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Project Challenge

The steel duct work had literally blown upwards in the original 1978 section of the Langlade County Health Care Center – it was now round rather than square.  The original 28,000 square foot building was equipped with a pneumatic system controlling one large air handling unit, 53 variable-air-volume (VAV) boxes with reheat coils, a 25HP supply, and 10HP return fan. 

Dan Schremp, maintenance supervisor for Langlade County, immediately contacted ACR Corp. for assistance. Having done mechanical service work with Schremp for upwards of 30 years, ACR was aware of the poor control and air noise challenges in the health care center.  “The ducts were constantly whining, clunking, and banging. We’d been trying for a long time to get the air flow regulated and static pressure under control,” explains Schremp. “We had to be wasting energy.  The system was working so hard to respond to calls for heating and cooling that it was slamming from one extreme to another with no happy medium. It was like pushing your car’s gas pedal down and hitting the brakes to control the speed.”

Langlade County Health Care Center

Project Solution

The culprit was a failed pneumatic controller in the make-up air unit inlet vane (not indicated in the original prints), driving it to the full open position, and exerting tremendous pressure on the duct work until it finally distended. In order to address the static pressure and noise control issues, ACR believed the health care center was an ideal candidate for variable frequency drives (VFDs).

Industrial Controls had recently put ACR through training on the Honeywell VFD products, including use of the VFD estimator and selection tools.  ACR and Industrial Controls got down to work.

Armed with an estimated annual electrical energy savings of over $4K, ACR proposed that Langlade County install Honeywell NXS VFDs on the supply and the return fans along with static pressure control, upgrading to a weather-tight exhaust damper, and air balancing for an approximate $8K project cost. A return on investment of less than two years was projected. Replacing the distended ductwork was deemed unnecessary.

Project Results

“The VFDs stopped the ductwork noise and temperature blasts completely,” says Schremp.  “Comfort is a whole lot better in the building since we’re now getting steady, even temperatures. And the ductwork noises have dropped dramatically. You can actually feel the difference in the building; there’s no more noise and we’re saving energy.”

Shremp is exceptionally pleased with the results, “Now we’re only using 50-60% motor capacity, saving about 40% on their electrical draw, and getting better control and flow using half of the air volume.”

“The installation was an enormous success and the results are dramatic,” says Craig Berkovitz, ACR sales manager. “Industrial Controls is a valuable resource for us – pricing, programming assistance, and excellent product support – which is not typical of most distributors. We need to help our industrial and commercial customers explore all energy savings options, so we’re anxious to bring them this new VFD technology.”

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