Energy management can have many forms. Whether retrofitting an existing building, designing a facility from the ground up, or adding square footage to increase workspace, facility managers are incorporating everything from new lighting elements, upgraded insulation, programmable thermostats and enhanced air movement systems to reduce energy consumption.
Mechanical and structural grade steel manufacturer Lock Joint Tube (LJT), based in Chattanooga, Tenn., took energy management to a whole new level. During the winter, the 235,000-square foot, 40-foot-high facility became difficult to heat, and the cost of using the existing heating system was too much for the company to handle. Drastic temperature differences between the floor and ceiling, condensation causing steel products to rust, and general discomfort for employees provided the impetus for change. As a result, not only were existing condensation issues curtailed, but the installation of large-diameter, low-speed fans to destratify (mix) the air in the building brought winter heating bills to an end.
“We needed fans that would not only provide the benefit of heat destratification by bringing the heat down from the ceilings in the winter but would also cool our employees during the summer,” explains Mike Donnelly, LJT's vice president and general manager.
Comfort was greatly enhanced, and the fans also reduced condensation by increasing airflow. “Because we are now able to move air through the plant, we can prevent our steel tubes from rusting. Our fans play a big role in reducing condensation, and we no longer have smoke issues [from the machinery] inside the plant,” says Donnelly. “In every aspect, it is a much more comfortable space.”
Over a two-year period starting in 2005, LJT installed 12 20-foot-diameter fans from Big Ass Fans throughout its warehouse. By circulating the heat conducted by the production machinery constantly in use, the company was able to eliminate the need for additional heating energy entirely. “I haven't paid a heating bill in six years,” says Donnelly.
Prior to installing the fans, LJT typically experienced a 20-degree temperature differential between the occupant level and the ceiling as all the hot air radiating from the equipment rose, eventually escaping through the roof. Through the use of large-diameter, low-speed fans, all the hot air at the ceiling could be mixed within the space, providing non-disruptive air movement. Though large and powerful, these fans are also energy efficient, using small, one- to two-horsepower motors to generate large volumes of air. By destratifying the existing air, LJT was able to regulate temperatures within the building, achieving a one to two degree temperature difference throughout the facility.
“Due to the heat generated from our machines, we have removed all of the heating systems from the building and have been using the fans for heat destratification in the winter and cooling in the summer,” says Donnelly. “My heating bill before the fans was over $4,000 a month. When we put the first ones in, they worked so well that I didn't even use scientific reasoning to figure out how many fans I would need for the rest of the warehouse.”
The summer months were also uncomfortable for employees. Complaints rolled in as outdoor temperatures approached the 90s, while indoor temperatures increased due to production-line heat.
During summer, the fans circulate the air, cooling the environment by evaporating moisture off of the skin's surface. Moreover, the operating cost is pennies per hour, compared to the costs of heating and cooling large spaces using conventional conditioning systems.
According to the National Bureau of Standards, energy savings of at least 3% can be achieved for each degree the thermostat is raised during the cooling season. If a facility manager using large-diameter, low-speed fans can raise the thermostat several degrees, energy savings can be 24% or more year round. Additional savings accrue during the winter months by circulating heat trapped at the ceiling down to the occupant/thermostat level.
Even though the thermostat setpoint remains the same in the winter, the heating system does not have to work as hard to maintain that setpoint. Reducing the amount of heat escaping through the roof is similar to turning the thermostat down five to seven degrees.
With the cost of heating fuel out of reach and the facility difficult to heat, LJT brought its comfort concerns within control, and reduced energy consumption, with the aid of proper air movement.
Donnelly has since incorporated large-diameter, low-speed fans in numerous other facilities — both retrofits and new construction — to help with heating, cooling and condensation issues.
“I put a fan every 100 feet, regardless of what I am doing in the building,” he says. Foregoing the need for heating elements, LJT has brought its energy management under control.
Nina Wolgelenter is a copywriter at Big Ass Fans Co. (www.bigassfans.com), based in Lexington, Ky.
Federated Cooperative Ltd.
Conducting a pilot test on an 80,000-square foot section of a 300,000-square foot loading dock, Federated Cooperative, a Canadian retail cooperative, tracked energy consumption and daily temperature changes from 2008 to 2009. During this period, it installed five large-diameter ceiling fans to help with destratification.
“We believe we saved $18,587 in natural gas consumption at that facility in fiscal 2009 as a result of the fans,” says Trevor Carlton, Federated's environmental and technical services manager. “That's a payback of approximately three years on the project.”
* Degree day corrected for variable weather