Improved energy conversion of a photovoltaic module-thermoelectric generator hybrid system with different cooling techniques: Indoor and outdoor performance comparison

Numerous studies have emphasized the role of cooling in maximizing the energy conversion efficiency of a photovoltaic (PV) module. Amongst them, the energy and exergy analyses of PV-thermoelectric generator (PV-TEG) hybrid systems with evaporative cooling have been rarely investigated. Hence, the present experimental study focuses on the performance comparison of PV-TEG hybrid system with different cooling techniques. The parameters studied are panel temperature, energy and exergy efficiency, power output, and I-V and P-V characteristics. As the indoor and outdoor radiation spectrum varies substantially, the comparative analysis results in high module temperature (9.4%-42% or 3°C-26°C increment) with less power output (41%-45% decrement) in indoor testing than in outdoor conditions. The indoor testing also overpredicts the TEG power by 3.1-5.3 times. Hence, the quality of the solar simulator plays a significant role in analyzing the PV module on an absolute scale. However, its application is defendable for relative analysis. Out of various cooling techniques undertaken for the PV-TEG system, although water circulation conveyed the highest energy conversion, wick-based evaporative cooling is justified based on resource and energy conservation. Even in water cooling, the flow rate needs to be optimized as the high rate does not always extract the heat sensibly. In all cases, as the power generated by the thermoelectric unit never exceeded 1% of the total generation, its application in the PV module is still debatable.