IMMERSION
COOLING DEALS
WITH THE
ENTIRE HEAT
FOOTPRINT,
DOESN’T CARE
ABOUT THE
SHAPE OF THE
EQUIPMENT
AND DOESN’T
NEED TO BE
SPECIFICALLY
PREPARED.
What kind of efficiencies could
a business expect to achieve by
utilising these solutions?
The typical PUE (Power Usage
Effectiveness) for a data centre
enterprise is 1.89 (it depends on many
factors). This means that for 1kW of
energy used to power a server, 0.89kW
are used to power the rest of the picture.
If you check Submer’s SmartPUE
calculator, you can notice that a PUE of
1.89 actually refers to a real PUE of 2.36.
In this scenario, more than half of the
electricity consumed is used for cooling
(air condition and fans on servers).
Diarmuid Daltún, CCO, Submer
Technologies
With LIC, you manage to get a PUE <1.03:
this means that for every 1kW of real IT
(i.e. servers with NO fans) being powered,
you’ll just need to add 0.03kW for primary
and secondary cooling together. So,
essentially you need less than half of
In summary, what are the
main benefits of liquid
immersion cooling?
Density (85% more dense than with air
cooling), efficiency (50% savings on
electricity), you can deploy it anywhere
(reducing building costs), it is a silent
cleantech and it reduces latency and
increases deployment speed. ◊
i
There are solutions that share a CDU
(Cooling Distribution Unit) with a number of
tanks. The challenge in this case is that the
coolant (typically a mineral oil) leaves the
CDU and this increases the chances of leaks.
In this case also, the CDU works according
to the heat generated in all the tanks, not
adjusting to the workload of each pod.
How easily could an organisation
transition to this type of solution?
An existing installation can adopt an
immersion cooling solution by modifying
the existing servers (by removing the
fans) to submerge them. You should also
invest in secondary cooling infrastructure.
Still in such a scenario, the energy savings
are so significant that the ROI is less than
one year. Implementing immersion cooling
solutions is definitely much easier when
it comes to a completely new building (a
typical new data centre is around US$5
to US$10 million per MW, with immersion
cooling it is US$3 million per MW).
What are the varying types of
immersion cooling?
Passive immersion cooling relies on
convection alone to move the fluid
around for the heat to be removed (not
suitable for high densities). In Submer’s
experience, the liquid must be actively
circulated in order to ensure that there
is a low delta between the coolant
temperature and the temperature of the
component to be cooled.
your electricity compared to a typical,
traditional air-cooled data centre.
Then we have single-phase and two-
phase immersion cooling. In the latter, the
coolant changes its states from liquid to
gas into liquid again. The liquid is boiling
directly on the components, generating
though challenges such as micro-
cavitation and evaporation of the coolant
itself (that is extremely expensive). In
the single-phase solution, as in Submer’s,
the liquid never changes its states and it
doesn’t leave the tank.
www.intelligentdatacentres.com
Issue 08
55