Fans with conventional inlet damper and inlet vane controls have static efficiencies, at MCR, of 70 to 80 percent or lower. This efficiency is approximately 10 to 20 percentage points below the ...

In most fan systems a single fan is selected for the required system design rating. Various methods of control are employed such as dampers, variable inlet vanes, variable pitch blades, or variable ...

Working Together Variable inlet vanes (VIV) is one of several names given to a type of damper that is attached to, or assembled integrally with, the inlet of a fan. The VIV, as it is usually called, ...

ENERGY CONSUMED AS A PERCENTAGE OF UNRESTRICTED FULL-FLOW ENERGY CONSUMPTION DIFFERENT FAN FLOW CONTROLS % OF FLOW OUTLET DAMPER INLET VANES VFD 100 111 109 105 95 109 100 86 90 107 93 73 85 106 ...