RadiCal: Low-pressure centrifugal fans with backward-curved blades

Backward-curved fan blades as dimensionally stable hybrid construction

RadiCal centrifugal fans with backward-curved blades set new standards in ventilation and air conditioning technology. RadiCal stands for both noise minimization and a further reduction in energy requirement. Because the RadiCal impeller with backward-curved blades is made of glass-fiber reinforced plastic. This permits an aerodynamically optimized shape that cuts noise generation by half and significantly reduces the power requirement.

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Optimized RadiCal impeller with backward-curved blades


The design of the impeller and the backward-curved blades was optimized through the use of complex simulation models and checking against measurements taken on prototypes. This resulted in optimum, low-loss impeller through-flow – without any of the abrupt changes in cross-section that are responsible for losses in the impeller. A uniform flow profile with no separation means there are fewer sources of noise, thus improving the acoustic characteristics. The good attenuation of the plastic also helps to reduce noise emissions.

The impellers are made from a special composite material in one piece, without any joints. This permits a high peripheral speed and thus a high fan power density.

Even without a special paintwork finish the impellers are extremely resistant to corrosion, for example when exposed to saltwater or a salty atmosphere. Direct sunlight has no detrimental effect on the UV-resistant material.

Compact low-pressure product range thanks to miniaturized motor-electronics combinations


RadiCal low-pressure centrifugal fans employ GreenTech EC motors that surpass the legally binding ErP limit values for efficiency. This makes it possible to cut energy consumption by up to 50% as compared to AC solutions. 

Miniaturization of the motor means that the RadiCal low-pressure centrifugal fans are far more compact than their predecessors. With the current dimensions, mechanical replacement of existing AC solutions is never a problem. 

Optimum motor heat management has also been achieved. The stator is fully encapsulated in high-performance plastic. Air inlets in the rotor guarantee perfect heat dissipation from the motor, giving a further boost to efficiency. The high degree of IP protection makes these fans suitable for use in critical applications as well.

Every RadiCal with GreenTech EC motor is controlled via a 0-10 V or PWM input signal. Up to size 250 mm, versions are also available with two fixed speed levels, with the higher of the two speeds representing a power reserve in comparison with the AC version. From size 250 mm, actuation via an RS485 interface is also possible, employing the MODBUS RTU protocol.




EC/AC centrifugal fans – RadiCal

(Edition 2013-05-01T09:11:31.000Z) [PDF] 40.03MB


Areas of application

RadiCal - the new standard in ventilation and air conditioning technology


RadiCal centrifugal fans with backward-curved blades are used in a wide range of ventilation and air conditioning applications, for example for control cabinet cooling, in duct fans, in home ventilation units and in heat pumps. In all these cases, it always makes sense to switch to high-efficiency RadiCal low-pressure centrifugal fans with GreenTech EC motors, or to fit them right from the start.


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