Step 1: Operating Costs of the Defrost Heaters
The evaporator coil in this system is equipped with six face heaters, each drawing 1,824 watts, plus a drain pan heater that consumes an additional 736 watts. Combined, these heaters require a total of 11,680 watts during operation.
Heater Power Calculation:
(6 face heaters × 1,824 watts) + (1 drain pan heater × 736 watts) = 11,680 watts
The defrost clock initiates four cycles per day, each lasting 15 minutes, resulting in a total runtime of 60 minutes daily. Using this data, we can calculate the daily and monthly energy consumption.
Heater Consumption:
11,680 watts × 1 hour per day = 11.68 kWh per day
11.68 kWh × 30.42 days = 355.3 kWh per month
With an electricity rate of $0.134 per kWh, the actual monthly cost of running these defrost heaters is as follows:
Heater Operating Cost:
355.3 kWh × $0.134 = $47.61 per month
Step 2: Operating Costs of the (2) Fan Motors Running 24/7
In addition to the heaters, the system operates two fan motors continuously, 24 hours a day, 7 days a week. Each fan motor runs on 460 volts at 1 amp with a power factor of 0.83, and because these are 3-phase motors, the square root of three is applied in the calculation.
Fan Motors Power Calculation:
460 volts × 1 amp × 2 motors × 0.83 efficiency × √3 = 1,380 watts
Fan Motors Consumption:
1,380 watts × 24 hours × 30.42 days = 1,007 kWh per month
1,007 kWh × 12 months = 12,089 kWh per year
With electricity priced at $0.134 per kWh, the cost of running these two motors is significantly higher than the heaters:
Fan Motors Operating Cost:
12,089 kWh per year ÷ 12 = 1,007 kWh per month
1,007 kWh × $0.134 = $134.99 per month
The Cost Difference is Clear
The two fan motors alone cost nearly three times more to operate than the defrost heaters each month. This highlights how much energy is wasted by traditional motors compared to modern, energy-efficient alternatives.
How Carlisle EC Motors and Controllers Reduce Costs
Carlisle Electronically Commuted (EC) Motors and Controllers are designed to replace conventional fan motors in refrigeration systems with brushless DC motors and advanced controllers. These units adjust fan speed based on cooling demand, dramatically reducing unnecessary energy use while maintaining proper refrigeration performance.
By upgrading to Carlisle EC Motors and Controllers, facilities can achieve:
- Energy savings of up to 50% compared to standard EC motors
- Reduced monthly operating costs for both heaters and fan motors
- Increased ROI with utility incentives and rebates
- Reliable performance in walk-in coolers, freezers, and industrial refrigeration systems
Contact Carlisle Energy Solutions
Learn how much your facility can save with Carlisle’s advanced EC Motors and Controllers. Call us today at (714) 684-1766.