Experimental and numerical investigation of a PV-MCHP- PCM-TEG hybrid system

Conventional photovoltaic systems suffer from heat accumulation due to low-conductivity polymer back sheets, which reduces efficiency and limits waste heat recovery. This study proposes a hybrid system integrating a photovoltaic cell with a micro-channel heat pipe array, a phase change material plate, and a thermoelectric generator. The polymer back sheet is replaced by an aluminum alloy to minimize interfacial thermal resistance. A four-day outdoor winter experiment was conducted in Kunming, China, and a one-dimensional transient numerical model was developed. The model is validated against measured data with root mean square errors of 1.6°C for photovoltaic temperature, 2.2°C for phase change material temperature, 1.1 W for photovoltaic power, and 0.06 W for TEG power. Results show that the hybrid system reduces photovoltaic temperature by 11.1°C, increasing standalone photovoltaic conversion efficiency from 12.1% to 17.8% of photovoltaic-micro-channel heat pipe-phase change material-thermoelectric generator hybrid system, with peak efficiencies of 21.0% and 23.9%, respectively. Over three days, the hybrid system generates 261.0 Wh of electricity, a 16.7% increase over the standalone photovoltaic cell (217.0 Wh) for the same active area of 0.12 m2. Notably, latent heat release from the phase change material enables sustained thermoelectric generator output for 55 min after sunset, creating a nocturnal long-tail generation effect. Sensitivity analysis identifies an optimal phase change material mass of 0.5 kg and a melting range of 25-37°C for high-altitude winter conditions. These findings demonstrate that the proposed architecture offers improved efficiency, passive thermal management, and waste heat recovery, making it suitable for all-season solar energy harvesting.