Technical and Environmental Assessment of a Combined Heat and Power Rankine Cycle System Based on Natural Gas Boiler

Hajinezhad, Ahmad; Yousefi, Hossein; Moltames, Rahim; Fattahi, Reza; Fathi, Amirhossein

doi:10.22109/jemt.2022.343968.1387

Technical and Environmental Assessment of a Combined Heat and Power Rankine Cycle System Based on Natural Gas Boiler

Document Type : Original Article

Authors

Ahmad Hajinezhad ¹

Hossein Yousefi ¹

Rahim Moltames ¹

Reza Fattahi ¹

Amirhossein Fathi ²

¹ Dept. of Renewable Energy and Environmental Eng., Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran

² School of Mechanical Engineering, Shiraz University, Shiraz, Iran

10.22109/jemt.2022.343968.1387

Abstract

In this paper, a Rankin cycle-based heat and power generation system is simulated. The input energy of the system is supplied by the combustion of natural gas in the boiler. Condenser heat recovery is used to supply thermal energy and on the other hand, the power generated by the turbine is used to supply electricity demand. The first and second laws of thermodynamics and the law of conservation of mass are used to analyze the energy and exergy performance of the system. Finally, the effect of changing each of the performance parameters on the energy and CO2 emission of the system is investigated. According to the results, the turbine output power, net power production, electrical efficiency, energy efficiency, exergy efficiency, and CO2 production is obtained as 354.63 kW, 353.53 kW, 24.23%, 94.92%, 74.38%, and 81.1 g/s, respectively. Furthermore, the simulation results show that increasing the turbine inlet temperature increases electrical efficiency and exergy. Increasing the condenser outlet temperature also reduces electrical and exergy efficiency. On the other hand, increasing natural gas consumption only increases CO2 production and does not affect electrical, energy, and exergy efficiencies.

Keywords

Cogeneration system

Rankine cycle

energy and exergy analysis

environment