Liquid Cooling in Data Centers, why is it needed?
Modern chips and processors are smaller than ever and are at the point that the manufacturing process has exhausted Moore’s Law.
These modern chips and processors are compacted so tight it creates a significant heat load, which then means we need more efficient and sustainable cooling solutions, e.g., they need to absorb heat more efficiently than standard air cooling. This has led the Data Center industry to investigate Liquid Cooling in more depth.
What is Liquid Cooling?
In theory it is a simple cooling methodology, using liquid as the primary means for capturing and expelling heat created by IT load.
Unfortunately, there are many misconceptions about the different technologies available, with a large portion of our industry believing there are only two types of Liquid Cooling:
- Immersion Cooling
IT equipment is submerged inside an electrically non-conductive liquid inside a tub that absorbs heat.
- Direct Chip Liquid Cooling (DCLC)
Small hoses bring cool water to heat sinks or cold plates and circulate warmed water to a heat exchanger.
Even though both technologies have merit, there are considerable downfalls. With immersion cooling there is significant setup costs, it does not capture 100% of the heat generated, which would mean you would require a secondary, supplementary cooling source, and this is the same with Direct Chip Level Cooling, which only captures between 60-80% of the heat.
So, is there an alternative technology?
Yes, there is…… Rear Door Heat Exchangers (RDHx), or known also as Rear Door Coolers (RDC), is a proven liquid cooling technology, sometimes known as Air Assisted Liquid Cooling, which is designed to operate as a closed loop system.
In principle there are two main types of Rear Door Cooling methods, passive and active.
First, with a passive Rear Door Cooler (RDC), works by allowing ambient air to be pulled into the rack via the IT equipment fans with the resulting hardware hot exhaust air expelled over a heat exchanger, transferring the heat into the liquid inside the coil, with the resulting chilled air being expelled back into the room.
Similarly, with an ProActive Rear Door Cooler (RDC), ambient air is pulled into the rack by the IT equipment fans, however the resulting hot exhaust air is assisted by EC fans mounted within the proactive door and the air expelled over a heat exchanger, transferring the heat into the liquid inside the coil, with the resulting chilled air being expelled back into the room at, or just below, the predetermined room ambient temperature.
In this way the ProActive Rear Door Cooler can control the whole room temperature environment, without supplementary cooling technology.
In summary,
When the whole data center is taken into account, all liquid cooling solutions require air to assist in the data center cooling process, the ColdLogik solution integrates this as standard without the need for supplementary cooling equipment.
There are many misleading industry articles, hopefully this document sets the record straight.
