Dynamic characteristics of a direct-heated supercritical carbon-dioxide Brayton cycle in a solar thermal power plant

Singh, Rajinesh, Miller, Sarah A., Rowlands, Andrew S. and Jacobs, Peter A. (2013) Dynamic characteristics of a direct-heated supercritical carbon-dioxide Brayton cycle in a solar thermal power plant. Energy, 50 194-204. doi:10.1016/j.energy.2012.11.029


Author Singh, Rajinesh
Miller, Sarah A.
Rowlands, Andrew S.
Jacobs, Peter A.
Title Dynamic characteristics of a direct-heated supercritical carbon-dioxide Brayton cycle in a solar thermal power plant
Journal name Energy   Check publisher's open access policy
ISSN 0360-5442
1873-6785
Publication date 2013-01-03
Year available 2013
Sub-type Article (original research)
DOI 10.1016/j.energy.2012.11.029
Volume 50
Start page 194
End page 204
Total pages 11
Place of publication London, United Kingdom
Publisher Elsevier
Collection year 2014
Language eng
Formatted abstract
The dynamics of a direct-heated closed Brayton power conversion system (PCS) with supercritical carbon-dioxide as the working-fluid (sCO2 PCS) is investigated in this study. Simulations of the dynamic response of the sCO2 PCS to changes in ambient air temperatures and solar energy input from parabolic trough collectors on representative days for summer and winter are presented. A control-oriented model describing sCO2 PCS dynamic behaviour has been constructed using mathematical models of heat-exchangers and turbomachinery. Changes in solar heat input causes movement of carbon-dioxide (CO2) mass between the hot and cold-sides of the PCS. Movement of mass results in variations in CO2 mass-flow rate, pressures, temperatures, and net-power output. The sCO2 PCS maintains a relatively stable net-power output when operating under conditions representative of an average day in summer with capped heat input. Turbine inlet temperatures rise well above nominal values due to reductions in CO2 mass-flow rates. A significant power output penalty is incurred on a winter day due to conditions at the compressor inlet becoming subcritical. The simulations highlight the potential for utilising CO2 charge manipulation for sCO2 PCS mass-flow rate control in summer, and the need for control of compressor inlet conditions in winter, for sustained fully supercritical operation of the PCS within allowable limits.
Keyword Closed Brayton cycle
Control
Dynamic modelling
Solar thermal power plant
Supercritical carbon-dioxide
Transient performance
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes Available online: 3 January 2013.

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mechanical & Mining Engineering Publications
Official 2014 Collection
 
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Created: Mon, 07 Jan 2013, 09:35:24 EST by Rajinesh Singh on behalf of School of Mechanical and Mining Engineering