A Fresh Look at Refrigeration
Refrigerated display cases and walk-in freezers and coolers are used in a variety of businesses: foodservice facilities, grocery and convenience stores, hotels and more. Although refrigeration is important, operating costs often leave facility managers and business owners in a cold sweat.
These cost-saving refrigeration technologies can help take the heat off your energy budget.
Anti-sweat heater controls
Refrigerated display cases use anti-sweat heaters to prevent moisture from forming on glass doors. Left uncontrolled, anti-sweat heaters run constantly, yet they are only needed for short periods. Humidity-sensing controls save energy and money by making the heaters run less often and by reducing the load on the refrigeration system to compensate for the extra heat. Controls are relatively inexpensive, and easy to install and maintain.
Efficient evaporator fan motors
Converting standard shaded-pole motors with electronically commutated motors (ECM) in refrigerated display cases, walk-in coolers and freezers can reduce energy costs up to 65%. ECMs are more energy-efficient than shaded-pole units and much easier to program and control.
Evaporator fan controllers
Walk-in coolers and freezers are cooled by forced-circulation evaporators equipped with fans. These fans typically operate continuously, even though full airflow is required only part of the time. Controllers slow fans when full-speed operation is unnecessary, saving up to 50% on refrigeration costs.
Floating head pressure controls
In fixed-head pressure systems, high condensing pressure is maintained by a condenser fan, regardless of the system load. This wastes energy when ambient temperatures are cold.
Allowing the compressor head pressure to vary (float) with outdoor conditions (fall/winter) reduces refrigerator compression ratios, improves system efficiency and helps extend the life of the unit.
Evaporator superheat is the extra heat added to vaporized refrigerant coming out of the evaporator into the compressor suction line beyond the heat needed to vaporize all of the liquid refrigerant. Too little superheat risks feeding a slug of liquid refrigerant to the compressor which would damage it. Too much superheat will cause phase change in the evaporator to occur too soon and reduce cooling capacity. It also overheats the compressor sump lubricating oil causing it to seize up. Replacing a mechanical thermostatic expansion valve with an electronic expansion valve controlled by pulse width modulation or a stepper motor will precisely control superheat.
Auto-closers automatically shut doors when they’re accidentally left open, saving energy by keeping refrigerated air where it is needed. Going low-tech, strip curtains are clear, flexible overlapped strips located at the opening of a walk-in cooler or freezer or reach-in display case.
They reduce air infiltration when the door is open, saving energy by reducing refrigeration load.
Lighting display cases and walk-in freezers take up a surprising amount of energy. LED bulbs provide an attractive and energy-efficient alternative to fluorescent and other conventional lighting technologies. Highly efficient, long-lasting and durable, with excellent cold temperature performance, LEDs are a perfect fit for many refrigeration applications.
These technologies, along with simple conservation measures, such as keeping refrigerators doors closed tight, can reduce your energy costs while maintaining food quality. Your local electric cooperative even offers Power Moves rebates for qualifying LED lighting upgrades for refrigeration cases and rebates for qualifying energy efficiency upgrades for refrigeration door and frame heater controls. Contact your local electric cooperative’s energy advisor for details.