We tested a thermosyphon loop with water as the working fluid using heating rates between 100 W and 400 W. Four kinds of core blocks were installed in the evaporator and tested: a hollow block, and blocks with narrow holes: Φ 2.2 mm × 90; Φ 2.5 mm × 55; and Φ 4.0 mm × 30. The temperature distribution indicated stable flow circulation inside the thermosyphon at low volume ratios but was unstable when the volume ratio was increased higher than 30%. The characteristics of the flow pattern are summarized as a flow map showing the heating rate versus the volume ratio. The recovered heat and the thermal resistance of the thermosyphon loop were clearly improved by using the core blocks with narrow holes instead of hollow blocks for the treated volume ratios from 20% to 80%. The thermal resistance increased when the volume ratio reached high values, suggesting that the effects from the abnormality of the flow circulation affected thermal resistance. The velocity of the gas stream in the thermosyphon was estimated by assuming an isothermal state, and it is diagrammed showing the heating rate at different temperatures. The current experiment of the thermosyphon loop is plotted in this diagram, which indicates the need for a wide margin due to the limitations of the sonic velocity and the pressure head at the full height of the heat pipe.

References

References
1.
Maezawa
,
K.
,
2011
, “
New Power Generation System by Concentrating Waste Heat Below 200 °C From Factory
,”
Clean Energy
,
20
, pp.
5
10
.
2.
Chi
,
S. W.
,
1976
,
Heat Pipe Theory and Practice
,
Hemisphere Publishing Corporation
, New York, pp.
1
35
.
3.
Dunn
,
P. D.
, and
Reay
,
D. A.
,
1977
,
Heat Pipes
,
Pergamon Press, Ltd.
,
London
, pp.
1
16
.
4.
Hsieh
,
C. C.
,
Wang
,
B.
, and
Pan
,
C.
,
1997
, “
Dynamics Visualization of Two-Phase Flow Patterns in a Natural Circulation Loop
,”
Int. J. Multiphase Flow
,
23
, pp.
1147
1170
.10.1016/S0301-9322(97)00026-8
5.
Khodabandeh
,
R.
,
2005
, “
Heat Transfer in the Evaporator of an Advanced Two-Phase Thermosyphon Loop
,”
Int. J. Refrigeration
,
28
, pp.
190
202
.10.1016/j.ijrefrig.2004.10.006
6.
Khodabandeh
,
R.
,
2005
, “
Pressure Drop in Riser and Evaporator in an Advanced Two-Phase Thermosyphon Loop
,”
Int. J. Refrigeration
,
28
, pp.
725
734
.10.1016/j.ijrefrig.2004.12.003
7.
Alklaibi
,
A. M.
,
2008
, “
Evaluating the Possible Configurations of Incorporating the Loop Heat Pipe Into the Air-Conditioning Systems
,”
Int. J. Refrigeration
,
31
, pp.
807
815
.10.1016/j.ijrefrig.2007.11.007
8.
Chen
,
Y.
,
Cheng
,
L.
,
Xin
,
G.
, and
Luan
,
T.
,
2010
, “
Steady State Modeling of LHP and Analysis
,”
ASME
14th International Heat Transfer Conference, Washington DC, Aug. 8–13, pp. 343–347, Paper No. IHTC14-22351.10.1115/IHTC14-22351
9.
Louahlia-Gualous
,
H.
,
Mecheri
,
B.
,
Nortershauser
,
D.
, and
Le Masson
,
S.
,
2010
, “
Transient Characteristics of a Two-Phase Thermosyphon Loop for Cooling Telecommunication Outdoor Cabinets
,”
ASME
14th Intl' Heat Transfer Conference, Washington DC, Aug. 8–13, pp. 467–472, Paper No. IHTC14-22218.10.1115/IHTC14-22218
10.
Dobriansky
,
Y.
,
2011
, “
Concepts of Self-Acting Circulation Loops for Downward Heat Transfer (Reverse Thermosiphons)
,”
Energy Convers. Manage.
,
52
, pp.
414
425
.10.1016/j.enconman.2010.06.073
You do not currently have access to this content.