For the concentrating solar power (CSP) applications, the supercritical carbon dioxide (s-CO2) power cycle is beneficial in many aspects, including high cycle efficiencies, reduced component sizing, and potential for the dry cooling option. More research is involved in improving this technology to realize the s-CO2 cycle as a candidate to replace the conventional power conversion systems for CSP applications. In this study, an isothermal compressor, a turbomachine which undergoes the compression process at constant temperature to minimize compression work, is applied to the s-CO2 power cycle layout. To investigate the cycle performance changes of adopting the novel technology, a framework for defining the efficiency of the isothermal compressor is revised and suggested. This study demonstrates how the compression work for the isothermal compressor is reduced, up to 50%, compared to that of the conventional compressor under varying compressor inlet conditions. Furthermore, the simple recuperated and recompression Brayton cycle layouts using s-CO2 as a working fluid are evaluated for the CSP applications. Results show that for compressor inlet temperatures (CIT) near the critical point, the recompression Brayton cycle using an isothermal compressor has 0.2–1.0% point higher cycle thermal efficiency compared to its reference cycle. For higher CIT values, the recompression cycle using an isothermal compressor can perform above 50% in thermal efficiency for a wider range of CIT than the reference cycle. Adopting an isothermal compressor in the s-CO2 layout can imply larger heat exchange area for the compressor which requires further development.

References

References
1.
Dostal
,
V.
,
Driscoll
,
M. J.
, and
Hejzlar
,
P.
,
2004
, “
A Supercritical Carbon Dioxide Cycle for Next Generation Nuclear Reactors
,” Advanced Nuclear Power Technology Program, MIT, Cambridge, MA, Report No. MIT-ANP-TR-100.
2.
SunShot Vision Study
,
2012
, “Sunshot Vision Study,” U.S. Department of Energy, Washington, DC, accessed May 5, 2017, www.energy.gov/eere/sunshot/sunshot-vision-study
3.
Turchi
,
C. S.
,
Zhiwen
,
M.
,
Ty W
,
N.
, and
Wagner
,
M. J.
,
2013
, “
Thermodynamic Study of Advanced Supercritical Carbon Dioxide Power Cycles for Concentrating Solar Power Systems
,”
ASME J. Sol. Energy Eng.
,
135
(
4
), p.
041007
.
4.
Çengel
,
Y. A.
, and
Michael
,
A B.
,
2012
,
Thermodynamics: An Engineering Approach
,
McGraw-Hill
,
New York
.
5.
Moore
,
J.
, and
Nored
,
M. G.
, 2008, “
Novel Concepts for the Compression of Large Volumes of Carbon Dioxide
,”
ASME
Paper No. GT2008-50924.
6.
Heo
,
J.
,
Ahn
,
Y.
, and
Lee
,
J. A.
, 2016, “
Study of S-CO2 Power Cycle for Waste Heat Recovery Using Isothermal Compressor
,”
ASME
Paper No. GT2016-57151.
7.
Lemmon
,
E. W.
,
Huber
,
M. L.
, and
McLinden
,
M. O.
,
2013
, “
NIST Standard Reference Database 23: Reference Fluid Thermodynamic and Transport Properties-REFPROP
,”
National Institute of Standards and Technology
, Gaithersburg, MD.https://www.nist.gov/publications/nist-standard-reference-database-23-reference-fluid-thermodynamic-and-transport
8.
Lee
,
J.
,
Seungjoon
,
B.
,
Seong
,
K. C.
,
Jae
,
E. C.
, and
Jeong Ik
,
L.
,
2016
, “
Issues in Performance Measurement of CO2 Compressor Near the Critical Point
,”
Appl. Therm. Eng.
,
94
, pp.
111
121
.
9.
Kim
,
M. S.
,
Ahn
,
Y.
,
Kim
,
B.
, and
Lee
,
J. I.
,
2016
, “
Study on the Supercritical CO2 Power Cycles for Landfill Gas Firing Gas Turbine Bottoming Cycle
,”
Energy
,
111
, pp.
893
909
.
10.
Neises
,
T.
, and
Turchi
,
C.
,
2014
, “
A Comparison of Supercritical Carbon Dioxide Power Cycle Configurations With an Emphasis on CSP Applications
,”
Energy Procedia
,
49
, pp.
1187
1196
.
11.
Musgrove
,
G.
,
LePierres
,
R.
, and
Nash
,
J.
,
2014
, “
Heat Exchangers for Supercritical CO2 Power Cycle Applications
,”
The Fourth International Symposium on Supercritical CO2 Power Cycles
, Pittsburgh, PA, Sept. 9–10.http://sco2symposium.com/www2/sco2/papers2016/Tutorials/HeatExchanger.pdf
12.
Kulhánek
,
M.
, and
Dostal
,
V.
,
2011
, “
Thermodynamic Analysis and Comparison of Supercritical Carbon Dioxide Cycles
,”
Supercritical CO2 Power Cycle Symposium
, Boulder, CO, May 24–25.http://www.sco2powercyclesymposium.org/resource_center/system_concepts/thermodynamic-analysis-and-comparison-of-supercritical-carbon-dioxide-cycles
13.
Kolb
,
G. J.
,
Ho
,
C. K.
,
Mancini
,
T. R.
, and
Gary
,
J. A.
,
2011
, “
Power Tower Technology Roadmap and Cost Reduction Plan
,” Sandia National Laboratories, Albuquerque, NM, Report No.
SAND2011-2419
.http://prod.sandia.gov/techlib/access-control.cgi/2011/112419.pdf
14.
Baik
,
S.
,
Kim
,
S. G.
,
Bae
,
S. J.
,
Ahn
,
Y.
,
Lee
,
J.
, and
Lee
,
J. I.
,
2015
, “
Preliminary Experimental Study of Precooler in Supercritical CO2 Brayton Cycle
,”
ASME
Paper No. GT2015-42915.
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