Experimental investigation on the hybrid PVT-solar still with rotating cylinder for enhanced electrical power and freshwater production

Recent advancements in hybrid systems have shown considerable promise in addressing sustainable energy and freshwater needs. To produce electricity and freshwater simultaneously, this study introduces a novel configuration that combines a modified solar still (MSS) with a rotating cylinder and a photovoltaic-thermal (PVT) collector. Experiments were conducted on the hybrid system in May 2025 at the University of Technology and Applied Sciences – Al Musannah, Oman, between 8.00 and 18.00 hours. The photovoltaic panel is cooled by passing saline water through a copper tube placed below it, and the preheated water from the PVT is supplied to the MSS, enhancing electricity and freshwater generation. The main objective of the present study is to find the optimum operating speed of the rotating cylinder for maximum overall efficiency and compare the results with the conventional solar still (CSS). The results demonstrate exceptional performance, achieving a peak electricity output of 161.8 W and a freshwater production rate of 1.53 L/h at the optimum cylinder speed of 0.3 rpm. The PV panel cooling with saline water improved PVT electricity generation by 6.2%, while integrating a rotating cylinder in the solar still boosted the daily freshwater yield by 321% compared to CSS. A preliminary economic assessment reveals that the present hybrid PVT-MSS system produces freshwater at an estimated cost of approximately $0.026/L. The proposed configuration demonstrates its potential as a sustainable solution for effectively meeting both power and potable water demands, benefiting underserved and remote communities.