Thermal analysis of photovoltaic-thermoelectric hybrids

There continues to be considerable research on the adverse effect of photovoltaic (PV) panel temperature on its power production. Aside from attempting to minimize heating up of the panel by providing heat sinks and the like, several studies looked into using the unconverted heat as an input to a Thermoelectric generator residing below the PV panel and questionably generating additional power. Using simple steady energy balances, simplified steady thermal models of PV panels, individually or thermally-in-series coupled to heat engines are studied. The nodal energy equations are solved to ascertain resulting temperatures and efficiencies under different insolations. After establishing a simplified model for a lone PV panel, a PV panel with an added thermoelectric generator attached to its back side is studied. Solving the associated steady energy equations, the photovoltaic-thermoelectric system is found to have a smaller than expected advantage in net power, no more than 4.15 %, over the lone PV panel and then only at high insolation's and concentrations. The implication of this work is that hybridizing a PV panel by bottoming it with a thermoelectric generator is not quite attractive except possibly at higher solar concentrations. The margin to Increase the overall efficiency of a photovoltaic-thermoelectric hybrid by improving the thermoelectric-figure-of-merit does not appear to be significant although further consideration of thermoelectric materials may be required.