On WorldChanging, Alex Steffen gives a briefing on the Freeaire System, which pipes in cold external air when available to cut energy bills.
"…designed to provide such free cooling for walk-in coolers, freezers and cold storage warehouses. The system utilizes an electronic controller to finely tune the operation of standard refrigeration equipment, and this controller simply monitors the outdoor temperature and desired temperature settings and stops refrigerator evaporator fans when not needed, which also reduces the compressor's refrigeration load. Proper airflow is maintained when the evaporator fans switch off by operating one or more energy-efficient circulating fans.
Roughly half the electricity consumed by a typical convenience store is used for refrigeration. The Freeaire System is designed to save energy year-round by allowing refrigeration equipment for a walk-in cooler or freezer to run only as much as it has to. Once the system is installed, evaporator fans typically operate 50 to 75% less often, and reach-in door heaters operate 90% less frequently. Condensing units also usually experience a 10 to 20% reduction in operations. Moreover, a Freeaire System saving 20,000 kilowatt-hours annually can prevent 40,000 pounds of CO2 from being emitted to the atmosphere.
