Influence of envelope and partition characteristics on the space cooling of high-rise residential buildings in Hong Kong

Abstract Nowadays, many apartments in residential buildings in Hong Kong are equipped with air-conditioners to provide comfort cooling for the living, dining and bedrooms. Air-conditioners serving the living and dining rooms would be operated mostly in the evenings and sometimes during daytime as well, but those serving the bedrooms could remain operating overnight. Other rooms, such as bathrooms and kitchens, will not normally be air-conditioned. The paper describes a study into the influence of the building envelope construction on the space cooling loads in residential buildings. The yearly cooling loads of apartments were predicted by using HTB2, a detailed building heat transfer simulation program. The study includes modifications to the base-line characteristics of walls and doors of two typical apartments. The modified walls have an additional 50 mm thick thermal insulation and/or a thickness of up to 400 mm of concrete. Modified doors have an additional 38 mm thick thermal insulation. The simulation predictions indicate that the highest reduction in the yearly cooling load could be obtained when the modified walls and doors were used at suitable locations. In addition, the study results show that the yearly cooling load would increase when the thermal insulation was applied to external walls without increasing the thickness of the concrete layer, and when the concrete layer was thickened but without addition of insulation.