<s>
Immersion	B-Device
cooling	I-Device
,	O
also	O
known	O
as	O
"	O
direct	O
liquid	O
cooling	O
"	O
,	O
is	O
a	O
technique	O
used	O
for	O
computer	O
cooling	O
,	O
battery	O
cooling	O
,	O
and	O
motor	O
cooling	O
in	O
which	O
electrical	O
and	O
electronic	O
components	O
,	O
including	O
complete	O
servers	B-Application
and	O
storage	O
devices	O
,	O
are	O
mostly	O
or	O
fully	O
submerged	O
in	O
a	O
thermally	O
conductive	O
but	O
electrically	O
insulating	O
liquid	O
coolant	O
.	O
</s>
<s>
Therefore	O
,	O
the	O
fluids	O
used	O
in	O
immersion	B-Device
cooling	I-Device
are	O
dielectric	O
liquids	O
to	O
ensure	O
that	O
they	O
can	O
safely	O
come	O
into	O
contact	O
with	O
energized	O
electronic	O
components	O
.	O
</s>
<s>
In	O
general	O
,	O
the	O
dielectric	O
liquids	O
used	O
for	O
immersion	B-Device
cooling	I-Device
fall	O
into	O
two	O
categories	O
:	O
hydrocarbons	O
(	O
i.e.	O
</s>
<s>
Immersion	B-Device
cooling	I-Device
reduces	O
energy	O
consumption	O
through	O
the	O
elimination	O
of	O
the	O
air	O
cooling	O
infrastructure	O
including	O
on-board	O
server	O
fans	O
,	O
CRACs	O
,	O
A/C	O
compressors	O
,	O
air-circulation	O
fans	O
,	O
necessary	O
duct	O
work	O
,	O
air	O
handlers	O
,	O
and	O
other	O
active	O
ancillary	O
systems	O
such	O
as	O
dehumidifiers	O
.	O
</s>
<s>
Power	O
use	O
at	O
data	B-Operating_System
centers	I-Operating_System
is	O
often	O
measured	O
in	O
terms	O
of	O
Power	O
Usage	O
Effectiveness	O
(	O
PUE	O
)	O
.	O
</s>
<s>
The	O
PUE	O
for	O
air-cooled	O
data	B-Operating_System
centers	I-Operating_System
includes	O
the	O
power	O
used	O
by	O
the	O
fans	O
and	O
other	O
active	O
cooling	O
components	O
found	O
in	O
the	O
servers	B-Application
.	O
</s>
<s>
The	O
PUE	O
for	O
liquid	O
immersion	B-Device
cooling	I-Device
excludes	O
these	O
values	O
from	O
the	O
IT	O
Equipment	O
Energy	O
component	O
because	O
these	O
system	O
elements	O
(	O
in	O
particular	O
on	O
board	O
fans	O
)	O
are	O
generally	O
removed	O
from	O
the	O
IT	O
equipment	O
as	O
they	O
are	O
not	O
necessary	O
to	O
circulate	O
the	O
dielectric	O
coolants	O
.	O
</s>
<s>
This	O
discrepancy	O
in	O
the	O
definition	O
of	O
PUE	O
for	O
the	O
different	O
cooling	O
methods	O
results	O
in	O
the	O
PUE	O
of	O
air-cooled	O
data	B-Operating_System
centers	I-Operating_System
generally	O
being	O
overstated	O
when	O
compared	O
against	O
the	O
PUE	O
of	O
a	O
liquid	O
immersion	O
cooled	O
facility	O
of	O
the	O
same	O
power	O
usage	O
.	O
</s>
<s>
Servers	B-Application
and	O
other	O
IT	O
hardware	O
cooled	O
by	O
immersion	B-Device
cooling	I-Device
do	O
not	O
require	O
fans	O
to	O
circulate	O
the	O
dielectric	O
liquid	O
,	O
thus	O
they	O
are	O
removed	O
from	O
the	O
system	O
prior	O
to	O
immersion	O
.	O
</s>
<s>
The	O
temperatures	O
used	O
in	O
immersion	B-Device
cooling	I-Device
are	O
determined	O
by	O
the	O
highest	O
temperature	O
at	O
which	O
the	O
devices	O
being	O
immersed	O
can	O
reliably	O
operate	O
.	O
</s>
<s>
For	O
servers	B-Application
this	O
temperature	O
range	O
is	O
typically	O
between	O
,	O
however	O
in	O
ASIC	O
based	O
crypto	O
mining	O
devices	O
this	O
range	O
is	O
often	O
extended	O
up	O
to	O
75C	O
.	O
</s>
<s>
