Experimental study of RRC-PV modules under hot summer and cold winter climate

Abstract

Building-integrated photovoltaic (BIPV) and building-integrated radiative cooling (BIRC) technologies are popular methods for utilizing renewable energy to address the energy crisis. However, limited facade areas of buildings restrict the amount of renewable energy that can be harvested. The design of reversible radiative cooling-photovoltaic (RRC-PV) module was introduced to address this issue. During the day, the PV side converts part of the incident solar radiation into electricity. At night, the module can be flipped and the RC side emits infrared radiation to the cold outer space, allowing for the free cooling energy exploitation.The performance of RRC-PV modules was tested in Shenzhen with hot summer and cold winter climate, by applying them as rooftop awnings and overhang shadings. Solar power generations were similar for both experiments, with daily electrical efficiencies in the range of 11.4–13.0 %. Meanwhile, the radiative cooling performance was better in the rooftop awning experiment, with an average nocturnal cooling power of 33.7–34.5 W/m2. In contrast, the average nocturnal cooling power reduced to 4.8–4.9 W/m2 in the overhang shading experiment. The results highlighted the importance of evaluating the radiative cooling potential by assessing the sky exposure of building facades.