The use of heat pipes in solar collectors offers several advantages regarding flexibility in operation and application, as they are very efficient in transporting heat even under a small temperature difference. Compared with other systems powered by evacuated tube collectors or flat plate solar collectors using a wickless heat pipe, little attention has been paid to a flat plate solar collectors wick assisted heat pipe. In this paper an analytical model based on energy balance equations assuming a steady state condition was developed to evaluate the thermal efficiency of a flat plate wick assisted heat pipe solar collector. Parameters which affect the collector efficiency are identified, such as tube spacing distance, gap spacing between the absorber plate and the glazing cover, and the emissivity of the absorber plate. The results reflect the contribution and significance of each of these parameters to the collector overall heat loss coefficients. Three heat pipe working fluids are examined and results show that acetone performs better than methanol and ethanol.

References

References
1.
Stumpf
,
P.
, Balzar, A., Eisenmann, W., Wendt, S., Ackermann, H., and Vajen, K.,
2001
, “
Comparative Measurements and Theoretical Modelling of Single and Double Stage Heat Pipe Coupled Solar Cooking Systems for High Temperatures
,”
Solar Energy
,
71
(
1
), pp.
1
10
.10.1016/S0038-092X(01)00026-3
2.
Arora, S., Chitkara, S., Udayakumar, R., and Ali, M.,
2001
, “
Thermal Analysis of Evacuated Solar Tube Collectors, A Review
,”
J. Pet. Gas Eng.
,
2
(
4
), pp.
74
82
.
3.
Hussein
,
H. M. S.
,
2007
, “
Theoretical and Experimental Investigation of Wickless Heat Pipes Flat Plate Solar Collector With Cross Flow Heat Exchanger
,”
Energy Convers. Manage.
,
48
, pp.
1266
1272
.10.1016/j.enconman.2006.09.021
4.
Hussein
,
H. M. S.
,
El-Ghetany
,
H. H.
, and
Nada
,
S. A.
,
2006
, “
Performance of Wickless Heat Pipe Flat Plate Solar Collectors Having Different Pipes Cross Sections Geometries and Filling Ratios
,”
Energy Convers. Manage.
,
47
, pp.
1539
1549
.10.1016/j.enconman.2005.08.009
5.
Hussein
,
H. M. S.
,
Mohamada
,
M. A.
, and
El Asfourib
,
A. S.
,
1999
, “
Optimization of a Wickless Heat Pipe at Plate Solar Collector
,”
Energy Convers. Manage.
,
40
, pp.
1949
196
.10.1016/S0196-8904(99)00082-5
6.
Esen
,
M.
, and
Esen
, V
. H.
,
2005
, “
Experimental Investigation of a Two-Phase Closed Thermosyphon
,”
Solar Water Heater Solar Energy
,
79
, pp.
459
468
.10.1016/j.solener.2005.01.001
7.
Abreu
,
S. L.
,
Colle
,
S.
, and
Skiavine
,
J. A.
,
2002
, “
Investigation of the Performance of a Two-Phase Thermosyphon With an Unusual Geometry
,”
Proceedings of the 12th International Heat Pipe Conference (IHPC)
, Moscow, May 19–24.
8.
Abreu
,
S. L.
,
Colle
,
S.
, and
Skiavine
,
J. A.
,
2003
, “
Working Characteristics of a Compact Solar Hot Water System With Heat Pipes During Start-Up and Geyser Boiling Periods
,”
Proceedings of the ISES Solar World Congress
,
Götheborg, Sweden
, June 14–19.
9.
Abreu
,
S. L.
, and
Colle
,
S.
,
2004
, “
An Experimental Study of Two-Phase Closed Thermosyphons for Compact Solar Domestic Hot Water Systems
,”
J. Solar Energy
,
76
, pp.
141
145
.10.1016/j.solener.2003.02.001
10.
Riffat
,
S. B.
,
Zhao
,
X.
