A numerical analysis of a composition-adjustable Kalina cycle power plant for power generation from low-temperature geothermal sources

Wang, E. and Yu, Z. (2016) A numerical analysis of a composition-adjustable Kalina cycle power plant for power generation from low-temperature geothermal sources. Applied Energy, 180, pp. 834-848. (doi: 10.1016/j.apenergy.2016.08.032)

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The Kalina cycle is believed to be one of the most promising technologies for power generation from low temperature heat sources such as geothermal energy. So far, most Kalina cycle power plants are designed with a working fluid mixture having a fixed composition, and thus normally operate at a fixed condensing temperature. However, the ambient temperature (i.e., heat sink) varies over a large range as the season changes over a year, particularly in continental climates. Recently, a new concept, i.e., composition-adjustable Kalina cycle, was proposed to develop power plants that can match their condensing temperature with the changing ambient conditions, aiming at improving the cycle’s overall thermal efficiency. However, no detailed analysis of its implementation and the potential benefits under various climate conditions has been reported. For this reason, this paper carried out a comprehensive numerical research on its implementation and performance analysis under several different climate conditions. A mathematical model is firstly established to simulate the working principle of a composition-adjustable Kalina cycle, based on which a numerical program is then developed to analyse the cycle’s performance under various climate conditions. The developed numerical model is verified with some published experimental data. The 2 dynamic composition adjustment in response to the changing ambient temperature is simulated to evaluate its effect on the plant’s performance over a year. The results show that a composition-adjustable Kalina cycle could achieve higher annual-average thermal efficiency than a conventional one with a fixed mixture composition. However, such an improvement of thermal efficiency strongly depends on the heat source temperature, climate conditions, etc. The composition-adjusting system introduces extra capital and operation costs. The economic viability of a composition-adjustable Kalina cycle power plant depends on the balance between these extra costs and the increase of thermal efficiency.

Item Type:Articles
Additional Information:This research is funded by Royal Society (RG130051) and EPSRC (EP/N005228/1) in the United Kingdom, and a joint programme ‘‘Royal Society–National Natural Science Foundation of China (Ref: IE150866)
Glasgow Author(s) Enlighten ID:Yu, Professor Zhibin and Wang, Dr Enhua
Authors: Wang, E., and Yu, Z.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Applied Energy
ISSN (Online):1872-9118
Published Online:13 August 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Applied Energy 180:834-848
Publisher Policy:Reproduced under a creative commons license

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
684301Dynamic Organic Rankine Cycle for Recovering Industrial Waste HeatZhibin YuEngineering & Physical Sciences Research Council (EPSRC)EP/N005228/1ENG - ENGINEERING SYSTEMS POWER & ENERGY
642241Investigating zeotropic mixtures as working fluids for high efficiency Organic Rankine Cycle (ORC) power plantsZhibin YuRoyal Society (ROYSOC)RG130051ENG - ENGINEERING SYSTEMS POWER & ENERGY