Heat resistance analysis and performance improvement of an innovative micro heat pipe PV/T system

Reducing heat resistance is an effective means to enhance the performance of photovoltaic/thermal (PV/T) systems. However, there is currently a lack of quantitative research on the heat resistance of PV/Ts, especially under outdoor conditions. To address this issue, experiments were conducted on typical days of spring, summer, autumn, winter in Lanzhou (36.1 degrees N/103.9 degrees E, 1517m), a city in northwest China. After determining the optimal tilt angle to be 45 degrees, the heat resistance of each component of the PV/T panel (EVA, TPT, M-HP, heat conductive adhesive, airfoil fin heat exchanger, and the internal wall of the airfoil fin heat exchanger and water) was analyzed. The heat resistance for internal wall of airfoil fin heat exchanger wall and water was the highest among PV/T collector, reaching 49.05 %. In order to reduce this heat resistance, a rectangular heat exchanger was designed. The heat resistance for the internal wall of the rectangular heat exchanger and water was 31.0 % of the heat resistance for the internal wall of the airfoil fin heat exchanger and water. Numerical simulations have shown that the M-HP-PV/T system equipped with a rectangular heat exchanger has an overall efficiency improvement of 12.8 % compared to an airfoil fin heat exchanger.