The absorption refrigeration cycle is considered the oldest known industrial process refrigeration, and originally was a request for freezing the main reason why in 1755 to deal with the development of heat pumps. In the first experiments of William Cullen (born April 15, † February 5, 1790), a physician and chemist, water was frozen with the aid of a vacuum. A continuously operating whole process was not developed.
Only 22 years later, in 1777, the principles of absorption were discovered and understood. John Leslie's 1810, an absorption refrigeration system with the refrigerant and the water absorbent sulfuric acid. The first reliable working refrigerator, with essential parts of cold steam engine in 1834 by Jacob Perkins (born July 9, 1766; † July 30, 1849) built a mechanically operated compressor. These advances have been filed in his patent No. 6662 "Apparatus for Producing Cold and Cooling Fluids". The explosive refrigerant ethyl ether hindered the development of so much only after his death, the economic interest of this invention to increase.
In 1840 one of John Leslie Perkins built on patent-based functioning ice machine. Then in 1850 produced one of Carré in sulfuric acid and water as working fluid based industrial ice machine. The development has been replaced by the working fluid pair Carré by ammonia and water, and written down in his patent 1859th In this and the following patents F. Carré described for a periodically operating machines for very small capacities and on the other machine with great performance. These patents laid the foundation for further development and were the first industrially important.
William Thomson, also 1 Baron Kelvin was called to demonstrate in 1852 that chillers can be used for heating rather than cooling. In its publication "Heating Machine" has been demonstrated to be devoted to a motor-driven heat pump is less primary energy, as in direct heating. Another pioneer in the field of absorption machines was Charles Tellier, who built his plant in 1864 with methyl ether. These developments were continued until 1927, until the first refrigerator was in Germany on the market.
Carrier Corporation, the company began in 1940 with research on a lithium bromide / water absorption chiller and 1945, led the first major investment. These units were designed to 100-700 tons capacity and working with low-pressure steam as the heat source.
Nowadays, in almost every camper an absorption refrigerator is installed in order to be independent of electrical supply. In these refrigerators, the heat required is generated by gas. Furthermore, these fridges are also used in hotel rooms, but here is supplied with electrical energy, and guarantee the desired quietness during continuous cooling.
Since few years, absorption heat pumps for domestic and industrial use in the area are available from a few kilowatts to several megawatts. These are available in different versions for different applications. Pure heat pumps serve the heating, cooling, or a combination of both. The absorption chiller combines the following fundamental ideas: The temperature required to vaporize a liquid decreases with decreasing pressure, ie the refrigerant evaporates at low temperatures due to the low absolute pressure in the evaporator. In the case of LiBr-water absorption refrigeration system is used as a refrigerant and sprayed in a almost evacuated container at a coil and vaporized at about 3 ° C. Which is required for the evaporation latent heat removed from the building's cold water in the coil, which is useful as refrigerants available. The evaporation process would stop when the saturation pressure of the refrigerant would be reached in the evaporator. Therefore, the refrigerant vapor is continuously removed in a second step. This makes you look at the properties of certain salt solutions advantage, refrigerant vapor from the air to prevent, ie to absorb. Hence the name "absorption chiller". The move comes in the so-called absorber. The absorption process would stop when the salt solution is saturated with refrigerant. Therefore, in the third step of the salt solution, the refrigerant will be removed permanently. This enriched with refrigerant salt solution in the so-called generator or expeller is pumped, in which the moisture by heating (80 ° - 120 ° C) is evaporated by boiling, and again - but at a much higher temperature and pressure level. The concentrated salt solution is in the closed circuit re-routed back to the absorber. The refrigerant vapor from the expeller is the last step in the condenser using cooling water from a cooling system (eg cooling tower) cooled back down to baseline levels, condensed, and then to the evaporator.
