It’s back to the future when it comes to cooling data center servers. In the era of mainframes, liquid cooling was an important method to cool silicon. But when the microprocessor took over to power general purpose computing, air cooled systems went mainstream. Today’s data centers have been outfitted mostly with air cooled infrastructure but with AI, liquid cooling is back and is one of the most important topics in AI server designs. In fact, direct liquid cooling is the future of energy-efficient data centers, according to Seguente Inc., a global energy and thermal management company, which participated in a panel on theCUBE at SC24. 

Seguente collaborates with server vendors such as Lenovo and Dell Technologies Inc. along with Nvidia Corp. to transform existing computing racks so that the cooling mechanisms are more sustainable and support higher workloads.

Seguente’s Raffaele Luca Amalfi, Dell’s Tim Shedd and Nvidia’s Dion Harris discuss their collaboration.

“Cooling is just a tool to enable energy-efficient computing,” said Tim Shedd (pictured, left), engineering technologist, Office of the CTIO, at Dell Technologies Inc. “What we did with the H100 servers … we’re deploying those 64 GPUs with a rear door heat exchanger. So, we liquid-cooled the rack while keeping water out of the chassis. It turns out that addressed a whole bunch of TCO energy efficiency and the ability to deploy very quickly to the customer met all those requirements all at once.”

Shedd, Raffaele Luca Amalfi (right), co-founder and chief executive officer of Seguente, and Dion Harris (second from left), director of accelerated data center GTM at Nvidia Corp., spoke with theCUBE Research’s Dave Vellante at SC24, during an exclusive broadcast on theCUBE, SiliconANGLE Media’s livestreaming studio. They discussed the difference between air and direct liquid cooling and how the latter could change computing. The group also discussed alternative direct to chip liquid cooling methodologies including warm water, hybrid liquid/air, phase change and immersive cooling. (* Disclosure below.) 

Currently, Dell, in response to guidance from the Open Compute Project (OCP) is a pursuing warm water liquid cooling. Seguente on the other hand is a proponent of phase change liquid cooling, a technology that involves changing the state of a thermally conductive medium from a liquid to a gas, and back, creating a heat exchanger. 

Saving energy with direct liquid cooling

New chips and systems from Nvidia are driving the need for liquid cooling and direct to chip approaches. Seguente is one of many companies supporting the shift from indirect to direct liquid cooling, where the liquid is in the cold plate right on top of the GPU. This allows for a more densely compact compute rack, according to Nvidia’s Harris.

“Nvidia is no longer selling a GPU,” he explained. “We’re really selling customers a data center. We’re looking at lots of different innovative ways to give more performance out of that computing stack, out of that networking stack. And oftentimes it involves driving more compute density, which therefore requires different innovations, whether it be through liquid cooling, through the bus bars, through the entire infrastructure that supports the specific computing infrastructure.”

Seguente claims its solutions are also more sustainable. Amalfi emphasized the company’s novel Coldware technology, which can capture and dissipate heat, saving energy within the entire system. He explained that his systems use the power of mother nature and physics to eliminate the need for complex and expensive pumping systems. Further Amalfi claimed stressed that new innovation is needed from a sustainability perspective and that phase change technology supports that imperative.  

Dell’s Shedd discussed the importance of sustainability and how the company is scaling today’s AI servers using proven solutions that are cost effective. “The rear door [solution] will allow us to basically capture the heat before it goes into the aisle of the data centers so that you can basically offload some of the energy consumption on the HVAC systems…If we can capture the heat at a high temperature, then we will be very sustainable because we get directly used.”

Since customers will have to retrofit existing data centers, Shedd and Harris foresee a lot of hybrid air and liquid cooling solutions. Their goal is to meet the customers where they are, with an eye toward long-term sustainability and efficiency.

“Instead of hot aisles and cold aisles, we’re talking about wet aisles and dry aisles now,” Shedd said. “We’re going to be distributing liquid through in one aisle and feeding liquid to those racks and maybe to redo heat exchangers. What this does is kind of opens up space, it opens up the operating environment so that we’re no longer constrained by all of the challenges of getting air to the racks.”

Here’s the complete video interview, part of SiliconANGLE’s and theCUBE Research’s coverage of SC24:

(* Disclosure: TheCUBE is a paid media partner for SC24. Neither Dell Technologies Inc. and WekaIO Inc., the premier sponsors of theCUBE’s event coverage, nor other sponsors have editorial control over content on theCUBE or SiliconANGLE.)

Photo: SiliconANGLE