Supercritical CO2 (S-CO2) power cycles offer the potential for better overall plant economics due to their high power conversion efficiency over a moderate range of heat source temperatures, compact size, and potential use of standard materials in construction. Sandia National Labs (Albuquerque, NM) and the U.S. Department of Energy (DOE-NE) are in the process of constructing and operating a megawatt-scale supercritical CO2 split-flow recompression Brayton cycle with contractor Barber-Nichols Inc. (Arvada, CO). This facility can be counted among the first and only S-CO2 power producing Brayton cycles anywhere in the world. The Sandia-DOE test-loop has recently concluded a phase of construction that has substantially upgraded the facility by installing additional heaters, a second recuperating printed circuit heat exchanger (PCHE), more waste heat removal capability, higher capacity load banks, higher temperature piping, and more capable scavenging pumps to reduce windage within the turbomachinery. With these additions, the loop has greatly increased its potential for electrical power generation, and its ability to reach higher temperatures. To date, the loop has been primarily operated as a simple recuperated Brayton cycle, meaning a single turbine, single compressor, and undivided flow paths. In this configuration, the test facility has begun to realize its upgraded capacity by achieving new records in turbine inlet temperature (650 °F/615 K), shaft speed (52,000 rpm), pressure ratio (1.65), flow rate (2.7 kg/s), and electrical power generated (20 kWe). Operation at higher speeds, flow rates, pressures, and temperatures has allowed a more revealing look at the performance of essential power cycle components in a supercritical CO2 working fluid, including recuperation and waste heat rejection heat exchangers (PCHEs), turbines and compressors, bearings and seals, as well as auxiliary equipment. In this report, performance of these components to date will be detailed, including a discussion of expected operational limits as higher speeds and temperatures are approached.

References

References
1.
Angelino
,
G.
, 1967, “
Perspectives for the Liquid Phase Compression Gas Turbine
,”
ASME J. Eng. Power, Trans.
,
89
(
2
), pp.
229
237
.
2.
Dostal
,
V.
, Driscoll, M., Hejzlar, P., 2004, “
A Supercritical Carbon Dioxide Cycle for Next Generation Nuclear Reactors
,” Massachusetts Institute of Technology. Dept. of Nuclear Engineering,
Cambridge
,
MA
, Paper No. MIT-ANP-TR-100.
3.
Wright
,
S.
, Conboy, T., and Rochau, G., 2011, “
Break-Even Power Transients for Two Simple Recuperated S-CO2 Brayton Cycle Test Configurations
,” Proceedings of the Supercritical CO2 Power Cycle Symposium,
Boulder
,
CO
, May 24–25.
4.
Wright
,
S.
,
Fuller
R.
, Noall, J., Radel, R., Vernon, M., and Pickard, P., 2008, “
Supercritical CO2 Brayton Cycle Compression and Control Near the Critical Point
,” Proceedings of International Congress on Advances in Nuclear Power Plants,
Anaheim, CA
, June 8–12.
5.
Barber-Nichols Incorporated, Arvada, CO, 2011, www.barber-nichols.comwww.barber-nichols.com
6.
Heatric, a Meggit Group, Dorset, UK, 2011, http://www.heatric.comhttp://www.heatric.com
7.
Noall
,
J.
, and
Forsha
,
M.
, 2008, “
Off-Design Turbomachinery Performance Mapping
,” Barber Nichols Inc., Internal Program Report.
8.
DellaCorte
,
C.
, Radil, K., Bruckner, R., and Howard, S., 2007, “
Design, Fabrication, and Performance of Open Source Generation I and II Compliant Hydrodynamic Gas Foil Bearings
,” NASA/TM-2007-214691, ARL-TR-4102 http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070022433_2007018412.pdfhttp://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070022433_2007018412.pdf
9.
Wright
,
S.
,
Pickard
,
P.
,
Vernon
,
M.
, and
Fuller
,
R.
, 2009, “
Turbomachinery Scaling Considerations for Supercritical CO2 Brayton Cycles
,” Level III Milestone Report to DOE.
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