Refrigerant replacements

As you know, most countries are phasing out certain refrigerants to lessen damage to the ozone layer. The chemicals being phased out are chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). Replacements are hydrofluorocarbons (HFCs) and certain blends. The DuPont web site (www.dupont.com) gives the handy Table 1 of recommended replacement refrigerants for various applications. 

DuPont also provides a computer program to simulate performance of different refrigerants in your system. It is called the DuPont Refrigeration Expert (DUPREX). 

DuPont de Nemours and Company web site (www.dupont.com), Selection of DuPont Refrigerants, reprinted by permission. 

Temperature commercial refrigeration R-500 MP39 SUVA MP66 134a 

This table Is intended as a guide, to cover the situations most likely to be encountered. The equipment owner may request the use of the permanent or New System refrigerant In a retrofit, usually to ensure the lowest ODR 

See the Properties section for a description of physical data available. 

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Issues of the impact of emissions on the Earth s stratosphere and its protective ozone layer has led to the imminent schedule of CEC and HCEC phase-out. The phaseout of CFCs (and HCFCs in the long-term) will force the food industry to evaluate their refrigeration systems for refrigerant replacement. The most important challenge is the need to develop refrigerant management plans to convert CFCs to... 

Materials which become super conductive at higher temperatures than the boiling point of helium could have a major impact on the demand for helium. These less costly refrigerant materials could replace the present need to cool superconductive materials to the boiling point of helium. 

One of the chief uses of chloromethane is as a starting material from which sili cone polymers are made Dichloromethane is widely used as a paint stripper Trichloromethane was once used as an inhalation anesthetic but its toxicity caused it to be replaced by safer materials many years ago Tetrachloromethane is the starting mate rial for the preparation of several chlorofluorocarbons (CFCs) at one time widely used as refrigerant gases Most of the world s industrialized nations have agreed to phase out all uses of CFCs because these compounds have been implicated m atmospheric processes that degrade the Earth s ozone layer... 

Production of hydrogen fluoride from reaction of Cap2 with sulfuric acid is the largest user of fluorspar and accounts for approximately 60—65% of total U.S. consumption. The principal uses of hydrogen fluoride are ia the manufacture of aluminum fluoride and synthetic cryoHte for the Hall aluminum process and fluoropolymers and chlorofluorocarbons that are used as refrigerants, solvents, aerosols (qv), and ia plastics. Because of the concern that chlorofluorocarbons cause upper atmosphere ozone depletion, these compounds are being replaced by hydrochlorofluorocarbons and hydrofluorocarbons. 

As CFG refrigerants are phased out of production, their replacements in the cold storage appHcations will be HFC candidates such as R-134a, R-404A, and R-507. The use of ammonia, which is considered an environmentally benign refrigerant, will continue to play an ever-increasing role. 

Polyurethane. Polyurethanes (pu) are predominantly thermosets. The preparation processes for polyurethane foams have several steps (see Urethane polymers) and many variations that lead to products of widely differing properties. Polyurethane foams can have quite low thermal conductivity values, among the lowest of all types of thermal insulation, and have replaced polystyrene and glass fiber as insulation in refrigeration. The sprayed-on foam can be appHed to walls, roofs, tanks, and pipes, and between walls or surfacing materials directly. The slabs can be used as insulation in the usual ways. 

Improved and redesigned rotors of modem compressors save considerable power. The ethylene fractionator and the propylene refrigeration condensers can be replaced with extended surface tube bundles instead of conventional tube bundles. 

Substitution If intensification is not possible, then an alternative is to consider using a safer material in place of a hazardous one. Thus it may be possible to replace flammaole solvents, refrigerants, and heat-transfer media by nonflammable or less flammable (high-boiling) ones, hazardous products by safer ones, and processes which use hazardous raw materials or intermediates by processes which do not. As an example of the latter, the product manufactured at Bhopal (carbatyl) was made from three raw materials. Methyl isocyanate is formed as an intermediate. It is possible to react the same raw materials in a different order so that a different and less hazardous intermediate is formed. 

A leader in the refrigerants industry, we manufacture and supply customers with economical chlorofluorocarbon (CFC) replacements and non-ozone depleting hydrofluorocarbon (HFC) refrigerants for automotive, home, commercial and transportation uses. In the Americas and Asia, you can find these products under the Genetron name and in Europe and the Middle East under Honeywell Refrigerants. 

There are, however, technical limitations to substitution. Some materials are used in ways not easily filled by others. Platinum as a catalyst, liquid helium as a refrigerant, and silver on electrical contact areas cannot be replaced they perform a unique function - they are, so to speak, the vitamins of engineering materials. Others - a replacement for tungsten for lamp filaments, for example - would require the development of a whole new technology, and this can take many years. Finally,... 

The choice of a SUVA S refrigerant will depend on the application as well as on the type of CFC to replace. 

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