Juicy meat fries in the pan, the pasta water is boiling and vegeta­bles are stewing in the pot, but no matter how tasty the food may be, nobody likes cooking smells that stick around. Luckily, there are range hoods for this. They remove rising steam, sepa­rate grease and elim­i­nate trou­ble­some odors.

Although the oper­ating times of a hood are usually not partic­u­larly high, they still consume energy, and house­hold appli­ances are gener­ally supposed to be consuming much less in future. This is what the new EU energy effi­ciency label wants to achieve, and this will also affect range hoods. To reach a high effi­ciency class, manu­fac­turers will then have to make sure that the devices meet much stricter require­ments than is currently the case.

The blowers installed are a key element in increasing energy effi­ciency. They create the neces­sary induced draft to convey the kitchen fumes outwards or, if it is a recir­cu­la­tion unit, back into the room after the filtering process. Tradi­tional hood manu­fac­turers often rely on blowers with AC motors. However, this tech­nology is quickly reaches its limits in bringing further effi­ciency improve­ments. This is not the case for blowers oper­ated with EC motors. Their high elec­trical effi­ciency means that higher powers are even possible with lower current consump­tion.

Fig. 1: The Radi­Flex is compact and, thanks to EC tech­nology, offers a high suction power. (Photo | ebm-papst)

With extrac­tion hoods, EC tech­nology is nothing new. It is already estab­lished as stan­dard in the upper mid and premium segments in partic­ular, because these usually require higher suction power. With the more strin­gent spec­i­fi­ca­tions from the new energy label combined with increasing comfort require­ments, EC tech­nology is ideal for broad use. For example, better filter systems tend to require higher suction power on the blower side. In partic­ular, industry requires blowers that can be used flex­ibly in a wide range of hood designs and instal­la­tion situ­a­tions. With Radi­Flex, the engi­neers at ebm-papst have devel­oped this type of EC blower, offering the industry the right stan­dard.

The pioneer for range hoods

ebm-papst built the first motor for a range hood blower back in 1963. Right up to today, this has resulted in a wide range of AC and EC centrifugal blowers for range hoods. The devel­op­ment of a stan­dard blower, with its char­ac­ter­istic propor­tions and a defined instal­la­tion geom­etry, was an impor­tant mile­stone around the turn of the millen­nium, and also turned out to be ground-breaking for the industry as a whole. The shape, dimen­sions, outlet diam­eter and connec­tion flange of these dual flow blowers are still the preferred option on the global market to this day.

And the fan specialist is now setting the pace once again with the Radi­Flex: the dual-intake centrifugal fan is not only of interest to manu­fac­turers due to its energy effi­ciency but also its universal appli­ca­tion options in a wide range of hood types.

A ques­tion of design

Just like with food, people have different tastes when it comes to kitchen designs: almost all vari­a­tions are possible, from simple built-in kitchens to large kitchens with island cook­tops. And the kitchen equip­ment is as diverse as the range hoods (see box text 1): a variety of types are now being used, from the simple built-in hood, T hoods, angled and vertical hoods, and extend­able table extrac­tors to down­draft extrac­tors and island range hoods. In terms of energy effi­ciency, it is impor­tant to consider numerous inter­ac­tions between design, func­tion and suction power.

A small hood customer

In prin­ciple, there are two different oper­ating modes: in circu­lated air mode, filtered air is returned to the room, while, in exhaust air mode, the kitchen aromas escape outside. For both modes, the number of different types of range hoods is as large as the number of different kitchen designs. Because of their angle of incli­na­tion, angled hoods (1) leave space above the cooktop, reducing the risk of someone hitting their head. Built-in hoods (2) are hidden in over­head struc­tures and are partic­u­larly suit­able for small kitchens. Chimney range hoods (3) are also suit­able for larger cook­tops. Island hoods (4) are intended for kitchen islands and are attached to the ceiling. Down­draft hoods (5) are also an option. They dissi­pate the kitchen fumes down­ward.

Almost all vari­a­tions are possible, from simple built-in kitchens to large kitchens with island cook­tops. And the kitchen equip­ment is as diverse as the range hoods. (Graphic | ebm-papst)

To keep the oper­a­tion econom­ical, it would be best to keep the suction power as low as possible, because then the current consump­tion is at its lowest. But it is not that simple. After all, an extrac­tion hood not only has to dissi­pate air, but also deals with ambient air quality. Filters, such as close-mesh metal filters and acti­vated carbon filters, are required for high-quality grease and odor sepa­ra­tion. The latter can be found in air recir­cu­la­tion units in partic­ular. However, the better the filter perfor­mance, the higher the asso­ci­ated pres­sure loss. A greater suction power is required in this scenario, which could be achieved very easily using a larger blower.

But this brings another issue: the space is limited. Despite having a higher power, the blower cannot take up any extra space. This is because some types of hood, such as vertical hoods, cannot be inte­grated into larger compo­nents because of their design, and valu­able storage space is also lost. This is an impor­tant thing to consider for compact kitchens. In addi­tion, the total weight of the hood cannot just be increased at will, for example an island hood may need to be securely mounted on the ceiling. Lastly, the entire process should also be quiet. To put it in a nutshell: more suction power is required in the same space and with low noise levels. EC tech­nology can show off all of its strengths here.

Universal use: the Radi­Flex

The Radi­Flex has been designed specif­i­cally for these require­ments (Fig. 1). It offers a lot of power despite its compact design and low energy consump­tion. The dual flow blower can convey up to 930 cubic meters of air per hour (free air) (Fig. 2). Thanks to EC tech­nology and a three-phase motor, it is possible to achieve high speeds without impairing the acoustics. Thanks to the high power density, the EC motor is more compact and weighs much less than a compa­rable AC motor: The total weight of the Radi­Flex is only 1.9 kilo­grams, making it up to 50 percent lighter.

Fig. 2: Good perfor­mance: the Radi­Flex can move up to 930 cubic meters of air per hour (free air). (Graphic | ebm-papst)

Another advan­tage is that its stan­dard­ized connec­tions make it easy to install. The housing of the Radi­Flex is designed so that it can be used in almost any type of hood. Protec­tion against contact is inte­grated on the intake side as stan­dard, meaning that the blower is also suit­able for circu­lating air mode. Acti­vated carbon filters for odor filtering can be attached at any time using the bayonet connec­tors on the housing. For exhaust air mode, the blower is also avail­able with an optional non-return valve. This prevents the exhaust air from flowing back or outside air from flowing in.

EC tech­nology offers a further advan­tage for closed-loop control. Depending on what is going on the stove, the hood does not always have to be turned up to full. With EC blowers, the four usual speed levels on the market can be imple­mented precisely using a rele­vant speed signal. However, the poten­tial here has not been fully exploited. In contrast to AC tech­nology, EC tech­nology enables infi­nitely vari­able closed-loop control and there­fore fine tuning to the actual extrac­tion require­ments.

Ready for the future

This infi­nitely vari­able closed-loop control also bene­fits smart func­tions that are increas­ingly in demand with range hoods. Sensors that can analyze the kitchen fumes already exist. This means that the speed of the blower can be auto­mat­i­cally adjusted to the actual suction require­ments, depending on whether steam is currently rising or some­thing is burning. It is also possible to couple it with the cooktop. Are all ranges running at full speed? Or is only one in oper­a­tion? This infor­ma­tion could be commu­ni­cated directly to the blower with the right hood control. The blower then sets itself up according to this infor­ma­tion. The Radi­Flex provides hood manu­fac­turers with state-of-the-art and future-proof tech­nology for broad use.