New megawatt cooling for AI from Rittal

The new modular bayed solution delivers cooling capacity of over one megawatt, ideal for the high power density of AI applications thanks to direct liquid cooling.
The possibilities offered by artificial intelligence seem enormous. In June 2023, McKinsey predicted that the increase in productivity through GenAI could add between 2.6 and 4.4 trillion US dollars a year to the global economy. "If even part of this is to be realized, the IT infrastructure must grow as quickly as possible and be rethought technologically in key areas," says Philipp Guth, CTO on the Management Board of Rittal International.

Modular cooling solution

The power density for AI applications such as the training and operation of large language models (LLMs) in future data centers or the already widespread high performance computing will quickly push today's conventional air cooling to its physical and economic limits. The new, ultra-fast graphics processors (GPUs) produce so much heat that manufacturers are designing them for powerful direct liquid cooling. In close cooperation with several hyperscalers, Rittal has developed a modular cooling solution that delivers a cooling capacity of over 1 MW with direct water cooling - making the required power densities achievable in the first place. "In order to enable the rapid expansion of infrastructure technically, economically and organizationally, a high degree of standardization and scalability through modular design and global availability is required," says Guth.

Rittal uses Coolant Distribution Units for single-phase direct liquid cooling with water, which are designed for particularly easy serviceability. Philipp Guth, CTO Rittal International: "In order to implement the rapid infrastructure expansion technically, economically and organizationally, a high degree of standardization and scalability through modular design and worldwide availability is required." How does this work? With modularization and the design advantages of the Open Rack V3, whose development Rittal has driven forward in the Open Compute Project (OCP): Following the example of the power supply, the server in the rack is linked to the central supply and drainage of the water circuit using standardized connections. Functional units such as the central controller unit and several coolant supply units (CCUs), depending on the performance requirements, are completely modular and are simply pushed into the rack. They guarantee high availability thanks to n+1 redundant design. Leakage monitoring starts at component level. This concept offers a significant advantage when it comes to servicing: components such as controllers, sensors or the pump units of the in-row solution can be serviced during operation and easily replaced via "hot swap". Power is supplied via the standardized DC busbar in the rack.

Over one megawatt cooling capacity

"The combination options of the platform modules are designed for high flexibility. They complement the Rittal system range as additional building blocks with coordinated modules for all pillars of the data center OT, such as rack, cooling, power, monitoring and security," explains Lars Platzhoff, Head of the Cooling Solutions business unit at Rittal.

The liquid-to-liquid solutions cool as a bayed solution for racks over 1 megawatt, in single rack units up to 100 kW. They are also ideal for reducing the CO2 footprint through heat recovery. To this end, Rittal uses its experience to provide support right from the data center planning stage to ensure that the heat is efficiently transferred from the manifold in the rack to its further use, for example in district heating networks.

Liquid-to-air variants are also available for data centers without a water connection, which dissipate the heat at the rear rack door or via a side cooler as a closed system to the air in the data center.

Infrastructure directly in the rack

"Power, cooling and monitoring are increasingly being integrated directly into the standardized rack as fundamental pillars of the IT infrastructure. The main drivers of this trend are several hyperscalers and server OEMs, which we supply with racks as their main supplier," says Guth: "We are convinced that this concept will soon become the standard for our global IT customers due to the need for ever higher performance and rapid scaling. In addition to hyperscalers, it will also become interesting for more and more colocators."

The compact integration into the rack and the modular design simplify the handling and servicing of the new technology in data center operations. Rittal offers its customers flexibility: "We are not limiting ourselves to the Open Rack V3 in 21 inches. There are also variants for our VX IT racks in 19 inches," says Platzhoff. Full integration into the Rittal system platform is a relevant lever for rolling out the necessary infrastructure for AI applications on a large scale - from large hyperscale data centers to small enterprise data centers. "Direct Liquid Cooling is the enabling technology for AI. Our development has been inspired by our major global customers and Rittal's many years of experience in IT and industry - 20 years of HD IT cooling and over three decades of climate control for controllers, circuits and machines under the toughest industrial conditions," explains Platzhoff: "We want to make the result available to customers of all sizes as quickly as possible."