Liquid Cooling CDU
Liquid cooling CDU systems deliver coolant from 300 kW to 1.2 MW for 120 kW+ AI racks.
Liquid cooling is mandatory above 120 kW
Wedbush projects AI racks cross 120 kW per cabinet in 2026, and liquid cooling stops being an option. At that density, air cooling cannot reject the heat within a standard 19-inch envelope, so the coolant loop becomes part of the power train. Procurement teams now treat the CDU as a critical-path item, not an accessory.
A coolant distribution unit (CDU) sits between the facility water and the rack loop, pumping dielectric or treated water through cold plates and manifolds. CDU units span 300 kW to 1.2 MW cooling capacity per unit, which matches current GPU tray and rack-scale loads. With roughly half of planned US data centers delayed or canceled in 2026, cooling-readiness is often the difference between a build that ships and one that stops.
CDU specification matrix
| Parameter | Value |
|---|---|
| Cooling capacity | 300 kW to 1.2 MW per CDU |
| Primary loop interface | Facility chilled water or dry cooler, 8-20 °C supply |
| Secondary loop | Rack-side coolant, 35-60 °C return, low conductivity |
| Pump redundancy | N+1 or N+N redundant pump sets |
| Cold plate compatibility | GPU trays per OAM and ORv3 layouts |
| Manifold design | Row-level or rack-level supply and return headers |
| Quick connects | UQD / dripless, hot-swappable line-replaceable units |
| Filtration | ≤ 50 micron particulate, optional ion exchange |
| Leak detection | Cable and point sensors with dry-contact alarms |
| Controls | Modbus TCP / BACnet IP, flow and ΔT monitoring |
Primary vs secondary loop
The CDU separates the facility primary loop from the rack secondary loop with a heat exchanger. Isolation keeps facility water chemistry, pressure and flow independent from electronics-cooling coolant, and lets each rack run at the temperature and flow its cold plates need. This architecture also simplifies commissioning because the secondary loop can be pre-filled, pressure-tested and flushed before it connects to the rack.
- Primary loop: facility chilled water, 8-20 °C, built to plant piping codes.
- Secondary loop: treated coolant, often 35-60 °C return, low conductivity for electronics.
- Heat exchanger: brazed plate or gasketed plate with approach temperature 1-3 °C.
- Pumps: redundant variable-speed drives sized for rack load.
- Controls: flow, pressure, conductivity and leak alarms per CDU.
Liquid cooling capabilities
Liquid cooling CDU FAQs
Plan your liquid cooling transition
Roughly half of planned US data centers were delayed or canceled in 2026 — don't let cooling capacity be the reason. Work with DC Power to shortlist audited CDU, cold plate and manifold suppliers before the backlog tightens.
