Theoretical study of a novel intermediate temperature photovoltaic/thermal system equipped with heat pipe and evacuated tube

Abstract

Solar photovoltaic/thermal (PV/T) technology has enormous promise in the field of renewable cogeneration as a key technology to increase the utilization rate of solar energy. The structural restrictions of PV/T and the high power temperature coefficient of solar cells make PV/T mostly used in low-temperature situations. However, the combination of intermediate temperature PV/T and low-grade energy utilization devices can create a wider range of application values, including absorption refrigeration, seawater desalination, and the organic Rankine cycle. To increase the overall efficiency and thermal energy grade of the PV/T system, a novel heat pipe evacuated tube PV/T (HE-PV/T) system is proposed. The heat transfer is modeled using distributed parameters, and the thermoelectric performance and temperature uniformity are computed through numerical simulation. The impacts of different parameters on the thermodynamic performance of the HE-PV/T system are examined. Compared with traditional flat plate PV/T, the system's overall energy utilization efficiency and exergy efficiency have been significantly increased. When the inlet temperature is 80.0 °C, the overall energy and exergy efficiency of the HE-PV/T system can reach 33.55 % and 7.92 %, which is 29.66 % and 21.97 % higher than that of flat plate PV/T. Besides, the temperature distribution of the HE-PV/T is more uniform, which is beneficial for reducing thermal stress and mechanical damage. The property superiority and thermodynamic feasibility of the HE-PV/T system at medium temperature are demonstrated.