Regular Article

Energy, exergy, and economic analysis of a new triple-cycle power generation configuration and selection of the optimal working fluid

Department of Mechanical Engineering, Pardis Branch, Islamic Azad University, Pardis New City, Islamic Republic of Iran

^* e-mail: aliehyaei@yahoo.com

Received: 27 May 2018
Accepted: 22 March 2019

Abstract

The present study investigated energy, exergy and economic analyses on a new triple-cycle power generation configuration. In this configuration, the energy of the exhaust gas and the wasted energy in the condenser of the steam cycle is recovered in the heat recovery steam generator (HRSG) and the evaporator of organic Rankine cycle (ORC), respectively. A computer code was written in MATLAB to analyze the triple-cycle configuration. Validation through this program showed that the highest errors were 5.6 and 7.1%, which occurred in gas and steam cycles, respectively. The results revealed that the highest generated entropy was associated with the combustion chamber and the evaporator in the steam cycle. The first and second laws of thermodynamics efficiencies were improved by roughly 270 and 8%, respectively, through adding each of the steam and organic Rankine cycles. The entropy generated by the cycle increased by roughly 400 and 4% by adding the steam and organic Rankine cycles, respectively. The price of the produced electricity was also reduced by roughly 60 and 70%, respectively, for these two cycles.