Performance prediction on a novel dual-mode heat pump with a hybrid photovoltaic/micro-channel heat pipe/fin heat exchanger

Abstract

In traditional photovoltaic heat pumps, the photovoltaic (PV) cells and condenser would hinder each other’s heat dissipation in the reverse cooling mode, resulting in a drop in both cooling and electrical performance. Besides, it also has an excessive dependence on irradiance in the heating mode. To address these problems, a novel dual-mode heat pump with a hybrid photovoltaic/micro-channel heat pipe/fin heat exchanger is proposed in this paper. The novel system utilizes micro-channel heat pipe and double-circuit to adjust the heat transfer direction of refrigerant and PV, so that the refrigerant could absorb heat from PV when heating and not release heat to it when cooling. The mathematical model is established and validated. The system performance in cooling and heating modes is investigated in dynamic condition. Additionally, a study on the impact of solar irradiance, ambient temperature, wind speed, and water temperature is conducted. On a typical summer day, the novel system can provide 1993 W cooling capacity and generate electricity at 127.9 W with 22.73 °C PV temperature averagely. On a typical winter day, its mean heating capacity, electricity generation, and comprehensive coefficient of performance are 1756 W, 148.6 W, and 5.28 respectively. In the cooling mode, with the irradiance increasing from 200 W/m2 to 1000 W/m2, the PV output is lifted by 182.5 W, and the cooling capacity drops by only 0.11%. In the heating mode, the ambient temperature has a more obvious influence on heating capacity than other factors. Results show that the novel system demonstrates an excellent comprehensive performance, especially improving the cooling and electrical capacity in the clear summer day.