, and
Doherty
,
P. S.
,
2005
, “
Developing of a Theoretical Model to Investigate Thermal Performance of a Thin Membrane Heat Pipe Solar Collector
,”
J. Appl. Therm. Eng.
,
25
, pp.
899
915
.10.1016/j.applthermaleng.2004.08.010
11.
Riffat
,
S. B.
, and
Zhao
,
X.
,
2004
, “
A Novel Hybrid Heat Pipe Solar Collector/CHP System System—Part II: Theoretical and Experimental Investigations
,”
J. Renew. Energy Renew.
,
29
, pp.
1965
1990
.10.1016/j.renene.2004.03.018
12.
Wu
,
B.-Y.
, and
Li
,
C.-T.
,
2008
, “
Numerical Simulation for Porous Medium Flat-Plate Solar Collector
,”
The 15th National Computational Fluid Dynamics Conference
,
Kaohsiung, Taiwan
, August 7–9.
13.
Ismail
,
K. A. R.
, and
Abogderah
,
M. M.
, “
Performance of a Heat Pipe Solar Collector
,”
ASME J. Solar Energy Eng.
,
120
, pp.
51
59
.10.1115/1.2888047
14.
Joudi, K. A., and Witwit, A. M.,
2000
, “
Improvements of Gravity Assisted Wickless Heat Pipes
,”
Energy Convers. Manage.
,
41
, pp.
2041
2061
.10.1016/S0196-8904(00)00003-0
15.
Duffy
,
J. A.
, and
Beckman
,
W. A.
,
1977
,
Thermal Processes Using Solar Energy
,
2nd ed.
,
Mir
,
Moscow
.
16.
Vasiliev
,
L. L.
,
Grakovivh
,
L. P.
, and
Khrustalev
,
D. K.
,
1984
, “
Optimization of Flat Plate Solar Energy Heat Pipe Collector Parameters
,”
Heat Recovery Syst.
,
4
(
3
), pp.
157
164
.10.1016/0198-7593(84)90004-3
17.
Hollands
,
K. G. T.
,
Unny
,
T. E.
,
Raithby
,
G. D.
, and
Konicek
,
L.
,
1976
, “
Free Convection Heat Transfer Across Inclined Air Layers
,”
ASME J. Heat Transfer
,
98
(
2
), pp.
189
193
.10.1115/1.3450517
18.
McAdams
,
W. H.
,
1954
,
Heat Transmission
,
McGraw-Hill
,
New York
.
19.
Bradley
,
D. E.
,
1997
, “
Promising Freeze Protection Alternatives in Solar Domestic Hot Water Systems
,” Ph.D. thesis, University of Wisconsin–Madison, Madison, WI.
20.
Peterson
,
G. P.
,
1994
,
An Introduction to Heat Pipes Modeling, Testing and Applications
,
John Wiley and Sons
,
New York
.
21.
Chi
,
S. W.
,
1976
,
Heat Pipe Theory and Practice: A Source Book
,
Hemisphere
,
New York
.
22.
Atig
,
M.
, and
Abdelmajid
,
J.
,
2009
,
Conception et Réalisation d'un Capteur Solaire à Caloduc
, MSc. thesis, Université de Monastir, Enim, Monastir, Tunisia.
23.
Azad
,
E.
,
2008
, “
Theoretical and Experimental Investigation of Heat Pipe Solar Collector
,”
Exp. Thermal Fluid Sci.
,
32
(
8
), pp.
1666
1672
.10.1016/j.expthermflusci.2008.05.011
24.
Facão
,
J.
, and
Oliveira
,
A. C.
,
2002
, “
Simulation of the Thermal Behaviour of a Hybrid Heat Pipe Solar Collector
,”
1st International Conference on Sustainable Energy Technologies
,
Porto, Portugal
, June 12–14, Paper No. REN6.
25.
Facão
,
J.
,
2001
, “
Estudo de Colectores Solares Incorporando Tubos de Calor com Aplicação em Ciclos Motores
,” Ph.D. thesis, Faculdade de Engenharia da Universidade do Porto, Porto, Portugal.
You do not currently have access to this content.