In a refrigerated space, some evaporators run 95% of the time (that is 24/7 minus defrost cycles). Compressors and condensor fans turn on to supply refrigerant to those evaporators when the set points need to be met. This leaves evaporator motors consuming electricity and generating heat inside a cooled space 95% of the time, while the duty cycle of the compressors may be more like 40-50% of a day. The combination of solutions below not only reduce evaporator consumption, but also allow the compressor and condensor fans to run less (less heat to pull out of the space due to reduced evaporator motor heat). These compounded savings add up to be quite significant, but must be engineered and proved to both the utility’s engineering team to offer a custom rebate, and our customers for piece of mind to prove the calculated payback. We refer to this Efficiency from the motors and Conservation from the controls as compounded savings.
Variable Air Volume Controls
VAV controls are used to save energy used in industrial refrigerators and freezers. Tests in actual operating refrigerators show that it can save at least 30 percent, and as much as 70 percent of the operating cost of the evaporator fan motors in a typical industrial refrigerator.
The control system functions by sensing the operational status of the cooling system, and controlling the speed of the evaporator fans. It has been determined that the evaporator fan motors contribute a significant amount of heat inside the refrigerated space. By operating the fans at a low speed when no cooling is called for, and at high speed only when the system is actively cooling the refrigerator, much less heat is introduced into the refrigerator. In three-phase systems, this also results in a significant saving in evaporator fan motor power, while the reduction in fan motor heat generated causes the refrigeration system to operate less, saving additional energy at the compressor. We have the ability to control both Single Phase and Three Phase systems.
EC Motor Replacement
Electronically Commutated (EC) Motors are brushless motors that rely on the interaction of magnetic fields to generate motion. Borrowed from the terminology used for the mechanism in DC motor (direct current motor) commutators, which are used in dc motors, electronic commutation switches current from winding to winding, causing the rotator to turn. Electronic commutation is the process during which brushless motors rely on semiconductors switches to turn stator windings on and off at the appropriate time.
During the past decade EC motors have been used increasingly for HVAC and Refrigeration Equipment due to the higher efficiency compared to traditional ac motors. While fractional HP AC motors are around 45% efficient, EC motors should be anywhere from 65% to 80% efficient. Coupling 2-speed and variable speed EC Motors to Frigitek control systems allow for 80-90% efficient systems.
With over 100 years of experience, Regal Beloit HVAC Division is a leading supplier of electric motors sold under the Genteq, Century and FASCO brands. After testing and trials on many brands of motors, we’ve made the decision to install Regal Beloit branded motors exclusively in our business at this time.
- ELIMINATE MOISTURE ISSUES: Some EC motors feature a fully enclosed electronic control board to take care of moisture, even in low temperatures.
- SHORT ROI TIMES: When measured against the initial purchase cost, energy savings gained by these motors means short payback times since the cost is not prohibitive at all. Per refrigerator fan, compared to a shaded pole motor, an ECM will use a third of the energy comparatively.
- EASY FOR REPLACEMENT: EC motors generally have a standard size, mounting and accessories for easy drop-in replacement of shaded pole motors.
- LONGER LIFE AND LOWER MAINTENANCE: With exceptionally high service lives along with maintenance-free quality, EC motors can result in additional savings.
NO WASTED ENERGY: One great advantage of EC motors is that you can program them to run when and how much you feel necessary. Needless to say, a well programmed motor can save upwards of 50% on energy consumption, and coupled with a VAV control system, saves 70-90% on Evaporator energy usage.