Concrete is tested as a sensible heat thermal energy storage (TES) material in the temperature range of 400–500 °C (752–932 °F). A molten nitrate salt is used as the heat transfer fluid (HTF); the HTF is circulated though stainless steel heat exchangers, imbedded in concrete test prisms, to charge the TES system. During charging, significant cracking occurs in both the radial and longitudinal directions in the concrete prisms. The cracking is due to hoop stress induced by the dissimilar thermal strain rates of concrete and stainless steel. A 2D finite element model (FEM) is developed and used to study the stress at the prism/exchanger interface. Polytetrafluoroethylene (PTFE) and a heat-curing, fibered paste (HCFP) are tested as interface materials to mitigate the stress in the concrete. Significant reduction in the size and number of cracks is observed after incorporating interface materials. A heat exchanger with a helical fin configuration is incorporated to improve the heat transfer rate in the concrete. Testing confirms that the fins increase the rate of heat transfer in the concrete; however, large cracks form at each of the fin locations. Only the HCFP is tested as an interface material for the finned heat exchanger. The HCFP decreases the number and size of the cracks, however, not to the desired hairline levels.

References

References
1.
DOE
,
2011
, “
Thermal Storage Research and Development
,” Solar Energy Technologies Program, U.S. Department of Energy, http://www1.eere.energy.gov/solar/thermal_storage_rnd.html
2.
Herrmann
,
U.
, and
Kearney
,
D.
,
2002
, “
Survey of Thermal Energy Storage for Parabolic Trough Power Plants
,”
ASME J. Sol. Energy Eng.
,
124
(
2
), pp.
145
152
.10.1115/1.1467601
3.
Laing
,
D.
,
Steinmann
,
W.-D.
,
Tamme
,
R.
, and
Richter
,
C.
,
2006
, “
Solid Media Thermal Storage for Parabolic Trough Power Plants
,”
Sol. Energy
,
80
, pp.
1283
1289
.10.1016/j.solener.2006.06.003
4.
Laing
,
D.
,
Steinmann
,
W.-D.
,
FiB
,
M.
,
Tamme
,
R.
,
Brand
,
T.
, and
Bahl
,
C.
,
2008
, “
Solid Media Thermal Storage Development and Analysis of Modular Storage Operation Concepts for Parabolic Trough Power Plants
,”
ASME J. Sol. Energy Eng.
,
130
, p.
011006
.10.1115/1.2804625
5.
Laing
,
D.
,
Lehmann
,
D.
,
Fiss
,
M.
, and
Bahl
,
C.
,
2009
, “
Test Results of Concrete Thermal Energy Storage for Parabolic Trough Power Plants
,”
ASME J. Sol. Energy Eng.
,
131
(
4
), p.
041007
.10.1115/1.3197844
6.
Laing
,
D.
,
Bauer
,
T.
,
Lehmann
,
D.
, and
Bahl
,
C.
,
2010
, “
Development of a Thermal Energy Storage System for Parabolic Trough Power Plants With Direct Steam Generation
,”
ASME J. Sol. Energy Eng.
,
132
, p.
021011
.10.1115/1.4001472
7.
John
,
E. E.
,
Hale
,
W. M.
, and
Selvam
,
R. P.
,
2010
, “
Effect of High Temperatures and Heating Rates on High Strength Concrete for Use as Thermal Energy Storage
,” ASME 4th International Conference on Energy Sustainability, Phoenix, AZ, May 17–22,
ASME
Paper No. ES2010-90096, pp. 709–713.10.1115/ES2010-90096
8.
Selvam
,
R. P.
, and
Castro
,
M.
,
2010
, “
3D FEM Model to Improve the Heat Transfer in Concrete for Thermal Energy Storage in Solar Power Generation
,” ASME 4th International Conference on Energy Sustainability, Phoenix, AZ, May 17–22,
ASME
Paper No. ES2010-90078, pp. 699–707.10.1115/ES2010-90078
9.
Coastal Chemical Company L.L.C.
,
2010
, “
Hitec Solar Salt
,” http://www.coastalchem.com/PDFs/HITECSALT/Hitec%20Solar%20Salt.pdf
10.
Nilson
,
A. H.
,
Darwin
,
D.
, and
Dolan
,
C. W.
,
2004
,
Design of Concrete Structures
,
McGraw-Hill Higher Education
,
Boston
.
11.
Selvam
,
R. P.
,
2011
, private communication.
12.
Deacon Industries,
2010
, “
Deacon 885 High Temperature Gasket Paste
,” http://www.deaconindustries.com/8875_tech.html
13.
Mehta
,
P. K.
, and
Monteiro
,
P. J. M.
,
2006
,
Concrete: Microstructure, Properties, and Materials
,
McGraw-Hill
,
New York
.
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