Peace and quiet at a pleasant temper­a­ture

Hotel air-condi­tioning: new state-of-the-art system saves up to 70 % on energy consump­tion

For many hotel owners, air-condi­tioning systems are often a neces­sary evil: while they may ensure optimum room temper­a­ture, they also use a lot of energy and their noise can prevent guests from getting a peaceful night’s sleep. In hotels for example, the average oper­ating time of fan coils is currently around 80 %, compared to around 40 % in office build­ings. The Abasto Hotel in Gern­linden, near Munich, has got to the root of the problem and now uses a new gener­a­tion of fan coils – to the satis­fac­tion of all parties concerned. Thanks to the highly effi­cient Green­Tech EC fans, rooms can be cooled bliss­fully quietly to the guest’s preferred temper­a­ture using 70 % less energy.

The Abasto Hotel opened in mid-september 2012 around 30 km from Munich, in the district of Gern­linden (figure 1). The 31 modern rooms have been fitted out to the latest stan­dards, and that includes the air-condi­tioning. for the hotel’s owner, robert rentzsch, who is himself a trained heating installer, the new system fully realises his vision for perfect air-condi­tioning.

Lower noise and energy consump­tion with increased comfort

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Figure 2: Green­Tech EC blowers from ebm-papst in a fan coil unit from Kamp­mann – invis­ible to the guest but indis­pens­able for the air-condi­tioning system.

Both the guest rooms and the “farmhaus” restau­rant in the base­ment are equipped with the latest air-condi­tioning tech­nology from Kamp­mann GmbH, based in the German town of Lingen (Ems). Fan coils known as “Venkons” are hidden behind the venti­lation slits (figure 2, page 6). The hotel guests cannot see them but they can certainly feel their effects. When the guest checks in at recep­tion, the booking soft­ware trans­mits the starting signal to the Venkon.

By the time the guest goes to unlock the door, the room will have been cooled or heated to room temper­a­ture (21 degrees Celsius). If the guest wants the room to be warmer or cooler, they can amend the temper­a­ture up to three degrees in either direc­tion via the Ka-Control control device. The unit does not make any noise. Describing an expe­ri­ence that nearly every hotel guest will be familiar with, Rentzsch recalls “I have been in many hotels where the air-condi­tioning got on my nerves. When you actu­ally have a unit in the room that both heats and cools and is prac­ti­cally inaudible it really makes your stay much more comfort­able.”


Figure 3a: The K3G146 energy-saving EC centrifugal blower from ebm-papst ensures a pleasant room temper­a­ture while remaining bliss­fully quiet.

In order to make this feeling of comfort the stan­dard in noise-sensi­tive appli­ca­tions, Kamp­mann has devel­oped a system design for its fan coils specially for appli­ca­tions in hotels. In order to fulfil the tough require­ments for low noise, the air-condi­tioning specialist has sought coop­er­a­tion with its chosen high-perfor­mance partner ebm-papst. At the heart of the Venkon is a centrifugal blower, and this is produced by fan manu­fac­turer ebm-papst based in Mulfingen, Germany (Figure 3a).

When Kamp­mann devel­oped the latest gener­a­tion of the Venkon, the key factors it looked at were space require­ments, noise level and power consump­tion. ulrich Budde, sales Manager for Kamp­mann in southern Germany and Austria explains that “The crucial factors for us with the fan coil was that the motors would have a partic­u­larly low noise level and that there would be a high level of control in the lower speed range.” Both factors are inex­tri­cably linked; hotel air-condi­tioning systems employ the lower speed range because it offers the lowest noise levels.

Contin­u­ously adjustable – for greater satis­fac­tion

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Figure 3b: RadiPac centrifugal fans such as the r3G355 used in the Airblock C, with aluminium-welded impeller and energy-saving EC tech­nology have an espe­cially space-saving construc­tion as compared with belt-driven motors.

The lower speed range is also the range with the greatest poten­tial for energy savings. Stan­dard AC motors only offer incre­mental control, whereas modern Green­Tech EC motors are contin­u­ously adjustable across the entire speed range. Even at low speeds, the high level of energy effi­ciency of the EC motors brings bene­fits, as the motors are supplied with an input of 0-10 V.

The Green­Tech EC centrifugal fans are avail­able as single, dual or triple fans with a power of between 40 and 250 W, to suit the room size. In all sizes, they offer energy savings of up to 70 % and noise reduc­tion of up to 5 dB(A). Thanks to the plug-and-play solu­tion, existing units can also be retro­fitted without a great deal of work (figure 4).

ebm-papst’s product range includes EC fans in the power range 400 W – 12 kW for venti­lation and air-condi­tioning tech­nology (VACT). The RadiPac range (Figure 3b) with aluminium-welded impellers and inte­grated control elec­tronics enable a design that saves on space compared to models with belt-driven motors.

