The short answer is decided by where the pump sits: use a brushless DC cooling pump inside rack-level CDUs and server loops, and use a 380 V AC multistage cooling pump in the facility plant room and distribution network. The two pump classes do not compete — they divide the building by flow scale, voltage, and head. DC pumps move liters per minute at 12–48 V; AC multistage pumps move cubic meters per hour at 380 V. This comparison lays out the trade-offs side by side and shows how the two tiers work together.

The Bottom Line by Tier

Read the table as a routing rule: if your circuit lives inside a rack, it is a DC decision; if it spans the hall, it is an AC decision.

Why Brushless DC Pumps Win Inside the Rack

Inside a rack-level CDU, space is tight and the loop is short, so compactness and controllability matter more than raw flow. DC brushless pumps fit that envelope:

They run on the same low-voltage bus as the rack — 12 V legacy, 24 V mainstream, 48 V OCP/AI.

Their flow and head match single-rack loads. The P4552 (24 V, 11 L/min, 11 m, 28 W) covers light loops, and the P6092 (24 V, 25 L/min, 27 m, 88 W) covers high-head dual-rack loops.

They are easy to vary with a control signal, which matters because pump speed directly affects PUE.

Why AC Multistage Pumps Win in the Plant Room

Facility loops push coolant across the whole data hall — risers, headers, long pipe runs, and the heat exchanger. That volume calls for a different machine:

Flow is the sum of many rack demands, measured in m³/h. The SP8/20-0.8 (380 V, 3–15 m³/h, 15–30 m, 800 W) and the larger SP8/30-1.1 (380 V, 3–17 m³/h, 17–32 m, 1100 W) cover small and mid-size distribution circuits.

Head comes from distance and components, not cold plates — long pipe runs and filters need sustained multistage pressure.

380 V three-phase power is already on site, so large kilowatt loads distribute efficiently.

How the Two Tiers Work Together

Modern liquid-cooled halls use both. The facility AC pump feeds the distribution network at the manifold; each rack CDU closes its own loop with a DC pump. This two-stage design decouples the building circuit from the rack circuit, so a problem at one rack does not ripple through the hall. The market is moving in exactly this direction: the data center liquid cooling market is forecast to grow from USD 6.77 billion in 2026 to USD 18.79 billion by 2031, a 22.65% CAGR (Mordor Intelligence), and that growth pulls demand for both pump classes at once.

FAQ

Q: Which pump is better — DC or AC?

A: Neither is universally better. Brushless DC pumps suit rack-level CDUs and server loops; AC multistage pumps suit facility distribution. Choose by the tier your pump serves.

Q: Can I use a DC pump for facility distribution?

A: Not practically. Facility circuits need m³/h flows over long distances, which low-voltage DC pumps (rated in L/min, tens of watts) cannot deliver.

Q: Can I use an AC multistage pump inside a rack CDU?

A: No. Rack loops are short and compact, and a 380 V, multi-hundred-watt pump would be oversized, inefficient, and impossible to package.

Q: What voltage should a rack CDU pump run on?

A: Match the rack: 12 V for legacy nodes, 24 V for most current racks, 48 V for OCP and AI architectures.

Q: Does pump choice affect PUE?

A: Yes. Pump efficiency and right-sizing directly affect PUE, which is why variable-speed DC pumps at rack level and well-matched AC pumps in the plant both matter.

DC and AC Cooling Pumps from Shenpeng Technology

Shenpeng Technology supplies both sides of the comparison: brushless DC pumps for rack-level CDUs, including the P4552 (24 V, 11 L/min, 11 m, 28 W) and P6092 (24 V, 25 L/min, 27 m, 88 W), and 380 V AC multistage SP-series pumps for facility distribution, including the SP8/20-0.8 (3–15 m³/h, 15–30 m, 800 W) and SP8/30-1.1 (3–17 m³/h, 17–32 m, 1100 W). Contact our engineering team with your loop layout — we will map out which pump class belongs at each tier of your data center cooling pump design.