EC Centrifugal Blower for Commercial AHUs: 1828 m3/h Case Study

What the AHU builder specified

A European HVAC OEM was developing a new line of commercial air handling units and needed an EC centrifugal blower delivering 1828 m3/h.

The enquiry asked only for a spec sheet and a drawing. That tells you the system layout was already fixed. Consequently the customer was choosing parts to fit it.

Here the duty needs a double-inlet EC centrifugal blower working against roughly 59 Pa of system pressure. High volume, and very little pressure.

• 220V single phase at 50 or 60Hz.
• A maximum length of 920mm, since the cabinet already existed.
• An EC motor with variable speed, since the ErP Directive and running cost both demand it.
• An ambient range from -25C to +60C.
• CE and LVD already held, so their own approval route stays short.

The ErP rule is what makes EC essential here rather than merely nice. An AC fan running flat out cannot meet modern part-load figures, whatever its peak efficiency looks like.

Selecting the EC centrifugal blower

High volume against low pressure points straight at a forward-curved wheel. After that, two decisions remained.

Direct drive rather than belt

We considered a belt-driven fan such as our AT series, then rejected it. On a new OEM design, direct drive is more reliable, takes less space, and takes belts and pulleys off the service list entirely.

Belt drive still earns its place on retrofits and on very large fans. On a new AHU platform, though, it mostly adds parts that later need attention.

EC rather than AC plus a drive

A plain AC motor would need an external VFD to give the variable speed the customer wants. That means more cost, more panel space and one more part that can fail.

An integrated EC centrifugal blower avoids all of it. Our SmartEC platform reads 0-10V and PWM directly, so their controller trims fan speed against real cooling demand. Consequently the wiring is simpler. Just as importantly, the part-load figures are what ASHRAE 90.1 and ErP actually ask for.

The recommended fan

Meanwhile the final recommendation was the LWFC-EC600S-01. It is a double-inlet forward-curved EC centrifugal blower from our direct-drive DDM family.

Galvanized sheet steel gives the toughness an indoor AHU needs at a sensible cost. Meanwhile the EC motor and the forward-curved wheel were matched to land exactly on 1828 m3/h at 59 Pa, drawing only 133W.

At 920mm it fits the customer envelope exactly. Therefore it drops in with no mechanical change at all.

Technical Specifications

Look at the input power row beside the airflow row. An EC centrifugal blower moving 1828 m3/h on 133W is what makes this selection worth reading about.

Technical Documentation

The official specification sheet provides procurement managers and design engineers with key performance curves, electrical data, and dimensional information.
Download LWFC-EC600S-01 Specification Sheet

Here the technical drawing details the exact mounting points, material callouts, and interface dimensions required by mechanical engineers for system integration.

Why the OEM specified our fan

For an OEM in a tight market, four things counted.

• Cost that shows in the bill of materials. Our EC engineering matches European rivals, yet the price point is materially lower. In commercial AHUs that gap is often the whole margin.
• Documentation immediately. This is a standard model, so the technical package went out at once. Where a customization is needed, our 90-day NPI cycle runs several times faster than the 12 to 18 months European suppliers commonly quote.
• Certification already in hand. The LWFC-EC600S-01 holds CE and LVD approval. For future certification work, our partnership with a China-local TUV NORD notified body shortens CE and ATEX timelines substantially.
• Performance you can build against. We design and test every fan to AMCA 210/211 and ISO 5801 methods. Consequently nobody discovers a shortfall after the AHU is built.

Browse our EC forward-curved fan range, or the AHU fan section for larger units. Ecodesign requirements come from the European Commission ErP Directive.

Questions AHU designers ask

What is the lead time on 500 units?

This is a standard HVAC product, so a make-to-order run of 500 units takes 15 to 25 days from order confirmation. Customers on a frame agreement can hold inventoried stock, which brings shipment down to 1 to 5 days.

Can a BMS control the speed?

Yes, and that is what the SmartEC motor is for. It accepts a standard 0-10V analogue signal or a PWM input. It can also be configured with a Modbus RS485 interface, which most commercial BMS platforms can drive and monitor directly.

What L10 bearing life applies at 40C?

The unit runs maintenance-free GB/T 276 6202ZZ ball bearings, and we commit to 60,000 hours MTBF at a 40C ambient across our HVAC fan series. That figure is validated through batch accelerated life testing based on ISO 281.

Why is a forward-curved impeller right at only 59 Pa?

Because forward-curved blades move a lot of air from a small wheel when pressure is low. Backward-curved is the better answer once resistance rises, since it holds efficiency and will not overload the motor. At 59 Pa, however, that advantage never comes into play.