The resulting space saving also facil­i­tates instal­la­tion and start-up. The intel­li­gent control elec­tronics of the Green­Tech EC centrifugal fans enable a number of different automa­tion and manage­ment tasks to be imple­mented via MODBus. Major savings can be made on the elec­trical oper­ating costs thanks to the ability to control the Green­Tech EC centrifugal fans based on actual require­ments.


Figure 4: At the example oper­ating point of 1100 m³/h, the green char­ac­ter­istic curve shows the clear energy saving of up to 60 % made by the K3G146 Green­Tech EC blower (52 W power consump­tion) in compar­ison to stan­dard AC centrifugal fans (black char­ac­ter­istic curve: 87 W power consump­tion, red char­ac­ter­istic curve: 128 W power consump­tion).

Bene­fits of a decen­tralised system

The hotel’s owner, Robert Rentzsch, explains that “for me, the energy-effi­cient EC motors were a crucial deter­mining factor, because i had designed the entire building with a view to keeping the oper­ating costs as low as possible.” The hotel owner has installed 40 Venkons in the Abasto Hotel: 31 in the guest rooms and nine in the restau­rant. Heat is provided via a heat pump with 45 °C flow temper­a­ture, and cooling is provided using ground water. The high­light of the system is that heating and cooling takes place actu­ally inside the room itself; the venti­lation unit under the roof merely provides fresh air and recovers 81 % of the heat from the air extracted from the room.


Figure 5: in venti­lation and air-condi­tioning systems such as this Airblock C system from Kamp­mann, r3G355 fans with Green­Tech EC tech­nology from ebm-papst reli­ably supply fresh air.

Stan­dard centralised units heat and cool the air centrally and then distribute the air around the building via air ducts. The Air-block C venti­lation unit (figure 5) manu­fac­tured by Kamp­mann using Green­Tech EC fans now only supplies the fresh air – the decen­tralised Venkons inside the hotel rooms are oper­ated indi­vid­u­ally. The unit is there­fore very compact and the supply air ducts can also be made smaller. As a result, trans­port losses are also greatly reduced.

For Robert Rentzsch, the factor of whether a system is decen­tralised or not is in itself no insignif­i­cant matter: “For heating installers, space is always a major issue.” This is because entralised systems neces­si­tate ducts with large cross-sectional areas. Rentzsch has managed to install the system with just 30 centime­tres of inter­me­diate ceiling at the Abasto Hotel. With a centralised system he would have required up to 80 centime­tres – dead space that would only have increased costs. “I was convinced straight away that we should be heating and cooling the air where it is actu­ally going to be used”, says Rentzsch.

The oper­ating costs at a glance

“I believe that the concept we have here is the best possible solu­tion for hotel appli­ca­tions”, claims Ulrich Budde with convic­tion. He is also pleased about the increased level of control­la­bility. If the air quality is OK, the system simply provides heat or cooling as required; if the temper­a­ture is OK, the system simply provides venti­lation. However, it is not always easy to commu­ni­cate the best solu­tion. Although at Abasto Hotel the investor is also the user, and there­fore close atten­tion was paid to the oper­ating costs. “As a general rule, investors look above all at the invest­ment costs and the minimum legal equire­ments”, says Budde, explaining the market situ­a­tion. A key factor is the life cycle costs over the
entire service life.

The minimum require­ments are also becoming more strin­gent: the Euro­pean union’s Energy-related Prod­ucts Direc­tive demands a much higher level of energy effi­ciency. Air-condi­tioning devices with Green­Tech EC tech­nology help with compli­ance as they already go signif­i­cantly beyond the require­ments. What is more, build­ings equipped with high-quality tech­nology with a long service life fare much better on the real estate market. Finally, guests are much happier when they can stay in a hotel room with bliss­fully quiet air-condi­tioning tech­nology; they will be more likely to come back for another stay and will spread the word.


The successful use of Green­Tech EC tech­nology in this hotel appli­ca­tion clearly illus­trates just how much this tech­nology has to offer hotel owners in compar­ison to a stan­dard air-condi­tioning system with AC motor and incre­men­tally controlled winding. Firstly they benefit from the reduc­tion in noise thanks to the EC motor, which is up to five deci­bels quieter – for the human ear this equates to a reduc­tion in the overall noise impres­sion of almost half. Secondly, they can reduce energy consump­tion by up to 70 % thanks to the high-perfor­mance, contin­u­ously adjustable control func­tion­ality across the entire range. Hotel owners save on energy costs, archi­tects and building plan­ners benefit from a future-proof solu­tion and guests can finally have a more peaceful night’s sleep.

Kamp­mann GmbH

This company head­quar­tered in the town of Lingen an der Ems in the region of lower saxony (Germany) develops, produces and sells systems for heating, cooling and venti­lation, always employing state-of-the-art tech­nology for its prod­ucts. The tech­nology leader employs around 700 employees in 15 branches. The collab­o­ra­tion with the fan manu­fac­turer ebm-papst has been going strong for more than 30 years.

Hotel Abasto

The hotel to the west of Munich was opened in September 2012 and offers 31 rooms for guests as well as its “Farmhaus” restau­rant.

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