Mechanical refrigeration appeared in the mid 19th century. James Perkins (Jacob Perkins) built the first practical machine in 1834. It uses ether as refrigerant, is a vapor compression system. CO2 (CO2) and ammonia (NH3) were first used as refrigerants in 1866 and 1873 respectively. Other chemicals, including chemical cyanide (petroleum ether and naphtha), sulfur dioxide (R-764) and methyl ether, have been used as refrigerant for vapor compression. Its application is limited to industrial processes. Most foods are still preserved in winter or industrially prepared ice cubes.
In the early 20th century, the refrigeration system began as the air conditioning means of large buildings. The Meilan building in San Antonio, Texas is the first full air-conditioned high-rise office building.
1926 Thomas Miccini (Thomas Midgely) developed the first CFC (CFC) machine, using R-12. CFC (CFCs) non-flammable, nontoxic (compared with sulphur dioxide) and high energy efficiency. The machine started commercial production in 1931 and quickly entered home. Willis (Willis Carrier) developed the first commercial centrifugal chiller, which ushered in an era of refrigeration and air-conditioning.
In the 1930 of the 20th century, a series of halogenated hydrocarbon refrigerants appeared successively, and DuPont named Freon (Freon). These substances have excellent performance, non-toxic, non-combustible, can adapt to different temperature areas, and significantly improve the performance of the refrigerator. Several refrigerants become commonplace in air-conditioning, including CFC-11.CFC-12. CFC-113. CFC-114 and HCFC-22.20 century 50 The 1990s, began using azeotropic refrigerant. The non-azeotropic refrigerant was used in the 60.
The air-conditioning industry grew from young to billions of billion dollars in industries, using the above refrigerant. By 1963, these refrigerants accounted for 98% of the entire organic fluorine industry.
By the mid-1970, attention to the thinning of the ozone layer surfaced, and CFC substances may be partly responsible. This led to the adoption of the Montreal Protocol of 1987, which requires the phase-out of CFC and HCFC communities. The new solution is to develop the HFC family to serve as the main role of refrigerant. The HCFC clan continues to be used as a transitional programme and will gradually be phased out.
In the 1990 years, global warming poses a new threat to life on earth. Although global warming is a lot of factors, because of the energy consumption of air-conditioning and refrigeration (the United States building energy consumption of about 1/3% of the total energy), and many refrigerant itself is a greenhouse gas, refrigerant is also included in the scope of the discussion. Although ASHRAE Standard 34 classifies many substances as refrigerants, only a few are used in commercial air-conditioning.