Abstract Although the integration of photovoltaic-thermal (PV/T) heat pump systems on buildings can assist in reducing the electricity demand of high-energy consuming buildings, the large occupation area of PV/T modules hinders its popularization. To overcome this problem, a novel PV/T evaporation roof coupled with a heat pump system composed of electronic expansion valves, a condenser and a compressor is proposed, which serves as an electric generator, evaporator for the heat pump system and the external surface of a building roof. This paper investigates the actual operating performance of the direct-expansion roof-PV/T heat pump system under different seasonal conditions. The structure and design of PV/T evaporation roof and the whole system are first presented, followed by the construction of an experimental platform and finally the operation of the system is analyzed through performance evaluation indices and field-testing. The experimental results indicated that the system performed better in the summer than in the winter, with the electrical efficiency, thermal efficiency and overall efficiency averaging at 11.23%, 64.25% and 83.32%, respectively. The average COP was 5.9, with a maximum value of 8.9. Additionally, it took 2 h to heat the water within a 1.5 m3 heat storage tank from 25 °C to 60 °C, which was twice as fast as under winter conditions. Meanwhile, a significant decrease in system performance resulting from changes in environmental parameters in the winter was observed. The average electrical efficiency, thermal efficiency, and overall efficiency were 11.67%, 60.17% and 78.84%, respectively, while the average and maximum COP were 3.7 and 5.24 respectively.

中文翻译：

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直膨式屋顶-PV/T热泵系统性能试验研究

摘要 光伏热泵系统在建筑上的集成虽然有助于降低高耗能建筑的用电需求，但光伏/T组件占用面积大，阻碍了其普及。为了克服这个问题，提出了一种新型的 PV/T 蒸发顶与由电子膨胀阀、冷凝器和压缩机组成的热泵系统相结合，作为发电机、热泵系统的蒸发器和热泵系统的外表面。建筑物屋顶。本文研究了直膨式屋顶光伏/T热泵系统在不同季节条件下的实际运行性能。首次介绍了PV/T蒸发顶及整个系统的结构和设计，随后搭建了实验平台，最后通过性能评价指标和现场测试对系统的运行情况进行了分析。实验结果表明，该系统夏季性能优于冬季，电效率、热效率和综合效率平均分别为11.23%、64.25%和83.32%。平均 COP 为 5.9，最大值为 8.9。此外，将 1.5 m3 储热罐内的水从 25 °C 加热到 60 °C 需要 2 小时，这是冬季条件下的两倍。同时，观察到由于冬季环境参数的变化导致系统性能显着下降。平均电效率、热效率和综合效率分别为11.67%、60.17%和78.84%，