Title: Comparative exergy analysis of ammonia-water based Rankine cycles with and without regeneration

Authors: Kyoung Hoon Kim; Chul Ho Han; Kyoungjin Kim

Addresses: Department of Mechanical Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk 730-701, Korea ' Department of Intelligent Mechanical Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk 730-701, Korea ' Department of Mechanical System Engineering, Kumoh National Institute of Technology, 61 Daehak-ro, Gumi, Gyeongbuk 730-701, Korea

Abstract: Power generation systems using an ammonia-water mixture instead of water as working fluid have attracted much research interest over the past 20 years, since they have a potential to convert more energy in low-grade heat source into power and to improve the power generating processes in several ways. In this work comparative exergy analysis based on the second law of thermodynamics is carried out for ammonia-water based Rankine (AWR) and regenerative Rankine (AWRR) power generation cycles. Special attention is paid to analyse the effect of ammonia concentration in working fluid on the anergies in various system components including exhausted heat source and coolant, heat exchangers as well as the exergy efficiency. The analysis found that the anergies are significantly affected by ammonia concentration in working fluid. The main source for the anergy in the systems is strongly dependent on ammonia concentration and turbine inlet pressure, and it is quite different in AWR and AWRR systems.

Keywords: ammonia-water mixture; ammonia concentration; anergy; exergy analysis; Rankine cycle; regeneration; power generation; second law; thermodynamics; exhausted heat source; coolant; heat exchangers; exergy efficiency.

DOI: 10.1504/IJEX.2013.054117

International Journal of Exergy, 2013 Vol.12 No.3, pp.344 - 361

Received: 10 Feb 2012
Accepted: 23 Jun 2012
Published online: 23 May 2013 *

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