In the present study, an experimental testing facility is created to analyze the heat losses from the cylindrical solar cavity. Tests are carried out under the temperature range from 225 °C to 425 °C for a cavity inclination from θ = 0–90 deg in steps of 30 deg. It is observed that for off-flux investigation of solar cavity receiver, near isothermal wall temperature condition can be realized with the differential heating arrangement. The total loss is found to be the highest when the cavity aperture is positioned at sideways (θ = 0 deg). It decreases by 43–51% when the cavity is inclined (θ = 90 deg). The conduction loss is found to be accounted for up to 32–34% of the total heat loss, whereas the cavity radiative loss is estimated to be 13%, 16%, and 20% of the total heat loss, respectively, for cavity wall temperature 225 °C, 325 °C, and 425 °C. The investigation of convective losses showed significant change with cavity tilt angles. It is 46–54% of the total heat loss when the cavity aperture is facing sideways (θ = 0 deg), whereas its value reduces up to 4% of the total heat loss when the cavity aperture is facing downward (θ = 90 deg). A Nusselt number correlation has been developed for predicting the convective heat loss from a open cavity. The Nusselt number correlation correlates 100% of data within ± 20% deviation.

References

References
1.
Harris
,
J. A.
, and
Lenz
,
T. G.
,
1985
, “
Thermal Performance of Solar Concentrator/Cavity Receiver Systems
,”
Sol. Energy
,
34
(
2
), pp.
135
142
.
2.
D'Utruy
,
B.
,
Blay
,
D.
, and
Coeytaux
,
M.
,
1978
, “
The French CNRS 1 MW Solar Power Plant
,”
International Solar Energy Society Congress
, New Delhi, Pergamon Press, New York, Vol.
3
, pp.
1701
1705
.
3.
Umarov
,
Y. I.
,
Fattakhov
,
A. A.
,
Umarov
,
A. G.
,
Trukhov
,
V. S.
,
Tursunbaev
,
I. A.
,
Sokolova
,
Y. B.
, and
Gaziev
,
Y. K.
,
1983
, “
Heat Loss in a Cavity-Type Solar Collector
,”
Geliotekhnika (Appl. Sol. Energy)
,
19
(
3
), pp.
43
47
.
4.
Taumoefolau
,
T.
, and
Lovegrove
,
K.
,
2002
, “
An Experimental Study of Natural Convection Heat Loss From a Solar Concentrator Cavity Receiver at Varying Orientation
,” Solar 2002,
ANZSES Annual Conference
, Newcastle, Australia, Nov. 27–29.
5.
Paitoonsurikarn
,
S.
, and
Lovegrove
,
K.
,
2002
, “
Numerical Investigation of Natural Convection Loss in Cavity-Type Solar Receivers
,” Solar 2002,
ANZSES Annual Conference
, Newcastle, Australia, Nov. 27–29.
6.
Paitoonsurikarn
,
S.
, and
Lovegrove
,
K.
,
2003
, “
On the Study of Convection Loss From Open Cavity Receivers in Solar Paraboloidal Dish Applications
,” Solar 2003,
ANZSES Annual Conference
, Melbourne, Australia, Nov. 26–29.
7.
Paitoonsurikarn
,
S.
, and
Lovegrove
,
K.
,
2006
, “
A New Correlation for Predicting the Free Convection Loss From Solar Dish Concentrating Receivers
,”
Solar 2006: Clean Energy?-Can Do!
ANZSES Annual Conference
, Canberra, Australia, Sept. 13–15.
8.
Paitoonsurikarn
,
S.
,
Taumoefolau
,
T.
, and
Lovegrove
,
K.
,
2004
, “
Estimation of Convection Loss From Paraboloidal Dish Cavity Receivers
,”
Solar 2004: Life, the Universe and Renewables, 42nd
ANZSES
Annual Conference, Perth, Australia, Nov. 30–Dec. 3.
9.
Taumoefolau
,
T.
,
Paitoonsurikarn
,
S.
,
Hughes
,
G.
, and
Lovegrove
,
K.
,
2004
, “
Experimental Investigation of Natural Convection Heat Loss From a Model Solar Concentrator Cavity Receiver
,”
ASME J. Sol. Energy Eng.
,
126
(
2
), pp.
801
807
.
10.
Melchior
,
E.
,
1989
, “
Receiver Concepts and Design-Construction and Tests of Components
,”
GAST (The Gas Cooled Solar Tower Technology Program)
,
M.
Becker
and
M.
Bohmer
, eds.,
Springer-Verlag
,
Berlin
.
11.
Prakash
,
M.
