Overall thermal transfer values for building envelopes in Hong Kong

The Overall Thermal Transfer Values (OTTVs) of building envelopes in Hong Kong have been considered. Parametric studies on a centrally air-conditioned building were performed. The DOE-2 program, developed at the US Department of Energy, has been used as the energy behaviour simulation tool. The year 1980 is taken as the reference weather year for Hong Kong. The window-to-wall ratio as well as the orientation of the windows for the example building were varied. Two values of OTTV, one for summer and the other for winter, have been established for accounting for seasonal changes in Hong Kong. The summer OTTV, calculated from the heat gain in the hot season, is recommended as the more important value for evaluating the thermal performance of building envelopes in Hong Kong.