Thermodynamic modeling and exergy analysis of a gas turbine and fuel cell hybrid system (SOFC + GT) equipped with single-effect and double-effect absorption chillers.

One of the reliable methods to make more use of energy production sources, is to use power generation units that use a fuel source, and by utilizing any wasted energy, bring the temperature of the exhaust gases closer to the ambient temperature. The use of waste energy of exhaust gases increases the efficiency and improves the performance of the system. The purpose of this paper is to make optimal use of gas turbine exhaust gases and use them to produce cooling in absorption chillers. And then analyze the thermodynamic and exergy performance of a triple hybrid system to generate electrical, heating and cooling energy. In this research, a hybrid cycle of a gas turbine and a fuel cell is considered as the primary actuator, and two single-effect and double-effect absorption chillers are considered as the secondary actuator. To perform this research, two proposed hybrid systems with their peripherals have been analyzed from a thermodynamic point. To have high accuracy results, in addition to thermodynamic analysis, the thermal and the electrochemical analysis has also been performed in order to the importance of the fuel cell in the hybrid system in this component. In the following, the effect of compressor pressure ratio, turbine inlet temperature, evaporator inlet water temperature, cooling tower inlet temperature and generator inlet temperature on energy and exergy efficiency, as well as exergy destruction rate in the system has been checked with the parametric study of the mentioned hybrid system. The results show that the increase in compressor pressure ratio causes the increase of electrical efficiency and exergy efficiency and the decrease of exergy destruction rate of the system. Also, if a double-effect absorption chiller is used instead of a single-effect absorption chiller, the energy efficiency and exergy will increase by 8% and 2%, respectively, and the exergy destruction rate will decrease by 5.4%. [ABSTRACT FROM AUTHOR]