HVLS = Cool efficiency

Now that summer’s here, increased temperatures and humidity have an increased impact on the climate within the plant. Between keeping energy consumption down and the workforce comfortable while on the floor, plant managers can find themselves in a conundrum. Do they keep the plant floor air conditioned and the workers content? Should they keep energy costs low and create what could be a less productive (and certainly warmer) environment?

Maybe they can do both.

The high-volume, low-speed fan sector has grown steadily since the first HVLS fans were introduced about 10 years ago. With the current climate – both economic and environmental – these low-energy devices are a solution for facility sustainability. When implemented correctly, HVLS fans can keep the workforce comfortable and productive while taking a big bite out of a facility’s energy consumption.

While air conditioning is not feasible in many plant environments, ventilation is important. It is often accomplished by some form of mechanical ventilation, louvers or other means, said Paul Lauritzen, director of sales for Big Ass Fans, Lexington, KY. But even with ventilation, process heat is troublesome to handle. This is one area where HVLS fans can help.

“A typical HVLS fan design is meant to move air downward vertically from the fan until it comes in contact with the floor,” Lauritzen said. “It then washes out in a radiant pattern, out away from the center of the fan in what we call a floorjet.

“If we move that air in very, very large volumes, we’re able to push the air out at an airspeed that is not disruptive and covers a very large open area,” Lauritzen added.

This movement of air in large volume helps balance air temperatures. Instead of hot and cold pockets, the air tends to mediate as it mixes, resulting in a relatively consistent temperature throughout the facility.

“You still have the problem of heat rising to the upper spaces and stagnating within the building itself. With the volume of air at the low airspeeds that we can move with the fans, they really help the efficiency of the existing ventilation systems within the building,” Lauritzen said. “You not only get the cooling effect from the air, but if you did have stagnant air pockets with the super-heated air that’s rising to the ceiling and isn’t pulled by the natural ventilation systems, the fans themselves can dramatically increase the effectiveness of the ventilation system.”

And that is the biggest advantage the fans provide, suggested Dan Anderson, product manager – environmental control solutions for Milwaukee-based Rite-Hite Corp. Because the fans move such large quantities of air, much of the process heat that travels to the ceiling becomes mixed in as well.

“Taking the heat that’s trapped at the ceiling and pushing it down, there are just huge savings,” Anderson said. “Then what (users are) able to do is to get this cooling with low energy consumption, basically paid for just by the reduction in the heat bill.”

Using HVLS fans in this way, to distribute process heat and mix the air in the facility leads to significant savings, said Josh Eddy, an engineering sales manager for Big Ass Fans. “You can see significant savings on the heating side, in the 40%-plus range a lot of environments. There’s a lot of savings associated with that.”

“HVLS fans also contribute to energy savings in air-conditioned facilities during the warmer months,” Anderson said. “Because the light breeze moving across employees’ skin has a cooling effect, the thermostat can be raised without reducing the level of employee comfort. Raising the thermostat 4F could save a facility 16% to 20% in its cooling costs.”

HVLS fans also can be an alternative to smaller, high-velocity fans. While suitable for situations where cooling is needed for one small area, the small fans aren’t a good solution for facility-wide cooling because of energy usage.

“By using (HVLS) fans, you can typically replace 30 of those little fans, be much more effective and use in the neighborhood of 300 times less energy to accomplish the same thing. It’s kind of a slam-dunk savings potential in the right kind of application,” Eddy said.

“Just from a pure energy usage standpoint, it’s much, much more efficient than even the highest efficiency mechanical conditioning system. So as an alternative to some of the other things facilities management have at their disposal, the fans are extremely efficient,” Lauritzen said.

While the contribution HVLS fans can make to energy efficiency is clear, their use as a tool for comfort on the floor is just as significant.

“Almost everybody has issues with comfort in the building, but almost every time we talk to somebody, it’s different issues,” Eddy said. “Even across the same company with similar type buildings, you go into a space and talk to a facility manager. His biggest problem might be complaints from the employees; another facility manager might be too high of energy costs.”

Whatever the issues of any given facility, one fact shines through clearly: As temperatures in a facility rise, productivity falls. By keeping the production floor cool and the workers comfortable, plant managers can ensure prompt and accurate operations. Let that comfort slip, though, and trouble won’t be far behind.

“The biggest thing is productivity and accuracy decrease as it gets hotter,” Eddy said. “There’re lots of studies out there – one of which was done by NASA – that say any time it’s above 80F in a space, accuracy and productivity goes down.

“The hotter it gets in that space, the more so that productivity and accuracy goes down, so obviously the more uncomfortable your employees, the less you’re going to get out of them,” Eddy added. And that will have a direct impact on the facility’s bottom line.

“The basic premise is if people are happy, employees are happy, you’re going to get more productivity out of them, less breaks and get more of whatever they’re doing done,” Eddy said.

Lauritzen added that not only productivity is affected by employee comfort. Accident rates, scrap rates and production mistakes are reduced when employees are comfortable.

“It’s a well-documented fact that people that are stressed by heat do not perform at the same level of production that they would if they were cooled off,” Lauritzen said. “There are a lot of economic factors beyond just the comfort that we always look at, that really make a big impact on the overall efficiency of the plant.”