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Synchronous and Cogged Fan Belts

FINDINGS #12, March 2014


Cogged V-belts and synchronous-drive fan belts are a low-investment way to reduce the inefficiencies in ventilation fans caused by belt slippage and bending resistance. GPG, Rocky Mountain Region, put both belts to the test on two different fans in Denver, Colorado, and found significant energy savings with a simple payback of less than four years. Click on the infographic below to enlarge.

GPG Findings 12, March 2014, Synchronous and Cogged Fan Belts. Opportunity: How much energy is used in ventilation in U.S. office buildings? 12% of electricity goes to fan ventilation. Additional savings possible. Belt-driven fans are also used in non-ventilation applications. Technology: How do synchronous and cogged fan belts save energy? Reduce friction and bending resistance by notching the inner side of the belt. Synchronous belts also reduce slippage by integrating teeth with slots on the motor pully. 2-5% more efficient than standard V-belts. Measurement and Verification: Where did M and V occur? National Renewable Energy Laboratory measured the performance cogged V-belts and synchronous drive belts at the Byron G. Rodgers Federal Building and U.S. Courthouse in Denver, Colorado. Results: How did synchronous and cogged fan belts perform in M and V? 2-10% energy savings for synchronous on VAV. 2% at 60 HZ, 20% at 15 HZ. Cogged fan belts on CV fans offered half the savings. 75% lower Operations and Maintenance for synchronous. Cogged O and M equivalent to standard V-belts. Less than 4 years payback for synchronous. Repeat installations have immediate payback; Cogged payback less than 1 year. Deployment: Where does M and V recommend using synchronous and cogged fan belts? Replace V-belts with synchronous drive belts on all VAV fans. Belts on fans with high operating hours should be replaced first. On CV fans, replace V-belts at end-of-life with cogged V-belts.

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