Energetic and exergetic investigation of an organic Rankine cycle at different heat source temperatures

Li, Jing; Pei, Gang; Li, Yunzhu; Wang, Dongyue; Ji, Jie

Abstract

The energetic and exergetic performance of an updated ORC (organic Rankine cycle) is investigated. The thermal efficiencies of the ORC at different heat source temperatures of about 100, 90, 80, and 70°C are explored. The thermodynamic irreversibility that takes place in the evaporator, condenser, turbine, pump, and separator is revealed. The ORC feasibility for low-temperature applications is demonstrated. With a hot side temperature of around 80°C, a thermal efficiency of 7.4% and a turbine isentropic efficiency of 0.68 can be achieved. The present research further indicates that exergy destruction caused by heat transfer through an appreciable temperature difference in the evaporator is the largest in the energy conversion process, followed by that in the condenser. The exergy destroyed in the heat exchangers amounts to 74% of the overall exergy loss. The total system exergy efficiency is approximately 40%; thus, ways to improve exergy efficiency are required. HCFC-123, a dry fluid, is experimentally confirmed to be highly superheated after expansion in this study. A regenerator should be used to preheat HCFC-123 prior to entering the evaporator. Meanwhile the heat-transfer configuration with two oil cycles can be a good solution to overcome the thermodynamic disadvantage of a one-stage evaporator. © 2011 Elsevier Ltd.

Citation

Li, J., Pei, G., Li, Y., Wang, D., & Ji, J. (2012). Energetic and exergetic investigation of an organic Rankine cycle at different heat source temperatures. Energy, 38(1), 85-95. https://doi.org/10.1016/j.energy.2011.12.032

• Journal Article Type: Article
• Acceptance Date: Dec 22, 2011
• Online Publication Date: Jan 14, 2012
• Publication Date: 2012-02
• Deposit Date: Mar 24, 2022
• Journal: Energy
• Print ISSN: 0360-5442
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 38
• Issue: 1
• Pages: 85-95
• DOI: https://doi.org/10.1016/j.energy.2011.12.032
• Keywords: Organic Rankine cycle; Irreversibility; Energy conversion; Exergy loss
• Public URL: https://hull-repository.worktribe.com/output/3647573