Experimental investigations on PVT-integrated hybrid desalination system: Energy, exergy, and economic analysis

Sustainable technologies and their combinations can meet the growing demand for freshwater and clean energy to create comfortable ecosystems on Earth. The present study focuses on the energy, exergy, and economic analysis of hybrid thermal desalination coupled with a photovoltaic-thermal (PVT) panel. A lab-scale experimental facility with a PVT module integrated with a stepped solar still (SSS) and a humidification-dehumidification (HD) desalination system will be designed, developed, and tested in the actual outdoor conditions of Vellore in May 2023. The novelty of the proposed hybrid system is the effective recovery of waste heat from the PVT panel to preheat the saline water supplied to SSS for enhanced freshwater yield and the effective reuse of SSS brine reject for further extraction of freshwater in the HD system. Experiments were conducted with a saline water flow ranging from 1.5 to 3 liters per minute. The experimental results show that the PVT's average electrical efficiency is 0.4% higher than that of the reference PV panel. The hybrid PVT-SSS-HD system produces an average daily freshwater of 6400 to 7450 ml/m2. The hybrid system's overall efficiency, exergy efficiency and the unit liter freshwater cost in USD vary in the range of 61.17%-67.71%, 17.16%-17.87% and 0.09-0.082, respectively.