Buildings last typically 50 to 100 years, and with climate change predicting hotter summers and warmer winters, buildings designed now and many existing buildings will need to cope with the future climate. The aim should be for buildings to provide comfortable environments for occupants without using excessive heating or cooling energy, which will exacerbate carbon emissions. This is particularly important for office buildings, as the productivity of occupants can be affected if conditions of the workplace are not ideal. Different models and scenarios for predicting future weather for the UK were studied in this thesis. These provide either monthly or daily data of weather variables for the next 100 years including daily maximum, minimum and average temperature, solar irradiation, wind speed and humidity levels. The data from two state-of-the-art models from the Hadley Centre in the UK, HadCM3 and HadRM3, were compared with real observed data to test their reliability, both with average values, as well as near-extreme values, which are useful for building design. It was found that for HadCM3, the temperature data has a severe cold-bias, but solar radiation matched well with real data. For HadRM3, the reverse is true. Its temperature data are fine, but there is an over-prediction of days with high solar radiation, even in days with high cloud cover as shown by an analysis of extra-terrestrial based clearness index values. For both models, the wind data is extremely high compared to real data. Test Reference Years (TRYs) and Design Summer Years (DSYs) were selected for 2020s, 2050s and 2080s using data from these climate models to estimate future energy usage for heating and cooling; and the feasibility of using natural ventilation as the sole means of providing summer cooling in future periods respectively. It was found that the existing methods for selecting TRYs and DSYs could be improved for future weather data. Since buildings respond to hourly changes to outside conditions, a number of algorithms were analysed and appropriate ones were developed to generate hourly weather data for dry bulb temperature (DBT), global irradiation (GSR) and diffuse solar irradiation (DSR) from daily data available from the climate models. These perform better than existing algorithms as they make use of all the daily parameters available. TRYs and DSYs with generated hourly values were run on a 2nd order room model that was developed during this research. This provides extra flexibility over existing building simulation programmes. It was found that the fall in heating demand is approximately equalled to the rise in cooling demand as a result of climate change up to 2080s in all four sites, and that natural ventilation alone would not be able to provide summer cooling in the UK in the near future. Office buildings complying with the Building Regulations of 2002 in the south of England would require air-conditioning by 2020s, those in the north of England by 2050s and those in Scotland by 2080s. However, the majority of existing office buildings in the UK have lower standards of specification. This thesis shows that cooling and emissions will be a major problem in the future climate. Making these buildings work in the future could prove to be an even greater challenge than to design energy efficient new buildings.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:505918 |
| Date | January 2005 |
| Creators | Chow, David Hou Chi |
| Publisher | University of Manchester |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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