Standards Development

Scope

This technical specification covers the aspects of the integration of liquid cooling components in electronic enclosures in the IEC60297 series of standards. Only components that are required for processor cooling without phase change are considered. The design of liquid cooling within information technology components such as servers is only described in the technical specification with regard to their liquid transfer interfaces. The design within the server is excluded from the description. The hydraulic connection outside the enclosure up to the heat transfer unit is also only considered up to the interface at the enclosure inlet and outlet.

The liquid distribution network for processor cooling within the enclosure in accordance with IEC 60297 is the subject of the technical specification. The interactions with other infrastructure components such as the cables for data transmission and the equipment for the distribution of electrical energy are taken into account.

The handling of the liquid cooling components and their arrangement in the enclosure are described. The interaction with the remaining air cooling is also the subject of the technical specification.

The thermal and hydraulic requirements for the liquid distribution network are described. The requirements for corrosion protection, the purity of the liquid networks and the need to prevent biological growth are mentioned.

Purpose

This technical specification covers the aspects of the integration of liquid cooling components in electronic enclosures in the IEC60297 series of standards. Only components that are required for processor cooling without phase change are considered. The design of liquid cooling within information technology components such as servers is only described in the technical specification with regard to their liquid transfer interfaces. The design within the server is excluded from the description. The hydraulic connection outside the enclosure up to the heat transfer unit is also only considered up to the interface at the enclosure inlet and outlet.

The rapidly growing global demand for information and communication technology applications with artificial intelligence and the widespread use of high-performance computers are causing energy requirements in information technology to increase almost exponentially. The development of powerful processors, especially graphics processors, which are particularly suitable for applications with artificial intelligence, has led to a further significant increase in the packing density of integrated processors.

For the operation of this computing technology, it is necessary to build it at a very small volume, especially to enable the internal transfer of very large amounts of data with minimal latency times. It is also advantageous and cost-effective for the design and operation of data centers to build them as compactly as possible.

As the electrical energy consumed during data processing is almost completely converted into heat, the effective dissipation of heat at extremely high heat flux is extremely important. Many data center operators do not want to do without changing the traditional design of installing computing technology in enclosures in accordance with the IEC 60297 standard series or similar. This leads to heat quantities in the enclosures that can be well over 100 kW today. It is expected that in the next few years, the amount of heat will increase to 200 kW per enclosure and later even up to 500 kW per enclosure.

The increasing density of the circuits in the integrated semiconductor components leads to heat flux on the surfaces of the processors that can no longer be dissipated economically and in a reasonably designed installation space with air cooling. Due to its low density as a gas mixture and its relatively low specific heat capacity, air reaches its physical limits as a medium for material-heat transport for cooling the latest generation of processors.

The budgets available to data center operators for electrical energy are limited. The solution to this problem lies in increasing the energy efficiency of the entire data center. The aim is to make the available energy primarily available to the servers and thus to the computing power.

As was the case several decades ago, liquid cooling offers an alternative to air cooling for the heat dissipation of high-performance processors. In this process, heat sinks through which liquid flows are mounted on the semiconductor processors. The heat is dissipated by increasing the temperature of the liquid, which is pumped to a heat exchanger station in a closed cooling circuit, where it dissipates the heat by means of a heat exchanger.

In most cases, water or a water-glycol mixture is used as the liquid, which is well suited as a cooling medium due to its high density and high specific heat capacity. The finely structured and complex design of the liquid- flow heat sinks places very high demands on the purity of the cooling liquid. Care must be taken to prevent contamination both during installation and operation. The use and monitoring of filters with very high filtration efficiencies is very important. The requirements for the coolant circuits are significantly higher than the chilled water circuits for air cooling, which are traditionally used in data centers to operate air cooling units, in-row coolers or rear door heat exchangers.