ebm papst's new axial fans for noise-sensitive applications

Date: 22 March 2023
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New axial fan for noise-sensitive applications

The AxiTone is a new type of fan developed by ebm‑papst. It is a three-blade EC axial fan and is particularly suitable for noise-sensitive applications. The new AxiTone is ideal for air-water heat pumps that require quiet fans and where counter-pressure is more of an exception due to design aspects. The fan will initially be available in size 450 mm and later in sizes 500 and 630 mm, as well. Condensers installed in residential areas and which have to adhere to particularly low noise emission levels would also benefit from this quiet axial fan. The AxiTone is also suitable for applications that use flammable refrigerants.

New blade geometry reduces noise

Its characteristic curve is flat, it supplies large volumes of air, and, as the name suggests, it makes very little noise during operation. The blade geometry plays a key role in this respect, as it has been optimized to aerodynamic criteria. The large area and steep inclination ensure high air flow, and the sickle-like shape reduces turbulence and thus the irritating blade passing noise. Other new features include the serrations at the front edge of the blade. They also have a positive effect on the noise characteristics, as they minimize the tonal components of noise.

Efficient thanks to EC technology

These fans are driven by efficient EC motors. In comparison to AC motors, EC motors function with considerably higher efficiency. They also generate less waste heat, an important advantage for chilling applications. It is also possible to control and monitor the fans based on the requirements using a 0-10 V signal or MODBUS. These features help the EC fans to work very efficiently, particularly in the partial-load range, and significantly reduce energy consumption. The AxiTone is available as a ready-to-install motor-impeller combination in both airflow directions, i.e., intake or blowing, and optionally with a guard grill or support ring.

New inverter electronics for efficient and low-noise compressor drives

For air-water heat pumps, ebm‑papst offers efficient, quiet EC centrifugal and axial fans for indoor and outdoor installation. Based on ebm‑papst's many years of experience with EC motors, their commutation electronics, and heat pump applications, the company has now developed inverter electronics that are suitable, for example, for speed-controlled permanent magnet synchronous motors (PSM), such as those used in compressors for heat pumps. The new electronics, which are available with output powers of up to 3.5 kW, 7.5 kW, and 12 kW, have many advantages in this context.

Quiet and efficient

The commutation process that ebm‑papst has been optimizing for decades plays a considerable role in noise reduction, and simultaneously improves efficiency. For example, in a heat pump with a 7.5 kW compressor drive, the COP value (Coefficient of Performance) could be increased by 3.5 %. For users, this means an annual saving of 70 euros at an assumed electricity price of 35 cents per kilowatt hour. The controls also "detect" whether they are operated in one or three phases, and switch over automatically depending on the type of voltage available in the heat pump. The electronics are also flexible in terms of their cooling. Thanks to their modular design, it is possible to use water or air cooling, or use a cold plate for cooling.

Active three-phase PFC level

The active three-phase PFC level integrated into the inverter electronics (power factor correction filter) ensures good EMC properties. No additional measures are required to comply with the standards with regard to current harmonics. Given that, depending on the size of the heat pump, conventional expansion valve assemblies can easily weigh up to 20 kg, the weight saving and the reduced wiring effort required by active PFC are considerable. The low weight of the heat pump simplifies its entire handling, from production to transport and installation by the end user. As a competent partner for heat pump manufacturers, ebm‑papst is already planning the next steps to become a system provider. In the future, further components will be integrated into the inverter electronics, for example commutation for the fan drive and the control of a heating rod.

New wind for residential ventilation and switch cabinet cooling

It has now been over 10 years since ebm‑papst launched the "RadiCal" centrifugal fan series. This has now proven itself in many ventilation and air conditioning systems. With the new RadiCal fans, the Mulfingen team is now presenting the second generation, which impresses with its high air flow rates, compact dimensions and pleasant noise characteristics.

New blade design improves aerodynamics

The opportunities in plastic production have enabled a new, innovative blade geometry, which contributes to significantly higher efficiency and lower noise levels. The "twisted" blades are mutually curved in on themselves. The shape of the inlet and outlet edges has been completely redesigned, which has a positive effect on the flow characteristics. The corrugated impeller cover plate and the struts profiled in the centrifugal module also improve the aerodynamic characteristics of the fans, and so too the air performance.

Significant noise reduction

Thanks to new production methods, it was possible to significantly reduce the air gap, i.e. the distance between the inlet ring and the impeller, depending on the size. This results in fewer losses, increases efficiency and reduces the noise. The new FlowGrid has also been optimized and lowers the noise level by up to 3 dB(A) compared to the current series version for installation-related intake-side disturbances.

New engine generation

Depending on the size of the fans, the new EC motors cover the power range for single-phase grids up to 800 W. Fans for three-phase grids and powers of up to 1.5 kW will follow at a later stage. There are no disruptive resonances when there is a change in speed. In addition to good noise characteristics, the new generation of motors also impresses with its good EMC characteristics and durability. The commutation and control electronics are tuned to the motors. The air flow and operating point can be precisely adjusted. Control and monitoring are possible from 0 - 10 V/PWM or, from the 170 W version, there is a MODBUS RTU option.

Compact and easy to integrate

Since no other installation situation is the same, the new centrifugal fans are very adaptable. They are available with or without a ready-to-install housing. The new Radical will be available in the familiar sizes 175, 190, 225, 250 and 280. Size 206 is new and improves the power rating. This means that the right centrifugal fans are available for efficient residential ventilation or switch cabinet cooling, not only delivering high air flow rates, but also operating extremely quietly.

Pressure-resistant axial fans for heat pumps

ebm‑papst presented the efficient AxiEco axial fans in various designs at the beginning of 2020. Thanks to their high pressure stability, ventilation and air conditioning devices in particular benefit from higher air flow volumes. The series has now been expanded with the new AxiEco plug-in fans in sizes 450, 500 and 630, which are typical for heat pumps in detached or semi-detached homes.

Pressure-resistant in the face of ice formation

Ice formation is a big topic in the world of heat pumps. It is a particular issue for evaporators when humidity settles on the heat exchanger as ice at cold ambient temperatures. This reduces the air routes and the drag. The fans then have to offer significantly greater pressure reserves. This is where the new AxiEco Plug-in comes in. Studies have shown that its flow technology reduces ice formation and its air flow only reduces very slightly as the pressure increases. This is also an advantage for heat pumps, which heat in winter and cool in summer, as the operating points then vary depending on operation.

Quieter thanks to FlowGrid

The new AxiEco Plug-in fans have now been equipped with an air inlet grille. This FlowGrid, which acts as a rectifier for air flow, drastically reduces noise-generating disturbances in the air flow. This reduces the sound pressure over the entire frequency range, in particular the disruptive blade passing noise, i.e. unpleasant "humming" in the low frequency range. At the same time, the air inlet grille serves as a motor suspension and, if necessary, the device manufacturer can insert heating tape. The new axial fan weighs 30% less than the comparable HyBlade version with steel wall ring. This means that less weight has to be handled during the installation and the compact dimensions often make it possible to optimize the design of the end device. The AxiEco Plug-in fans are supplied as a ready-to-install plug & play solution, including nozzle plate and FlowGrid.

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