A multi-energy production system utilizing an absorption refrigeration cycle, and a PEM electrolyzer powered by geothermal energy: Thermoeconomic assessment and optimization

Abstract

This study aims to optimize a multi-energy production system that utilizes sustainable geothermal energy as its primary power source. The system comprises several subsystems, including a geothermal well, an organic rankine cycle (ORC) unit, an absorption chiller, and a proton exchange membrane (PEM) electrolyzer. The study examined the impact of variations in seven key parameters, including turbine inlet temperature, evaporator pinch point temperature, pump inlet temperature, evaporator inlet temperature, evaporator inlet mass flow rate, turbine efficiency, and pump efficiency, on the overall system performance. The Response Surface Methodology (RSM) was employed to find the optimum point of the system. To facilitate the practical implementation of the system, the research team assessed its viability in 10 different Iranian cities, all known for their substantial geothermal energy potential. Among the cities, Zahedan emerged as the most suitable location for deploying the system, given its robust energy production potential. The results showed that January, with a production of 626.4 MW h of electricity, and November, with a production of 622.8 MWh of electricity, are the best months for the system to operate in Zahedan city. The environmental aspect of the system also yielded noteworthy results. By setting up the proposed system in Zahedan city, it is possible to prevent the emission of 1472.411 tons of carbon dioxide by producing 7217.7 MWh of electricity throughout the year at a cost of 35337.86 $. Additionally, the proposed system can help expand 7 ha of green space, providing the electricity needed by 2349 people throughout the year.