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Hybridisation of solar and geothermal energy in both subcritical and supercritical Organic Rankine Cycles

Abstract

Highlights: • Hybrid solar and geothermal energy conversion system was modelled using subcritical and supercritical ORCs. • Solar thermal and geothermal energy can be effectively hybridised. • Greater thermodynamic advantages and economic benefits can be achieved using the supercritical hybrid plant. • Hybrid plants can produce up to 19% more annual electricity than the two stand-alone plants. • Solar-to-electricity cost in the supercritical hybrid plant is about 4–19% less than in the subcritical plant. - Abstract: A supercritical Organic Rankine Cycle (ORC) is renowned for higher conversion efficiency than the conventional ORC due to a better thermal match (i.e. reduced irreversibility) presented in the heat exchanger unit. This improved thermal match is a result of the obscured liquid-to-vapor boundary of the organic working fluid at supercritical states. Stand-alone solar thermal power generation and stand-alone geothermal power generation using a supercritical ORC have been widely investigated. However, the power generation capability of a single supercritical ORC using combined solar and geothermal energy has not been examined. This paper thus investigates the hybridisation of solar and geothermal energy in a supercritical ORC to explore the benefit from the potential synergies of such a hybrid platform. Its performances were also compared with those  More>>
Authors:
Publication Date:
May 01, 2014
Product Type:
Journal Article
Resource Relation:
Journal Name: Energy Conversion and Management; Journal Volume: 81; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Subject:
29 ENERGY PLANNING, POLICY AND ECONOMY; ECONOMIC ANALYSIS; ELECTRICITY; EXERGY; GEOTHERMAL ENERGY; GEOTHERMAL ENERGY CONVERSION; HEAT EXCHANGERS; HYBRIDIZATION; PERFORMANCE; POWER GENERATION; RANKINE CYCLE; SIMULATION; SOLAR ENERGY
OSTI ID:
22316393
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0196-8904; CODEN: ECMADL; Other: PII: S0196-8904(14)00115-0; TRN: GB15R1960022590
Availability:
Available from http://dx.doi.org/10.1016/j.enconman.2014.02.007
Submitting Site:
INIS
Size:
page(s) 72-82
Announcement Date:
Mar 19, 2015

Citation Formats

Zhou, Cheng. Hybridisation of solar and geothermal energy in both subcritical and supercritical Organic Rankine Cycles. United Kingdom: N. p., 2014. Web. doi:10.1016/J.ENCONMAN.2014.02.007.
Zhou, Cheng. Hybridisation of solar and geothermal energy in both subcritical and supercritical Organic Rankine Cycles. United Kingdom. https://doi.org/10.1016/J.ENCONMAN.2014.02.007
Zhou, Cheng. 2014. "Hybridisation of solar and geothermal energy in both subcritical and supercritical Organic Rankine Cycles." United Kingdom. https://doi.org/10.1016/J.ENCONMAN.2014.02.007.
@misc{etde_22316393,
title = {Hybridisation of solar and geothermal energy in both subcritical and supercritical Organic Rankine Cycles}
author = {Zhou, Cheng}
abstractNote = {Highlights: • Hybrid solar and geothermal energy conversion system was modelled using subcritical and supercritical ORCs. • Solar thermal and geothermal energy can be effectively hybridised. • Greater thermodynamic advantages and economic benefits can be achieved using the supercritical hybrid plant. • Hybrid plants can produce up to 19% more annual electricity than the two stand-alone plants. • Solar-to-electricity cost in the supercritical hybrid plant is about 4–19% less than in the subcritical plant. - Abstract: A supercritical Organic Rankine Cycle (ORC) is renowned for higher conversion efficiency than the conventional ORC due to a better thermal match (i.e. reduced irreversibility) presented in the heat exchanger unit. This improved thermal match is a result of the obscured liquid-to-vapor boundary of the organic working fluid at supercritical states. Stand-alone solar thermal power generation and stand-alone geothermal power generation using a supercritical ORC have been widely investigated. However, the power generation capability of a single supercritical ORC using combined solar and geothermal energy has not been examined. This paper thus investigates the hybridisation of solar and geothermal energy in a supercritical ORC to explore the benefit from the potential synergies of such a hybrid platform. Its performances were also compared with those of a subcritical hybrid plant, stand-alone solar and geothermal plants. All simulations and modelling of the power cycles were carried out using process simulation package Aspen HYSYS. The performances of the hybrid plant were then assessed using technical analysis, economic analysis, and the figure of merit analysis. The results of the technical analysis show that thermodynamically, the hybrid plant using a supercritical ORC outperforms the hybrid plant using a subcritical ORC if at least 66% of its exergy input is met by solar energy (i.e. a solar exergy fraction of >66%), namely producing 4–17% more electricity using the same energy resources. Exergy analysis shows that with a solar exergy fraction of more than 66% the exergetic efficiency of the hybrid plant is about 27–34% for the supercritical hybrid plant and 23–32% for the subcritical hybrid plant. The figure of merit analysis indicates that the hybrid plant produces a maximum of 15% (using a subcritical ORC) and 19% (using a supercritical ORC) more annual electricity than the two stand-alone plants. Economically, the hybrid plant using the supercritical ORC has a solar-to-electricity cost of approximately 1.5–3.3% less than those of the subcritical scenario.}
doi = {10.1016/J.ENCONMAN.2014.02.007}
journal = []
volume = {81}
journal type = {AC}
place = {United Kingdom}
year = {2014}
month = {May}
}