Einstein’s Refrigerator Using No Electricity/No Freon Revived at Oxford

It looks like Einstein did his best not only in quantum physics, but also in classic, immediately-helpful science. Back in the 1930’s, helped by his friend Leo Szilard, he invented a non-electric refrigerator. Scientists from Oxford are struggling to revive his invention today.

Modern refrigerators are working on the principle on contraction and expansion of the freon. We all have freon in our refrigerators. It’s a synthesized gas, causing greenhouse effects worse than CO2. It’s said that the Einstein refrigerator is one of the most important invention of the 20th century, since it stopped the spread of infectious diseases caused by rotten food – worldwide. So there are more and more refrigerators being used, then dumped, and their freon going into the upper layers of the atmosphere, causing greenhouse effects.

Malcolm McCulloch, an electrical engineer from Oxford, whose passions are green technologies, is leading a project to revive Einstein’s refrigerator and other lost-and-found inventions that require no electricity to make our lives better.

Einstein and Szilard’s non-electric refrigerator used only pressurized ammonia, butane and water to keep the things cool. Their invention was used in the early refrigerators, then it was dropped once the technology evolved and more efficient freon compressors have been used since the 1950s.

The main principle behind Einstein’s refrigerator is that the water boils at lower temperatures when the surrounding air pressure is lower. For example, if you go on a mountain, you’ll see the difference between the boiling point from there and the boiling point from your home (or the sea altitude). If you live on a mountain, then you’re lucky – you’ll boil your eggs faster in the morning.

McCulloch describes the device rebuilt by him. At one side is the evaporator, a flask that contains butane gas. “If you introduce a new vapour above the butane, the liquid boiling temperature decreases and, as it boils off, it takes energy from the surroundings to do so. That’s what makes it cold”, he says.

But Einstein and Szilard refrigerator was inefficient with that time’s technology, so the producers passed on to using freon gas and compressors. McCulloch, on the other hand, believes that by modifying the design and replacing the gas types he uses, he will be able to obtain 4 times Einstein’s efficiency. Going a little bit further, he wants to insert a solar powered heat pump (to be green) into the non-electric refrigerator. ‘No moving parts is a real benefit because it can carry on going without maintenance. This could have real applications in rural areas,’ he says.

Other researchers, working at Cambridge, got the idea of cooling without adding extra energy by using magnetic fields. “Our fridge works, from a conceptual point of view, in a similar way (to freon fridges) but instead of using a gas we use a magnetic field and a special metal alloy. When the magnetic field is next to the alloy, it’s like compressing the gas, and when the magnetic field leaves, it’s like expanding the gas. This effect can be seen in rubber bands – when you stretch the band it gets hot, and when you let the band contract it gets cold.” said managing director Neil Wilson. We had an article earlier this year reporting that a crew from Denmark was able to do that in practice.

But Einstein/Szillard/McCulloch’s refrigerator is still in a study process, and it is at this point far from being commercialized (as he says). It’s still a promise to keep our eyes on and a very interesting alternative that we never thought would exist! He says “Give us another month and we’ll have it working”.

There are still a lot of things that we take for granted as they are and don’t do a thing to improve them. And if we don’t do that, and invent good things above relatively bad ones, what do we get? Evolution? No. All we get is a sand castle that’s going to fall soon.


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  • Jory

    Any update how the study is going? Are they succeeding? Do they have a functional prototype?

  • TechU

    Hmm “the main principle behind it is that the water boils at lower temperatures when the surrounding air pressure”

    No it Not…..

    its your basic Evaporation fact that it takes/steal’s energy from the surrounding area/surfaces while it got something to Evaporate.

    OC given so much times now passed and the Fact that Electrolux bought the Albert Einstein and his former student Leó Szilárd patent rights in 1930 (now expired) to make their gas fridges….
    you could just use/Licence Emily’s invention given we have not seen anything since this OP’s 2008 post.

    British student Emily Cummins, 21 even took Einstein/Szilárd’s imspired design and simplified it to make a basic evaporation/solar-powered fridge that gets to and stays around 6 Celsius in the African summer heat
    http://www.dailymail.co.uk/sciencete…-Africans.html see the “how it works” to see just how simple it is.

  • http://www.cavalok.com Alex Cavity

    Interestingly, Einstein and Szillard were motivated to design this fridge after reading in a newspaper about a Berlin family who had been killed when a seal in their refrigerator broke and leaked toxic methyl formate or sulphur dioxide fumes into their home. If McCulloch succeeds in reviving Einstein’s concept, I can’t imagine how much savings everyone will enjoy running fridges without electricity.

