Thermodynamic and economic analysis of a novel geothermal based multigeneration system integrated with cascade Claude cycle for power, heat, cooling, and liquid hydrogen production

In this study, a novel geothermal based multi-generation system has been developed. The proposed system integrates an organic Rankine cycle with an internal heat exchanger, a double-effect absorption refrigeration cycle, a proton exchange membrane electrolyzer unit, a dual flash geothermal source, and an innovative cascade liquefaction cycle. A comprehensive thermodynamic and economic assessment has been conducted on the system under investigation. The proposed system achieves an energy efficiency of 43% and an exergy efficiency of 56%. It is expected that this system will generate hydrogen at a rate of 114 kg/h, with an output power recorded at 36,558 kW. The analysis indicates that the overall exergy destruction in the examined system is 98,956 kW. The liquefaction cycle, with an exergy flow of 7513 kW, constitutes the largest portion of the system cycles, whereas the modified Rankine cycle demonstrates the lowest exergy flow at 1014 kW. The steam heat exchanger generator is the most expensive component, with a cost rate of 263,050 $/GJ, while the electrolyzer experiences the highest exergy destruction at 54,008 kW. Increasing the inlet water temperature to the electrolyzer can enhance system efficiency. The economic assessment reveals a total system cost of 0.37 $/GJ. Additionally, the annual capital cost and net present value are calculated to be 0.02 and 3.59 $/year, respectively. Furthermore, the levelized cost of electricity generation is 0.03 cents/kWh, while the levelized cost of hydrogen production stands at 2.009 $/kg. The novel liquefaction cycle exhibits a performance factor of 36%, with the exergy efficiency of this unit calculated at 39%.