Exergy analysis of a combined vapor power cycle and boiler flue gas driven double effect water–LiBr absorption refrigeration system

• Published in: Energy conversion and management 2016-01, Vol.108, p.468-477
• Main Authors: Talukdar, K., Gogoi, T.K.
• Format: Article
• Language: English
• Subjects: Absorption; Boilers; Cooling systems; Double effect absorption refrigeration; Exergy; Flue gases; Generators; Refrigeration; Steam electric power generation; Vapor power cycle; Water–lithium bromide
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2015.11.020

•A combined vapor power and double effect water–LiBr absorption refrigeration system is proposed.•The flue gas of the power cycle boiler is the heat source for the double effect refrigeration system.•Energy and exergy analyses are performed to evaluate performance of the combined system.•Effect of high pressure generator temperature on combined system performance is highlighted.•Comparison is provided with a single effect absorption system integrated combined system. A combined vapor power cycle (PC) and double effect water–LiBr absorption refrigeration system (ARS) is proposed in this study. The boiler leaving flue gas of the PC is the heat source for the high pressure generator (HPG) of the double effect ARS. Exergy analysis of the proposed system is performed to show the performance variation of both the topping PC and the bottoming ARS with changing HPG temperature from 120°C to 150°C. Further the performance of double effect ARS integrated combined power and cooling system is compared with a similar system integrated with a single effect ARS. HPG temperature of the double effect ARS and generator temperature of the single effect ARS are considered as 120°C and 80°C respectively. Results show that the power and efficiency of the topping PC decreases with HPG temperature due to reduction in steam generation rate in the boiler. COP and exergy efficiency of the double effect ARS also reduces with increasing HPG temperature. The irreversible losses in the PC components decrease while the total irreversibility of the combined power and cooling system increases with HPG temperature due to increase in exergy loss with the HPG leaving flue gas and irreversibility of the ARS components. PC performance does not vary much due to replacement of the double effect ARS with the single effect ARS, however higher COP and exergy efficiency of the double effect system are achieved with much lower irreversible losses in the HPG and ARS condenser of the double effect system.