At the University of North Dakota, the local climate complicated maintaining the hockey ice sheet while ensuring comfortable temperatures for patrons. Two chilled water systems, teamed with six heat recovery systems using heat transfer fluid mixed with water, achieved the goal.
INDOOR AND OUTDOOR CLIMATE CHALLENGES
Heating and cooling systems for Engelstad Arena presented a number of engineering challenges to the facility’s designers and contractors. Providing the proper temperatures needed to build and maintain the hockey ice sheet while ensuring comfortable temperatures for athletes and facility patrons was complicated by the North Dakota climate. Winter temperatures in Grand Forks can drop as low as -40°F with wind chills below -80°, while summer temperatures can rise up to the mid-80°s.To ensure a comfortable interior environment in all seasons, engineers designed two chilled water systems to supply the ice arena and the remainder of the structure, plus a total of six heat recovery systems. Depending on the application, heating and cooling is delivered by 30% to 50% solutions of DOWTHERM™ SR-1 inhibited ethylene glycol-based heat transfer fluid and water. The fluid circulates through a tube and shell-type heat exchanger where it is heated in winter by steam supplied by the central campus heating plant. The same fluid circulates through chillers in the summer to provide facility-wide cooling. Chilled fluid is used year-round to build and maintain the ice skating sheet at the optimum temperature for hockey or other skating events.
DOWTHERM™ SR-1 for the Engelstad Arena project was supplied by Univar USA, an authorized Dow distributor. According to Kerry Cipra, Univar sales manager in St. Paul, MN, shipment of the heat transfer fluid is carefully managed to ensure the fluid is delivered on time and that product purity is maintained.
Cipra said Univar USA, “follows stringent procedures to prevent contamination of the mixture and, for larger capacity systems, we use dedicated 5,000-gal tankers for delivery directly to the jobsite. The Engelstad Arena project required us to arrange for the delivery of DOWTHERM™ SR-1 Fluid using two tankers, with deliveries scheduled two hours apart to provide one smooth, quick fill.”
BIG FLUID ON CAMPUS
Fargo, ND-based Agassiz Chemical & Equipment Inc., an authorized reseller ofDow Heat Transfer Fluids, served as the water treatment chemical and glycol subcontractor for the project. Agassiz Chemical president, Steve Hareland, stated, “DOWTHERM™ SR-1 Fluid was the logical choice for use in the arena. We selected this particular heat transfer fluid because of our experience with the product in addition to its solid performance.”The fluid has been used in a variety of past UND campus projects including dormitory systems, chemistry labs, a biomedical research facility, and many others. Over the past 20 years, Agassiz Chemical has done extensive design-phase work with engineers in the initial stages of new and retrofit projects on UND’s campus.
David Obermiller, principal with Fargo-based Obermiller-Nelson Engineering, Inc., was the design engineer on the Engelstad Arena project. “We’ve had good results with DOWTHERM™ SR-1 Fluid in a number of projects for the university, ranging from the new $18 million Wellness Center to facilities for student housing. The fluid’s inhibitor package means that equipment operates maintenance free for years to come,” he said.
Hareland said the system has lived up to its promise and continued to operate maintenance free. “We haven’t had to add any inhibitor to the system since it was installed. The system has responded very well,” he said.
In fact, Hareland noted that UND is so pleased with the system utilizing DOWTHERM™ SR-1 Fluid that they are already planning on using it in two other upcoming projects on campus.
