My parents had a completely noiseless refrigerator similar to this. It did not have a compressor and had an electric heating element instead. It worked for many decades until the plastic and door hinges etc was too damaged for it to be used any more.
It's a very clever trick: a refrigerator without a compressor which uses heat as the energy source. It could run on either a gas flame or an electric heating element.
There are three working fluids (butane, water and ammonia) and it works by exploiting differences in partial pressure (that is, the pressure contributed by each component of a gas mixture). Instead of using a compressor to change the overall pressure, it changes the composition of the mixture.
The cycle basically works by adding and removing ammonia at different points to make the butane refrigerant evaporate and condense in the appropriate places.
On the "condenser" side of things, water is used to remove the ammonia from the gas mixture by absorption. Because the total pressure is approximately the same throughout the system, removing ammonia increases the butane mole fraction and therefore its partial pressure, causing the butane to condense. This is the heat rejection side.
On the evaporator side, ammonia is added again. This lowers the butane partial pressure, shifting the equilibrium and causing the liquid butane to evaporate. That's where the cooling effect occurs.
The other part of the cycle is regenerating the ammonia by separating it from the water again. That's where heat is added, and that heat input is what ultimately drives the process.
Szilard is an underrated genius. Also was an early formulator of the nuclear chain reaction concept, to tap into nuclear energy, but did not zero in uranium right at the outset as the element to make it feasible.
On a related note, there is a reasonably well known commentary on an adjacent technology by Ruth Schwartz Cowan (1985) titled "How The Refrigerator Got Its Hum". It describes a 1930s market battle between heat-driven ad/absorption chiller technology ("Kelvinator") and work-driven compressor chiller technology ("GE"). Tl;DR GE won.
The ab-chiller is likely best known these days as the "propane fridge" in RVs.
Sadly, the only online resources for Cowan's work I can find are either Scribd paywalled [1], the entire book in which Cowan's piece is a chapter on the Internet Archive [2] or a pointer-to-a-pointer from a piece in the Guardian [3] to a boingboing piece [4] that seems to be offline.
(Background: I work in Direct-Use geothermal. Such ad/absorption chillers are one major tool in the toolbox for low-T cases where it is uneconomical to turn geothermal heat into electrical energy -- mostly due to Carnot's Law considerations.)
There is no compressor. No moving parts. The only thing that I personally heard was heater relay clicking (that was 70s tech) and some intermittent bubbling.
> The three working fluids in this design are water, ammonia, and butane. [1] The Einstein refrigerator (co-invented with Leó Szilárd) was actually a modification of an earlier three-fluid absorption design created by Swedish engineers Baltzar von Platen and Carl Munters
There are three working fluids (butane, water and ammonia) and it works by exploiting differences in partial pressure (that is, the pressure contributed by each component of a gas mixture). Instead of using a compressor to change the overall pressure, it changes the composition of the mixture.
The cycle basically works by adding and removing ammonia at different points to make the butane refrigerant evaporate and condense in the appropriate places.
On the "condenser" side of things, water is used to remove the ammonia from the gas mixture by absorption. Because the total pressure is approximately the same throughout the system, removing ammonia increases the butane mole fraction and therefore its partial pressure, causing the butane to condense. This is the heat rejection side.
On the evaporator side, ammonia is added again. This lowers the butane partial pressure, shifting the equilibrium and causing the liquid butane to evaporate. That's where the cooling effect occurs.
The other part of the cycle is regenerating the ammonia by separating it from the water again. That's where heat is added, and that heat input is what ultimately drives the process.
The ab-chiller is likely best known these days as the "propane fridge" in RVs.
Sadly, the only online resources for Cowan's work I can find are either Scribd paywalled [1], the entire book in which Cowan's piece is a chapter on the Internet Archive [2] or a pointer-to-a-pointer from a piece in the Guardian [3] to a boingboing piece [4] that seems to be offline.
(Background: I work in Direct-Use geothermal. Such ad/absorption chillers are one major tool in the toolbox for low-T cases where it is uneconomical to turn geothermal heat into electrical energy -- mostly due to Carnot's Law considerations.)
[1] https://www.scribd.com/document/527479452/Cowan-How-the-refr...
[2] https://archive.org/details/socialshapingoft0000unse_g5b0
[3] https://www.theguardian.com/science/political-science/2014/f...
[4] https://boingboing.net/2012/08/20/how-the-refrigerator-got-i...
Einstein–Szilard refrigerator: https://en.wikipedia.org/wiki/Einstein_refrigerator :
> The three working fluids in this design are water, ammonia, and butane. [1] The Einstein refrigerator (co-invented with Leó Szilárd) was actually a modification of an earlier three-fluid absorption design created by Swedish engineers Baltzar von Platen and Carl Munters