The effects of tube layout on the heat losses of solar cavity receiver were numerically investigated. Two typical tube layouts were analyzed. For the first tube layout, only the active surfaces of cavity were covered with tubes. For the second tube layout, both the active cavity walls and the passive cavity walls were covered with tubes. Besides, the effects of water–steam circulation mode on the heat losses were further studied for the second tube layout. The absorber tubes on passive surfaces were considered as the boiling section for one water–steam circulation mode and as the preheating section for the other one, respectively. The thermal performance of the cavity receiver with each tube layout was evaluated according to the previous calculation model. The results show that the passive surfaces appear to have much lower heat flux than the active ones. However, the temperature of those surfaces can reach a quite high value of about 520 °C in the first tube layout, which causes a large amount of radiative and convective heat losses. By contrast, the temperature of passive surfaces decreases by about 200–300 °C in the second tube layout, which leads to a 38.2–70.3% drop in convective heat loss and a 67.7–87.7% drop in radiative heat loss of the passive surfaces. The thermal efficiency of the receiver can be raised from 82.9% to 87.7% in the present work.

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.
Jilte
,
R. D.
,
Kedare
,
S. B.
, and
Nayak
,
J. K.
,
2014
, “
Investigation on Convective Heat Losses From Solar Cavities Under Wind Conditions
,”
Energy Procedia
,
57
, pp.
437
446
.
3.
Wang
,
F. Q.
,
Lin
,
R. Y.
,
Liu
,
B.
,
Tan
,
H. P.
, and
Shuai
,
Y.
,
2013
, “
Optical Efficiency Analysis of Cylindrical Cavity Receiver With Bottom Surface Convex
,”
Sol. Energy
,
90
, pp.
195
204
.
4.
Steinfeld
,
A.
, and
Schubnell
,
M.
,
1993
, “
Optimum Aperture Size and Operating Temperature of a Solar Cavity Receiver
,”
Sol. Energy
,
50
(
1
), pp.
19
25
.
5.
Ngo
,
L. C.
,
Bello-Ochende
,
T.
, and
Meyer
,
J. P.
,
2015
, “
Numerical Modeling and Optimisation of Natural Convection Heat Loss Suppression in a Solar Cavity Receiver With Plate Fins
,”
Renewable Energy
,
74
, pp.
95
105
.
6.
Abbasi-Shavazi
,
E.
,
Hughes
,
G. O.
, and
Pye
,
J. D.
,
2015
, “
Investigation of Heat Loss From a Solar Cavity Receiver
,”
Energy Procedia
,
69
, pp.
269
278
.
7.
Flesch
,
R.
,
Grobbel
,
J.
,
Stadler
,
H.
,
Uhlig
,
R.
, and
Hoffschmidt
,
B.
,
2016
, “
Reducing the Convective Losses of Cavity Receivers
,”
AIP Conf. Proc.
,
1734
(
1
), pp.
801
807
.
8.
Kumar
,
N. 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
.
9.
Ma
,
R. Y.
,
1993
, “
Wind Effects on Convective Heat Loss From a Cavity Receiver for a Parabolic Concentrating Solar Collector
,” Sandia National Laboratories, Albuquerque, NM, Report No.
SAND92-7293
.http://energy.sandia.gov/wp-content/gallery/uploads/SAND92-7293_wind_effects_on_cavity.pdf
10.
Flesch
,
R.
,
Stadler
,
H.
,
Uhlig
,
R.
, and
Pitz-Paal
,
R.
,
2014
, “
Numerical Analysis of the Influence of Inclination Angle and Wind on the Heat Losses of Cavity Receivers for Solar Thermal Power Towers
,”
Sol. Energy
,
110
, pp.
427
437
.
11.
Hinojosa
,
J. F.
,
Cabanillas
,
R. E.
,
Alvarez
,
G.
, and
Estrada
,
C. E.
,
2005
, “
Nusselt Number for the Natural Convection and Surface Thermal Radiation in a Square Tilted Open Cavity
,”
Int. Commun. Heat Mass Transfer
,
32
(
9
), pp.
1184
1192
.
12.
Reddy
,
K. S.
,
Veershetty
,
G.
, and
Vikram
,
T. S.
,
2016
, “
Effect of Wind Speed and Direction on Convective Heat Losses From Solar Parabolic Dish Modified Cavity Receiver
,”
Sol. Energy
,
131
, pp.
183
198
.
13.
Wu
,
S. Y.
,
Guo
,
F. H.
, and
Xiao
,
L.
,
2014
, “
Numerical Investigation on Combined Natural Convection and Radiation Heat Losses in One Side Open Cylindrical Cavity With Constant Heat Flux
,”
Int. J. Heat Mass Transfer
,
71
, pp.
573
584
.
14.
Shen
,
Z. G.
,
Wu
,
S. Y.
,
Xiao
,
L.
,
Li
,
D. L.
, and
Wang
,
K.
