Model framework and performance analysis of photovoltaic-driven multistage membrane distillation systems for efficient water-power co-supply

Water and electricity are fundamental resources for human survival and societal development. This work designs a photovoltaic and membrane distillation (PV-MD) system for the distributed co-production of power and freshwater by harvesting both solar radiation and PV waste heat. An integrated heat-mass-power transfer model is developed and experimentally validated, allowing for accurate performance prediction under various structural and environmental conditions. Parametric analysis identifies membrane thickness and PV efficiency as critical design factors, while solar irradiation and humidity are the dominat external influences. Energy flux analysis underscores the trade-off between freshwater production and power generation under varying operation conditions. Furthermore, the hybrid cooling configuration demonstrates superior performance over conventional heat sinks, enhancing freshwater yield by 24.64% and PV power output by 4.28%. For opyimally designed systems, climate-specific modeling across diverse representative climates demonstrates strong adaptability, achieving freshwater production gains of 0.54%–19.71% and PV power increase of 0.10%–1.06% compared to heat sinks. This study provides valuable insights into the power-water synergy within PV-MD systems and offers the targeted guidance for system-level design and performance optimization across diverse climates.