The integrated system is modeled and analyzed based on thermodynamic principles.
Bifacial photovoltaics maximize renewable energy utilization and power generation by capturing sunlight on both sides.
Scientists have proposed a novel method to use a PV-powered system to desalinate water and produce H2 for desert agriculture. Proposed by Qatar’s Hamad Bin Khalifa University, the system integrates water desalination, green hydrogen production, air conditioning, and electricity production.
The method can help conduct agricultural activities in remote desert locations, which face significant challenges due to high water and energy demands and the lack of necessary infrastructure.
Published in the journal Desalination, the study proposes a standalone, solar-powered freeze desalination and electrolysis system for freshwater and green hydrogen production from brackish groundwater in remote desert regions.
System is equipped with energy recovery and storage solutions
Researchers claimed that the system is equipped with several energy recovery and storage solutions, such as cistern, ice storage air conditioning, and metal hydride canisters with fuel cells, 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, according to researchers.
They claimed that, 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.
Each module producing 600 W at 23.2% efficiency
The system features 10,785 square meters of bifacial c-Si PV panels, with each module producing 600 W at 23.2% efficiency under standard testing conditions. The system generates 1.5 MW of electricity, allocating 100 kW for direct energy supply to farmers. The remainder powers the standalone system, which initially pumps and precools groundwater, reported PV Magazine.
Researchers also maintained that the design of the system features a unique integration of bifacial photovoltaics, brackish groundwater production, freeze desalination with ice storage air conditioning, green hydrogen production, storage, and fuel cell, thermally coupled with hydrogen storage canisters. This synergic integration aims to utilize input energy efficiently and store it in useful forms for times when solar energy is not sufficient or unavailable, according to the study.
Researchers explained that the hydrogen produced in the daytime is stored in metal hydride tanks with a total volume of 3 m3 to operate a 229.7 kW fuel cell through the night for continuous operation.
Hydrogen release from metal hydride tanks is facilitated by applying the heat (129.2 kW) recovered from the fuel cell stack. Total membrane area for the electrolyzer and fuel cell stacks is calculated to be 52.6 m2 and 36.7 m2, respectively, according to PV Magazine.
In the study, researchers also highlighted that bifacial photovoltaics enable maximizing renewable energy utilization and power generation by capturing solar light from both faces. With an efficiency of 23.6 %, a 10,456 m2 BPV area is required to power the electric components of the system and generate an additional electric power of 100kW. They also claimed that solar irradiation has a significant impact on the system output rates.