The air body­guards

Event spaces expe­ri­ence two extremes: they are either unused or packed with people. The venti­la­tion system in the event loca­tion Stiftskeller in Beutels­bach could no longer cope with the changing require­ments: after a retrofit, it not only circu­lates air more effi­ciently but is also vigi­lant about the air quality using sensors.


Beutels­bach in the magnif­i­cent vicinity of Stuttgart. The monastery is located in the old city center, adorned with timber framing. Among other things, a gym, a commu­nity cinema and an event loca­tion in the old monastery cellar have been set up. A single venti­la­tion system supplies the rooms with air, using a lot of elec­tricity in the process.

A plan­ning office commis­sioned by the city turned to the company Pfänder, which mainly auto­mates build­ings. “We do not build venti­la­tion or heating systems ourselves, but rather take care of their control system, program­ming for example when and where venti­la­tion, heating or cooling is required,” says Lukas Pfänder. Many customers come to Lukas and his brother Tobias Pfänder with old venti­la­tion systems that consume too much elec­tricity.

A new control system does not always suffice, but completely replacing the systems is expen­sive and time-consuming. When looking for a partner for diffi­cult modern­iza­tion projects, the two brothers were aware of the retrofit projects of the ebm-papst Service Center Breuell & Hilgen­feldt. Since then, they have been imple­menting these types of upgrades in collab­o­ra­tion with the fan manu­fac­turer from Mulfingen and retrofit expert Dieter Hilde­brandt from Breuell & Hilgen­feldt.

Old system, new control?

For the Beutels­bach Stiftskeller, the task was to only modernize the venti­la­tion system’s control system. “We took a look at the control cabinet on site. It was still in good condi­tion. But we were taken aback when we looked at the venti­la­tion: old belt-driven fans were still installed.” A new control system for an old system? As a result, the greatest poten­tial for savings would be unused.   

Our aim was to reduce the venti­la­tion system’s energy consump­tion by at least 60 percent.Lukas Pfänder, Managing Director Pfänder GmbH

Dieter Hildebrandt’s sugges­tion: eight new RadiFit centrifugal fans in four systems that supply fresh air to the vaulted cellar, gym, showers, changing rooms, and cinema much more effi­ciently. The venti­la­tion shafts in a good condi­tion and the limited space in the cellar were perfect condi­tions for a retrofit: System open, old fans out, RadiFit in.

Saving energy, sixty percent and more

The vaulted cellar, which is used for events, is located deep below the old monastery. It is impor­tant that the cellar air is not stuffy. (Photo | Lukas Zwies­sele)

They then went to look at the electrics in the control cabinet. The Pfän­ders read the new venti­la­tion system’s perfor­mance values for the first time: “Our aim was at least 60 percent less current consump­tion. This permits infi­nitely vari­able regu­la­tion of the RadiFit EC motor.

Instead of two stages that corre­spond to a power of 0 or 100 percent, we can now call up outputs of 16, 37, or 89 percent as required.” The 60 percent savings target was already achieved by replacing the fans, but there was still room for improve­ment.

This is because there is even more effi­ciency to be had if the demand is precisely iden­ti­fied and auto­mat­i­cally controlled. The rooms of the Stiftskeller are perfectly suited to this, as Lukas Pfänder explains: “The gym is not used for half of the day. However, if there is a lesson being taught there, the CO₂ content increases sharply and, there­fore, the demand for fresh air rises signif­i­cantly too. After the lesson, the showers and changing rooms are used, causing high temper­a­tures and humidity.”

With demand-based control, the venti­la­tion system reacts inde­pen­dently to these rapidly changing require­ments. The replaced control cabinet already offered the right condi­tions for this. All that was missing was sensors and gate­ways. Dieter Hilde­brandt recog­nized the oppor­tu­nity and presented Lukas and Tobias Pfänder with gate­ways from the start-up ebm-papst neo, which deals with intel­li­gent solu­tions for data-based build­ings.

CO2 content, humidity and temper­a­ture are measured in the gym and the changing rooms. The system regu­lates the supply of fresh air accord­ingly. (Photo | Lukas Zwies­sele)

Sensors make it smart

The sensors contin­u­ously measure CO content, humidity, temper­a­ture, and fine dust concen­tra­tion in the air. The values are sent to the Intel­li­gate Air Gateway, which forwards it to the venti­la­tion system control system. The control system has been indi­vid­u­ally adapted and programmed for the Stiftskeller. If the CO value in the vaulted cellar  or the humidity in the shower   exceeds a certain limit value, the system auto­mat­i­cally adjusts up and back down once the air quality is good and, thanks to the EC motor, this is done smoothly and effi­ciently.

We have perfectly tailored the control system to the require­ments of the monastery cellar to save even more energy. Lukas Pfänder, Managing Director Pfänder GmbH

Ralf Braun, Sales Director for Germany at ebm-papst, explains: “Of course, you can also adjust it manu­ally. However, the inter­ac­tion between the sensors and the system is very reli­able and, above all, econom­ical.” Indi­vidual func­tions, such as sending a warning to the building’s care­taker by e-mail, are also possible if a certain value is exceeded. “This ensures a very high air quality on an ongoing basis. After the last few years and espe­cially at larger events, that is a good feeling,” says Braun. There­fore, visi­tors to the monastery cellar can feel completely at ease. Thanks to the retrofit, in addi­tion to effi­cient venti­la­tion, the quality of the air is ensured at all times.

Next-level air quality

With the Multi-IAQ sensor from ebm-papst neo, there is a simple and effi­cient way of ensuring consis­tently high air quality in event rooms. The sensor measures a total of five values, namely temper­a­ture, humidity, VOC (volatile, organic compounds that are harmful to health), CO2, and fine dust in the air. The viral index is calcu­lated using the five measured values and a complex math­e­mat­ical equa­tion. This indi­cates the quality of the air and the risk of virus trans­mis­sion and can be read off from the freely acces­sible IAQ Connect app. The multi-IAQ sensor can be installed in flush-mounted sockets similar to a light switch.

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