Energy consumption in data centers has seen a drastic increase in recent years. In data centers, server racks are cooled down in an indirect way by air-conditioning systems installed to cool the entire server room. This air cooling method is inefficient as information technology (IT) equipment is insufficiently cooled down, whereas the room is overcooled. The development of countermeasures for heat generated by IT equipment is one of the urgent tasks to be accomplished. We, therefore, proposed new liquid cooling systems in which IT equipment is cooled down directly and exhaust heat is not radiated into the server room. Three cooling methods have been developed simultaneously. Two of them involve direct cooling; a cooling jacket is directly attached to the heat source (or CPU in this case) and a single-phase heat exchanger or a two-phase heat exchanger is used as the cooling jacket. The other method involves indirect cooling; heat generated by CPU is transported to the outside of the chassis through flat heat pipes and the condensation sections of the heat pipes are cooled down by coolant with liquid manifold. Verification tests have been conducted by using commercial server racks to which these cooling methods are applied while investigating five R&D components that constitute our liquid cooling systems: the single-phase heat exchanger, the two-phase heat exchanger, high performance flat heat pipes, nanofluid technology, and the plug-in connector. As a result, a 44–53% reduction in energy consumption of cooling facilities with the single-phase cooling system and a 42–50% reduction with the flat heat pipe cooling system were realized compared with conventional air cooling system.

References

References
1.
MIC Research Institute Ltd., 2010, “
Survey on Datacenter Electricity Consumption and Green IT FY2010
,” in Japanese.
2.
The Green Grid, 2009, “
Fundamentals of Data Center Power and Cooling Efficiency Zones
,” White Paper #21.
3.
Karki
,
K. C.
, and
Patanker
,
S. V.
, 2006, “
Airflow Distribution Through Perforated Tiles in Raised-Floor Data Centers
,”
Build. Environ.
,
41
, pp.
734
744
.
4.
McAllister
,
S.
,
Carey
,
V. P.
,
Shah
,
A.
,
Bash
,
C.
, and
Patel
,
C.
, 2008, “
Strategies for Effective Use of Exergy-Based Modeling of Data Center Thermal Management Systems
,”
Microelectron. J.
,
39
, pp.
1023
1029
.
5.
Cho
,
J.
,
Lim
,
T.
, and
Kim
,
B. S.
, 2009, “
Measurements and Predictions of the Air Distribution Systems in High Compute Density (Internet) Data Centers
,”
Energy Build.
,
41
, pp.
1107
1115
.
6.
Tahir
,
C.
,
Levi
,
W.
,
Vali
,
S.
, and
Andres
,
M.
, 2009, “
Liquid Cooling in Data Centers
,”
ASHRAE Trans.
,
115
, pp.
231
241
.
7.
Anandan
,
S. S.
, and
Ramalingam
,
V.
, 2008, “
Thermal Management of Electronics: A Review of Literature
,”
Therm. Sci.
,
12
, pp.
5
26
.
8.
Chien
,
L.
, and
Chang
,
C.
, 2011, “
An Experimental Study of Two-Phase Multiple Jet Cooling on Finned Surfaces Using a Dielectric Fluid
,”
Appl. Therm. Eng.
,
31
, pp.
1983
1993
.
12.
Abe
,
Y.
,
Fukagaya
,
M.
,
Kitagawa
,
T.
,
Ohta
,
H.
,
Shinmoto
,
Y.
,
Sato
,
M.
, and
Iimura
,
K.
, 2009, “
Advanced Integrated Cooling Systems for Thermal Management in Data Centers
,”
Proceedings of IPACK2009
, Paper No. IPACK2009-89009.
13.
Hetsroni
,
G.
,
Mosyak
,
A.
,
Segal
,
Z.
, and
Ziskind
,
G.
, 2002, “
A Uniform Temperature Heat Sink for Cooling of Electronic Devices
,”
Int. J. Heat Mass Transfer
,
45
, pp.
3275
3286
.
14.
Naphon
,
P.
, and
Wiriyasart
,
S.
, 2009, “
Liquid Cooling in the Mini-Rectangular Fin Heat Sink With and Without Thermoelectric for CPU
,”
Int. Commun. Heat Mass Transfer
,
36
, pp.
