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LONGWELL / Data-center AHUs

Fans for data-center air-handling unit airflow

Define how the AHU supplies the data center before choosing a fan. Airflow through coils, filters and the distribution path must support the facility cooling strategy in normal and reduced-capacity operation. Bring the operating modes, installation geometry and monitoring requirements into the same equipment review.

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Air-side dutyOperating modesService access
Multiple fan modules arranged in a fan grid
Fan-grid arrangement reference. The proposed unit needs its own layout and operating-point review.
01 / Application & operating conditions

Connect the fan section to the facility cooling strategy

An AHU serves a room-level air path. It may operate with recirculation, outside air or an economizer sequence, depending on the facility design. Fan selection should reflect these modes without confusing the AHU with chassis fans, chilled-water capacity or a complete redundancy design.

01

Describe each air-handling mode

Provide the required supply airflow and the resistance of coils, filters and downstream distribution for each planned mode. Where outside-air operation is considered, include the facility limits for inlet temperature, humidity and contamination. The fan review should follow the equipment designer’s sequence rather than assume one summer duty covers the year.

  • Recirculation and outside-air modes
  • Filter condition and downstream losses
  • Permitted inlet temperature and humidity
02

Plan the fan section and maintenance route

A multi-fan section needs a workable arrangement for inlets, wiring and service. Provide fan spacing, plenum dimensions and access-door sizes. Review how a module will be isolated and removed without obstructing adjacent inlets, and consider the actual airflow path after a module stops rather than counting fans alone.

  • Fan spacing and inlet approach
  • Module removal and electrical isolation
  • Stopped-fan air path and access
03

Define fault response with the controls team

Agree what the controller must do when a fan, supply or feedback signal fails. State the remaining airflow required by the facility and the conditions under which it must be delivered. Confirm command and alarm interfaces for the selected models, then test the sequence in the assembled AHU.

  • Required duty after defined faults
  • Power and command distribution
  • Alarm mapping and recovery sequence
02 / Product routes for this application

Match the fan family to the equipment.

Compare the proposed model at the required airflow and pressure, then check the installation and control interface.

LONGWELL RLM plug-fan assembly with motor, impeller and support frame

RLM plug-fan assemblies

Use plug-fan assemblies as a starting point for AHU fan sections with suitable support and inlet space. Review the exact assembly under each required operating mode.

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LONGWELL backward-curved centrifugal fan assembly

Backward-curved centrifugal fans

Consider backward-curved configurations for custom AHUs and parallel fan sections. Evaluate individual fan duty, spacing and control compatibility within the proposed enclosure.

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Select a model for this applicationLONGWELL Fan Selector — every model with its catalogue curve, datasheet and drawing. No login.
Backward Curved Centrifugal Fans314 models · compare at your duty point →Plug Fans (RLM Plenum Fans)111 models · compare at your duty point →EC Axial Fans116 models · compare at your duty point →
Or enter the duty point directly

Airflow and static pressure at the installed condition — the selector returns every model whose curve covers it, with margin, power and noise.

Library: Ø25–1,000 mm, single units up to about 52,000 m³/h — larger duties go straight to an engineer. Prefer to talk it through? Send your specs to an engineer

Product images show family configurations. Request the drawing, curve and electrical information for the exact model being considered.

03 / Prepare a useful selection brief

What should your fan enquiry include?

Share these application details so the fan proposal can be reviewed against your equipment.

01AHU cooling strategy and air-side schematic
02Airflow and pressure for each mode
03Filter and coil resistance states
04Fan-section dimensions and access routes
05Defined fault cases and remaining duty
06Power, command, feedback and alarm schedule
LONGWELL airflow test-rig demonstration. Request the pressure-flow curve and test conditions for the exact proposed model. Open video ↗
04 / Technical resources

Reference material for the next step.

Series catalog · PDFRLM series plug fans ↗

Review assembly formats and series dimensions, then request the current curve and approved drawing for the complete offered model.

Series catalog · PDFEC backward-curved centrifugal fans ↗

Use the series information to narrow the mechanical format; confirm inlet conditions, controls and the proposed model performance separately.

Engineering checklistFan replacement: fit and controls ↗

Check operating duty, mounting, supply, wiring and control behaviour before treating an existing fan and a proposed replacement as interchangeable.

Catalogs support initial selection. Confirm the current specification and approved configuration with the project team.

Does an AHU remove the need for mechanical cooling?

That depends on climate, humidity limits, air quality and the full facility cooling design. The AHU fan moves air through the specified path; it does not establish when economizer operation is available or whether the refrigeration system can be omitted.

Is the fan array automatically an N+1 system?

The number of fans does not establish redundancy. Define the failure being considered and the remaining airflow required, then assess fan operating points, reverse flow, power distribution and controls. Verify the result with the installed AHU and the facility acceptance criteria.

Related applications

Continue with the equipment you are designing.

FanGrids →Precision air-conditioning units →Server cooling →Back to Air conditioning technology →
From application to a concrete proposal

Share your equipment and operating conditions.

Send the drawing, target duty and project timing. Add the existing fan details when you need a replacement.

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