Einstein's Refrigerator

It's noiseless, inexpensive and durable. But reinventing the great genius' invention may not be the answer to one of today's environmental problems. Then again, it may be
By Gary Goettling

Einstein's Refridgerator A Georgia Tech graduate student's research into Albert Einstein's work has produced some chilling results. An idea-potentially even a great idea-gathering dust for almost 70 years has been unearthed and built by mechanical engineering doctoral candidate Andy Delano. He calls it "Einstein's refrigerator." "It's basically an absorption-type refrigerator that uses ammonia, water and butane to create a chemical phenomenon that allows you to run the whole thing at a constant pressure, so you don't need moving parts like a pump or a compressor," Delano explains. "It provides cooling with only heat as an input. Literally, you heat one end and the other end gets cold."

The device is based on a 1930 patent issued to Einstein and Leo Szilard, who would become a distinguished theoretical physicist in his own right and the first to conceive the neutron chain reaction. Beginning in 1926 and continuing for the next seven years, the men collaborated on ways to improve home refrigeration units, eventually accruing 45 patents in their names for three different models.

They were motivated by newspaper accounts of a Berlin family that had died when a seal in their refrigerator ruptured, leaking toxic fumes throughout their home. Theorizing that a device without moving parts would eliminate the potential for seal failure, Einstein and Szilard explored practical applications for different refrigeration cycles.

At the time, Einstein was already world famous for his theory of relativity, and Szilard was a graduate assistant at the University of Berlin.

Delano has a "gut feeling" that most of the inventing was done by Szilard, with Einstein providing consultation and help with the paperwork since he had once worked as a patent examiner. Naturally, the association with Einstein also imbued the research with considerable prestige and credibility-enough, Szilard hoped, to attract financial backing.

The most promising patents, including those followed by Delano, were quickly bought by the Swedish company AB Electrolux to protect its refrigeration technology from competition. A few demonstration units were constructed from the other patents, but to Delano's knowledge, the particular model he constructed has never before been built or tested.

The refrigerator represents the culmination of Delano's master's and doctoral thesis work on the novel cooling cycle employed by Einstein and Szilard.

"I was researching the refrigeration cycle analytically, modeling it on a computer," he says. "There was no funding to build such a unit, so I pulled together my resources and built it myself with my own money."

Those resources included his former roommate, Rob Bush, CE '93, who helped weld the refrigerator together, and his brother, Robert Delano, an industrial design senior at Tech who developed an animated rendition of the original patent diagram showing the movement and interaction of fluids in the device's cooling cycle.

Dr. Sam Shelton, Delano's faculty adviser, secured equipment to build the refrigerator.

"Since it was going to take three or four months to build, I wasn't too encouraging of Andy to take the extra time," laughs Shelton, who worked with Delano three years ago to design the Olympic torch. "But he showed remarkable perseverance in seeing the project through to the end-and it worked the first time he tried it."

Einstein and Szilard's push for new refrigeration technology was cooled off by the Depression and the invention in 1930 of Freon, which fixed the vapor-compression process as the refrigeration standard. But concerns over Freon's ozone-depleting nature may warrant a new look at the Einstein-Szilard invention, which is also noiseless, inexpensive to produce and durable, according to Delano.

"Because it has no moving parts, you could make one that would last a hundred years without any kind of maintenance," he says.

While Delano's prototype is outfitted with electricresistance heaters for convenience, perhaps the most marketable quality of "Einstein's refrigerator" is that it does not require electricity to operate.

"Since all you need is a heat source, models could be designed that use a small gas burner or even solar energy," he says. Thus the refrigerator could be useful in remote or underdeveloped areas and for camping and recreationalvehicle applications.

So Einstein's refrigerator is cool, but can it freeze?

"When I first put the chemicals in it, I got ice," says Delano. "Then I fiddled with the various chemicals, and now it just gets pretty cold. So with a few modifications, I think a refrigerator-freezer combination could be developed."

Delano may patent some of his improvements, but says he harbors no illusions about the refrigerator's future.

"It's neat; it's quite interesting, but it's not going to revolutionize anything. I will probably do some more research on my own, but I'll still be looking for a job when I get out of school."

Gary Goettling is a freelance science and technology writer in Tucker, Ga.