Arctic Bear Cub 700 Indirect Fired Air Heaters:
Safely Feelin' the Heat...Even at a Mile High

During the football season, the “Bronco Barn” is a staple outside of Ivesco Field in Denver, CO, and plays host to VIP and fan autograph sessions and several other community events. With thousands of fans pouring through the barn doors during home games, a primary concern for the Broncos organization was to safely keep their guests warm and comfortable inside the structure during those cool fall and cold winter months.

“In the past, small direct fired units were used to heat the barn,” says Esiah McNeil, branch manager for United Rentals, Inc. “However, they did not want the flame or emissions concerns that went along with the direct fired units.” In short, the organization was looking to achieve a higher degree of safety, while keeping the temperatures inside the “Bronco Barn” at a constant warm temperature.

The giant structure spans 220 ft in length and 25 ft wide and encompasses nearly 100,000 ft³ of space. The Broncos turned to representatives from the North Denver branch of United Rentals for a new heating system. “Initially, we discussed some different direct fired units with the facilities manager, but he was set on indirect fired heaters,” McNeil mentions.

Since these initial discussions took place right before the opening of the 2007-08 football season, time was of the essence. United Rentals quickly demonstrated a Ground Heaters Arctic Bear Cub™ 700 indirect fired heater. Officials were so impressed at the heater’s performance they purchased two Cub 700 medium duty heaters. “Two 700s are actually a bit of overkill (from a construction application point of view),” McNeil explains, but the Broncos wanted more units to ensure faster, even heat cycles to the barn.

The efficient Ground Heaters Arctic Bear Cub 700 feature a 720,000 BTU/hour fuel input with a heat output of 576,000 BTU/hour, boasting a high, 80% heater efficiency. With an outlet temperature of 200 degrees Fahrenheit, the Cub 700 delivers up to 7700 CFM – double the air flow of competitive heaters – with up to four times the static pressure.

The secret behind the unit’s safe operation lies in its indirect fired design. “The flame of the Cub 700 is contained inside a combustion chamber, and the unit delivers clean heat as well as improved operating safety over direct fired units,” says Ken Cannella, Climate Technology product manager for Wacker Neuson. While direct fired units expel noxious CO, CO₂ and other emissions directly into the area surrounding the heater, the Cub 700 works in a similar fashion to many gas forced-air heating systems found in businesses and residential homes. The products of combustion are vented to the structure’s exterior and do not enter the structure.

The Cub 700 features the Ground Heaters exclusive Recircul-Air™ technology, which allows adjustable recirculation of warm air. Recircul-Air pressurizes the structure to keep cold air out and maintain even air temperatures inside the structure. “The structure is equipped with an optional thermostat to help keep the ‘Bronco Barn’s’ inside temperature at a constant 72 degrees F,” says McNeil.

By recirculating the inside air, fuel economy for the Cub 700 is optimized. This indirect fired heater offers three fuel options – natural gas, propane or diesel – to meet any jobsite condition. Its large, 145-gallon fuel tank assures the Cub 700 offers at least a 24-hour run time without refueling.

While the 2007-08 season did not end as well as expected for the Denver Broncos football team, the two Arctic Bear Cub 700 heaters were a most valuable performer for the “Bronco Barn.” Although the barn has been taken down for the off season, it will be back again for the 2008-09 football season with the two Cub 700s quarterbacking its heating needs.