Exploring modern cooling : Innovations in air and liquid systems
The global data centre cooling market shows no signs of slowing . It is expected to surge from US $ 16.84 billion in 2024 to an impressive US $ 42.48 billion by 2032 , reflecting a robust Compound Annual Growth Rate ( CAGR ) of 12.3 %. The primary driver of this growth is AI , of course .
• Air cooling
Still the most common data centre cooling method , air cooling involves circulating cool air to absorb and dissipate heat generated by the equipment . Hot-aisle ( or cold-aisle ) containment is an essential element of any efficient design .
Air cooling can be achieved in many ways , but a common trend has been to use perimeter-mounted Computer Room Air Handling ( CRAH ) units to ‘ flood ’ the room with cool air . CRAH units have fans to move the air and coils that absorb heat into circulating chilled water or refrigerant . Alternatives include inrow coolers , downflow CRAHs delivering air to raised floors , and above-rack coolers configured in various ways , to name a few .
• Liquid cooling
Liquid cooling directly targets heat sources , such as CPUs ( Central Processing Units ) and GPUs ( Graphics Processing Units ), by circulating a coolant fluid through cold plates that absorb heat from the processors , or alternatively , using immersion cooling approaches . The most common cooling fluid used today for cold plate applications is high-purity water blended with 25 % propylene glycol ( PG25 ) plus inhibitors to limit corrosion and biological growth .
However , two-phase fluids ( refrigerants ) are gaining momentum because they improve heat transfer potential , eliminate biological concerns and reduce the risks associated with damaging IT gear in the event of a leak . These fluids , PG25 or refrigerant , are circulated in a closed loop , normally by a Coolant Distribution Unit ( CDU ) mounted in the rack or externally , that interfaces with facility-chilled water or refrigerant that ultimately transports the heat to the atmosphere .
A new approach introduced by Munters and ZutaCore integrates Munters SyCool ( thermosiphon-based heat rejection ) with ZutaCore ’ s HyperCool ( in-rack two-phase thermal management system ). This novel waterless approach provides endto-end two-phase heat rejection .
ASHRAE and OCP ( Open Compute Project ) offer guidance for liquid cooling designs . For ASHRAE , the full suite of their documentation is available by subscribing to its Datacom Encyclopedia . OCP has multiple ongoing working groups , and one focused on fluid pipe distribution .
• Hybrid cooling
Hybrid cooling combines both air and liquid cooling methods . The heat from CPUs and GPUs is removed with liquid ( PG25 or refrigerant ) delivered to cold plates , while most other server components are air-cooled . Typically , 70-85 % of server heat can be liquid-cooled , leaving a residual of 15-30 % to be aircooled . Moving forward , it is likely
www . intelligentdatacentres . com 75