Impact of cool roof on energy consumption for a railway station

Abstract

The roof reflectance surface and skylight shade reflectance are two significant factors affecting air-conditioning energy consumption and indoor lighting in a single-storey large volume building, such as a railway station. Based on qualitative analysis on the effect of cool roof on building performance, a model of a large tall railway station built in the software EnergyPlus was verified by field data. The model was applied to analyse the effect of cool roof reflectance and skylight shade reflectance on the installed capacity of air-conditioning system, lighting energy consumption and indoor thermal comfort under different climates. The results show that the high reflectance surface of opaque cool roof is beneficial by reducing the energy consumption for indoor cooling and the installed capacity of air-conditioning system and improve the indoor thermal comfort in summertime. However, the opposite is true in wintertime, and this could consequently lead to more annual energy consumption. The high reflectance of skylights could reduce the energy consumption for cooling in summer and limit the energy consumption for heating and lighting in winter, thus reducing the annual energy consumption by a large amount. This study indicates that the local climates and the inherent characteristics of roof structure should be considered in the practical use of cool roof technology.