The Trend of Data Center Cooling – Immersion Cooling Technology

Immersion cooling is achieved by immersing computer components such as CPU, GPU, SSD and DDR memory, as well as other electronic components including the complete server, in a completely heat-conducting dielectric fluid or coolant, and then cooling through a circulating system using liquid pumps, pipes, liquid-liquid heat exchangers and/or dry cooler to remove heat from the dielectric fluid/coolant.

The common dielectric fluid for immersion cooling of electronic components includes mineral oil-based or completely synthetic chemicals. These chemicals are divided into 2 major types of applications: single-phase liquid immersion coolant(SLIC) and two-phase liquid-gas immersion coolant(2PIC).

Immersion cooling is becoming a popular cooling solution for data centers worldwide, especially for the eco-friendly data centers, because it does not need to install expensive air-cooling infrastructure (including on-board server fans), and it can greatly save energy.

The on-board server fans can be removed from the system before immersion, because the servers and other IT hardware cooled by immersion cooling do not need fans to circulate the dielectric fluid. The hydrocarbon-based heat transfer paste, which is usually used with the heat sink on the CPU and other chips, needs to be replaced with different compounds to avoid its dissolution in the coolant. Indium foil and thermal conductive epoxy resin are often used as substitute materials.

The temperature used in liquid immersion cooling depends on the maximum temperature at which the immersed equipment can reliably operate. For servers, this temperature range is usually between 15° C and 65 ° C, but for ASIC-based cryptocurrency miners, this range can be extended to 75 ° C. The increase in temperature range allows data center operators to use dry coolers instead of air cooler, and also to use SLIC to more effectively utilize the changes of ambient temperature to obtain more effective cooling, because the effectiveness of single-phase systems is not limited by boiling points.

SLIC will not change phase, nor will it evaporate in the air, and it is not necessary to seal the cooling system to ensure that the evaporation liquid is recaptured. This also makes it easier to uninstall or replace server components, improving the maintainability of the system. Compared with SLIC, 2PIC is a coolant that changes from liquid to gas at low temperature. When immersed in 2PIC, the heat generated by the server is enough to make the coolant evaporate to gas. The gas is then captured by the condensing system, which condenses the gas into liquid, otherwise it will evaporate. The cost of 2PIC is much higher than SLIC and 2PIC system has to be closed.

Intel, Mega and other related brands have verified the advantages of immersion servers.

At present, the commercial applications of immersion cooling include commodity server cooling solutions for data centers, server clusters, HPCC applications and Bitcoin mining, mainstream cloud-based web hosting architecture, and electric vehicle and battery manufacturers also use immersion cooling in batteries, power transmission system, kinetic energy recovery systems, motors, motor controllers and other on-board electronic subsystems. Immersion cooling is also used for thermal management of LED, laser, X-ray machine and magnetic resonance imaging equipment.

Dalian Yongsung Refrigeration Co., Ltd. provides “Preferref” dry cooler for immersion cooling, who has expertise and experience in the industry.