Investigation of Urban Heat Island Effect on the Performance of Buildings in Hong Kong

For successful building thermal and energy simulation, weather data is one of the key factors. Computer simulation software requires hourly weather data such as dry bulb temperature, dew point temperature, solar radiation, wind speed and direction, etc. Since weather conditions can vary significantly from year to year, there is a need to derive a set of typical weather year (TWY) data to represent the long-term typical weather condition over a year. It is internationally recognised that typical meteorological year (TMY) weather dataset can represent the long-term typical weather condition and is more reliable in replicating average historical conditions. Therefore, TMY weather data files are commonly used by researchers in the world for studying building thermal and energy performance.In recent years, Hong Kong has encountered a problem of urban heat island (UHI). The UHI effect means an urban area is significantly warmer than its rural surroundings. The major causes of this effect include over-crowding of high-rise buildings with bulky thermal mass property; tall buildings blocking sea breeze and releasing of thermal radiation; and lack of vegetation in urban areas. Since the meteorological data used for developing the TMY weather file come from the measured data from the Hong Kong Observatory stations which are mainly located in rural or sub-urban area, the impact of UHI effect cannot be reflected by these meteorological data as well as the TMY file developed. As a result, using this TMY weather file for evaluating the thermal and energy performance of buildings located in city centre with UHI effect may not be accurate or the average energy consumption of these buildings may be underestimated.Therefore, there is a potential need to derive modified TMY weather datasets for Hong Kong and evaluate the difference of thermal and energy performance of buildings located in different regions including rural area, sub-urban area and city centre. This objectives of this research project are to develop modified TMY weather files for rural area, sub-urban area and city centre in Hong Kong, taking the UHI effect into account; and to investigate the thermal and energy performance of commercial and residential buildings located at rural area, sub-urban area and city centre with the modified TMY weather files; and to investigate and compare the thermal performance of naturally-ventilated residential buildings located at rural area, sub-urban area and city centre with the modified TMY weather file developed.