Energy and exergy evaluation of a new bi-evaporator electricity/cooling cogeneration system fueled by biogas

Bi-evaporator electricity/cooling cogeneration systems can be a favorable addition to the integrated power plants since the generated cooling load should be addressed for different demands. More consequentially, taking advantage of such an integral set-up operated with highly reliable heat source such as biogas can be appreciable for nowadays industries. Regarding this demand, an innovative bi-evaporator electricity/cooling cogeneration system is introduced at first. Next, the suggested system is integrated with a gas turbine cycle fueled by biogas. In the subsequent part, the plausibility of the introduced integrated power plant is examined from first and second laws of thermodynamics (as the most robust tools in performance evaluation of energy systems) under steady state condition and using Engineering Equation Solver (EES) software. It was exhibited that the recommended system could generate overall cooling load and net electricity of 505.2 kW and 1168 kW, correspondingly, achieving energetic efficiency of 54.54% and exergetic efficiency of 36.83%. It was substantiated that integrating the introduced cogeneration system with biogas-fueled gas turbine cycle could improve the basic performance up to 67.3% (from the 1st law of thermodynamics) and 19.15% (from the 2nd law of thermodynamics). The outcomes of the second law analysis portrayed that among all components, the combustion chamber attributes as the utmost destructive part of the system, followed by the vapor generator. Also, to examine how the introduced set-up reacts to any external disturbances, a comprehensive sensitivity examination around the basic operating input parameters was fulfilled. It is discovered that performance of the integrated system could be maximized with respect to the air compressor pressure ratio. (C) 2019 Elsevier Ltd. All rights reserved.