Numerical investigation on the impact of an on-top sunspace passive heating approach for typical rural buildings in northern China

In this paper, a novel passive heating design approach—On-top Sunspace (OS)—is proposed to solve the problem of rural heating in the severely cold regions of the northern China. Passive strategies for heating should be applied before considering mechanical equipment. The framework of ‘‘Passive–Simulation–Optimization–Active” was adopted in the study. The OS was first built on the roof of a building. The simulation was completed using the Design Builder software. Based on this foundation, a solar hot water system was installed at the northern wall to further reduce the building energy consumption. The results revealed that the lowest building energy consumption can be achieved when the angles of the roofs are 28° and the glass-to-roof ratios of the front and rear roofs are 0.5 and 0.6, respectively. The daylight could also satisfy two criteria based on the useful-daylight-illuminance (UDI_100-2000 ≥ 80%)and median daylight factor (DF ≥ 2.1%). Moreover, the ultimate average temperature of the building reached 14.75 °C after installation of the solar hot water system, which may have a significant impact on the studies of the indoor thermal environment.