Experimental investigation of a photovoltaic thermal collector with energy storage for power generation, building heating and natural ventilation

A phase change material (PCM) can be used for thermal management of photovoltaics and thermal energy storage. This paper presents a photovoltaic thermal (PVT) system integrated with a PCM as a thermal storage medium for managing the photovoltaic temperature and together with a ventilation duct for preheating supply air or natural ventilation of a building. The novelty of the integrated PVT/PCM system lies in using the PCM as a passive technique not only for PV cooling but also for building heating and ventilation. Experiments have been carried out on a prototype PVT system for different sizes of PCM. The results show that a 30 mm thick PCM layer with a phase change temperature of 25 degrees C can maintain the PV temperature below 45 degrees C and improve the PV electrical efficiency by 10% for about 210 min under 600 W/m(2) insolation. Increasing the PCM thickness by 10 mm increases the time for thermal control by 60-70 min. The PVT/PCM system is able to generate a 15 L/s ventilation rate in a vertical duct of 1100 mm wide, 1200 mm high and 100 mm deep during the melting phase and at least 20 L/s during the solidification phase. Use of metal fins to enhance heat transfer in the PCM can increase the PV electrical efficiency further by 3% and the ventilation rate by 30%. (C) 2019 Elsevier Ltd. All rights reserved.