  • http://[email protected] Kim Wilson

    Consider this on a car or bus running on the exhaust for a heat source no mechanical energy would be used as shaft work by the engine. No fuel used to turn the compressor shaft. This would work on a hybrid as well. The real concept to be explored is appropriate heat levels in recycling energy. This can work without electric by solar energy or fired by gas or wood. I don’t believe the efficiency was great guess 30% does anyone know precisely?

  • http://N/A Nikos J. Farsaris

    It is interesting. Uses heat to absorbe heat!
    Even if it burns out much more fuel that it gains, (Thermodynamically ineficient), it can be useful to special environments.

  • Kim Wilson

    I note this is a sealed system that can use thermal energy that is otherwise wasted like for one example the exhaust gas of a automobile could easily power this device with no input of energy other than the waste gas of the automobile exhaust. That is free energy no carbon wasted in powering the shaft of a compressor and the sealed unit does not leak unlike compressor units with seals. Cheap simple easy to produce, economical in the cost of operation as the capital cost of the unit is basically the total cost.

  • Wow,,,,

    Don’t think the point of the article was the eggs. Although corrections are helpful, flame posts like the one above are stupid and annoying.

    Stop proofreading the internet, get a life.

  • the guy you never wanted to meet

    Okay, so obviously, there’s a distinct error here. Eggs take longer to cook in higher altitudes, because of the lower boiling point of water in low-pressure situations of the like. Check yourself before you go out on a limb.

    I’d also like to pose the question: when did CO2 become such a bad thing? We exhale carbon dioxide for crying out loud! That’s almost like saying people should ban dihydrogen monoxide. That’s H2O; who’s going to ban water? Of course, we need water to live, but the point is that CO2 isn’t a problem as far as greenhouse gases. Carbon dioxide is everywhere, and without it, plants can’t give us oxygen. I believe what you meant was carbon monoxide, or CO. That would be the odorless, colorless, toxic gas that internal combustion engines such as those of automobiles emit from their exhaust manifolds. That is a greenhouse gas. Check that stuff first, or else you look ridiculous.

    Also, don’t forget proofreading. In “It’s still a promise to keep our eyes on and a very interesting alternative we never thought it would exist!” the bold-faced pronoun doesn’t belong, making the sentence stand out either as being really awkward or by making little sense.

    In essence, you really need to study and research your topics and support, not to mention grammar, before writing a blog entry or any other sort of article. Better luck next time.

  • http://none John Jensen

    I think it would be interesting to connect a solar powered thermal gatherer to be used as the heater in this application. I don\\\’t know IF it would work but it probably would keep some food cool enough. Matter of fact, why don\\\’t we connect copper tubes to our heat pumps from a thermal sink in the ground, instead of blowing air through a bunch of fins? the energy savings could/would be enormous considering the ambient air can be as much as 40 degrees different from air but only 15 or so from ground supplies.

  • http://www.ptacsource.com Zoneaire

    i think its would be awesome if they ever found a way to revive eisteins refrigeration circuit

  • James

    Certainly this method has some appropriate and very specialized application, but to portray it as a forgotten technique superior to DX is more wishful ignorance than “green optimism”.

    Benefits of freon are:
    (1) Absorbs/releases a lot more heat than older refrigerants like ammonia and butane, hence more efficient & less quantity of it needed
    (2) Larger molecules, hence way less leakage

    Why do you think we advanced to more complex refrigerants?

  • t


    I actually get the impression of “no extra energy” meaning “consumes no energy”. It’s minor, but there certainly are people surfing this site who take things exactly as you put them.

    Whatever you say..

    Yea, so I just wanted to point out that the electric magnet required will consume energy just as much as it (without friction) would take for you to squeeze a balloon into a smaller space. This is simply due to the “none taken, none gained” – principle of thermodynamics.

  • absolutely

    Eggs are harder to cook at high altitude, not the opposite.
    At high altitude water boils at lower temperature, so it never reaches 100 degrees Celsius.
    Look at http://en.wikipedia.org/wiki/Pressure_cooking for more information

  • seioursly

    Check your facts, please. If you live on a mountain, your eggs won’t boil faster, everything takes longer to cook because of the lower boiling temp. of water. Because everything/almost everything we eat suffers from either the evaporation of water, or the temp. of boiling water during cooking, it all takes longer to cook. Clear out the dope smoke and remember high school physics, please!

  • Just watching

    It is strange how much smarter our forefathers get as we get older.