Enhanced water and energy productivity in arid climates using a hybrid pv-thermal, multi-effect distillation, and thermoelectric system cooled by CuO nanofluids

Abstract

Water scarcity in arid and semi-arid regions necessitates innovative and sustainable approaches for freshwater production. This study presents the development of a novel hybrid system that integrates three complementary technologies: photovoltaic/thermal (PV/T), a vertical multi-effect distillation (VMED) unit (a plate-type, multi-stage evaporator-condenser), and thermoelectric modules (TEC), further enhanced with copper oxide (CuO) nanofluid. The system is designed to simultaneously improve water and energy efficiency, offering a practical response to the growing challenges of water shortages and climate change. In addition, a new empirical correlation was formulated to predict daily freshwater productivity of the proposed system. Experimental investigations, supported by TRNSYS simulations, demonstrated that the proposed hybrid system (PV/T–VMED–TEC) with CuO nanofluid (0.05–0.075 vol.%) increased freshwater yield by 8–15% and thermal efficiency by 10–20% compared to a conventional PV/T distillation system without TEC modules and without nanofluid.Under the climate of Kashan, Iran, the system produced on average 3.5 L m−2 of freshwater per day (~ 17.5 L day−1 for a 5 m2 collector). Depending on operational conditions, peak daily productivity reached up to 7.2 L m−2 day−1 (36 L day−1 for the same collector area). These findings highlight the potential of the proposed hybrid configuration as a viable and sustainable solution for addressing water scarcity in arid regions worldwide.