Recent visitors to the Detroit Lakes Community & Cultural Center have noticed the four large, silver cylinders standing between the entrance into the Historic Holmes Theatre and the center’s north side parking lot. Though they may look like miniature grain silos, each cylinder is embossed with the words “Ice Bank” – an obvious clue to what lies inside. The tanks do, in fact, contain ice, and these “chiller tanks” are the basis of the cooler half of the center’s new heating and cooling system. “The cooling side is a hybrid,” said Stu Omberg, the center’s CEO. “During off-peak hours, the chillers cool the ice tanks to a degree that they actually make ice. During the day, the chillers are not running. There’s a glycol coil inside each ice tank, and the glycol runs through the tanks via a pump, cooling the glycol to 40 degrees.” That cold glycol is then pumped into the center’s air handlers, which in turn blow air across the ice-cold coils, thus cooling the air before it is disbursed out into each room. Conversely, heated air is disbursed via a more conventional boiler system; what brings this ha...