Suitability of electrical coupling in solar cell thermoelectric hybridization

Abstract

It is well known that the major constraints to the efficiency of photovoltaic devices come from the generation of heat. In this context, thermoelectric generators have been proposed as a viable heat recovery solution, leading to an increase of the overall efficiency. Within this kind of hybrid solution, the photovoltaic and thermoelectric parts can be either electrically separated or connected in the same circuit. In the latter case, the presence of the thermoelectric generator in series to the solar cell may lead to electrical losses. In this work, we analyze the effect of several parameters on the output power of electrically hybridized thermoelectric-photovoltaic systems. Both electrical measurements and simulations are used. The results show that while an electrical lossless condition exists (as also reported in previous works), it does not necessarily lead to significant power gains compared to the sole photovoltaic case. In addition, the strong temperature sensitivity of the lossless condition makes electrical hybridization difficult to implement. Since solar irradiation varies over time, such sensitivity would make the system work mostly in a suboptimal regime. Therefore, this study provides clues on the actual applicability of electrically hybridized devices.