A passive evaporative cooling strategy to enhance the electricity production of hybrid PV-STEG system

The dependable and efficient thermal regulation technology for combined photovoltaic-solar thermoelectric generator (PV-STEG) system is of great importance to ensure output performance. To enhance the electrical behavior of PV-STEG system, a passive evaporative cooling (PEC) technique was presented in this work. Some critical parameters such as solar concentration ratio, ambient temperature, relative humidity, air velocity, and water layer thickness were discussed in detail for a comprehensive assessment of the influence on system temperature, electricity production, and energy conversion efficiency. The obtained findings suggested that adopting PEC technology may greatly lower the operating temperature of the PV-STEG system when compared to the uncooled PV-STEG system. At the solar concentration ratio of 5, the maximum temperature reduction of 92.09 K can be achieved with the assistance of PEC technology. Furthermore, the system performance is greatly influenced by ambient conditions. For example, if the system is exposed to lower ambient temperature, lower relative humidity, and higher air velocity, it produces more electrical power. In addition, compared with other factors, the impact of the water layer thickness is quite gentle, and the temperature difference is less than 1 K. However, there also exists an optimal water layer thickness, and the specific value is 1 mm when the solar concentration ratio is 3. Moreover, compared to traditional passive fin cooling technology, this system demonstrates superior performance.