In the mid-1990s, ORNL researchers evaluated and tested design concepts at the Building Technologies Research and Integration Center for a domestic refrigerator/freezer unit that would represent approximately 60% of the U.S. market. Buildings researchers demonstrated advanced technologies that reduced, by greater than 50 percent, the 1993 National Appliance Energy Conservation Act standard energy consumption for a 20 ft. top-mount, automatic defrost, refrigerator/freezer.
For a unit this size, the goal translated to an energy consumption of 1 kilowatt per day. This research facilitated the introduction of cost-efficient technologies by demonstrating design changes that can be effectively incorporated into new products. A 1996 model refrigerator/freezer was selected as the baseline unit for testing. Energy saving features incorporated into the original design of the baseline unit included a low-wattage evaporator fan, increased insulation thickness and liquid line flange heaters.