Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman Energy, exergy, and economic evaluations of a CCHP system by using the internal combustion engines and gas turbine as prime movers Mohammad Abbasi, Mahmood Chahartaghi ⁎ , Seyed Majid Hashemian Faculty of Mechanical Engineering, Shahrood University of Technology, P.O.B. 3619995161, Shahrood, Iran ARTICLE INFO Keywords: CCHP Gas engine Gas turbine Energy analysis Economic analysis Exergy analysis ABSTRACT In this paper, a combined cooling, heating and power (CCHP) system has been designed under an electric charge supply strategy for a residential complex in Iran. The aim of this research is energy, exergy and economic analyses of the CCHP system with using different prime mover arrangements and presenting appropriate condition of its operation according to these viewpoints. For this purpose, three types of gas engine, diesel engine, and gas turbine as prime movers have been pre- sented and analyzed separately and simultaneously at six different scenarios and the appropriate scenario has been proposed for the CCHP system. In addition, the performance of system has been estimated at various part load conditions. The system is modeled and simulated using thermodynamic and economic relationships by using a computer code in the MATLAB software. The results show that the CCHP system under the electricity supply strategy with the simultaneous combination of two prime movers has significant advantages over one of them. The CCHP efficiency with two prime movers increases up to 10% compared to that of a single prime mover as well as the exergy efficiency. Additionally, scenario 4 by combining the gas engine and diesel engine is selected as the best scenario. It has 87% energy efficiency, 62.8% exergy efficiency, and operating cost reduction of about 80%. Also, the payback period is 6.3 years by taking interest rate into account and 1.36 years regardless of it. 1. Introduction By rise of the world's population, the need for energy supply is also increasing. On the other hand, due to increasing the pollutants and environmental hazards and low efficiency of power plants, the re- searchers seek new ways to supply energy [1]. Combined cooling, heating and power (CCHP) systems can significantly increase the en- ergy efficiency by generating electricity on site and recovering hot flue gas for heating, cooling or dehumidification [2]. Wee [3] identified natural gas (CH4) as the cleanest source of en- ergy among fossil fuels, following renewable energies such as hydro- electric power, solar energy, and etc. In order to reduce greenhouse gas emissions, he studied the hybrid systems of gas turbine and molten carbonate full cell as distributed energy sources. This hybrid system was considered due to higher power efficiency and by using molten carbo- nate fuel cells, a higher quality of electricity with efficiency of about 47% could be achieved. Chahartaghi and Alizadeh-Kharkeshi [4] in- vestigated the performance of a CCHP system in a research that their prime mover was the proton exchange membrane (PEM) fuel cell. Their results illustrated that the energy and exergy efficiencies, and fuel energy saving ratio (FESR) were 81.55%, 54.55% and 45%, respec- tively. Ebrahimi and Majidi [5] presented a combined cooling heating and power system with gas turbine as prime mover and the energy, exergy and environmental analyses were performed in their study. In addition a sensitivity analysis was presented to estimate the effect of main op- erating parameters on the system performance. Jradi et al. [6] examined all the prime movers and cooling systems that were capable for operating in a combined systems. They also stu- died a variety of recent strategies to optimize the performance of the CCHP system and to increase energy efficiency. Also, Roman et al. [7] studied three prime movers for a combined system and performed en- ergy, economic, and environmental analyses of the internal combustion engine, microturbine and fuel cells. They showed that the internal combustion engine and microturbine were suitable for the CCHP system. Their results for the CCHP system indicated a reduction in pollutant emissions and energy savings of more than 8% for both generators. Kim et al. [8] also explored the characteristics of gas turbine per- formance under part load conditions. Their results illustrated that by https://doi.org/10.1016/j.enconman.2018.07.095 Received 9 March 2018; Received in revised form 5 July 2018; Accepted 28 July 2018 ⁎ Corresponding author. E-mail address: chahartaghi@shahroodut.ac.ir (M. Chahartaghi). Energy Conversion and Management 173 (2018) 359–374 0196-8904/ © 2018 Elsevier Ltd. All rights reserved. T