This	O
increase	O
in	O
the	O
high	O
end	O
of	O
the	O
temperature	O
range	O
allows	O
data	B-Operating_System
centers	I-Operating_System
operators	O
to	O
use	O
entirely	O
passive	O
dry	O
coolers	O
,	O
or	O
much	O
more	O
efficient	O
evaporative	O
or	O
adiabatic	O
cooling	O
towers	O
instead	O
of	O
chiller-based	O
air	O
cooling	O
or	O
water	O
chillers	O
.	O
</s>
<s>
Multiple	O
relevant	O
brands	O
like	O
Intel	O
and	O
Facebook	B-Application
have	O
already	O
validated	O
the	O
advantages	O
of	O
submerging	O
servers	B-Application
.	O
</s>
<s>
Current	O
commercial	O
applications	O
for	O
immersion	B-Device
cooling	I-Device
range	O
from	O
datacenter	B-Operating_System
oriented	O
solutions	O
for	O
commodity	O
server	O
cooling	O
,	O
server	O
clusters	O
,	O
HPCC	B-Operating_System
applications	O
and	O
Cryptocurrency	O
mining	O
.	O
</s>
<s>
Electric	O
vehicle	O
and	O
battery	O
manufacturers	O
also	O
employ	O
liquid	O
immersion	B-Device
cooling	I-Device
in	O
batteries	O
,	O
drive-train	O
,	O
Kinetic	O
energy	O
recovery	O
systems	O
,	O
electric	O
motors	O
,	O
electric	O
motor	O
controllers	O
,	O
and	O
other	O
on-board	O
electronic	O
sub	O
systems	O
.	O
</s>
<s>
Liquid	O
immersion	B-Device
cooling	I-Device
is	O
also	O
used	O
in	O
the	O
thermal	O
management	O
of	O
LEDs	O
,	O
Lasers	O
,	O
X-Ray	O
machines	O
,	O
and	O
Magnetic	O
Resonance	O
Imaging	O
devices	O
.	O
</s>
<s>
Immersion	B-Device
cooling	I-Device
is	O
applied	O
to	O
electronic	O
components	O
in	O
deep	O
sea	O
research	O
where	O
Remotely	O
Operated	O
Underwater	O
Vehicles	O
with	O
electronic	O
equipment	O
are	O
filled	O
with	O
Single-phase	O
Liquid	O
Dielectrics	O
to	O
both	O
protect	O
them	O
from	O
corrosion	O
in	O
seawater	O
and	O
as	O
a	O
pressure	O
compensating	O
fluid	O
to	O
avoid	O
being	O
crushed	O
by	O
the	O
extreme	O
pressure	O
exerted	O
on	O
the	O
ROV	O
while	O
working	O
in	O
the	O
deep	O
sea	O
.	O
</s>
<s>
Even	O
though	O
the	O
expected	O
increase	O
in	O
global	O
energy	O
consumption	O
by	O
data	B-Operating_System
centers	I-Operating_System
has	O
remained	O
steady	O
,	O
there	O
is	O
an	O
increased	O
focus	O
on	O
energy	O
efficiency	O
which	O
has	O
driven	O
the	O
utilizing	O
of	O
liquid	O
immersion	B-Device
cooling	I-Device
in	O
both	O
data	B-Operating_System
centers	I-Operating_System
and	O
crypto	O
mining	O
operations	O
to	O
reevaluate	O
its	O
application	O
.	O
</s>
<s>
The	O
advent	O
of	O
new	O
very	O
high	O
density	O
CPUs	O
and	O
GPUs	O
for	O
use	O
in	O
real-time	O
processing	O
,	O
Artificial	O
intelligence	O
,	O
machine	O
learning	O
,	O
and	O
data	O
mining	O
operations	O
is	O
resulting	O
in	O
users	O
and	O
data	B-Operating_System
center	I-Operating_System
operators	O
to	O
evaluate	O
liquid	O
immersion	B-Device
cooling	I-Device
for	O
ability	O
to	O
cool	O
high	O
density	O
racks	O
as	O
well	O
as	O
reduce	O
the	O
total	O
mechanical	O
footprint	O
of	O
data	B-Operating_System
centers	I-Operating_System
.	O
</s>
<s>
In	O
1968	O
,	O
Richard	O
C	O
.	O
Chu	O
and	O
John	O
H	O
.	O
Seely	O
,	O
working	O
for	O
IBM	O
patented	O
an	O
"	O
Immersion	B-Device
cooling	I-Device
system	O
for	O
modularly	O
packaged	O
components.	O
"	O
