AB Arctic, which was bought by Electrolux in 1925. In the 1960s, absorption refrigeration saw a renaissance due to the substantial demand for refrigerators for caravans (travel trailers). AB Electrolux established a subsidiary in the United States, named Dometic Sales Corporation. The company marketed refrigerators for recreational vehicles (RVs) under the Dometic brand. In 2001, Electrolux sold most of its leisure products line to the venture-capital company EQT which created Dometic as a stand-alone company. Dometic still sells absorption fridges in 2021. In 1926, Albert Einstein and his former student Leó Szilárd proposed an alternative design known as the Einstein refrigerator. At the 2007 TED Conference, Adam Grosser presented his research of a new, very small, "intermittent absorption" vaccine refrigeration unit for use in third world countries. The refrigerator is a small unit placed over a campfire, that can later be used to cool of water to just above freezing for 24 hours in a environment. Principles Common absorption refrigerators use a refrigerant with a very low boiling point (less than ) just like compressor refrigerators. Compression refrigerators typically use an HCFC or HFC, while absorption refrigerators typically use ammonia or water and need at least a second fluid able to absorb the coolant, the absorbent, respectively water (for ammonia) or brine (for water). Both types use evaporative cooling: when the refrigerant evaporates (boils), it takes some heat away with it, providing the cooling effect. The main difference between the two systems is the way the refrigerant is changed from a gas back into a liquid so that the cycle can repeat. An absorption refrigerator changes the gas back into a liquid using a method that needs only heat, and has no moving parts other than the fluids. The absorption cooling cycle can be described in three phases: Evaporation: A liquid refrigerant evaporates in a low partial pressure environment, thus extracting heat from its surroundings (e.g. the refrigerator's compartment). Because of the low partial pressure, the temperature needed for evaporation is also low. Absorption: The second fluid, in a depleted state, sucks out the now gaseous refrigerant, thus providing the low partial pressure. This produces a refrigerant-saturated liquid which then flows to the next step: Regeneration: The refrigerant-saturated liquid is heated, causing the refrigerant to evaporate out. The system thus silently provides for the mechanical circulation of the liquid without a usual pump. A third fluid, gaseous, is usually added