be demolished and re-built? As mechanical cooling becomes a necessity in the future, the energy required for running the fans also contribute greatly to the total CO2 emissions in office buildings in the future.