When Refrigerators Warm the Planet

The kitchen refrigerator is an obvious contributor to global warming because it usually sucks in electricity that was made by burning fossil fuels. But it turns out that the refrigerator does harm to the environment before it is even plugged in because the insulating foam in its innards is made with a gas that is more than 1,000 times worse, molecule for molecule, than carbon dioxide.
GE's first HFC-free refrigerator.General Electric GE’s first HFC-free model.

Now, however, manufacturers are seizing on a single change can reduce both warming mechanisms at once. General Electric said Tuesday that it had become the first American manufacturer of a full line of refrigerators to take that step, which is to eliminate a gas called HFC 134a, a so-called blowing agent.

The blowing agent is used to whip the foam into a frothy milkshake-like mix and move it into the doors and walls of their machines, where it hardens. Unlike the styrofoam in a disposable coffee cup, the material in appliances is filled with bubbles.

Manufacturers once used chlorofluorocarbons, known as CFCs, for that job. When such gas is used, it flows into the atmosphere, either immediately or years later when the machine is junked and the tiny bubbles escape. But CFCs were banned because they accumulated in the upper atmosphere and the chlorine would break down molecules of ozone, which shield the Earth’s surface from harmful rays of the sun.

CFCs were also used as the working fluid in the refrigerator, the material that the compressor squeezes down into a liquid that gives off heat. Then the liquid is allowed to expand back into a gas, absorbing heat that the refrigerator removes from its interior.

The replacement for CFCs in both roles, blowing agent and refrigerant, was a class of chemicals called hydrofluorocarbons, or HFCs. These do not destroy ozone, but they do form a blanket at high altitudes, holding in heat.

HFC 134a, the material GE had been using as the blowing agent, has a “global warming potential” of 1,430, according to GE. Carbon dioxide has a global warming potential of 1.
And as a refrigerant, the HFCs were slightly less efficient than CFCs, requiring a little more electricity to do the same work.

Now manufacturers are working to replace the HFCs. One choice is a hydrocarbon molecule called cyclopentane, which has a global warming potential of 3 to 10. But the cyclopentane turns out to have another benefit; it makes a better insulator. The new foam is about 4 percent better, said Paul Surowiec, general manger for refrigeration at GE’s appliances and lighting division.

That is helpful because the Environmental Protection Agency and the Energy Department are slowly tightening the rules on appliances, requiring them to do the same work with less and less energy.

“Let’s face it, the standards are getting stricter,’’ Mr. Surowiec said. “We’re trying to find cost-effective ways to do all of the above,’’ from cutting energy consumption to reducing greenhouse gas emissions.

The company has converted its refrigerator factory in Decatur, Ala., for use of the new blowing agent. The effect will be to eliminate emissions that are equivalent to 400,000 metric tons of carbon dioxide a year, about the same global warming impact as 78,000 cars, the company said.

The company has also applied to the Environmental Protection Agency for permission to use a refrigerant with less global warming potential.

The next step is to recapture some of the harmful gases that were locked up years ago in those foam bubbles. About 90 percent of refrigerators are recycled, according to the company, but that does not usually include processing the foam.

In February, GE announced a deal with a company called Appliance Recycling Centers of America that will collect old refrigerators from six states. GE will crush the styrofoam and capture the gas that was in the bubbles.