Drives for industrial HVAC: ventilation and air conditioning
Industrial HVAC combines large boiler-house ID and FD fans, centrifugal and axial fans for general exhaust and emergency ventilation, tunnel ventilation fans for metros and highways, chiller plants with centrifugal and screw compressors, commercial-grade heat pumps and cooling towers on circulating water systems. Drive equipment runs S1 duty around the clock, and the key economic lever is flow control via VFDs, which delivers 25–30 % energy savings compared with damper throttling.
Industry-typical tasks
- Drives for ID and FD fans of large boiler houses and CHPs — HV motors 800–4,000 kW, 6/10 kV, VFD speed control
- Drives for centrifugal general exhaust ventilation fans in production buildings — 5.5–1,500 kW, continuous S1 duty
- Tunnel axial fans for metros and highway tunnels — 75–350 kW, reversible duty, smoke extraction in case of fire
- AHUs / make-up air units with heat recovery for industrial HVAC — 1.5–250 kW per section, soft starting
- Drives for centrifugal and screw chiller compressors — 250–2,500 kW, frequent starts
- Commercial-grade heat pumps for space heating and DHW — 75–800 kW, inverter control
- Drives for cooling-tower fans on circulating water systems — 22–315 kW, humid and corrosive environment
- Drives for dampers, butterfly valves, gates and inlet guide vanes — gear motors 0.12–7.5 kW with feedback
Motors for fans and compressors
HVAC motors are selected by two main criteria: continuous S1 round-the-clock duty and VFD compatibility, since airflow or compressor capacity is regulated through the inverter. A VFD saves 25–30 % electricity versus inlet-guide-vane throttling, so on new projects it is used almost universally. ID fans and compressors of large chiller plants require 6/10 kV HV motors with forced cooling.
HV motors for boiler-house ID and FD fans
HV induction motors 800–4,000 kW at 6 or 10 kV, 740–1,000 rpm, continuous S1 duty. The Wolong YHTM series with HVAC rating supports operation with an HV inverter and offers extended bearing life thanks to an insulated bearing on the coupling end. Rated efficiency above 96 %, which is critical for year-round operation.
- — Power rating 800–4,000 kW, voltage 6/10 kV
- — Insulated bearing (protection from shaft currents under VFD operation)
- — Class F insulation with class B thermal margin
- — Vibration monitoring per ISO 10816-3 zone B
- — IP55 plus dust protection at the air intake
Motors for centrifugal general exhaust ventilation fans
General-purpose induction motors 5.5–1,500 kW, 380/660 V, IE3/IE4, S1 duty. Suitable lines are Huali Y2/YE3/YE4 and Wolong WD1000 with copper windings and reduced windage losses. Large facilities use 315–1,500 kW motors with water-cooled enclosures (IC81W) to reduce noise in the plant room.
- — IE3 or IE4 efficiency class
- — VFD compatibility (class H insulation, NEMA MG1 Part 31 for P ≥ 110 kW)
- — IP55, tropical execution for southern regions
- — Rotor balancing to G2.5 (low vibration in fan rooms)
- — Bearings with extended re-greasing interval (10,000 h)
Motors for tunnel axial ventilation fans
Two-speed induction or VFD-driven motors, 75–350 kW. In normal duty they run at low speed for standby ventilation; in case of fire they switch to full power and reverse for smoke extraction. They must withstand 250–400 °C for 1–2 hours (F300/F400 classes per EN 12101-3). Wolong YGTd with heat-resistant insulation and Huali YHA are dedicated tunnel-fan series.
- — F300 or F400 certification (operation at 300/400 °C)
- — Two-speed design or operation with a reversible VFD
- — Reinforced class H insulation (180 °C)
- — IP55, protection against water during firefighting
- — Winding temperature monitoring via Pt100
Motors for chiller compressors and heat pumps
For centrifugal and screw chiller compressors — 250–2,500 kW with frequent starts (S4–S6, up to 6 starts per hour). Commercial-grade heat pumps of 75–800 kW use either inverter-driven permanent-magnet synchronous motors or induction motors with a VFD. The Wolong YHTM-HVAC series is specifically rated for chiller applications, with an extended bearing temperature range.
- — Thermal margin for S4–S6 (up to 60 starts per hour)
- — Class H insulation for VFD operation
- — Bearings with ceramic balls (protection from shaft currents)
- — Suitable for installation in the chiller room without a separate fan room
- — Low noise level ≤ 78 dB(A) at 1 m
Motors for cooling-tower fans
22–315 kW, low-speed (490–740 rpm) or with a step-down gearbox. They operate in a humid, corrosive environment with droplet carry-over, so IP56, anti-corrosion enclosure coating and a marine or tropical execution are mandatory. Suitable lines are Huali YHF and Wolong WD-CT with double bearing-shield seals and drain holes.
