Experimental thermal and electrical performance analysis of a concentrating photovoltaic/thermal system integrated with phase change material (PV/T-CPCM)

Applying compound parabolic concentrator (CPC) and phase change materials (PCMs) in photovoltaic/thermal (PV/T) systems are effective methods to promote the electrical and thermal performance simultaneously. Much work has intensively investigated the performance enhancement of separate PV/T-CPC or PV/T-PCM system and conducted experiments under lab environment. However, there were few studies devoted to the thermal and electrical performance collaborative improvement especially at an actual outdoor environment. In this study, a compound parabolic concentrating PV/T system integrated with PCM (PV/T-CPCM) is constructed and different parameters are analyzed in an open-air environment. As solar irradiance and ambient temperature vary during the test period, PCM melts from solid to mushy state, and the temperature non-uniformity factor of PV modules/PCM drops from 4.28/1.34 to 1.42/0.66, indicating the PCM obviously improves the non-uniformity of temperature distribution. Set the pump state as OFF-ON-OFF, PV modules temperature firstly rises from 10.6 °C to 33.2 °C, then quickly drops down to 28.5 °C, and after that slowly drops down to 27.1 °C, showing the combination of PCM and liquid cooling is beneficial to further reduce the PV modules temperature. During the pump-on period, the instantaneous thermal, electrical and primary energy efficiency decrease from 19.6% to 5.0%, 4.8%–3.0%, 30.4%–16.8%, and the averaged values are 7.1%, 4.0% and 17.6%, respectively. The maximum primary energy efficiency of the PV/T-CPCM system is about 7.9% and 10.7% higher than that of the separate PV-CPC and PT-CPC system respectively, demonstrating that the PV/T-CPCM system owns superior heat-electricity cogeneration performance.