Comprehensive analysis of a geothermal-based poly-generation plant to achieve optimal exergy, economic, and environmental performance

Using energy resources has a far-reaching impact on various aspects of life. While there has been extensive research on poly-generation systems, it is crucial to enhance the efficiency of systems that can fulfill multiple energy needs, effectively utilize energy resources, and reduce consumption while increasing efficiency for sustainable development and environmental protection. This study introduces an innovative cycle that harnesses geothermal energy to produce electricity, fresh water, and hydrogen simultaneously. The research aims to develop a model for the proposed poly-generation system, focusing on energy and exergy analyses, and exergo-economic and exergo-environmental evaluations. The study also aims to determine the system's optimal performance using the nondominated sorting genetic algorithm III (NSGA-III) and the TOPSIS decision-making method. The findings of this research are truly remarkable, with the total system's net electrical output, freshwater generation rate, and hydrogen production calculated at 684.3 kW, 864 m3/day, and 371.86 kg/day, respectively. These results underscore the potential of the suggested innovative cycle and demonstrate its effectiveness and efficiency. It is crucial to note the significance of the reverse osmosis (RO) unit, with its highest exergy destruction rate at 204.8 kW among all system components, plays a significant role in the system's energy efficiency, providing a critical insight into its operation. Furthermore, adjusting the reference temperature to a maximum of 320 K leads to an increase in energy efficiency from 39.78 % to 55.43 % and a decrease in the total exergy destruction rate to 396.5 kW from 790.6 kW.