Development course:
1. Humans have long known that food stored at low temperature is not easy to rot. Over 2000 BC, the ancient inhabitants of the Euphrates River and Tigris River basins in ancient Babylonia, West Asia, began to build ice cubes in pits to refrigerate meat. In Shang dynasty (BC17th century, BC 1 1 century), China also knew how to keep food in ice. In the Middle Ages, many countries had primitive refrigerators, and put ice cubes in special water cabinets or stone cabinets to preserve food. Until the 65438+1950s, this kind of refrigerator was still sold in America.
2. 1822, Faraday, a famous British physicist, found that gases such as carbon oxides, ammonia and chlorine will become liquids under pressure, and will become gases when the pressure is reduced. In the process of changing from liquid to gas, it will absorb a lot of heat and make the surrounding temperature drop rapidly. Faraday's discovery provided a theoretical basis for later generations to invent artificial refrigeration technologies such as compressors.
3. 1834, American engineer Jacob? Perkins invented the world's first compression refrigeration device, which is the embryonic form of modern compression refrigeration system. In the same year, Perkins obtained the first patent of freezer issued by Britain.
The first artificial refrigeration compressor was invented by Harrison in 185 1 year. Harrison, the owner of Quilen Advertising, an Australian newspaper, used ether to clean the type and found that the ether coating on the metal had a strong cooling effect. Ether is a liquid with a very low boiling point, which is easy to evaporate and absorb heat. Harrison developed a refrigerator using ether and refrigerator pressure pump through research, and applied it to a brewery in Victoria, Australia, for cooling during brewing.
5. 1873, German chemist and engineer Karl von Linde invented the refrigerator with ammonia as refrigerant. Linde uses a small steam engine to drive the compression system, so that ammonia can be repeatedly compressed and evaporated to produce refrigeration. Linde first applied his invention to Sai Doummar Brewery in Wiesbaden, and designed and manufactured an industrial refrigerator. Later, he improved the industrial refrigerator. Miniaturizing it, the world's first domestic refrigerator with artificial refrigeration was made in 1879. This kind of steam-driven refrigerator was put into production soon, and 189 1, 12000 units have been sold in Germany and the United States.
6. 19 10 The world's first compressed refrigeration household refrigerator came out in the United States.
7. 19 13, Chicago, USA, developed the world's earliest household refrigerator. This kind of refrigerator named "Dumel" is made of wood and has a compression refrigeration system installed inside, but the use effect is not ideal.
8. 19 18, Cobrand engineer of KE-LVZNATOR company in the United States designed and manufactured the world's first mechanical refrigeration automatic household refrigerator. This kind of refrigerator is huge, the shell is made of wood, the insulation material is a mixture of seaweed and sawdust, and the compressor is water-cooled and noisy. However, its birth announced that the development of household refrigerators has entered a new stage.
9. The first refrigerator with motor-driven compressor was invented by Swedish engineers Brighton and Mendes in 1923. Later, an American company bought their patent and produced the first batch of household refrigerators at 1925.
10. 1925 Lido Company of Sweden has developed a household absorption refrigerator. In the first refrigerator, the electric compressor and the refrigerator were separated, and the latter was usually placed in the cellar or storage room of the family and connected with the electric compressor through pipes, and then they were combined into one.
11.Before 1930s, most refrigerants used in refrigerators were unsafe, such as ether, ammonia water and sulfuric acid. Flammable, corrosive or irritating. Later, I started looking for a safer refrigerant and found Freon. Freon is a non-toxic, non-corrosive, non-flammable fluorine compound, which quickly became the refrigerant of various refrigeration equipment and has been used for more than 50 years. However, it has been found that freon has a destructive effect on the ozone layer of the earth's atmosphere. So people began to look for new and better refrigerants.
Freon: Also known as Freon, the name comes from Freon in English. It is a registered refrigerant trademark of DuPont company in the United States. There are differences in the definition of freon in China, which is generally defined as the general name of halogenated compounds of saturated hydrocarbons (mainly methane, ethane and propane). According to this definition, freon can be divided into four categories: CFC, HCFC and HFC. Some scholars define freon as CFC refrigerant; Freon only refers to dichlorodifluoromethane (CCl? f？ R 12, a CFC).
Freon is colorless gas or volatile liquid at room temperature, tasteless or slightly smelly, non-toxic or low-toxic, and its chemical properties are stable.
The use of chlorofluorocarbon refrigerants, such as dichlorodifluoromethane, has been restricted because they will destroy the atmospheric ozone layer. There have been many holes in the ozone layer on the earth, some of which have exceeded the area of Africa, which is largely due to the chemical properties of chlorofluorocarbons. Another harm of freon is the greenhouse effect.
Source: Baidu Encyclopedia-Freon