Building renovations and energy-saving houses have a giant potential for contributing to climate protection. However, many concepts today stop at insulating the residential space as best as possible. This is where the swiss start-up company Air-On AG gets started and offers what so far has been a unique climate control solution, which takes into account not only the energy-optimised building, but also the people. The Air-On® single-room air-conditioning unit is a genuine all-round talent, which regulates the three essential factors for a healthy room climate, from temperature, to humidity, to CO2 content. To achieve this, the air-conditioning unit masters five functions at once: heating, ventilating, purifying air, dehumidifying and humidifying. And since the device operates only when one of the three room climate factors is not in the nominal range, it also saves a whole lot of energy.
The secret to these savings is in the CO2 measurement. For air-conditioning devices without a CO2 sensor, fans have to provide an uninterrupted air exchange. If there is not much carbon dioxide in the air, however, then a substantially smaller air exchange quantity is sufficient. And when less air has to be moved, less power is used. Also, Air-On developed its own filters, which drive in the same direction. Just how well these purify the air is made clear by Dr Stefan Heule, the manager for filter technology and aerodynamics at Air-On. In the laboratory he eliminated the particulate matter of a burning candle using the Air-On®device within a short time and produced quality approaching that of a clean room. “A candle is a real nanoparticle canon, but the device filtered out most of the little particles,” says Heule, describing the experiment. This is true thanks to a unit consisting of a coarse filter and an electrofilter, which also removed particulate matter to an impressive degree under real-world conditions in a prototype test in a housing area. We speak of “excellent” room air quality when there is a maximum of 10,000 nanoparticles per cubic metre. In the test residences the devices permitted no more than approximately 1,500 particles. Moreover, an active carbon filter removes ozone and unpleasant odours. “If your neighbour starts up his fireplace, your home will not be dominated by a smoky bonfire atmosphere.”
The Air-On®air-conditioning unit has only three moving parts – centrifugal fans from ebm-papst st. Georgen. And these are responsible for moving the air through the filters. Two smaller RER 125 fans draw the outside air to the inside and push the used room air to the outside via a heat exchanger. The large Type RER 160 fan controls the total volume flowing from the device into the room. Air-On searched for a fan supplier which could meet the high quality and service life requirements. “Only one supplier came into consideration,” emphasises Heule. The first contact with ebm-papst took place in 2007 via the swiss subsidiary in Oberhasli in the Canton of Zurich, and the appropriate fan models were also quickly found.
However, Heule frequently travelled to the German location in st. Georgen for the technical optimisation of the fans. In return, several engineers from ebm-papst made a visit to the little company in Cham am Zugersee. “So much customer care really impressed us,” Heule admits. “We were convinced of the application from the beginning,” emphasises Uwe rupertus, sales Engineer in st. Georgen, with respect to the joint development. “Therefore it was a matter of course for us to work together at full power towards success.”
The fans are inherently tremendously energy-efficient, thanks to their good controllability, and also permit low power input at constant speeds over a long time period. This is significant above all in night-time mode, when the fans have to run as uniformly as possible, since noise changes can be particularly unpleasant for those sleeping. “During our visits in ebm-papst’s test lab, our primary concern was noise,” explains Heule. “We gained very convenient access to the professional test environment there.” And he adds with a grin, “Then, however, the dialogue during development took a typical course: We said, ‘It is still too noisy.’” Rupertus explains how ebm-papst was finally able to accomplish the prescribed level of 22 decibels in night-time mode, “Use of the RER 160, which runs in comparable applications, was critical. It has a special commutation, in order to keep the noise level as low as possible. Nevertheless, we had to develop the motor software further to achieve Air-On’s specifications.”
Maximum efficiency is one thing, user-friendliness is another. Air-On thought about that also: The device is not only easy to install, it is also self-regulating. The user has only to clean the filters from time to time. This is why the Air-On team made their self-developed coarse filter and electrofilter unit dishwasher-proof: Open the cover, take out the filter unit, put it in the dishwasher – done.
An in-depth view of the air-conditioning unit
The Air-On® single room air-conditioning unit combines five functions at once: heating, ventilation, air purification, dehumidifying (gentle, active cooling as an additional function), humidifying. Moreover, two different installation variants are currently possible: Air conduction directly through the facade or below the weather shield.
Find more information on the German web page of Air-On