Title: First- and second-law analyses of thermal power plants in connection with irreversibility ratio

Authors: Ahmet Z. Sahin; Bekir S. Yilbas

Addresses: Mechanical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran, 31261 Saudi Arabia ' Mechanical Engineering Department, King Fahd University of Petroleum and Minerals, Dhahran, 31261 Saudi Arabia

Abstract: The rigorous assessment of thermal characteristics of power plants is important for the cost-effective operations. Thermodynamic analysis of the first- and the second-law efficiencies can be merged through the irreversibility ratio (IR = T0gen/Q˙H), which provides useful information on the thermal system characteristics and reduces the efforts for the thermal analysis. In this study, thermodynamic analysis of a power plant is carried out and the first- and the second-law efficiencies are formulated simultaneously incorporating the irreversibility ratio. The maximum output power and the maximum first- and second-law efficiencies are formulated. The effect of temperature ratio and irreversibility ratio on the output power as well as the first- and the second-law efficiencies is investigated. It is found that the influence of the irreversibility ratio is higher on the second-law efficiency than that of the first-law efficiency, which is more pronounced at low values of the temperature ratio (θ ≤ 0.6).

Keywords: thermal power plants; second law efficiency; irreversibility ratio; thermodynamics; first law efficiency; exergy efficiency.

DOI: 10.1504/IJEX.2015.072896

International Journal of Exergy, 2015 Vol.18 No.3, pp.356 - 366

Received: 20 Aug 2014
Accepted: 16 Nov 2014

Published online: 06 Nov 2015 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article