The machine is a box containing four physic-chemical processes inside. One absortion, two evaporation processes and one gravity separation. In one side heat should be supplied (gas burning or other source) and in another side “cold will apper”. A magic box : no electricity, no moving parts, no compressor….

Einstein´s refrigerator belongs to Chemical Engineering Science, better than Electrical or Mechanical.

As Electrolux (the company interested in Einstein-Szilard patent in 1930) and others, sells electromechanic goods the idea probably had some resistance and, anyway, its thermal efficiency is low. As Freon and chlorofluorcarbon gases starts applications in the same time, it is easy to understand the Electrolux preference. They tried 39 times to improve the idea without success.

Really, Freon gas is fantastic ! No comparison for thermal applications between Freon and Ammonia. Like a Devil, it solved all our domestic problems for a while (70 years)…The price : a massive destruction of the Ozone Angels in atmosphere !

Let´s go back to explanation.

1 – The temperature decreases when ammonia gas bubble in liquid butane. It happens as butane gas pressure in top of this container decreases (ammonia stay there dividing the same space and we say butane partial pressure is now lower). Energy is absorbed from the liquid, and so from the environment, decreasing its temperature in order to mantain equilibrium with gas phase. Less butane in the gas phase requires liquid at lower temperature. Its like water, which boils at lower temperature in higher altitudes (lower pressures) than at sea level.

2 – In another container butane gas and ammonia receives water and ammonia is totally absorbed generating aquous ammonium.

3- The liquid on the bottom can be separated as it forms two different liquid phases. Water / ammonia solution on the bottom (ammonium) goes to a heated compartment and liquid butane, on the top phase, returns to initial container.

4 – The heat compartment contains ammonium. Supplying heat we´ll have ammonium gas delivered and water with low ammonium concentration. Cooling the water (e.g. : in a coil like we found behind our refrigerator) it can be used again for absortion. The ammonia gas enter again in the cool side compartment closing the circuit, which is continuous.

Easy ?

Simple, but not easy. A perfect hidraulyc circuit balance is a challenge.