Modelling and potential of hybrid micro-scaling multi-junction solar cell and thermoelectric generator

Concentrator photovoltaic (CPV) systems replace semiconductor material by cost-efficient optical elements. This technology has doubled the efficiencies of conventional non-concentrating PV systems. However, the cost of CPV still needs to be lowered to be competitive. In these systems, approximately 60 % of the incident energy is dissipated as heat. One way to further enhance CPV systems is taking advantage of the dissipated heat energy as a source for an extra generation of electricity using a thermoelectric generator (TEG). The feasibility of hybrid CPV-TEG modules for enhancing the efficiency and lowering the cost has been discussed in recent work, with special emphasis on actively cooled designs. On the other hand, the micro-scaling of the technology could allow simple and reliable passive cooling mechanisms to be used. In this work, a numerical analysis of three-dimensional micro hybrid CPV-TEG receiver at ultra-high concentration ratios is presented. The procedure solves both the thermal and electrical effects for estimation of the power generated and the efficiency of the system. The results of performance are compared with a CPV-only receiver composed with equal solar cell properties working at similar conditions. Results show that micro CPV-TEG systems can reach an efficiency of 33.6 % versus the 31.6 % achievable with a CPV-only system, working under 4,000 suns.