Organic rankine cycle with positive displacement expander and variable working fluid composition

Collings, P. and Yu, Z. (2016) Organic rankine cycle with positive displacement expander and variable working fluid composition. In: 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malaga, Spain, 11 - 13 Jul 2016, ISBN 9781775921240

Abstract

Organic Rankine Cycles are often used in the exploitation of low-temperature heat sources. The relatively small temperature differential available to these projects makes them particularly vulnerable to changing ambient conditions, especially if an air-cooled condenser is used. The authors have recently demonstrated that a dynamic ORC with a variable working fluid composition, tuned to match the condensing temperature with the heat sink, can be used to achieve a considerable increase in year-round power generation under such conditions [1]. However, this assumed the expander was a turbine capable of operating at multiple pressure ratios for large scale applications. This paper will investigate if small scale ORC systems that use positive-displacement expanders with fixed expansion ratios could also benefit from this new concept. In this paper, a numerical model was firstly developed. A comprehensive analysis was then conducted for a case study. The results showed that the dynamic Organic Rankine Cycle concept can be applied to lower-power applications that use that use positive-displacement expanders with fixed expansion ratios and still result in improvements in year-round energy generation.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Collings, Mr Peter and Yu, Professor Zhibin
• Authors: Collings, P., and Yu, Z.
• Subjects: T Technology > TJ Mechanical engineering and machinery
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > Systems Power and Energy
• Research Group: System Power and Energy
• ISBN: 9781775921240
• Copyright Holders: Copyright © 2016 The Authors
• First Published: First published in 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics Proceedings 2016
• Publisher Policy: Reproduced with the permission of the Editor

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