Synchronous belts save energy in HVAC
Reichhold Inc. is a global supplier to the composites and coatings industries, with 18 manufacturing facilities in 11 countries. Its facility in Durham, N.C., was spending about $80,000 per month in energy costs to operate this equipment during the summer.
The Company approached Gates Corp., maker of industrial power transmission belt drive systems, to survey the plant for potential energy savings. Gates found that there were 21 HVAC units with 30 hp motors, 44 fume hood exhaust fans with 5 hp to 10 hp motors, and four cooling tower fan drives with 50 hp motors, all V-belt-driven.
The Gates representative recommended purchasing two tools to accurately align and tension the belt drives: a laser alignment device and a sonic tension meter. When properly aligned and tensioned, a new V-belt drive operates at 98% efficiency. Mis-alignment of the pulleys and improper belt tension can cause efficiency to drop below 90%, wasting energy and shortening the life of the drive. By implementing these simple procedures, the Reichhold plant saved $60,000 in energy the first year.
As a second step, the Gates analyzed the existing belt drives on each piece of equipment. They performed the analysis using a belt-drive selection tool called Design Flex Pro, a free software program. In addition to designing belt drives, the program determines proper belt installation tension, calculates belt pull, determines the belt horsepower capacity, and estimates the energy savings of a synchronous belt drive over a V-belt drive.
The Reichhold facility had four cooling tower fan drives, each fitted with six-strand V-belts. With the motors running at 100% capacity, the drives were generating 26 hp. The software analysis recommended conversion to a 14-mm Gates synchronous Poly Chain GT Carbon belt drive.
Initially, only one of the fan drives was converted so results could be compared. With the motor operating at 100% capacity (60 Hz), the synchronous belt drive generated nearly twice the horsepower (51 hp versus 26 hp for the V-belt drive). This greater efficiency allowed the plant to operate the motor at 80% capacity (48 Hz) and still achieve the desired horsepower. With the motor drawing 20% less power to achieve the same result, energy costs were reduced. Estimated yearly cost savings is $12,595 by converting all four fans, including reduced downtime and maintenance costs.
A similar approach with the HVAC drive units and rooftop exhaust fans gave estimated savings of $10,608 and $11,000 per year respectively, for a total of more than $34,000 per year in reduced energy costs. In addition, the synchronous belts will run for years without re-tensioning or replacement, saving additional downtime and maintenance costs.-
Tuesday, March 17, 2009
Energy Saving
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