M. R. Salimpour - Department of Mechanical Engineering, Isfahan University of Technology, Isfahan
M. Arbab - Department of Mechanical Engineering, University of Kashan, Kashan, Isfahan, Iran
R. Yekkalam - Department of Mechanical Engineering, University of Kashan, Kashan, Isfahan, Iran

In the present study, a heat recovery steam generator (HRSG) used in a combined cycle power plant was analyzed based on the first and second laws of thermodynamics. For this purpose, an analytical procedure for HRSG thermal calculations at both design and off-design modes was developed and the effects of two HRSG prominent parameters i.e. pinch point and approach point, on the combined cycle performance were investigated. Based on the results, it was found that increasing pinch and approach points would decrease steam generation rate and second law of thermodynamics efficiency. Also, effects of pinch and approach points on the first law of thermodynamics efficiency of the HRSG were investigated.

Pinch point, approach point, HRSG, exergy, entropy