Performance evaluation of an active pipe-embedded building envelope system to transfer solar heat gain from the south to the north external wall

Abstract

The unequal heat gain in south and north orientation of a building causes higher energy consumption which should have been avoided. In this paper, an active pipe-embedded building envelope system is proposed to achieve heat redistribution between north and south rooms to reduce building heating load. The system is mainly composed of closed-loop pipes embedded in external walls which will absorb and transfer the solar heat gain from the south façade to the north. On cloudless days, the structure can effectively raise the surface temperature of the north wall, thus reducing the heat loss through the envelope. We present all the mathematical equations and a mathematical model validated against experimental data in the literature. To further check the feasibility of the system, the heat transfer of a pipe-embedded external wall and a conventional wall are compared, with the same configurations under typical weather conditions in five building climate zones of China. The results show that the heating load reduction during heating season for the room adopting this system relative to the one without it is 12.8% for hot summer and cold winter climate. For severe cold climate and cold climate, the heating loads in January are reduced by 4.6% and 8.7%, respectively. The system plays a minor role in reducing building energy consumption in the hot summer and warm winter zone. Besides, energy consumption of building in summer can also be reduced, although not as effectively as in winter. This study may guide a better design and control of low energy building in further research and practice.