Meta has detailed how it can introduce higher-density liquid-cooled GPUs into air-cooled data centers designed for much lower rack densities.

As noted by semiconductor research firm Semianalysis and WCCTech this week, the company outlined a six-rack design featuring two liquid-to-air cooling side pods to one rack of high-density compute.

Meta first debuted a new liquid-cooled rack designed to host Nvidia GB200 Blackwell chips last year, known as Catalina, that was able to support up to 140kW.

At Hot Chips this week, Meta showed off its NVL36x2 rack configuration Catalina pod. Adapted from Nvidia’s NVL72 offering, which comes equipped with GB200 GPUs, the Catalina pods can be used in 20kW air-cooled data centers.

For two 120kW racks of compute – each rack featuring 18 compute trays (72 Grace CPUs and 144 Blackwell GPUs) and nine NV switches, Meta utilizes four racks of cooling racks (two on each side). The air-assisted liquid cooling sidebar racks convert the cool air into cooled liquid.

SemiAnalysis noted the six-rack deployment “isn't too significant, as colocation charges rent by kW for hyperscale customers and not by the square footage.”

Meta paused development of around a dozen data centers in late 2022 as part of a "rescoping" of its designs to better cater to GPUs and liquid cooling. It has since resumed its build-out with the updated design. The company recently said that its first data centers with AI-optimized designs are slated to come online in 2026, and will “blend high-performance and flexibility with a mix of custom hardware solutions.”

Meta has around 30 data center campuses live or in development, with more in the pipeline, including plans for gigawatt-scale developments. The majority of its footprint is within the US. It is also a major lessee of facilities. Meta is building out at such a pace that the company is placing IT hardware in large temporary tents in some locations.

Liquid-to-air systems take cool air from the data floor, and run it through a local heat exchanger, which is used to cool a local closed-loop liquid cooling systems.

With such systems, companies like Meta can deploy higher-density liquid-cooled racks in facilities not tailored for such dense compute needs - as long as they are willing to sacrifice space for extra power and cooling equipment.

Microsoft has deployed its own liquid-cooled side pod to retrofit into air-cooled data centers. The company’s newer data center designs are designed to be optimized for liquid cooling. Newer designs will opt for a closed-loop, zero-water evaporation design.

Microsoft, Meta, and Google are working with OCP partners to design a new power rack side pod that the companies say will enable IT racks to reach densities of up to 1MW per rack. Announced last year, the design is known as Project Diablo.