Comprehensive performance evaluation of a photovoltaic-thermal driven energy storage and co-production of electricity and water system

Thermo-osmosis represents an advanced pathway for low-grade heat recovery, yet its practical deployment is hindered by salt accumulation and inefficient utilization of concentrated brine. To overcome these limitations, this study develops a solar-driven integrated system that couples thermal osmosis with salinity gradient power generation and incorporates thermal energy storage, achieving simultaneous freshwater and electricity production under intermittent solar input. Subsystem feasibility was experimentally validated. Based on real-time solar irradiance data from representative coastal cities, system performance was evaluated under various operating conditions, accompanied by comprehensive thermodynamic and techno-economic analyses. Results indicate that during 12 h of summer daylight, system can produce 1065.27 kg of freshwater, and the integrated energy storage feature enables the system to operate for an additional 12 h after sunset. An optimal feed flow rate to the photovoltaic-thermal component was identified, maximizing both overall solar utilization efficiency and exergy efficiency. Notably, when the photovoltaic-thermal module area increases beyond its optimal value, the water production cost exhibits an increasing trend, and the system's investment payback period reaches 4.25 years. The proposed system demonstrates self-sustained, all-day production of freshwater and electricity, highlighting its promising application potential in regions facing water and energy scarcity.