Energy, exergy and exergy-economic analysis of a new multigeneration system based on double-flash geothermal power plant and solar power tower

Abstract

In this research, a multigeneration system consisting of a double-flash geothermal power plant, solar power tower, organic Rankine cycle, alkaline electrolyzer and a single-stage absorption chiller is presented. In this research, the solar power tower has been used to improve the performance of the double-flash geothermal power plant. Combining such a Concentrated solar power system with a double-flash geothermal power plant was not previously addressed. Also, to increase the whole system's efficiency, the waste heat from the double-flash geothermal power plant and the solar power tower in the proposed system have been used. The proposed system is capable of producing power, hydrogen, heating, and cooling. The multigeneration system has been analyzed by EES software for energy, exergy, and exergy-economy. To study the impact of important parameters on system performance, it has been analyzed parametrically in different conditions. The proposed system is capable of generating 43,640 kW of electricity, 161,604 kgh of hydrogen, cooling of 1243 kW and hot water consumption of 8870 kW in full use of the geothermal source. In the present research, in order to improve the lifetime of the geothermal well, the flow rate of geothermal fluid entering the system is reduced to reach the production capacity of the reference geothermal power plant to achieve the same amount of electricity generation as the base system by the proposed multigeneration system. In this case, 21% less geothermal fluid is extracted from the geothermal source. Under these conditions, the multigeneration system has Energy and Exergy efficiency of 19% and 19.29%, respectively, and the cost of electricity and H2production is equal to 0.1477 $kWhand 7.626 $kg.