Experimental study on a solar-powered cogeneration system for freshwater and electricity production

In this study, a photovoltaic/thermal (PVT) collector and a stepped solar still system were constructed and integrated. The PVT collector was used to improve the performance of a stepped solar still device. Saltwater enters into the PV-T system and the temperature of the solar panel declines, and then ultimately the efficiency of the PV-T collector increases. After leaving the PVT collector, the temperature of the saltwater increased and was used as a pre-heater for further evaporation in the solar still, which ultimately caused an increase in its efficiency. The more tremendous temperature difference generated between the stepped surface and the glass increases efficiency and produces more freshwater. A flow rate of 7.5 L/hour of saline water was used to study the efficiency of the solar still device and the PVT collector. The value of productivity of solar still system with photovoltaic/thermal collector was 0.76 kg/m² more than that of conventional solar still. Despite the PVT collector, the daily efficiency of the solar still system increased to 34.8%, which shows an increase of 13.9% compared to the passive solar still device. Also, by cooling the PV-T system, the average electrical efficiency has increased from 13.1 to 13.7%. Production power reached 72.46 W from 65.96 W in two consecutive days at 11:15.