Technology Breakthrough for Energy Efficient Refrigerators

The refrigerator is a common and convenient workhorse in your home, operating 24/7 to keep your food cold and fresh. Maybe you prefer a model with the freezer on top or with a drawer on the bottom, but you probably don’t think too much about the amount of electricity it takes to keep it running continuously. That could be because of the impressive strides that have improved refrigerator efficiency—in the 1970’s refrigerators used about 3.5 times as much energy as they do now. Today’s models have better insulation in the cabinets and sealing around the doors and they use more efficient compressor motors and new refrigerants. In fact, it was starting to feel as if the appliance industry might have done all it could to reduce energy use in refrigerators. But then came the introduction of the advanced adaptive compressor and with it a big increase in energy savings. Leading manufacturers are now bringing them to market and EPA has recognized these highly efficient refrigerator models with the 2020 ENERGY STAR Emerging Technology Award.

How do refrigerators work?

The compressor plays a central role in cooling the refrigerator by pressurizing a cold fluid (the refrigerant) and running it through a circulation system into the refrigerator cabinet. In a typical refrigerator, the compressor is simply on or off. However, there are significant losses in the stopping and starting of a compressor, which leads to inefficiency. 

Diagram showing the cycle of the refrigerant as it goes through the circulation system.,
The compressor pressurizes the refrigerant, which travels through the cooling cycle—
converting from a gas to a liquid and then back to a gas as it absorbs heat from the
freezer and refrigerator compartments.

What makes advanced adaptive compressors so special?

Refrigerators with advanced adaptive compressors use electronic controls and variable speed compressors which operate smoothly and, on average, at a lower level over time to maintain the ideal temperature. Think about it like you would if you were going somewhere in your car: you could either go 60MPH, then stop for a while, then go 60MPH, or you could go a constant 30MPH, similar to using cruise control, which is constantly making smooth, small adjustments to maintain your speed.

Diagram comparing a conventional compressor versus an advanced compressor.
The advanced adaptive compressor system allows for the refrigerator to save a significant amount of energy while regulating
the temperature by minimizing wide temperature variations.

More precise sensors throughout these refrigerators tell the compressor exactly where to direct any additional cooling, and how much cooling is needed, allowing the refrigerator to maintain different temperatures in different compartments. Again, this is a significant improvement over traditional refrigerator models that are simply designed to maintain set temperatures in the fresh food and freezer compartments, which can be wasteful. Finally, refrigerators with advanced adaptive compressors use refrigerants with low greenhouse gas impact (i.e., a Global Warming Potential rating of 15 or less).

The added energy savings from this technology are impressive. Refrigerators employing these systems cut energy use by at least 30%. If every refrigerator and freezer sold in the United States achieved this level of efficiency, we would end up using 1.8 billion kWh less energy per year, with an annual electric bill savings of $226 million. The associated reduction in greenhouse gas emissions would be 1.2 million metric tons.

Learn more about Advanced Adaptive Compressors that meet the ENERGY STAR Emerging Technology Award criteria and view the full list of award-winning products. Visit the ENERGY STAR Rebate Finder to find utility incentives in your area for these and other ENERGY STAR certified refrigerators.

Author: Peter Banwell