The monastery cellar is located in the middle of the old city center in Beutels­bach, Germany. It includes a gym with showers and changing rooms, which are used by the nearby school, a small cinema, and
a large vaulted cellar where events take place. These four rooms were supplied with fresh air by a venti­lation system located in a narrow cellar room, using belt-driven fans. They could be controlled in just two stages. However, as the rooms were often used to varying extents, for example the cinema room often went from empty to full of people, this is a key area where more effi­ciency can be gained.

There­fore, the city of Wein­stadt commis­sioned an engi­neering firm and Pfänder GmbH to find an energy-saving and econom­ical solu­tion (Fig. 1). The city’s wish was initially only to modernize the control system. “That wouldn’t have been a problem either – the system’s control cabinet was in very good condi­tion. However, the energy-saving poten­tial would have been limited due to the old belt-driven fans,” says Lukas Pfänder, Managing Director of Pfänder GmbH.

As Lukas Pfänder had already imple­mented several successful retrofit projects in coop­er­a­tion with the ebm-papst Breuell & Hilgen­feldt service center, he also suggested a retrofit for the monastery cellar. The lack of space meant that a plug-and-play solu­tion was the only way to modernize the venti­lation system’s intake and exhaust air econom­i­cally and to reduce the power consump­tion of the fans.

Fig. 2: The system’s control cabinet was still well main­tained and could there­fore be supple­mented with sensors and ebm-papst neo gateway without great effort (Photo | Lukas Zwies­sele)

Fig. 3: The old, belt-driven fans used too much elec­tricity and could only be controlled in two stages. (Photo | Lukas Zwies­sele)

Retrofit with a focus on air quality

Dieter Hilde­brandt, Sales Manager at Breuell & Hilgen­feldt, calcu­lated the required perfor­mance and suggested eight RadiFit EC centrifugal fans as a replace­ment. However, the monastery cellar’s special require­ments – the fast change in the level of utiliza­tion of the space and the resulting changing demand for fresh air – gave Hilde­brandt and Pfänder the idea of equip­ping the venti­lation system with sensors and gate­ways in order to constantly monitor the require­ments and regu­late the system to them accord­ingly (Fig. 2, Fig. 3 in gallery).

Our goal was to reduce the power consump­tion of the venti­lation system by at least 60 percent.

Lukas Pfänder, Managing Director Pfänder GmbH

They approached Ralf Braun, Sales Director Germany and contact person for ebm-papst neo, with this sugges­tion. The start-up of the fan specialist ebm-papst offers intel­li­gent solu­tions for data-based build­ings. Braun was imme­di­ately convinced by the idea, as demand-based, sensor-based closed-loop control would open up more energy-saving poten­tial, along­side the effi­cient fans.

The RadiFit – the compact solu­tion for venti­lation tech­nology

The main aim of the retrofit was to save energy, which is why the RadiFit EC centrifugal fan was chosen, the new system solu­tion for venti­lation tech­nology from ebm-papst. Due to its compact dimen­sions, it was suit­able for the instal­la­tion dimen­sions of the old fans, enabling space to be saved and the instal­la­tion to be quick and easy. As it was supplied as a plug-and-play design, it was also easy to connect the elec­tronics.

The RadiFit features a scroll housing and back­ward-curved blades, which enables a high pres­sure increase and ensures a high level of effi­ciency. The RadiFit is also main­te­nance-free and durable, which further reduces the oper­a­tional and life cycle costs. The main­te­nance super­visor and the city benefit from this equally. Thanks to their high effi­ciency, the retrofit also pays for itself very quickly. Dieter Hilde­brandt and Lukas Pfänder esti­mated energy savings of 60 percent with the eight new RadiFit.

Energy saving thanks to EC motor

This value comes primarily from the RadiFit’s Green­Tech EC motor. Such high savings are possible thanks to the effi­ciency level of over 90 percent alone. Because the old belt-driven AC fans could only be switched on or off, regard­less of the actual capacity utiliza­tion of the different rooms, the system always ran at too high a power, even if a lower air flow would have been suffi­cient for the actual fresh air require­ment.

We have tailored the control system perfectly to the require­ments of the monastery cellar to save even more energy.

Lukas Pfänder, Managing Director Pfänder GmbH

The new, commu­ni­ca­tion-capable EC fan, on the other hand, is infi­nitely vari­able between 0 and 100 percent. This means that the new RadiFit can accept any speed as required and operate with the lowest possible power consump­tion at any oper­ating point. The savings target of 60 percent was already achieved by replacing the fans – but there was still room for improve­ment.

Demand-based control with sensors

The second part of the retrofit involved reworking the control system. After all, it becomes even more effi­cient if the demand for fresh air is precisely deter­mined and controlled auto­mat­i­cally accord­ingly. The changing condi­tions of the monastery cellar provided the perfect case for this.

“The gym is not used for half of the day. However, if a school class has a sports class, the CO2 content rises and the venti­lation system has to supply more fresh air. After the lesson, the showers and changing rooms are used, which suddenly increases the temper­a­ture and humidity there,” explains Pfänder.

For this reason, sensors for CO2 content, humidity, temper­a­ture and fine dust concen­tra­tion have been installed in the monastery cellar. The measured values are sent to the Intel­li­Gate Air Gate­ways from ebm-papst neo, which forward them to the venti­lation system’s control system. The closed-loop control has been indi­vid­u­ally adapted and programmed for the monastery cellar. Specially defined limit values now specify when the system increases its power by how much and when it reduces the power once again, with infi­nite vari­a­tions and effi­ciently. Indi­vidual func­tions such as a warning e-mail to the care­taker, have also been set up if a certain value is exceeded (Fig. 6).

The inter­ac­tion between sensors and systems is reli­able and econom­ical. This will enable more than the planned and achieved energy savings of 60 percent. The city not only saves on costs but can also guar­antee high air quality for all visi­tors at large events, festi­vals or concerts.

Ensuring air quality with the multi-IAQ sensor

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.

Watch the video here: