Thermoeconomic Optimization of a Superheated Kalina Cycle for Various Geothermal Source Temperatures in Iran

Geothermal sources are one of the renewable heat sources. In the present study, at first, the feasibility of using a superheated Kalina cycle to generate power by geothermal sources in Iran has been investigated. Using thermodynamic and thermoeconomic analyses, the effect of operating parameters including turbine pressure and water-ammonia concentration on the performance of the superheated Kalina cycle at a heat source temperature of 170˚C has been investigated. The results show that at a heat source temperature of 170˚C and a concentration of 65%, the highest net power of cycle occurs at turbine pressure of 28.33 bar and the lowest exergy cost of power generation happens at the pressure of 19.44bar. Also, at a constant pressure of 22 bar, the maximum net power and minimum exergy cost of power generation occur at the concentration of 66% and 70.33%, respectively. Finally, minimizing the exergy cost of power generation was selected as the objective function and the values of turbine pressure and water-ammonia concentration were optimized simultaneously using a genetic algorithm. Eventually, in order to achieve maximum performance, for different temperatures of geothermal sources in Iran optimal values of pressure and concentration were introduced in a table.