The quickest way to increase energy efficiency is to start with the basics:
- Minimize door openings to reduce air flow outside of the freezer space. Install strip curtains on all doors to reduce energy loss.
- Maintain the refrigeration system properly by keeping fans, coils and vents free of dust and debris, which can reduce system efficiency and performance.
- Adjust thermostats to raise freezer temperatures to the highest possible operational limits in order to ensure product safety and quality.
Upgrades that can help manage freezer energy use include economizers, energy-efficient motors, heat recovery and floating head pressure controls.
Economizers. If the freezer is a packaged system (versus a split system), then bringing in cool outside air to reduce compressor operating time will save energy. Economizers continuously measure the temperature of outside air and when it is cold enough to meet the needs of the refrigeration system; it automatically pulls outdoor air into the refrigerated space to substitute for compressor-generated cooling. Economizers come with a variety of options, including defrost controls for access doors, evaporator fan control and enthalpy monitoring equipment.
Energy-efficient motors. Motors are another significant factor driving refrigeration energy costs. Replacing older evaporator fan motors with new, energy-efficient electronically commutated motors (ECMs) can yield significant savings and a reasonable return on investment. The major advantage of ECMs for refrigeration applications is their ability to track variable loads; allowing the evaporator fan to automatically adjust its torque and speed.
Heat recovery. Refrigeration systems exhaust a substantial amount of heat during the cooling cycle. Reclaiming this heat for space or water heating can save money and improve overall facility energy efficiency.
Floating heat pressure controls. In many refrigeration systems, compressor heat pressure is set in relation to the maximum outdoor air temperature. Controls allow the head pressure to vary (or float) to match the actual outside air temperature. This saves energy by reducing the operating pressure of the compressor. Floating heat pressure controls are complicated. Consult with the freezer manufacturer or a qualified refrigeration system professional.
If you have more questions about how to save energy and reduce your operating costs, use the Ask an Expert service to get the answers.