,
2015
, “
Experimental and Numerical Investigations of Combined Free Convection and Radiation Heat Transfer in an Upward-Facing Cylindrical Cavity
,”
Int. J. Therm. Sci.
,
89
, pp.
314
326
.
15.
Fang
,
J. B.
,
Wei
,
J. J.
,
Dong
,
X. W.
, and
Wang
,
Y. S.
,
2011
, “
Thermal Performance Simulation of a Solar Cavity Receiver Under Windy Conditions
,”
Sol. Energy
,
85
(
1
), pp.
126
138
.
16.
Kim
,
J. S.
,
Liovic
,
P.
,
Too
,
Y. C. S.
,
Hart
,
G.
, and
Stein
,
W.
,
2011
, “
CFD Analysis of Heat Loss From 200 kW Cavity Reactor
,”
SolarPACES Conference
, Granada, Spain, Sept. 20–23.
17.
Li
,
X.
,
Kong
,
W. Q.
,
Wang
,
Z. F.
,
Chang
,
C.
, and
Bai
,
F. W.
,
2010
, “
Thermal Model and Thermodynamic Performance of Molten Salt Cavity Receiver
,”
Renewable Energy
,
35
(
5
), pp.
981
988
.
18.
Teichel
,
S. H.
,
Feierabend
,
L.
,
Klein
,
S. A.
, and
Reindl
,
D. T.
,
2012
, “
An Alternative Method for Calculation of Semi-Gray Radiation Heat Transfer in Solar Central Cavity Receivers
,”
Sol. Energy
,
86
(
6
), pp.
1899
1909
.
19.
Tu
,
N.
,
Wei
,
J. J.
, and
Fang
,
J. B.
,
2015
, “
Numerical Investigation on Uniformity of Heat Flux for Semi-Gray Surfaces Inside a Solar Cavity Receiver
,”
Sol. Energy
,
112
, pp.
128
143
.
20.
Kandlikar
,
S. G.
,
1991
, “
Development of a Flow Boiling Map for Subcooled and Saturated Flow Boiling of Different Fluids Inside Circular Tubes
,”
ASME J. Heat Transfer
,
113
(
1
), pp.
190
200
.
21.
Kandlikar
,
S. G.
,
1998
, “
Heat Transfer Characteristics in Partial Boiling, Fully Developed Boiling, and Significant Void Flow Regions of Subcooled Flow Boiling
,”
ASME J. Heat Transfer
,
120
(
2
), pp.
395
401
.
22.
Baker
,
A. F.
,
Faas
,
S. E.
,
Radosevich
,
L. G.
, and
Skinrood
,
A. C.
,
1989
, “
Spain Evaluation of the Solar One and CESA-1 Receiver and Storage Systems
,”
Sandia National Laboratories
, Albuquerque, NM.
23.
Gnielinski
,
V.
,
1976
, “
New Equations for Heat and Mass Transfer in Turbulent Pipe and Channel Flow
,”
Int. Chem. Eng.
,
16
(
2
), pp.
359
368
.
24.
Hsu
,
Y. Y.
,
1962
, “
On the Size Range of Active Nucleation Cavities on a Heating Surface
,”
ASME J. Heat Transfer
,
84
(
3
), pp.
207
216
.
25.
Thom
,
J. R. S.
,
Walker
,
W. M.
,
Fallon
,
T. A.
, and
Reising
,
G. F. S.
,
1965
, “
Boiling in Sub-Cooled Water During Flow Up Heated Tubes or Annuli
,”
Symposium on Boiling Heat Transfer in Steam Generating Units and Heat Exchangers
, Manchester, UK, Sept. 15–16, Paper No. 6.
26.
Bowring
,
W. R.
,
1962
, “
Physical Model of Bubble Detachment and Void Volume in Subcooled Boiling
,”
OECD Halden Reactor Project
, Kjeller, Norway, Report No. HPR-10.
27.
Saha
,
P.
, and
Zuber
,
N.
,
1974
, “
Point of Net Vapor Generation and Vapor Void Fraction in Subcooled Boiling
,”
Fifth International Heat Transfer Conference
, Tokyo, Japan, Sept. 3–7, pp.
175
179
.
28.
Gungor
,
K. E.
, and
Winterton
,
R. H. S.
,
1986
, “
A General Correlation for Flow Boiling in Tubes and Annuli
,”
Int. J. Heat Mass Transfer
,
29
(
3
), pp.
351
358
.
29.
Sutton
,
O. G.
,
1923
, “
Note on Variation of the Wind With Height
,”
Q. J. R. Meteorol. Soc.
,
58
, pp.
74
76
.
30.
Wang
,
R. T.
, and
Wei
,
X. D.
,
2009
, “
Shadow of Heliostat Field in the Solar Tower Power Plant
,”
Acta Photonica Sin.
,
38
(
9
), pp.
2414
2418
.
You do not currently have access to this content.