- — IP56 (protection against powerful water jets)
- — C4-H anti-corrosion coating (marine environment)
- — Tropical execution (T2/T3 per GOST 15150)
- — Double bearing seals
- — Stainless-steel anchor plates
Gear motors for dampers and low-speed drives
In HVAC systems gear motors drive air dampers, butterfly valves on compressors, flue gates, fan inlet guide vanes and rotary heat-exchanger wheels. The main requirements are a high reduction ratio for low-speed operation, accurate position control with feedback, long service life under frequent reversals (VAV dampers switch tens of thousands of times per year) and operation in the tight space of an AHU plenum.
Drives for control dampers and butterfly valves
Compact worm or helical-bevel gear motors Boneng K, S, R rated at 0.12–1.5 kW with ratios of 50–500. They are used in VAV (variable air volume) systems with frequent switching (up to 50 cycles per hour). Standard equipment includes limit switches and potentiometric or digital position feedback.
- — Power rating 0.12–1.5 kW, i = 50–500
- — Open/closed position limit switches
- — Feedback via 4–20 mA or Modbus RTU
- — Manual override (handwheel) for emergency operation
- — IP54, ambient temperature −20…+60 °C
Drives for flue and gas-duct gates
Boneng HB or K gear motors with a heat-resistant execution rated for gate-housing temperatures up to +200 °C are used on boiler-house and roof-mounted flue gas fans. Torque is transferred via a chain or gear reducer to the gate shaft. Service life is at least 100,000 open/close cycles.
- — Heat-resistant execution (thermal barrier from the gate)
- — Reduction ratio 200–800
- — Service factor of at least 1.5
- — Jam protection (torque limit relay)
- — Manual override and position signaling
Drives for fan inlet guide vanes
Capacity control of ID and FD fans via inlet guide vanes. Boneng F or K gear motors of 0.75–4 kW with digital feedback and an integrated positioner are used. They are gradually being displaced by VFDs, but remain widely used on legacy installations.
- — Positioning linearity ≤ 1 %
- — Full stroke time 30–120 s
- — Compatibility with the boiler-house DCS (Modbus, Profibus)
- — Thermal margin for up to 100 cycles per hour
- — Serviceability without dismantling the fan housing
Drives for rotary heat-recovery wheels
Large AHUs with heat recovery use rotary regenerative heat exchangers 1–4 m in diameter. The drive is a Boneng R or S gear motor of 0.12–0.75 kW with a ratio of 200–500, giving a wheel speed of 8–20 rpm. Power is transferred to the wheel rim by a belt or chain drive.
- — Low output speed (8–20 rpm)
- — VFD compatibility for recovery rate control
- — Long seal service life (≥ 50,000 h)
- — Foot-mount design with belt tensioner
- — Overload protection in case of wheel jamming
Fan couplings and brakes
Connecting the motor to a centrifugal or axial fan calls for a coupling that can absorb thermal shaft displacement after the machine warms up and dampen starting shocks. On large fans with a high rotor moment of inertia (thousands of kg·m²), after the motor is switched off the rotor coasts down for 5–15 minutes; disc brakes are used for emergency stops or to bring a standby unit online quickly.
Flexible pin couplings for general exhaust ventilation fans
Yongjing LX (LMC), Longxuan TL and Jiaohua YOXp series with elastomer bushings transfer torque from the motor to the centrifugal fan impeller. They dampen starting shocks and compensate for small radial shaft offsets after the bearings warm up. Elastomer service life is 30,000–50,000 h, with replacement possible without pulling the hubs.
- — Torque rating 1–63 kN·m
- — Radial misalignment compensation 0.2–1.0 mm
- — Balancing to G6.3 for n > 1,500 rpm
- — Option to integrate a brake drum
- — Oil-resistant elastomer, working range −20…+80 °C
Gear couplings for large ID fans
ID and FD fans rated above 500 kW use Yongjing GIICL and Longxuan WGZ drum gear couplings. They transmit high torque while compensating for shaft offsets caused by thermal expansion between the motor and the fan. Grease is applied through a fitting at six-month intervals.
- — Torque rating 50–630 kN·m
- — Angular misalignment up to 1.5°, axial up to 5 mm
- — Balancing to G6.3 at peripheral speeds > 15 m/s
- — Safety guard (per safety standards)
- — Lubricant level monitoring (sight gauge)
Centrifugal starting couplings
Yongjing and Longxuan centrifugal couplings ease the starting duty for motors driving large centrifugal fans and compressors with high inertia. On start-up the motor accelerates virtually unloaded, and engagement only occurs after the motor reaches 70–80 % of rated speed. This reduces starting current by 30–40 % and extends winding life.
- — Engagement torque 0.7–0.8 of rated
- — Thermal margin for up to 6 starts per hour
- — Steel-shot or roller-type design
- — Compatibility with direct-on-line starting or a soft starter
- — Balancing prior to installation
Brakes for fans with high coasting inertia
Huawu YPZ2/YWZ5 disc brakes with electrohydraulic actuators are used for emergency stops of large ID and tunnel fans after motor shutdown. They stop the rotor in 30–60 s instead of the natural coast-down of 5–15 minutes. This is critical for systems that require fast standby-fan changeover or personnel access for maintenance.
