University campus retrofits heating system, needing 85% less power during record lows



A university in USA retrofitted its heating system during the coldest winter in 30 years. The new Grundfos MAGNA3 circulators not only improved indoor comfort, but also increased efficiency and cut power consumption up to 85% a year.


The situation

The state of Minnesota, USA, is known for extreme winters with temperatures down below freezing point. Its people have a well-earned reputation for toughing out the snow and cold each season. Many commercial buildings require more energy to keep tenants comfortable with below-freezing temperatures.

At Saint John’s University in the Minnesotan town of Collegeville, four building wings at the Peter Engel Science Center run heat from fall through spring. The centre was built in the 1960s of concrete, typical of that era and of the construction style found throughout the rural campus. Its existing pumping system was outdated, with a fixed flow without variation, thereby operating at full power throughout the heating season.

After an audit of the pumps, the University discovered that the system was not only of fixed flow, but also oversized. The insides of the piping were lined with ridges, an indication of damage from excess velocity.

“Oversizing wastes energy and is hard on the pipes,” says Brian Soderholm, Grundfos sales representative in Ramsey, Minnesota.


The solution

The University undertook a heating system retrofit just in time, installing the intelligent, energy-efficient Grundfos MAGNA3 smart circulator pumps.

The MAGNA3 is an energy‐optimized pump with an integrated logic algorithm to “learn” the varying energy-usage patterns of any application. It features a permanent magnet motor design that cuts power consumption up to 85 percent — the highest energy efficiency rating as compared to other circulators in its class.

“I wasn’t aware of them before, but the existing pumps were nearing the end of their lives, so we decided, ‘Why don’t we do something more efficient?’” says Campus Service Technician David Schlumpberger, who oversaw the project, “we had a feeling the old pumps were oversized, but there was no way to tell — until we did the replacement.” 


The outcome

Schlumpberger explains the MAGNA3 pump has many benefits. He says it is possible for his team to get data from the pump’s readout and learn more about the building’s needs.

“The bottom line is that the MAGNA3 is sophisticated,” says Schlumpberger, “it can tell itself to slow down or speed up, based on current demand.”

Replacing the four older pumps with the MAGNA3 has not only increased efficiency, but it also improved building comfort. The pump has an AUTOADAPT function, which continuously fine‐tunes power consumption, discharge head and flow rates to meet the dynamic needs of the system.

“These pumps adapt to existing situations and can be adjusted accordingly,” Soderholm, who worked on the St. John’s project, says.

The University expects the payback for three of the new circulators in less than three years, and just slightly longer for the fourth.  

“We sized the pumps to match the old pumps, not knowing what their true system requirements were,” Soderholm says, explaining they only had the rating plates to go by.

“Even though the Grundfos pumps are larger than necessary for this building,” he continues, “it’s not wasteful, because we were able to dial them down with impressive results.” That translates into an estimated yearly savings of $693.  

“We just had the coldest winter in 30 years and we were running pumps at 25% of the head that the old pumps had, while keeping the building warm,” says Schlumpberger, “in other words, we’re actually able to run the system at the original designed flow rate, using less power, less energy and at less cost.”

This energy-saving outcome means a lot to St. John’s, since environmental stewardship is a core Benedictine tradition at the University. Located on 2,700 acres that range from wetlands to lakes and prairies to forests, the campus boasts of an Office of Sustainability.

“The MAGNA3 smart technology is a really good fit for a school that teaches students a respect for the land,” Schlumpberger says.


Optimising a campus heating system


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Collegeville, Minnesota


Saint John’s University

The MAGNA3 circulator pumps brought up to 84% savings and a three-year payback time at St. John’s University. They helped improve the indoor comfort, says to David Schlumpberger. (Note: 1 US gal = 3.8 l, and 1 ft = 0.3 m)


Dave Schlumpberger, HVAC Service Technician at St. John’s University



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