DECARBONIZING AI-FUELED DATA CENTERS OFFER PATHWAYS FOR LIQUID COOLING

Novel liquid cooling solutions are poised for growth and innovation as data centers experience a boom driven by exploding demand for AI and hyperscale computing, according to Cleantech Group

“Cooling solutions that can compete on performance, address the needs of higher-powered GPUs, and be easily integrated into data center infrastructure will see near-term growth,” -- Cleantech Group Associate, Energy & Power, Zainab Gilani

Liquid cooling technology innovators are seen as a beneficiary as data centers face new challenges of managing more sophisticated and higher-cost IT infrastructure and maintaining high performance levels. According to Goldman Sachs, ChatGPT-based searches, for example, consume nearly 10X more electricity than a simple Google search, and training generative AI models consume orders of magnitude more energy than training incumbent AI models. This, in turn, is expected to double electricity consumption at data centers by 2026, drastically raising demand for more efficient cooling technologies

Interview with Zainab Gilani

By Suzanne Forcese

WT: What are the challenges facing AI-fueled data centers?

Gilani: As demands for artificial intelligence and machine learning grow, the IT hardware, energy infrastructure and data center architecture needed to support these systems will have to adapt to keep up with these advancements. High-performance computers (HPC) will require chips and processors that operate differently than traditional chips used in most data centers.

Many of these chips require more energy, release more heat, and are packed together in racks that make it difficult for traditional air-cooled technologies to dissipate the heat effectively.

As a result, new types of cooling methods including various variations of liquid cooling will have to be used to address the needs of high-performance computers.

In addition to updating cooling technologies, data centers will also require a variety of energy systems to be deployed to meet the power needs.

Estimates suggest that the power consumed by data centers globally could double by the end of the decade - potentially requiring around 800TWh of power.

Ideally, much of this would be done through a mix of renewables such as wind and solar. However, standing up new projects and connecting sources of energy to data centers is a challenge. As a result, many data centers and utilities may turn towards natural gas to quickly meet power needs.

WT: Air cooled vs liquid cooling -- why is the latter the preferred approach?

Gilani: Air cooling is currently used in 80% of data centers worldwide. Many of these technologies work well for existing data centers that have rack densities of 10-15kW per rack

However, as data centers deploy IT systems and chips that are required for artificial intelligence, these systems may require power over 40kW which cannot easily be cooled using air cooling technologies.

Liquid cooling technologies offer higher heat transfer as systems use liquid to move heat away from the chips and cycle heat faster. These types of systems will likely be required as more and more data centers deploy powerful IT systems that require effective cooling systems.

WT: Are you seeing policy support for sustainable solutions?

Gilani: Policy support is encouraging new sustainable solutions and designs. The UK and Germany are among countries that are supporting reuse of waste heat generated by data centers and setting new power usage efficiency standards.

Initiatives in Sweden and the U.S. aim to phase out coolants that use PFAS that threaten to pollute food chains, while Chile has focused on environmental concerns arising over high levels of water requirements.

Iceland is leveraging its renewable energy mix and lower ambient temperatures, while China experiments with underwater modules.

WT: Are there specific cooling systems technologies that are now on stream?

Gilani: Within liquid cooling systems, technologies can be broken down into various categories. Two of these can include single-phase and two-phase immersion cooling and single-phase and two-phase direct-to-chip cooling.

Two-phase systems are when the liquid undergoes a phase change into a gas and pulls more heat away from the IT systems during that phase change. However, many liquid solutions that do this use PFAS-based liquids.

There are several solution providers that use the liquid form of PFAS which is different than solid PFAS and these liquid PFAS solutions can potentially have lower global warming potential and better sustainability impacts than solid PFAS.

WT: Please explain the difference in cooling systems.

Gilani:Direct- to-chip cooling solutions use a cold plate which allows fluid to pass through regions where the chip is releasing heat and moves heat away from those components and target areas which generate the most heat.

Microchannel direct-to-chip cooling solutions, which constitute most direct-to-chip cooling technologies, involve small channels on the cold plate that allow for fluid to pass through those sections. Besides high cooling efficiency, direct-to-chip technology offers several advantages. It mitigates risks associated with leaks and hardware/IT equipment reliability.

Microconvective liquid cooling uses perpendicular systems to better target hotspots using microjets. This technology has been advanced by a company called Jetcool which was recently acquired by Flex.

WT: What trends are you seeing in venture investments?

 Gilani: There's been quite a bit of activity in this space. Flex, raised $17M in 2023 with investors Bosch Group, In-Q-Tel, Raptor Group, and Schooner Capital. Accelsius, developer of two-phase, direct-to-chip liquid cooling system raised $24M in their Series A round recently. Zutacore is also advancing direct-to-chip liquid cooling solutions and partnered with Wiwynn to expand and develop their technology. Other companies that have also raised significant rounds this year include Liquidstack ($20M) and Submer ($55.5M).

Overall, data centers will require advanced cooling technologies to meet the needs of high-performance computers and the liquid cooling market will likely see several more investments and acquisitions in this space.

WT: Liquid Cooling has arrived.

Gilani: Liquid Cooling’s time has come. Rack densities that surpass 100kW cannot be managed by air cooled systems alone. They will require liquid cooling, which can be up to 300X more efficient. These technologies are especially needed for chips with high thermal design, or high-cost GPUs and other computing infrastructure that cannot risk breakdown.

Liquid cooling can be combined with incumbent air-cooling technologies, whose limitations include an inability to manage higher rack densities and an inability to scale.

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