Contractor, distributor spec a better drive system for rooftop HVAC units
When their North Carolina plant was built three years ago, Cardinal Glass FG Industries specified energy efficient motors for their roof-top HVAC units. They had the right idea for reducing energy costs, but didn’t realize the full savings. HVAC Technologies, the local contractor, had an idea for a more efficient drive system that also would reduce maintenance on the often-ignored roof fans.
The idea was prompted by Wilson Wallace of Allied Bearing and Supply, Statesville, N.C. Wallace and John Croley, a Gates senior field engineer, hosted a preventive maintenance seminar for HVAC Technologies technicians. During the session, Wallace and Croley explained the no-slip, no-retensioning Gates PowerGrip GT2 and PolyChain GT2 synchronous belt drive systems.
Using Gates Design Flex proprietary software, they were able to analyze several drive systems that would outperform the conventional four-strand BX section V-belt drives that had been installed on the fans. They chose a 20mm-wide PolyChain GT2 drive, and immediately the technicians decided to apply this solution at the Cardinal Glass plant, where the multi-belt drives required annual replacement, not to mention retensioning four times per year.
The PolyChain GT2 synchronous belt and sprocket system is designed to reduce lifetime power transmission costs by saving space, weight and maintenance. The belt is built with a polyurethane body, aramid fiber tensile cords, and nylon tooth facing that provide more strength and durability than typical V-belt and roller chain belt systems.
The energy-efficient synchronous drives are doing more than eliminate costly parts replacement and maintenance. The new system eliminates belt slip, saves power, and improves temperature and humidity control, critical to the float glass products being stored in Cardinal Glass’ warehouse. An added benefit is longer bearing life, as the overhung load is lower.
The drive conversions were completed in late 2002 and since then, Allied’s sales engineer Pat Mecimore reports that HVAC Technologies has not had to do any maintenance to the six drives. The contractor has reduced its service charges to Cardinal Glass by $150/month, and the company is so pleased with the savings that it is planning to convert several 200-hp process fans to Poly Chain GT2 positive drives.
“The efficient Gates drive system, when paired with the energy efficient motors, should save Cardinal about $700 per year, per drive,” explains Mecimore. “Even though the up-front cost is about 10% higher than a V-belt drive, the energy savings will pay for the drive system in less than a year and keep saving money for years to come.”
Croley concludes, “Using an inefficient belt drive on an energy efficient motor does not make good sense; it is like heating the kitchen with a toaster.”