Minnesota Power is a regional utility company serving 145,000 customers in northeastern Minnesota. Like many of its customers, Minnesota Power faces efficiency challenges within existing and aging facilities. This led leadership to pursue a high-performance HVAC retrofit in one of its offices.
After seven years of failing compressors, humidity issues, and frigid winters, a defective HVAC system in its Cloquet, Minnesota, office left the utility company at its wit’s end. The office is home to Minnesota Power’s customer service department and linemen who are in and out of the building several times each day. While only serving about 20 employees at a time, the 5,000-square-foot office space was in need of attention.
“For four summers in a row, we didn’t have air conditioning,” said Craig Kedrowski, business service advisor, Minnesota Power. “We went through winters with only baseboard heat and hot summers with fans running constantly. The HVAC units seemed to be fighting one another, and the vendor was not responsive in helping us with our system’s issues. It prompted us to seek out another solution.”
In 2018, local mechanical contractor, Zach Wehr from Eclipse Inc., who had worked with Minnesota Power’s conservation program, invited Jake Sajevic, account manager for Trane, to tour the office. The goal was to determine the issues with the existing VRF system and offer a solution.
“Every time Zach and I did a walkthrough, the system wasn’t working,” said Sajevic. “Sometimes we’d notice the outdoor unit fans were spinning, but you’d hold up your hand to the units, and they weren’t rejecting any heat.”
Ultimately, Wehr and Sajevic knew a CITY MULTI® VRF system was the solution Minnesota Power needed and invited Mark Totino, commercial area sales manager for Mitsubishi Electric Trane HVAC US (METUS), to visit the property and consult on the system’s design.
“Mark and I met with two Minnesota Power staff members and talked through their system’s issues,” said Sajevic. “A big selling point was installing a two-pipe system instead of a three-pipe system. Less piping rules and fewer joints simplify the installation, which can lead to a more successful project.”
Totino identified several errors in the existing installation.
“The manufacturer had done a custom prototype for the system, and it basically failed,” Totino said. “They had added a boiler on to the air-cooled condensing unit to keep it running in the wintertime, and it was not functional. There were record-breaking low temperatures in our region this winter. The only way the building stayed warm was by using its electric baseboard auxiliary heat.”
Once a design was established, the group presented its plan to Minnesota Power as a turnkey manufacturer project.
“The previous vendor didn’t take into account the makeup air units or building controls,” Kedrowski said. “The METUS team and Eclipse took everything into account.”
The design includes an R2-Series Heat Recovery System with Hyper-Heating INVERTER® (H2i®) technology, two PKFY Wall-Mounted Indoor Units, 10 PEFY Horizontal-Ducted Indoor Units, and three Lossnay® ERVs. Additionally, 12 Smart MEs and one AE-200A Centralized Controller were specified for system management. Each tie into Minnesota Power’s BAS at its Duluth headquarters, streamlining efficiency and comfort control while displaying performance for current and future customers.
For Minnesota Power, having an effective, electric-powered VRF system does more than solve comfort issues.
“Because we recommend this equipment in our conservation program, we were interested in having a showcase where we present simultaneous heating and cooling,” said Kedrowski. “Beneficial electrification is something that’s really coming along. University and city buildings are looking for options to increase sustainability and move away from fossil fuel use.”
In the Cloquet office’s conference room, two indoor units each connect to an individual thermostat that lights up either blue or red for cooling or heating, respectively.
“Side-by-side, they’ll be able to show and explain the concept of heat recovery,” Totino said. “This building is a testament to their support of electrification.”
However, Minnesota’s extremely cold winters pose a big challenge with electrification.
“There are some unique hurdles the farther north you go,” said Sajevic. “Our design’s low-ambient temperature is minus 20°F, but it can get even colder here. I’ve talked with engineers all over the region, and they think VRF is a great technology, but only a few are comfortable specifying it because of the low-ambient conditions we face.”
Combining supplemental heat with VRF technology provides clean, efficient energy with backup heating for freezing winters.
“For many developers and engineers, their gut reaction is to explain why electric heat is super expensive to run,” Sajevic said. “When paired with Mitsubishi Electric’s H2i units, the auxiliary heat will almost never run. For this project, we’re going to continue to submeter the electric heat going into next winter, and we’ve interlocked the controls system with our CN-24 accessory, which enables supplemental heat sources. We’ll be able to verify how often the supplemental heat actually runs and under what outdoor conditions it is enabled.”
The technology has come a long way, especially in terms of payback, life expectancy, rate of return on investment, and performance, said Wehr.
“I can understand the apprehension of some based on past technology,” he said. “That said, the system we installed at Minnesota Power will kick off at minus 25° and switch to supplemental heat. I’ve had it in my building since 2008 with no issues.”
Installation took place in April 2019, and the system has only received positive feedback.
“Our coworkers love it,” Kedrowski said. “Some people want the room 80° in the summer and some want it 65°. The Mitsubishi Electric system allows them to do that.”
Even more, the system allows Minnesota Power staff to continue delivering its clean energy efforts and educating customers.
“Public utilities like Minnesota Power are making the investment and doing the research for the betterment of the communities they serve,” said Wehr.
“Projects like this are especially important for engineers and building owners to see because they’re the ones with the funds to take electrification mainstream.”