More efficient and quieter fan coils with ebm-papst GreenTech EC fans

In the operation of a fan coil, the fan is much more than a simple component designed to move air. Its efficiency, aerodynamic quality, and ability to modulate airflow determine the terminal's power consumption, the acoustic comfort perceived by occupants, and the stability of the room's temperature.

With these needs in mind, ebm-papst has developed a range of centrifugal fans with GreenTech EC technology , designed for integration into fan coils and air curtains. The solutions combine motors, control electronics, and aerodynamic components in compact units, available in single, double, and triple configurations.

The goal is to enable HVAC terminal manufacturers to achieve the required flow rate with low consumption, quiet operation and more precise continuous regulation compared to traditional AC motor solutions.

The fan determines the actual behavior of the fan coil

Inside a fan coil unit, room air is drawn in by the fan, passed through the heat exchanger, and then reintroduced into the room. To maintain comfortable conditions, the flow rate must continuously adapt to the actual heat load, which can vary depending on occupancy, solar radiation, outside temperature, and user settings.

A fan sized exclusively for maximum airflow can be inefficient during most operating hours, when the unit operates at partial load. The ability to continuously adjust the speed allows for only the necessary air flow, avoiding frequent on-off cycles and limiting both energy consumption and perceptible variations in temperature and noise.

EC technology uses an electronically commutated synchronous motor with permanent magnets. Compared to traditional asynchronous AC motors, losses due to rotor slip are eliminated and electrical and magnetic losses are reduced. The integrated electronics also maintain high efficiency levels even during low-speed operation, a particularly important feature for fan coil units, which spend much of their time away from their maximum operating point.

EC technology and continuous modulation to reduce consumption

According to data from ebm-papst, GreenTech EC centrifugal fans can use up to 70% less energy than fans with traditional AC motors . This benefit comes not only from the motor's efficiency, but also from the interaction between the electronics, impeller aerodynamics, and speed regulation.

Continuous modulation allows the fan to more precisely follow system demand. Models in this range can be controlled via a PWM or 0–10 V DC/PWM signal, depending on the chosen configuration. The fan coil manufacturer can then integrate the fan into the terminal's control logic, adapting the flow rate to the room temperature, water temperature, or settings defined by the supervisory system.

This behavior is particularly important in buildings with many terminal units, such as hotels, offices, healthcare facilities, and commercial complexes. Even a small reduction in the power consumption of a single fan, multiplied by tens or hundreds of fan coils and many hours of annual operation, can significantly impact the building's overall energy consumption.

The increased efficiency, combined with the long service life and declared maintenance-free operation, also helps to contain costs throughout the terminal's entire life cycle , not just the initial energy consumption.

Acoustic comfort: not just speed, but aerodynamic design

Acoustic comfort is one of the most critical requirements for fan coil units installed in hotel rooms, offices, homes, hospitals, and other environments where people spend long hours. In these settings, even a constant, low-intensity noise can become perceptible and disrupt rest, concentration, or daily activities.

To reduce noise emissions, simply reducing rotation speed is not enough. It's necessary to address the entire system, limiting turbulence, vibrations, and airflow disruptions. In ebm-papst's GreenTech EC centrifugal fans, the aerodynamic profile of the housing , the impeller geometry, and the suspension system are designed to promote smooth flow.

The impeller and rotor unit are dynamically balanced on two planes, while the special motor mount helps isolate the housing from vibrations. The rigid plastic structure also allows for complex shapes and optimized profiles without excessively increasing weight and size.

Continuous regulation completes the aerodynamic work: when maximum flow is not required, the fan can operate at a lower speed, avoiding sudden jumps between predefined levels and maintaining a more stable perceived noise level. The result is a terminal that progressively adapts its performance to the needs of the environment.

Compact configurations for different fan coils

Fan coils can be installed on the wall, floor, ceiling, or inside a suspended ceiling and connected to a duct system. Each configuration poses different constraints in terms of available space, motor orientation, flow rate, and static pressure.

To meet these needs, GreenTech EC centrifugal fans are available in single, double, and triple versions, which can also be used in parallel to increase the volume of air moved. Depending on the model and configuration, the range specified by ebm-papst reaches flow rates of up to approximately 2,500 m³/h , with power ratings ranging from approximately 40 to 250 W.

Elements that facilitate integration include:

• compact size;
• possibility of installation with horizontal or vertical motor axis;
• central connection for power and control signals;
• continuous speed regulation;
• integrated protection against rotor blockage and overheating;
• speed signal output and, on some versions, alarm output;
• compatibility with 50 and 60 Hz electrical networks;
• voltage configurations intended for different markets.

The plug & play concept, with the motor, electronics, and control system supplied as a coordinated unit, reduces the effort required for installation and commissioning. The compactness also facilitates the replacement of existing AC fans with EC solutions, making the range attractive both for the development of new fan coils and for upgrading existing terminals.

Active PFC for operating multiple fans in parallel

In higher-powered fan coils or units with multiple fans, it may be necessary to connect multiple motors to the same power supply. In these configurations, the presence of harmonics and current peaks can affect the equipment's electrical quality and require additional compensation measures.

For some versions of the range, ebm-papst offers the optional Active PFC (Power Factor Correction ) function. The electronics correct the power factor and reduce the harmonics generated by the load. The technical documentation for the range specifies power factors up to λ = 0.99 and a reduction in current peaks of up to 50%.

This solution simplifies the parallel operation of multiple fans and can help the terminal manufacturer create more electrically efficient units, reducing the need for additional external components and improving overall equipment integration.

From fan coil units to air curtains

The same characteristics required in a fan coil—adjustable flow rate, silent operation, compactness and efficiency—are also crucial in air curtains installed near building entrances.

In these applications, the fan must create a sufficiently uniform and stable flow to separate the internal and external environments, limiting the entry of hot or cold air through frequently opened doors. Excessive flow rate would increase energy consumption and potentially create annoying drafts, while insufficient flow rate would reduce the effectiveness of the air curtain.

The GreenTech EC fans' electronic control allows them to adapt their operation to actual entrance conditions, temperature differences, and the frequency of door openings. This allows the air curtain to maintain its effectiveness without constantly operating at maximum speed.

With the GreenTech EC range of centrifugal fans, ebm-papst offers a flexible platform for air movement in HVAC terminals: a solution in which motor efficiency, aerodynamic quality, electronic control and ease of integration contribute to improving the overall performance of fan coils and air curtains.