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.
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.
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.
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.
The RadiFlex – all the advantages at a glance
- Thanks to EC technology, the blower is energy efficient and quiet
- High suction power at up to 930 m3/h
- Compact design and, at 1.9 kg, an absolute lightweight
- Integrated protection against contact and therefore also suitable for circulated air mode
- Integrated bayonet connectors enable activated carbon filters to be attached quickly and easily
- There is an optional non-return valve for exhaust air mode
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.