Energy, exergy, economic, and environmental (4E) analyses and optimization of a CCHP system with steam turbine

Abstract

Due to finding solutions to reduce energy consumption and improve the electricity production efficiency in the power cycles, using the waste heat of power cycles in the combined generation systems can be a useful approach. Also, by using the wasted energy of the power generation cycles, the cooling and heating demands can be met. Therefore, this study presents energy, exergy, economic, and environmental evaluations of a new configuration of combined cooling, heating, and power (CCHP) or tri-generation system with a steam turbine. This CCHP system includes a steam boiler, a steam turbine, a heat exchanger, a single-effect absorption chiller, and pumps. Some important performance parameters such as electrical efficiency, combined electrical and cooling efficiency, combined electrical and heating efficiency, and tri-generation efficiency, as well as exergy efficiency, are considered. Also, various output and environmental performance parameters such as percentage of operational cost reduction, percentage of fuel consumption reduction, percentage of pollutant emission reduction, and economic and technical issues based on different inlet temperatures and pressures of the steam turbine are investigated. In addition, the performance of the absorption chiller at different operating conditions has been investigated. This study shows that the usage of the CCHP system leads to reduction of 24.91% in carbon dioxide emission, 15.83% in fuel consumption, and 35.34% in operating costs compared with conventional systems. Also, the results show that there is a good improvement in the overall performance of the system with the tri-generation efficiency of 82.46%.