Study on Thermal Performance in Winter of Building Envelope Walls Insulated with Expanded Polystyrene Board

Building energy consumption is tremendous in China. The energy consumption of building envelope walls is 4- 5 times higher compared with that of developed countries. The envelope walls built by solid clay brick and other masonry materials have a poor thermal insulation performance, and can not meet the requirements of building energy efficiency. This paper investigates the thermal performance in winter of thermal insulation composite walls in Beijing area by using response factor method and finite difference method. The results show that the external solid brick walls composed with 50 mm thick expanded polystyrene board on their outside surfaces can reduce the hourly heat transfer about 67.5%, the peak value of heat transfer of the composite wall reduced and changed flatly, it has a good heat stability which is benefit for building energy conservation and the operation and control of heating equipment, the hourly unsteady-state temperature of the inner surface of the composite wall is much closer to the requirement of the indoor temperature in winter compared to that of the traditional solid brick wall, the indoor environment of composite wall has a good thermal comfort.