HVAC | Chilled Water Distribution

Keep the Servers Cool. Keep the Harmonics Clean.

VFDs that optimize chiller plant efficiency without polluting the power that feeds your data center.

Primary chilled water pumps circulate thousands of gallons per minute through chiller evaporators and building distribution loops. In mission‑critical facilities—data centers, hospitals, semiconductor fabs—pump reliability directly impacts equipment uptime. Yet standard VFDs introduce harmonic currents that interfere with sensitive electronics and may violate IEEE 519 compliance at the point of common coupling. Drawing on over…

The Hidden Costs of Unfiltered Pump Drives

- We shold know the pain point! -

Harmonics corrupt sensitive electronics

Unfiltered VFDs inject harmonic currents into the facility's power distribution. In data centers, this translates to server power supply stress, UPS input filtering issues, and unexplained equipment resets.

IEEE 519 compliance failures

At the point of common coupling, total harmonic distortion (THD) exceeding 5% may violate utility interconnection agreements. Penalties and mandated remediation follow.

Low ΔT syndrome wastes chiller capacity

Constant‑speed primary pumps deliver fixed flow regardless of cooling load. At part‑load conditions, chilled water return temperature drops—reducing chiller efficiency and limiting plant capacity.

Motor bearing damage from common‑mode voltage

VFD‑generated common‑mode voltage induces shaft currents that arc through motor bearings. Over time, bearing fluting and premature failure interrupt critical cooling loops.

Clean Power. Efficient Cooling. Uninterrupted Operation.

- How We Solve It? -

We address both efficiency and power quality through an integrated drive design that includes a minimum 3% impedance DC‑link choke and built‑in EMC filters compliant with C3 emission limits—reducing input current THD to levels that meet IEEE 519‑2022 recommendations without requiring external harmonic traps or active filters. Near‑unity power factor (>0.98) is maintained across the pump’s entire operating speed range, eliminating reactive power penalties on utility bills. Our optimized PWM switching algorithm reduces common‑mode voltage and dv/dt stress, mitigating the risk of bearing electrical discharge machining (EDM) damage without requiring shaft grounding rings or insulated bearings in most installations. For chiller plant optimization, the VFD accepts a 4–20 mA ΔT setpoint from the building automation system, adjusting primary flow to maintain design temperature differential across the evaporator bundle—preventing low ΔT syndrome and maximizing chiller plant capacity. Integrated flying start capability allows seamless transition to VFD control on pumps already spinning from bypass operation.