An engi­neering degree program can be rather theo­ret­ical. Gustav Hell­sten, a student at the Univer­sity of Copen­hagen, knows all about it. “A pocket calcu­lator is prob­ably the closest thing to a tool that we use at univer­sity,” he explains with a laugh. This is why as part of his semester project with fellow student Klavs Holst Chris­tensen, he was very inter­ested in taking on a task that had a manual compo­nent in addi­tion to calcu­la­tions. The two ended up working on a project involving the Panum Building at the Univer­sity of Copen­hagen: modern­izing the air condi­tioning unit. The complex was built in the 1960s and is now the home of the university’s medical faculty.

Searching for part­ners

Since Hell­sten and Chris­tensen had not had much to do with venti­lation systems until that point, they had to start the project at their desks. They did research to find suppliers that could give them the infor­ma­tion they needed to draw up the project’s busi­ness plan. “Many of the compa­nies we contacted did not take us seri­ously because we are students and could not promise large orders,” said Hell­sten. “From the very begin­ning, Niels Knokgård from ebm-papst was different. He took time to help us and was inter­ested in what we were doing.” Knokgård provided the students with the soft­ware they required for their calcu­la­tions and explained how to approach the neces­sary effi­ciency calcu­la­tions to them. The Market Manager in Refur­bishing from

The air flow is thor­oughly measured through small holes drilled in the venti­lation ducts. (Photo | Bent Grøn­lund)

Knokgård provided the students with the soft­ware they required for their calcu­la­tions and explained how to approach the neces­sary effi­ciency calcu­la­tions to them. The Market Manager in Refur­bishing from ebm-papst said: “It was a lot of fun to work with the students and bat ideas back and forth. We feel a respon­si­bility to pass on our knowl­edge, and of course, it will also benefit ebm-papst in the long run, with increased aware­ness of energy savings, as these new Chief Ingi­neers will be tomor­rows deci­sion makers.”

As soon as the engi­neering students knew exactly what types of fans they needed, they contacted various fan manu­fac­turers with detailed inquiries. “It was soon obvious that with their inte­grated control system and high effi­ciency, the EC fans from ebm-papst had clear advan­tages compared to other compa­nies’ prod­ucts,” explained Hell­sten. “Other suppliers wanted us to pay the same amount for the sepa­rate control system as we did for the fan itself. This would have made the project much too expen­sive.” Ulti­mately, Hell­sten and Chris­tensen decided to go for RadiPac centrifugal fans from ebm-

Ulti­mately, Hell­sten and Chris­tensen decided to go for RadiPac centrifugal fans from ebm-papst and submitted a busi­ness plan based on their data. “The univer­sity admin­is­tra­tion approved our plan surpris­ingly quickly,” said Chris­tensen. “This was primarily because our calcu­la­tions showed that the invest­ment would be amor­tized after eight months.”

Finally getting down to work

After receiving the go-ahead, Hell­sten and Chris­tensen were finally able to get down to work. Supported by an instal­la­tion tech­ni­cian, first they removed the old, belt-driven fans. “They were unbe­liev­ably big, heavy and dusty,” said a grin­ning Chris­tensen. Since the Radi­Pacs were much smaller than their prede­ces­sors, the students had to adapt the entrances to the venti­lation shafts before installing the new EC fans.

In the project the students also had the chance to do some hands-on work. (Photo | Bent Grøn­lund)

“It was a wonderful, impor­tant expe­ri­ence for us to actu­ally remove the old fans,” said Hell­sten. “Both of us have worked on bikes, motor­cy­cles and cars, but this was very different.” After a few hours, they had finished the work and the new unit with the new fans could be started up.

Only a few weeks after the retrofit, measure­ments confirmed the fore­cast savings and they held to the promised amor­ti­za­tion period. Since the retro­fitted unit air condi­tioned the changing rooms and sani­tary area for 80 medical students, the option to control the fans was partic­u­larly welcome. “Before, they could only turn them on or off,” said Chris­tensen. “Now the system can be adjusted depending on the time of day and the number of people in the changing rooms. That saves even more energy.”

Carsten Mørch, chief engi­neer for the medical department’s build­ings, was impressed with the results. “Klavs and Gustav’s work opened our eyes. We have often worked with amor­ti­za­tion periods of 10 to 20 years, but the short amor­ti­za­tion period for their opti­miza­tion led us to add the solu­tion to our conver­sion plan for 2020.”

An option for the future

This is why after the project, the univer­sity started succes­sively replacing other air condi­tioning units and plans to continue doing so – after all, each replace­ment saves plenty of time and money. The project encour­aged the two students to continue doing this type of work. Imme­di­ately there­after, they supported ebm-papst as student employees in calcu­lating the possible energy savings for other projects. Chris­tensen finds the idea of working in the field after grad­u­ating appealing: “I enjoy working on projects where I can use my tech­nical skills to save energy. I can absolutely imagine working in this field later.”