Performance investigation of a concentrating photovoltaic thermal hybrid solar system combined with thermoelectric generators

Concentrated photovoltaic thermal (CPVT) hybrid solar systems present an attractive technology for the simultaneous production of electrical and thermal energy. Combining thermoelectric generators with CPVT systems is an innovative way to further enhance the solar energy conversion and increase the electric power. In this study, a concentrated photovoltaic thermal (CPVT) and concentrated photovoltaic thermal thermoelectric (CPVT-TE) hybrid solar systems were investigated. A hybrid CPVT and thermoelectric generator unit prototypes were designed, manufactured and experimental tests were carried out. Mathematical models were established to analyze the electrical and thermal performances of the CPVT and CPVT-TE solar systems. The models were validated by means of the data obtained during the experiments. Results show that the electric power output of the CPVT-TE is higher than that of the CPVT and improvements on the electrical efficiency can be achieved through the integration of the thermoelectric generators. The daily electrical efficiency of the CPVT-TE system was improved by 7.46% as compared with the CPVT system, for a sunny day characterized by solar radiation level reaching 935 W/m2 and ambient temperature around 33 °C. This study was also an opportunity to analyze the large-scale application of the CPVT-TE solar system. For a typical year in Tunisia and a solar system aperture area of 39 m2, an extra electric energy of 359 kWh could be generated by the CPVT-TE system due to the integration of the thermoelectric generators. In addition, the analysis proves that the system is able to produce a considerable yearly electric and thermal energy and can save fossil energy and equivalent CO2 emissions.