Energy, exergy, and economic analysis of a geothermal power plant

The current study aimed at designing a geothermal power plant in the Nonal area in Damavand district for simultaneous generation of thermal energy the electric power in the network of Damavand City and a part of Tehran province, the organic working fluid for the above cycle is R245fa which is a non-flammable fluid of dry type. The values of energy efficiency, exergy, the net rate of entropy change, and the specific output power were calculated as 18.2%, 21.3%, 172.97 kW/K, and 31.43 kJ/kg, respectively. The cost of drilling a well, as well as designing and construction of Damavand’s geothermal power plant, were calculated to be 4.2 and 521.5 million (USD), respectively. Also, the cost per generation of each kW/h of power in Damavand power plant was 17 cents. The estimated payback time is calculated as 15 years. The analysis of the cycle in different months of the year showed that exergy efficiency has little change. The only significant effect of temperature changes was on the exergy efficiency as approximately a change of 2% can be seen during a year. © The Author(s) 2018.