Modern society is so used to the incredible ivyboru refrigeration from freezers to refrigerated warehouses that we do not even imagine how a century ago, people did without such necessary for the preservation of the art products. For the first time mankind has faced a refrigeration unit in the 19th century, when the first compression machine (1834) was created. It appeared at this time on the basis of the first refrigerant diethyl ether.
Large quantities of refrigeration units launched in the early 20th century in the United States. Refrigerants for those refrigerators were dangerous for the environment and can cause harm to human health in the event of a leak. The first refrigerators were working on the basis of ammonia and various esters. Frequent breakdowns of refrigerators such species and human contact with the ammonia is often fatal, and that was the advancement of science and the forward finding safe refrigerants. The following were called Freon refrigerants methane or ethane series.
CFCs – gas is colorless and odorless, completely safe for human life. Nowadays, these refrigerants differ in their properties and chemical composition. The only condition for refrigerants – boiling point at atmospheric pressure should be negative, high refrigeration capacity, the condensation at low pressure, high heat transfer coefficient and thermal conductivity. It is also important to have a low cost of refrigerants. All these requirements are met by freon R-11, R-12, R-22. For refrigeration systems with very low temperatures are used refrigerants R-13, R-13B1 and R-503.