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Energy Efficiency

Variable Frequency Drive Savings

Savings for VFDs on pumps and fan are application specific.  Please select the application (i.e. fan, pumps, cooling tower) appropriate for your environment.

VFD on Hot-Water or Chilled Water Pumps
Water Pump Type:
Hot Water
Chilled Water
Operating Motor HP:
Cost per kWh ($/kWh):
 
   
Estimated kWh Savings per Year (kWh):
Estimated Annual Cost Savings:
   
 
VFD on VAV Fan
VAV Circulation Fan Motor HP:
Estimated Hours of Occupancy per Week:
Airflow Currently Controlled by:
Constant Volume
Inlet Vane
Outlet Damper
Cost per kWh ($/kWh):
 
   
Estimated kWh Savings per Year (kWh):
Estimated Annual Cost Savings:
   
VFD on Fan
Fan Motor HP:
Airflow Currently Controlled by:
Constant Volume
Inlet Vane
Outlet Damper
Estimated Average Airflow
as a Percentage of Maximum Flow:
Estimated Hours of Operation per Week:
Cost per kWh ($/kWh):
 
   
Estimated kWh Savings per Year (kWh):
Estimated Annual Cost Savings:
   
VFD on Pump
Pump Motor HP:
Pump Currently Controlled by:
Constant Volume
Throttled
Estimated Average Flow
as a Percentage of Maximum Flow:
Estimated Hours of Operation per Week:
Cost per kWh ($/kWh):
 
   
Estimated kWh Savings per Year (kWh):
Estimated Annual Cost Savings:
   
VFD on Cooling Tower Fan (for typical space cooling)
Cooling Tower Fan Motor HP:
Cost per kWh ($/kWh):
 
   
Estimated kWh Savings per Year (kWh):
Estimated Annual Cost Savings:
   
VFD on Injection Molder Hydraulic Pump
Injection Molder Hydraulic Motor HP:
Estimated Hours of Operation per Year:
Cost per kWh ($/kWh):
 
   
Estimated kWh Savings per Year (kWh):
Estimated Annual Cost Savings:
   
NOTES:
1.  Motor max brake hp was assumed to be 80% of nameplate motor hp.
2. Hot-water pumps were assumed to operate 6,000 hours per year and chilled water pumps were assumed to operate 3,000 hours per year. Also, VFD savings only applies to hot-water and chilled-water systems without supply temperature reset.
3. Savings for VFDs on pumps and fan are application specific hence the variety of calcs.  Select application (i.e. fan, pumps, cooling tower) that are specific to your environment.

Notice:  This calculator is intended for estimation purposes only and the savings shown are not guaranteed. For more specific information about how your business can benefit from energy efficent technologies, contact Alliant Energy today.