AI Compute Is Reshaping Data Center Cooling Loads

Cooling demand in data centers is growing with AI compute. Higher-density racks and sustained high utilization mean cooling systems that were sized for steady, moderate loads now run harder and for longer. Two consequences follow. First, more airflow and more pressure capability are needed per unit of floor area. Second, and more important for operating cost, virtually no data center cooling plant runs at its design point continuously — it spends most of its life at part load, tracking IT load, ambient conditions and redundancy requirements.

Why Part-Load Efficiency Decides Fan Selection

An AC induction fan motor is at its best efficiency near full load. When airflow is reduced by damper, inlet vane or variable frequency drive, the motor and the fan's operating point move away from that optimum. Fan laws make the penalty visible: at 80% speed, flow falls to 80%, pressure to 64%, and shaft power to roughly 51% of the full-speed value. The AC motor, however, does not necessarily give up its losses at the same rate, and a VFD adds its own losses.

EC (electronically commutated) motors behave differently. A permanent-magnet rotor and integrated commutation electronics mean the motor retains high efficiency across a wide speed range, and speed control is built into the motor rather than added downstream. In practical terms, an EC fan gives high efficiency at part load compared with an AC fan, which is exactly the operating regime a data center cooling fan spends most of its hours in.

Where EC Fans Fit in the Cooling Chain

  • Precision cooling units — backward-curved centrifugal fans matched to the unit's internal resistance and ductwork.
  • Dry coolers and air-cooled fluid coolers — axial fans moving large volumes against moderate resistance.
  • Cooling towers — axial fans, with attention to humid, corrosive air paths and to the exposure of motor electronics.

The choice between an EC axial fan and an EC centrifugal type follows normal fan engineering: axial for high flow at low to medium pressure, backward-curved centrifugal for higher pressures and more stable operation when system resistance varies.

What SINDFAN Is Developing

SINDFAN is developing EC axial and centrifugal fans for cooling towers, dry coolers and precision cooling. Target duty classes, aligned with what industry peers currently offer, are 630–910 mm axial and 450–630 mm backward-curved centrifugal. These sizes cover a large share of the airside duty in liquid cooling and precision cooling equipment.

Available Today: Standard and Custom Fans

While the EC range is in development, SINDFAN supplies standard axial fans from Ø250 mm to Ø3150 mm. Every unit is AMCA 210 tested, and rotors are dynamically balanced to ISO 1940 G4.0. Custom impellers are available on an OEM basis, which is often the practical route when a cooling unit designer needs a specific hub, blade angle set or mounting interface.

Specifying an EC Fan: What to Ask For

  • The actual duty point, not the nominal one — flow and static pressure at the design condition.
  • The part-load curve, so energy use can be compared at 50%, 70% and 100% speed.
  • The control interface, and how it integrates with the unit controller.
  • Ambient and air-stream temperature at the motor electronics, since commutation electronics have their own thermal limits.
  • Balance grade, test standard, and the documentation that comes with them.

First cost for EC fans is generally higher than for comparable AC units, so the justification rests on measured part-load energy and on reduced control hardware. A supplier who can show the part-load curve alongside the peak duty point makes that comparison possible.

Contact SINDFAN

Send your duty — flow, static pressure, speed, ambient temperature and control requirements — and SINDFAN will advise on the closest standard axial fan or discuss a custom impeller. Contact us on WhatsApp +852 9524 8434 or by email at info@sind-tech.com.