A CDU separates the facility’s main cooling loop from the loop at the server rack, controlling flow, pressure and temperature for stable, precise cooling. It also keeps the facility’s water supply separate from the purified water used on the rack side. NGC offers active (10–50 kW) and passive (300–500 kW) platforms to match different rack densities. Both are built for straightforward integration into new or existing data center infrastructure.

It depends on rack density and whether you need active pumping or a passive, pressure-driven design. High-density AI and HPC racks typically need active CDUs (10–50 kW) for tighter flow control and faster response to load changes — adjusting within 1-2 seconds. Larger-scale deployments can use passive CDUs (300–500 kW), built for higher total capacity. Facility temperature range and available space also factor into the right choice.

Active CDUs use built-in pumps for precise flow control at smaller scale (10–50 kW), while passive CDUs use a modulated valve to move coolant at much larger loads (300–500 kW). Active units offer tighter, faster response to load changes — adjusting within 1-2 seconds, versus 6-8 seconds for passive. The right choice depends on rack density, workload variability, and available facility infrastructure.