As heat dissipation levels increase, standard methods of cooling involving air become
inadequate. In order to achieve acceptable levels of performance at the IC level,
liquid cooling systems are being used in increasing number of applications. Liquid
cooling systems will generally include a coldplate (to collect heat from the heat
source), a pump (to circulate the cooling fluid), and a heat exchanger (where the
heat is removed).
In many applications the liquid cooling system is considered a hybrid system, where
the fluid flows to a fluid-air heat exchanger rather than flowing to a chiller device
for direct cooling of the fluid. As a result, the hybrid liquid cooling system requires
both a pump (to circulate the internal fluid) and a fan (for heat exchanger cooling).
In general terms, hybrid liquid cooling systems take the heat from hot ICs and transfer
it to a location where it can be release into the air. If we consider a 4 CPU motherboard.
Placing 4 large fansinks on each CPU would require a large volume, making the design
unattractive. By comparison, it is more effective, from a space point of view, to
collect the heat via coldplates (with low aspect ratios) and bring it to one side
of the enclosure where fans and a heat exchanger can be more conveniently located.
Liquid cooling system design requires special attention as proper operation entails
that pressures drops and pump characteristics be well balanced. Since many systems
have the additional requirement of small dimensional envelope, the small pumps are
also typically limited in the amount of pressure they can work against. As a result,
the internal pressure drop of the coldplates and the heat exchanger are of primordial
The mechanical design and reliability of the cooling system is very important as
well, In many cases, our customers require 50,000 hours life from the system, which
means that all components and the complete system must be validated to this level.
In addition to long life requirements, the system must also meet safety specifications
whether EU, UL, CSA, or other international standards.
If you have any questions regarding the above or for a specific design question which
you may have, please contact us and we will be pleased to help you.