RadiPac: Compar­ison of fans

The true effi­ciency of a fan when measured is not equal to the product of the maximum indi­vidual effi­ciency levels of the motor, drive unit, control system and impeller. But why is that?

Correct deter­mi­na­tion

For a retrofit project, enquiries are made about various fans and the perfor­mance data of the fans offered are then compared. It is impor­tant to remember that perfor­mance spec­i­fi­ca­tions based on calcu­la­tions are gener­ally not real­istic. They tend to be far too opti­mistic because the maximum effi­ciency levels of the indi­vidual compo­nents (motor, drive unit, control system and fan impeller) are usually taken from cata­logues for calcu­la­tion purposes.

It cannot however be assumed that each compo­nent will actu­ally achieve maximum effi­ciency under real­istic condi­tions. Multi­plying the optimum indi­vidual effi­ciency levels yields a far more favourable total effi­ciency than is possible at the actual oper­ating point (Fig. 1).

As a result of this error, the values obtained from calcu­la­tion of the power consump­tion will be far better than in actual oper­a­tion. To ensure that real­istic values are acquired, ISO 12759:2010 “Fans – Effi­ciency clas­si­fi­ca­tion for fans” expressly recom­mends working with measured values when plan­ning.

As good as it gets 

Fig. 2: EC motors require less instal­la­tion space

ebm-papst can always be relied on to provide the correct values because what we measure and supply is the minimum config­u­ra­tion of a complete, ready-to-install fan assembly consisting of high-perfor­mance impeller, EC motor and control elec­tronics. As these compo­nents are opti­mally matched, it is possible to achieve static total effi­ciency levels well in excess of 60 %.

These levels have been measured and entered in the Product Selector. Far higher figures quoted by other suppliers are always open to ques­tion.

In addi­tion to optimum effi­ciency, a RadiPac with Green­Tech EC motor offers a whole range of advan­tages over other fans for air handling systems.

Instal­la­tion – simple and safe 

Fig. 3: Green­Tech EC motors – the all-in-one solu­tion

The high-perfor­mance impeller is mounted directly on the rotor of the external rotor motor. This saves space and permits balancing of the entire rotating unit in one clamping oper­a­tion (Fig. 2). The elec­tronics and motor are combined in a single unit (Fig. 3). Thanks to the inte­grated control elec­tronics there is no need for an external frequency converter, which makes instal­la­tion easy.

As the motor and elec­tronics in the motor system are perfectly matched and in close prox­imity to one another, addi­tional elec­tronic filters and shielded cables are also super­fluous and no external motor protec­tion circuit breaker is required. Air handling units can be commis­sioned without the need for any costly adjust­ment, earthing or shielding work. In other words “Plug & Play” for venti­lation tech­nology.

Ecode­sign

Minimum effi­ciency require­ments for RadiPac EC centrifugal fans as per the 2015 ecode­sign direc­tive

The eco­design direc­tive for fans (EU 327/2011) spec­i­fies minimum effi­ciency require­ments for fans driven by elec­tric motors. The require­ments first came into force in 2013 and will become more strin­gent as of 01.01.2015. They apply to all fans with an input power between 125 W and 500 kW and a drive perfor­mance range of 125 W to 500 kW. A spec­i­fied effi­ciency level has to be attained based on the type of fan concerned. Calcu­la­tion of the minimum effi­ciency values is described in this direc­tive. All Green­Tech EC fans in the ebm-papst RadiPac product range now already surpass the require­ments applic­able as of 2015.

Resource preser­va­tion

The Green­Tech EC motor helps to preserve resources without any supply risks. The effi­ciency of the mains-powered perma­nently excited synchro­nous motor with elec­tronic commu­ta­tion (also known as BLDC or PM motor) far surpasses effi­ciency class IE4 – and manages to do so without using any poten­tially prob­lem­atic rare earth magnets.

On account of their design, other perma­nent magnet motors of the internal rotor type and offering compa­rable effi­ciency require rare earth magnets. And so RadiPac is THE compact, effi­cient, user-friendly, sustain­able all-in-one fan solu­tion for air handling units (Fig. 3).