In close cooperation with hyperscalers and server OEMs, Rittal has developed a modular cooling distribution unit (CDU) that delivers a cooling capacity of over 1 MW. It will be the centerpiece exhibit at Rittal's booth A24 at 2024 OCP Global Summit. The CDU uses direct liquid cooling based on water - and is thus an example for new IT infrastructure technologies that are enablers for AI applications.

New technology, familiar handling?
"To put the technology into practice, it is not enough to simply provide the cooling capacity and integrate the solution into the facility - which also still poses challenges," says Lars Platzhoff, Head of Rittal's Business Unit Cooling Solutions: "Despite the new technology, the solutions must remain manageable by the data center team as part of the usual service. At best, this should be taken into account already at the design stage."OCP as a model for user-centered design
How does this work? With modularisation and the design advantages of the Open Rack V3, the development of which Rittal has driven forward in the Open Compute Project (OCP): Following the OCP design example of the power supply, the server in the rack is connected to the central inlets and outlets of the water circuit via standardised connections at the manifold. Power is supplied via the rack's standardised DC busbar. Functional units of the CDU such as the central controller unit and several coolant circulation units (CCUs) are completely modular and can be easily slid into the rack. This concept offers a major benefit in terms of service: Components such as controller, sensors, filters and the pump units of the In-Row solution can be maintained during operation and easily replaced via "hot swap". The structure is designed in such a way that the modules can be moved in a similar way to the usual handling of servers.

What will become the next best practice? And how?
"We are convinced that the powerful liquid-to-liquid solution will be a crowd puller at the 2024 OCP Summit. This kind of set-up will be used mainly by hyperscalers and other operators of large data centers," Platzhoff explains: "The approaches taken by international hyperscalers after extensive testing will quite probably set the standards in the medium term. But the agile colocation sector cannot wait so long." Most colocators are highly customer-focused and want to rapidly offer their customers good conditions for AI and HPC as well. Several of them are also planning data centers with liquid-to-liquid solutions. Rittal will also offer alternatives without the need for a water connection. The liquid-to-air versions cool the processors with water but dissipate the heat into the air through the rear door of the rack or a side cooler. They do not achieve the same cooling output and efficiency as liquid-to-liquid solutions, but they can be deployed more quickly in data centers without a water connection. Thus, they enable data center operators to perform their tests with less effort and investment or to create individual 'HPC islands' in air-cooled data centers for their users. These versions have a leverage function, bringing direct liquid cooling into data centers as an enabling technology for AI," Platzhoff explains.