In electronics manufacturing, Make-Up Air Units (MAUs) often operate around the clock to maintain stable indoor air quality and production environments.
While many facilities continue to rely on traditional belt-driven fan systems, rising energy costs and increasing maintenance requirements are prompting manufacturers to rethink their HVAC strategy.
Recently, Beijing Hengrui completed a feasibility study for an EC fan wall retrofit on two MAU systems in an electronics manufacturing facility.
The objective was straightforward:
Maintain the required airflow while reducing energy consumption and simplifying long-term maintenance.
The Challenge
The existing MAUs were equipped with conventional belt-driven centrifugal fans powered by AC motors.

Pic.1 Equipment nameplate before renovation
Although the systems were operating normally, they presented several common challenges:
· High energy consumption
· Belt wear and regular maintenance
· Mechanical transmission losses
· Limited airflow control
· Reduced efficiency over long-term operation
For facilities running 24/7, these issues translate into higher operating costs year after year.
The Retrofit Solution
Instead of replacing the entire MAU, the proposed upgrade focused on replacing the original fan assemblies with high-efficiency EC fan wall systems.
The retrofit maintained the original airflow requirements while introducing multiple EC backward-curved centrifugal fans.

Pic.2 Comparison before and after renovation
Compared with traditional belt-driven systems, EC fan walls offer:
· Higher operating efficiency
· Direct-drive design without belts
· Easier maintenance
· Improved airflow uniformity
· Precise speed control
Performance Results
The engineering evaluation showed significant energy-saving potential while maintaining the original airflow requirements.

Pic.3 Estimated savings (based on continuous 24/7 operation and local electricity pricing)
Beyond Energy Savings
The benefits of EC fan wall retrofits extend well beyond lower electricity consumption.
The upgrade also helps improve:
· Airflow stability
· System reliability
· Maintenance accessibility
· Reduced mechanical wear
· Lower lifecycle operating costs
Because the fan wall uses multiple EC fans instead of a single belt-driven assembly, the system also provides greater operational flexibility and easier servicing.
Why More Manufacturers Are Upgrading MAUs
For many industrial facilities, HVAC systems are no longer viewed as supporting equipment.
They have become an important part of overall operational efficiency.
As electricity prices continue to rise and manufacturers pursue smarter, lower-maintenance facilities, upgrading existing MAUs with EC fan wall technology offers a practical way to improve performance without replacing the entire air handling system.
Let's Discuss
Are your MAU or AHU systems still relying on traditional belt-driven fans?
Have you evaluated how much energy and maintenance cost an EC fan wall retrofit could save over the equipment's lifecycle?
At Beijing Hengrui, we work with electronics manufacturers, HVAC OEMs, cleanroom contractors, and industrial facility operators to optimize airflow performance through EC fan retrofit solutions. If you're considering an MAU or AHU upgrade, we'd be happy to exchange practical engineering insights from real-world retrofit projects.
The following is a display of related products

The ebm-papst R3G630-PC08-03 is a high-performance EC centrifugal fanfrom the renowned RadiPac series, engineered specifically formission-critical data center cooling applications.

The 9GA0912P4S03 is a Sanyo Denki 12 VDC, 92 × 92 × 25 mm DC axial fan for servers, UPS systems, and telecom equipment. Long-life series construction is the main characteristic stated in the supplied reference. The recorded operating point should guide duty-point matching. Confirm control inputs against the complete ordering code.

Focused on Air Handling Units, the ebm-papst VBH0500CTTRS is a 400 V EC backward-curved centrifugal fan, centered on a listed pressure capability of 1,680 Pa. This clarifies the model's listed capability.

Intended for Air Handling, ebm-papst K3G310-BE90-N1 is a 380-480V EC backward-curved centrifugal fan, noted for a documented speed of 2,900 rpm. This supports duty-point selection.

(1)_1.png)