166
171
.
15.
Ohta
,
H.
,
Shinmoto
,
Y.
,
Ishikawa
,
Y.
, and
Ariki
,
K.
, 2006, “
High Heat Flux Cooling of Large Areas by Improved Liquid Supply for Flow Boiling in Narrow Channels
,”
Proceedings of 13th International Heat Transfer Conference
, BOI-32, p.
12
.
16.
Shinmoto
,
Y.
,
Asada
,
Y.
,
Kobayashi
,
H.
,
Kanazawa
,
S.
,
Ohta
,
H.
,
Fukagaya
,
M.
,
Abe
,
Y.
,
Ouchi
,
M.
,
Sato
,
M.
, and
Iimura
,
K.
, 2011, “
Development of High Heat Flux Cooling Jacket for Electronics Devices by Using Flow Boiling
,”
Proceedings of ICEP2011
.
17.
Shinmoto
,
Y.
,
Miura
,
S.
,
Suzuki
,
K.
,
Abe
,
Y.
, and
Ohta
,
H.
, 2009, “
Development of Advanced High Heat Flux Cooling System for Power Electronics
,”
Proceedings of IPACK2009
, Paper No. InterPACK2009-89082.
18.
Vochten
,
R.
, and
Petre
,
G.
, 1973, “
Study of the Heat of Reversible Adsorption at the Air-Solution Interface
,”
J. Colloid Interface Sci.
,
42
, pp.
320
327
.
19.
Zhang
,
N.
, 2001, “
Innovative Heat Pipe Systems Using a New Working Fluid
,”
Int. Commun. Heat Mass Transfer
,
28
, pp.
1025
1033
.
20.
Fumoto
,
K.
,
Kawaji
,
M.
, and
Kawanami
,
T.
, 2010, “
Effect of Working Fluid on Pulsating Heat Pipe Thermal Performance
,”
Proceedings of IHTC14
, Paper No. IHTC14-22714.
21.
Armijo
,
K. M.
, and
Carey
,
V. P.
, 2010, “
An Experimental Study of Heat Pipe Performance Using Binary Mixture Fluids That Exhibit Strong Concentration Marangoni Effects
,”
Proceedings of IHTC14
, Paper No. IHTC14-23255.
22.
Abe
,
Y.
, 2009, “
Applications of Self-Rewetting Fluids as a Working Fluid in Heat Transfer
,”
Int. J. Transp. Phenom.
,
11
(
1
), pp.
1
18
.
23.
Godson
,
L.
,
Raja
,
B.
,
Lal
,
D. M.
, and
Wongwises
,
S.
, 2010, “
Enhancement of Heat Transfer Using Nanofluids—An Overview
,”
Renewable Sustainable Energy Rev.
,
14
, pp.
629
641
.
24.
Do
,
K. H.
,
Ha
,
H. J.
, and
Jang
,
S. P.
, 2010, “
Thermal Resistance of Screen Mesh Wick Heat Pipes Using the Water-Based Al2O3 Nanofluids
,”
Int. J. Heat Mass Transfer
,
53
, pp.
5888
5894
.
25.
Shafahi
,
M.
,
Bianco
,
V.
,
Vafai
,
K.
, and
Manca
,
O.
, 2010, “
Thermal Performance of Flat-Shaped Heat Pipes Using Nanofluids
,”
Int. J. Heat Mass Transfer
,
53
, pp.
1438
1445
.
26.
Liu
,
Z.
, and
Zhu
,
Q.
, 2011, “
Application of Aqueous Nanofluids in a Horizontal Mesh Heat Pipe
,”
Energy Convers. Manage.
,
52
, pp.
292
300
.
27.
Tsuji
,
M.
,
Nishizawa
,
Y.
,
Hashimoto
,
M.
, and
Tsuji
,
T.
, 2004, “
Syntheses of Silver Nanofilms, Nanorods, and Nanowires by a Microwave-Polyol Method in the Presence of Pt Seeds and Polyvinylpyrrolidone
,”
Chem. Lett.
,
33
(
4
), pp.
370
371
.
28.
The Green Grid, 2008, “
Green Grid Data Center Power Efficiency Metrics: PUE and DCIE
,” White Paper #6.
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