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Machinists Deal With Memphis Heat With Big Fans

Fri, 06/14/2013 - 1:02pm

Machinists at Memphis-based Engineered Medical Systems (EMS) were working up a sweat carving and shaping bars of steel into lifesaving surgical equipment.

“If you’ve ever been to Memphis, you know it gets really hot here with really high humidity,” said EMS Controller Charles Stanford. “You sweat walking out to the mailbox. And that heat lasts for a long stretch of time.”

The 60 machines in EMS’ shop venting air at 110 F didn’t make it any easier to keep the facility cool. “Complaints were just a daily event around here, and it was understandable,” continued Stanford.

EMS had to run its 125 tons of air conditioning year-round just to keep shop conditions somewhat tolerable. With the AC running nonstop, summer indoor temperatures hovered around 85° F, while winter indoor temperatures remained around 80° F.

Furthermore, stocking up on pre-made supplies and slowing operations in the summer months was not an option. “Everything we do is made to order,” said Stanford. “We don’t carry any inventory, and we don’t make anything if we don’t have an order for that instrument.”

A heat-load study indicated that the 40,000 square-foot shop would require an additional 40 tons of air conditioning to lower the indoor temperatures — and that extra tonnage would cost $100,000 to $150,000. “We thought, even if we added air conditioning, the machinists were going to be standing in a pocket of hot air,” said Stanford.

This issue is not unique to EMS. Manufacturing plants worldwide suffer from excess heat, which poses real threats to workplace morale, safety and comfort. Researchers from the Center for the Built Environment report that temperature and air quality are two of the most important factors when considering workplace productivity[i]. Finding a cost-effective and successful method to improve work environments can be a headache for facility managers, but one solution might be more familiar than you think.

Rather than adding the additional tonnage to their existing AC unit, EMS installed three 16-ft. Powerfoil®X fans from the Big Ass Fan Company down the center of the square shop. The fans mix the conditioned air and circulate pockets of hot air around the machines to achieve a more balanced temperature along with a cooling breeze. This gentle breeze drops the perceived temperature of the space by several degrees, offering machinists welcomed reprieve from the heat plumes.

“Before we installed the fans, it was just sweltering in that shop,” said Stanford. “Big Ass Fans have really just circulated that air.”

Big Ass Fans use their immense size — not speed — to move a massive amount of air while consuming very little energy. When the airfoil length is doubled, the surface area that those airfoils cover is increased by four. The amount of air the fan moves increases at a much faster rate than the amount of power it takes to turn it as the size gets larger. So, with all things being equal, the fans will become more efficient as their size increases.

Additionaly, AirFencesTM installed along the airfoil redirect air that would otherwise slide off and be lost, increasing the efficiency of the fan and contributing to a 28 percent improvement in coverage area.

In warmer months, Big Ass Fans improve occupant comfort through increased air movement. With the fans operating between 60-100 percent, the additional air movement creates a cooling sensation as a breeze passes over occupants’ skin. In the winter, most facilities use the fans at a reduced speed for heat destratification. EMS, however, continues to use the fans along with the AC in the winter to maintain comfort.

“The front of the shop, where about 70 percent of the HVAC is, stays about 5-7 degrees cooler than the back, so we run that fan at a slower speed.  The middle fan runs a little faster and the back fan, where we are short on HVAC, runs pretty strong,” Stanford explained.

“It has worked great. As a matter of fact, I didn’t hear any complaints this summer. This is my third year here, and this was my first year not to hear any complaints.”


[i] Center for the Built Environment. “TechNotes: Productivity and IEQ Satisfaction.”

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