</s>
<s>
In	O
2011	O
,	O
Iceotope	O
launched	O
the	O
first	O
commercial	O
rack-style	O
enclosed	O
chassis	O
based	O
technology	O
,	O
specifically	O
designed	O
for	O
datacenter	B-Operating_System
deployments	O
.	O
</s>
<s>
2017	O
shows	O
a	O
large	O
volume	O
of	O
start-ups	O
in	O
the	O
immersion	B-Device
cooling	I-Device
domain	O
.	O
</s>
<s>
Mostly	O
related	O
to	O
cryptocurrency	O
and	O
the	O
increasing	O
power	O
and	O
cooling	O
challenges	O
in	O
the	O
datacenter	B-Operating_System
industry	O
.	O
</s>
<s>
In	O
2020	O
,	O
Telecommunications	O
Industry	O
Association	O
publishes	O
their	O
first	O
mention	O
of	O
Immersion	B-Device
Cooling	I-Device
as	O
a	O
viable	O
cooling	O
option	O
.	O
</s>
<s>
In	O
2021	O
,	O
as	O
chips	O
thermal	O
properties	O
have	O
gone	O
beyond	O
air-cooling	O
capabilities	O
,	O
various	O
hyperscale	O
cloud	O
companies	O
,	O
chip	O
manufacturers	O
and	O
server	O
OEMs	O
have	O
announced	O
their	O
adoption	O
of	O
immersion	B-Device
cooling	I-Device
.	O
</s>
<s>
In	O
2022	O
,	O
Intel	O
announces	O
investment	O
of	O
700	O
million	O
USD	O
in	O
a	O
mega	O
lab	O
focused	O
on	O
immersion	B-Device
cooling	I-Device
and	O
publishes	O
a	O
fluid	O
specification	O
for	O
immersion	B-Device
cooling	I-Device
which	O
will	O
allow	O
the	O
support	O
of	O
warranty	O
of	O
Intel	O
products	O
.	O
</s>
<s>
Open	O
bath	O
immersion	B-Device
cooling	I-Device
is	O
a	O
data	B-Operating_System
center	I-Operating_System
cooling	O
technique	O
that	O
implies	O
fully	O
submerging	O
IT	O
equipment	O
in	O
dielectric	O
liquid	O
.	O
</s>
<s>
These	O
baths	O
allow	O
the	O
coolant	O
fluid	O
to	O
be	O
moved	O
through	O
the	O
hardware	O
components	O
or	O
servers	B-Application
submerged	O
in	O
it	O
.	O
</s>
<s>
Energy	O
transferred	O
from	O
the	O
servers	B-Application
into	O
the	O
two-phase	O
coolant	O
will	O
cause	O
a	O
portion	O
of	O
it	O
to	O
boil	O
off	O
into	O
a	O
gas	O
.	O
</s>
<s>
Sealed	O
server	B-Device
immersion	I-Device
cooling	I-Device
encloses	O
servers	B-Application
in	O
liquid-tight	O
casings	O
.	O
</s>
<s>
The	O
main	O
advantage	O
of	O
this	O
approach	O
is	O
that	O
servers	B-Application
are	O
mounted	O
in	O
self	O
contained	O
vessels	O
that	O
can	O
be	O
replaced	O
in	O
the	O
rack	O
without	O
accessing	O
the	O
fluid	O
.	O
</s>
<s>
A	O
disadvantage	O
is	O
that	O
not	O
all	O
hardware	O
can	O
be	O
used	O
as	O
the	O
vendor	O
defines	O
the	O
hardware	O
specs	O
of	O
the	O
sealed	O
servers	B-Application
.	O
</s>
<s>
Some	O
hydrocarbon	O
based	O
immersion	B-Device
cooling	I-Device
fluids	O
provide	O
a	O
fire	O
hazard	O
as	O
they	O
have	O
a	O
fire	O
point	O
.	O
</s>
<s>
In	O
the	O
last	O
few	O
years	O
,	O
immersion	B-Device
cooling	I-Device
in	O
particular	O
for	O
bitcoin	O
mining	O
has	O
become	O
a	O
popular	O
method	O
to	O
generate	O
usable	O
heat	O
.	O
</s>
<s>
Immersion	B-Device
cooling	I-Device
offered	O
a	O
means	O
to	O
silently	O
convert	O
the	O
waste	O
heat	O
from	O
the	O
mining	O
operation	O
to	O
heat	O
water	O
,	O
melt	O
snow	O
,	O
power	O
in	O
floor	O
heating	O
,	O
heat	O
hot	O
tubs	O
and	O
pools	O
,	O
shops	O
,	O
outbuildings	O
,	O
sheds	O
and	O
greenhouses	O
.	O
</s>