,
Kedare
,
S. B.
, and
Nayak
,
J. K.
,
2009
, “
Investigations on Heat Losses From a Solar Cavity Receiver
,”
Sol. Energy
,
83
(
2
), pp.
157
170
.
12.
Prakash
,
M.
,
Kedare
,
S. B.
, and
Nayak
,
J. K.
,
2010
, “
Determination of Stagnation and Convective Zones in a Solar Cavity Receiver
,”
Int. J. Therm. Sci.
,
49
(
4
), pp.
680
691
.
13.
Ryu
,
S.
, and
Seo
,
T.
,
2000
, “
Estimation of Heat Losses From the Receivers for Solar Energy Collecting System
,”
KSME Int. J.
,
14
(
12
), pp.
1403
1411
.
14.
Seo
,
T.
,
Ryu
,
S.
, and
Kang
,
Y.
,
2003
, “
Heat Losses From the Receivers of a Multifaceted Parabolic Solar Energy Collecting System
,”
KSME Int. J.
,
17
(
8
), pp.
1185
1195
.
15.
Kugath
,
D. A.
,
Drenker
,
G.
, and
Koenig
,
A. A.
,
1979
, “
Design and Development of a Paraboloidal Dish Solar Collector for Intermediate Temperature Service
,”
International Solar Energy Society, Silver Jubilee Congress
(
SUN II
), K. W. Böer and B. H. Glenn, eds., Atlanta, GA, Pergamon Press, New York, Vol.
1
, pp.
449
453
.
16.
Lezhebokov
,
A. I.
,
Sokolova
,
Y. B.
, and
Trukhov
,
V. S.
,
1986
, “
Heat Losses From a Receiver of Concentrated Radiation in a Solar Energy Unit With a Thermodynamic Transducer
,”
Geliotekhnika (Appl. Sol. Energy)
,
22
(
2
), pp.
34
38
.
17.
Stine
,
W. B.
, and
McDonald
,
C. G.
,
1988
, “
Cavity Receiver Heat Loss Measurements
,” ASME Solar Energy Division Conference, Denver, CO, Apr. 10–14.
18.
Stine
,
W. B.
, and
McDonald
,
C. G.
,
1989
, “
Cavity Receiver Convective Heat Loss
,”
International Solar Energy Society Solar World Congress
, T. Horigome, ed., Kobe, Japan, Sept. 4–8, Pergamon Press, Oxford, London, Vol.
2
, pp.
1318
1322
.
19.
Ma
,
R. Y.
,
1993
, “
Wind Effects on Convective Heat Loss From a Cavity Receiver for Parabolic Concentrating Solar Collector
,” Contractor Report, Sandia National Laboratories, Albuquerque, NM, Report No.
SAND92-7293
.
20.
McDonald
,
C. G.
,
1995
, “
Heat Loss From an Open Cavity
,” Sandia National Laboratories Report, Report No.
SAND95-2939
.
21.
Leibfried
,
U.
, and
Ortjohann
,
J.
,
1995
, “
Convective Heat Loss From Upward and Downward-Facing Cavity Solar Receivers: Measurements and Calculations
,”
ASME J. Sol. Energy Eng.
,
117
(
2
), pp.
75
84
.
22.
Kumar
,
S.
, and
Reddy
,
K. S.
,
2008
, “
Comparison of Receivers for Solar Dish Collector System
,”
Energy Convers. Manage.
,
49
(
4
), pp.
812
819
.
23.
Perez-Rabago
,
C. A.
,
Marcos
,
M. J.
,
Romero
,
M.
, and
Estrada
,
C. A.
,
2008
, “
Heat Transfer in a Conical Cavity Calorimeter for Measuring Thermal Power of a Point Focus Concentrator
,”
Sol. Energy
,
80
(11), pp.
1434
1442
.
24.
Kumar
,
S.
, and
Reddy
,
K. S.
,
2007
, “
Numerical Investigation of Natural Convection Heat Loss in Modified Cavity Receiver for Fuzzy Focal Solar Dish Concentrator
,”
Sol. Energy
,
81
(
7
), pp.
846
855
.
25.
Reddy
,
K. S.
, and
Kumar
,
S.
,
2009
, “
An Improved Model for Natural Convection Heat Loss From Modified Cavity Receiver of Solar Dish Concentrator
,”
Sol. Energy
,
83
(
10
), pp.
1884
1892
.
26.
Williams
,
O. M.
,
1980
, “
Design and Cost Analysis for an Ammonia-Based Solar Thermochemical Cavity Absorber
,”
Sol. Energy
,
24
(
3
), pp.
255
263
.
27.
CliqueSolar
, 2016, private communication.
You do not currently have access to this content.