ECM Retrofits to Reduce Refrigerator Energy Consumption
Commercial Refrigeration is non-stop energy consumption, but that doesn’t have to mean energy inefficient. While refrigerators have to run 24-7, there are ways to maximize on the times when they are using less energy.
When a refrigerator is at the proper temperature, the compressor and condenser shut off, but the evaporator is still running. As the evaporator motor uses electricity, it produces heat and introduces that heat into the refrigerator. The temperature in the refrigerator begins to rise and the whole system starts up again.
To maximize the time the compressor and condenser can be off without sacrificing the temperature of your refrigerator, consider retrofitting your current evaporator fan motor with an Electronically Commutated Motor (ECM or EC motor) with a controller.
Electronically Commutated Motors
ECMs have been shown to use 50 to 70% less energy in walk-in refrigerators than shaded-pole motors and 30 to 40% less energy than permanent split capacitor (PSC) motors. In one test performed by the Food Service Technology Center (FSTC), a standard-efficiency, shaded-pole evaporator fan motor that used 135 watts in a walk-in refrigerator was replaced with an ECM motor that used 45 watts. They found the new motor produced 90 watts less heat, used 90 watts less energy, and saved $200 a year, $50 more than the motor cost.
With the ECM controller, the motor can be turned down to run at a lower speed and draw in less energy when the compressor and condenser fan are off. With this cut back on energy draw, the motor produces less heat that the system then has to work to dispel.
While EC motors are becoming the norm in newly manufactured walk-in refrigerators and freezers, as well as several ENERGY STAR commercial refrigeration systems, they are not standard in most models before at least 2009. Retrofitting a new EC motor into existing refrigeration systems is often fairly easy as many are manufactured as drop-in replacements for shaded pole motors.
Let’s review the benefits
- ECMs consume less energy than SP and PSC motors, which means lower energy bills.
- ECMs produce less heat than SP and PSC motors, which means the compressor and condenser run less, use less energy, and extend their lifespan.
- ECMs offer a short ROI. With the energy saved from less energy consumption by the motor itself and less energy consumption by the system as a whole as a result of lower heat infiltration, annual energy savings are usually at least $100 a year.
- ECMs have longer life spans and lower maintenance needs, which means lower operation costs.
- ECMs are typically easy to retrofit