- — Braking torque margin of 1.5–1.75 over rated
- — Full stopping time 30–60 s
- — Electrohydraulic thruster Ed-50–Ed-201
- — Manual release for maintenance
- — Pad wear monitoring (limit switch)
Electronics, VFDs and heat exchangers
Modern HVAC economics rest on two pillars: VFDs for air or fluid flow control, and efficient heat exchangers on chilled water systems. Replacing damper throttling with a VFD delivers 25–30 % electricity savings on an annual cycle, with a payback of 1–3 years depending on the load profile. Plate heat exchangers on chilled water are 3–5 times more compact than shell-and-tube units and allow temperature approaches as close as 1–2 °C.
VFDs for centrifugal and axial fans
Inovance MD500/MD520 and INVT Goodrive HVAC inverters are optimized for variable-torque (quadratic) loads where torque rises with the square of speed. They include dedicated soft-start algorithms without inrush current, sleep modes under low demand, and PID control on a pressure or room-CO₂ sensor. Energy savings of 25–30 % versus inlet-guide-vane throttling.
- — Power range 0.75–2,500 kW (LV) and up to 6 MW (MV)
- — Built-in PID controller and sleep mode
- — Modbus RTU / Profibus / BACnet for BMS integration
- — EMC filter for installation in fan rooms
- — IP54 enclosure for cabinet-mounted units
VFDs for chiller compressors
Screw and centrifugal chiller compressors are driven by higher-power inverters Inovance MD810 and INVT GD350, 250–2,500 kW. Key features include an optional active front end (regenerative braking), precise control on chilled-water temperature, and integration with the chiller controller.
- — Power rating 250–2,500 kW, 380–690 V
- — Active front end (AFE) — option for larger machines
- — Compressor overload protection (S6, frequent starts)
- — Interface to the chiller controller (Modbus / CAN)
- — Harmonic distortion THDi ≤ 5 % (per GOST R 51317.3.2)
Plate heat exchangers for chilled water
In air-conditioning systems, DEO BR/SH heat exchangers separate the chiller's chilled-water loop from the secondary loop of indoor units (fan coils, condensing units). Plates are AISI 316 stainless steel; gaskets are EPDM (water) or NBR (glycol). They are compact: a 1 MW unit occupies 0.3–0.5 m³, which is 3–5 times less than a shell-and-tube exchanger.
- — Capacity 100 kW – 10 MW
- — Temperature approach 1–2 °C
- — AISI 316 plates, EPDM / NBR gaskets
- — Working pressure up to 1.6 MPa (standard) or 2.5 MPa (reinforced)
- — Gasketed design for cleaning and plate replacement
Oil coolers for compressors and fan gearboxes
Screw chiller compressors require continuous oil cooling through a heat exchanger. DEO DFL plate or shell-and-tube models are used. The same applies to gearboxes of large ID fans running 24/7. A standard package includes an oil circulation pump, a thermostat to switch on the fan cooler and differential-pressure monitoring to flag clogging.
- — Heat duty 5–500 kW
- — Oil grade VG 32–46 (compressors) or VG 220–320 (gearboxes)
- — Differential-pressure monitoring on the oil filter
- — Thermostatic oil temperature controller
- — Air- or water-cooled execution
Applications gallery
Our solutions for this industry
SDS portfolio brands that cover typical applications in this industry.
- WOLONGMV motors for ID fans and chiller compressors (YHTM-HVAC, WD3000) 800–3,000 kW; general-purpose WD1000 for fans and tunnel-rated YGTd with F300/F400 certification
- HUALIgeneral-purpose Y2/YE3/YE4 motors for centrifugal and axial fans 5.5–1,500 kW, YHF series for cooling towers with tropical execution
- BONENGK/F/S/R/HB gear motors for dampers, butterfly valves, flue gates and rotary heat-recovery wheels — 0.12–7.5 kW
- INOVANCEMD500/MD520/MD810 VFDs for fan flow control and chiller compressors, 25–30 % energy savings versus damper throttling
- INVTGoodrive HVAC series VFDs purpose-built for ventilation and air conditioning — built-in PID, sleep mode, BACnet
- DEOBR/SH plate heat exchangers for chilled water, DFL oil coolers for chiller compressors and gearboxes of large ID fans
- YONGJINGLX flexible pin couplings, GIICL drum gear couplings for large ID fans, centrifugal starting couplings to ease motor start-up
- LONGXUANWGZ/TL couplings for centrifugal fans, brake drums for drives with high coasting inertia
- HUAWUYPZ2/YWZ5 disc brakes for emergency stops of large ID and tunnel fans with high rotor inertia
- JIAOHUAYOXp flexible couplings for general exhaust ventilation fan drives, fluid couplings for heavy-duty compressor starts
Image credits: Georg Pik (Public domain) · Stupich, Martin, creator (Public domain) · Kecko (CC BY 2.0) · Rsparks3 (CC0) · Steve Johnson from Valparaiso Indiana, USA (CC BY 2.0)