Refrigeration characteristics of a hybrid heat dissipation photovoltaic-thermal heat pump under various ambient conditions on summer night

This paper presents a radiative/convective hybrid heat dissipation photovoltaic-thermal heat pump (HHD-PVT-HP) refrigeration system based on the traditional PVT solar heat pump, which can be used to meet the cooling demand of buildings. PVT modules are used for the system condenser. The PVT modules emit heat to the ambient surroundings (hybrid heat dissipation) mainly by two ways: radiation to the night sky and convection with the surrounding air. An experimental study and parametric analysis of the HHD-PVT-HP system is conducted. The experimental results indicate that the HHD-PVT-HP system is able to stably refrigerate on summer night, with an average COPref value ranging from 1.8 to 2.1. Moreover, the heat dissipation performance of the PVT modules is good, with an average hybrid heat dissipation flux of similar to 420 W/m(2). To predict the operation characteristics of the HHD-PVT-HP under various ambient conditions, a system simulation model is established and validated with experimental data. The simulation results show that changes in the ambient air temperature and wind velocity have obvious effects on the heat dissipation characteristics of the PVT modules and system refrigeration performance. However, when the outdoor wind velocity is greater than 1 m/s, its influence is obviously lessened. Additionally, the relative humidity of the ambient air has little effect on the refrigeration capacity and COPref of the HHD-PVT-HP system. (C) 2019 Published by Elsevier Ltd.