Proposal and multi-criteria optimization of two new combined heating and power systems for the Sabalan geothermal source

Combined heating and power (CHP) systems can be a favorable addition to the geothermal power plants since the generated heating commodity can be addressed for wide-range of mountainous districts. Regarding this consequential demand, two innovative CHP systems for the Sabalan geothermal in Iran are designed which were based on organic Rankine cycle (ORC) and Kalina cycle (KC). The plausibility of the introduced monolithic CHP systems is examined from thermodynamic and economic vantage points. Later, multi-criteria optimization via genetic algorithm procedure is accomplished considering major thermodynamic and economic parameters as objective functions. It was exhibited that the recommended ORC-based CHP system could generate overall optimum heating load and net electricity of 5151 kW and 3697 kW, correspondingly as well as achieving energetic efficiency of 61.38% and exergetic efficiency of 36.91%. On the other side, the KC-based CHP system generated overall heating load and net electricity of 2867 kW and 3912 kW, correspondingly, achieving energetic efficiency of 46.12% and exergetic efficiency of 32.52%. The outcomes of the second-law analysis portrayed that among all constituents, condenser attributed as the utmost destructive part of the systems due to the regasification processed firstly occurred through this constituent, followed by the generator. Also, to examine how the introduced set-ups react to any external disturbances, a thoroughgoing sensitivity examination around the basic operating input parameters was fulfilled. It is discovered that the energetic efficiency of the ORC-based CHP system could be maximized with condensation temperature, whilst the exergetic efficiency of the KC-based CHP system could be maximized with ammonia concentration. (C) 2019 Elsevier Ltd. All rights reserved.