Step 1: Operating Costs of the Defrost Heaters
The evaporator coil has 6 face heaters. Each face heater consumes 1,824 watts. There is also one drain pan heater that draws 736 watts.
Heater Power:
(6 face heaters x 1,824 watts’/face heater) + (1 drain pan heater x 736 watts/drain pan heater) = 11,680 watts
The defrost clock runs 4 times a day, in 15 minute cycles. That’s a total run-time of 60 minutes a day. We can now use the total watts to calculate the energy consumption in watt-hours.
Heater Consumption:
11,680 watts * (1 hour) = 11.68 kWh per day = 355.3 kWh per month
The cost of electricity is $0.134 per kWh, so the true cost of the electric defrost heaters can be determined in the calculations below:
Heater operating cost:
355.3 kWh per month x ($0.134/kWh) = $47.61 per month
Step 2: Operating Cost of the (2) Fan Motors running 24/7
Fan motors power:
Volts per motor x Amps per motor x # of motors x Power factor (efficiency) x square root of three (for a 3-phase motor) = 460 Volts * 1 Amps * 2 * 0.83 * square root of 3 = 1,380 kW drawn by the fans
Fan motors consumption:
1,380 kW * 30.42 days/month = 1007 kWh per month = 12,089 kWh per year
The cost of electricity is $0.134 per kWh, so the true cost of the (2) fan motors running 24/7 can be determined below:
Fan motors operating cost = 12,089 kWh per year x ($0.134/kWh) = $134.99 per month
THE COST TO OPERATE THE (2) FAN MOTORS IS ALMOST 3 TIMES MORE THAN THE DEFROST HEATERS!
For more information on Carlisle Electronically Commuted (EC) Motors and Controllers and how Carlisle Energy can save you money, please contact us directly at (714) 684-1766.