Integrated solar-powered freeze desalination and water electrolysis system with energy recovery and storage for sustainable agriculture in desert environments

Agricultural activities in remote desert locations face significant challenges due to high water and energy demands and the lack of necessary infrastructure. The use of portable diesel generators, while common in smallholder farmers, leads to substantial pollution on-site. Efficient utilization of naturally available energy and water sources for the supply of essential commodities would greatly support the execution of agricultural activities in desert climates. Freeze desalination offers many benefits over distillation processes, such as low energy demand, negligible fouling, scaling, or corrosion, and no requirement of pretreatment for purification. Besides, hydrogen fuel cell is a clean alternative to a diesel generator as it possesses high conversion efficiency and eliminates greenhouse gas (GHG) emissions and noise pollution. This study proposes a stand-alone solar-powered freeze desalination and electrolysis system for freshwater and green hydrogen production from brackish groundwater in remote desert regions. The system is equipped with several energy recovery and storage solutions such as cistern, ice storage air conditioning, and metal hydride canisters with fuel cell to efficiently utilize energy and water and compensate for fluctuations in solar irradiation. The integrated system is modeled and analyzed based on thermodynamic principles, and results demonstrated the daily capacity of producing 52.8 m³ freshwater, 6.3 MWh air conditioning, 177 kg hydrogen, and 2.4 MWh electricity using 10,785m² bifacial photovoltaics system. Moreover, the energetic and exergetic efficiency of the system is calculated as 17.8 % and 13.5% during day and 56 % and 34.9 % during night, respectively.