Sponsored: In-Rack CDU V. Floor-Mounted CDU: Which Option Is Better for Your Data Center?

Why It Matters

Selecting the right CDU architecture directly impacts data‑center efficiency, capital expenditure, and the ability to scale AI compute without overheating constraints.

Key Takeaways

• In‑rack CDUs serve single racks, handling 100‑300 kW loads
• Floor‑mounted CDUs support multiple racks, optimal above 300 kW
• In‑rack units save floor space but consume rack space
• Floor‑mounted CDUs centralize cooling, simplifying service and scalability
• Motivair’s MCDU‑70 scales from 105 kW to 2.5 MW, fitting both layouts

Pulse Analysis

Liquid cooling has become a cornerstone for modern data centers that host AI and high‑performance computing (HPC) workloads. As GPUs and ASICs push power densities beyond 200 kW per rack, traditional air‑cooling struggles to maintain thermal stability. CDUs act as the circulatory hub, moving chilled liquid from heat exchangers to server components in a closed loop. Their placement—either embedded within the rack or mounted on the floor—determines how efficiently heat is removed, how much rack real estate is sacrificed, and the overall complexity of the plumbing infrastructure.

In‑rack CDUs offer a self‑contained solution, eliminating long hose runs and reducing distribution losses. This architecture is best suited for isolated, high‑density racks where power draw stays between 100 kW and 300 kW. However, the trade‑off is reduced usable rack space, which can limit the number of servers per unit. Floor‑mounted CDUs, by contrast, centralize cooling for clusters of racks, making them cost‑effective for deployments exceeding 300 kW. While they introduce longer piping and require careful under‑floor or overhead routing, they free up rack space for additional compute and simplify maintenance through a single access point.

The market is responding with flexible solutions like Schneider Electric’s Motivair MCDU‑70 series, which can be configured from 105 kW up to 2.5 MW per unit. This scalability lets operators start with in‑rack installations for pilot projects and transition to floor‑mounted configurations as demand grows. As AI workloads continue to expand, the ability to adapt CDU placement without wholesale infrastructure overhaul will be a competitive advantage, driving broader adoption of liquid‑cooling architectures across hyperscalers and enterprise data centers alike.