Study of space heating by dual-function solar collectors

Abstract

A novel solar collector named dual-function solar collector (DFSC) has been proven feasible for supplying warm air for space heating in winter and hot water during none-heating season by theoretical and experimental studies. While integrated with building, the DFSC becomes component of the envelope. Because complexly coupling of several heat transfer modes and subjecting to random weather condition, the thermal influence of DFSC on a building remains obscure. In order to investigate the effect of DFSC for passive and active heating, a demonstrating office building integrated with DFSC panels on the southern wall and roof has been built in Hefei, in the east region of China. A simulation project of the whole building system in winter was built by the software TRNSYS with the new component developed for DFSC and compiled into the TRNSYS library based on the validated theoretical method and experimental results from previous studies. The simulation results show that the energy supplied by the DFSC can meet the heating requirement at most of the time of a sunny day, except early morning. More than 30 % solar fraction can be provided during the whole heating season in Hefei, the value further increases to 59 % in a region of high solar irradiance, such as Lhasa. While active DFSC panels are operated to provide fresh warm air through ventilation system, the flow rate shows strong influence on the solar fraction of heating load. With appropriate operation scheme of the active DFSC, more energy savings and thermal comfort can be achieved.