New Hampton Metal Fab, a third generation, family-owned business, has always held the needs of their customers and employees to the same high standards. When they built an 8,500 sq ft addition on a northeastern Iowa metal fabrication facility in 2005, they didn't anticipate that the supplemental space, which included a higher roof, would be so uncomfortable.
With winter temperatures averaging 25 to 27ºF and heat rising to the rafters, the New Hampton facility typically experienced a 20 degree temperature difference between the floor and ceiling of the warehouse. Summer months were just as grueling, due to heat generated from the facility's plasma burn table and welding station. Air movement was needed to circulate the existing air within the space, narrowing the temperature gap from floor to ceiling.
Finding a Balance
Purchasing manager Pete Gallup was looking to save on heating bills and to balance out temperatures during colder months, while providing a cooling effect during New Hampton's hot summers.
"All of the heat was going up," Gallup explained. "We'd send somebody up to fix something and they would strip down to their long johns, while the guys on the floor were standing there in Carhartts, basically freezing to death." As an added concern, wearing so much flammable clothing was a safety issue.
Destratification
Heat stratification occurs because hot air is less dense than cold air. The air coming out of a forced air heater, or in the case of some manufacturing facilities, the heat produced from the equipment itself, is approximately 5 to 7% lighter than the air in the space and thus tends to rise to the ceiling. This results in a significant temperature difference in the space -- anywhere from approximately 10 to 30°F.
It is becoming increasingly more common to use large diameter, low speed ceiling fans to destratify a space, resulting in as little as 1ºF temperature difference from floor to roof deck. The extra fuel required to heat the space ultimately results in wasted energy, as much of the heat escapes through the walls and ceiling once it rises to the roof line. Savings accrue by slowly circulating this trapped heat down to the occupant/thermostat level before it's able to escape from the building. Even though the thermostat setpoint remains the same, the heating system does not have to work as hard to maintain the given setpoint.
Gallup installed an 18 ft large diameter, low speed Powerfoil®X fan from the Big Ass Fan Company®. The idea was to circulate the trapped heat at the ceiling down to the occupant level without a chilly draft, creating uniform temperatures within the facility, and therefore a more comfortable environment for employees year-round.
With 40 ft ceilings, the new space was known to have cold corners where few employees wanted to work. With the addition of the fan, the ceiling-to-floor temperature differential was brought down to less than 1°F.
"Nobody would work back in those corners," said Gallup. "But now anybody can work pretty much anywhere. The fan has made the temperature uniform all the way up."
Equality
With little to no insulation in the building, New Hampton Metal employees were at the mercy of the weather outside. According to Gallup, New Hampton Metal Fab saved 33% to 38% on heat bills last winter. He said the fans will pay for themselves in 5 years.
