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An efficient cooling system can effectively reduce the temperature and improve the power generation performance of photovoltaic cells. In this study, spray cooling is applied to the cooling of photovoltaic cells, and the mathematical model of a solar photovoltaic power generation system is established by considering the power consumption of the cooling system. The net output power and electrical efficiency of the system are compared under different cooling modes. The results show that spray cooling has more obvious advantages than water cooling at large concentration ratios and there exists an optimal spray flow rate that can maximize the net electrical efficiency. The optimal flow rate increases as the concentration ratio increases. Furthermore, the temperature of the spray fluid significantly affects the system performance, and a 10 K reduction in spray fluid temperature can improve the net output power by 7.3%. Regarding the environmental factors, the influence of the ambient temperature is evident when the concentration ratio is small; however, the influence of wind speed is more evident when the concentration ratio is large. The results of this study provide new insights that may prove useful for optimizing the design of photovoltaic cooling systems.

A thermoelectric generator generates electricity by effectively recovering the waste heat from the exhaust of automobiles. The intermediate fluid thermoelectric generator transfer exhaust heat by the gasification and condensation of the medium, which can improve the power output and reduce the optimal module area, thus significantly increasing the power density. To study the influence of exhaust parameters on the performance of new generator, a mathematical model of the thermoelectric generator is used to analyze the effects of exhaust parameters on the system performance. Compared with the conventional thermoelectric generator, the novel thermoelectric generator becomes more advantageous with a lower exhaust heat transfer coefficient. And it is found that the key parameter affecting the performance is the thermal conduction of the exhaust heat exchanger. The exhaust temperature has no effect on the optimal module area, but the maximum output power increases almost linearly with the increase of exhaust temperature. With the increase of exhaust flow, the optimal module area increases linearly under the condition of sufficient heat exchange of exhaust. The results of this study have certain significance for fully understanding the operation principle and guiding the optimal design of IFTEG.

Thermoelectric generators (TEGs) can effectively recover waste heat from the exhaust of automobiles and generate electricity. An intermediate-fluid TEG system is based on the vaporization and condensation of an intermediate medium, exhibiting high-efficiency thermoelectric conversion. In this study, a mathematical model of an intermediate-fluid TEG system is established, and the influences of cooling methods and condensed-boiling heat transfer performance in the cavity on the thermoelectric performance are analyzed. The results show that the new generator exhibits better characteristics than the traditional TEG system under both water-cooling and air-cooling methods. We not only improved the power output, but also reduced the optimal thermoelectric module area under the water-cooling method. Moreover, the condensation heat transfer coefficient in the cavity had a significant effect on the power performance of the proposed system. The boiling and condensation heat transfer coefficients should both remain greater than 5000 W/m2K for a high efficiency of the TEG. This work provides guidance for the design of new TEGs and high-efficiency utilization of exhaust.