Compositions – Vaporization – or expansion – refrigeration or heat or energy...
Patent
1998-02-18
2000-08-22
Skane, Christine
Compositions
Vaporization, or expansion, refrigeration or heat or energy...
62114, 62502, C09K 504
Patent
active
061067407
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to non-azeotropic refrigerant compositions and more particularly to non-azeotropic refrigerant compositions which can be used in the low temperature refrigeration applications currently satisfied by refrigerant R-502 which is an azeotropic mixture of chlorodifluoromethane (refrigerant R-22) and chloropentafluoroethane (refrigerant R-115).
Heat transfer devices of the mechanical compression type such as refrigerators, freezers, heat pumps and air conditioning systems are well known. In such devices a refrigerant liquid of a suitable boiling point evaporates at low pressure taking heat from a surrounding heat transfer fluid. The resulting vapour is then compressed and passes to a condenser where it condenses and gives off heat to another heat transfer fluid. The condensate is then returned through an expansion valve to the evaporator so completing the cycle. The mechanical energy required for compressing the vapour and pumping the liquid may be provided by an electric motor or an internal combustion engine.
In addition to having a suitable boiling point and a high latent heat of vaporisation, the properties preferred of a refrigerant include low toxicity, non-flammability, non-corrosivity, high stability and freedom from objectionable odour.
Hitherto, heat transfer devices have tended to use fully and partially halogenated chlorofluorocarbon refrigerants such as trichlorofluoromethane (refrigerant R-11), dichlorodifluoromethane (refrigerant R-12), chlorodifluoromethane (refrigerant R-22) and the azeotropic mixture of chlorodifluoromethane and chloropentafluoroethane (refrigerant R-115); the azeotrope being refrigerant R-502. Refrigerant R-502, for example, has been widely used in low temperature refrigeration applications.
However, the fully halogenated chlorofluorocarbons in particular have been implicated in the destruction of the earth's protective ozone layer and as a result the use and production thereof has been limited by international agreement.
Whilst heat transfer devices of the type to which the present invention relates are essentially closed systems, loss of refrigerant to the atmosphere can occur due to leakage during operation of the equipment or during maintenance procedures. It is important, therefore, to replace fully halogenated chlorofluorocarbon refrigerants by materials having low or zero ozone depletion potentials.
In addition to the possibility of ozone depletion, it has been suggested that significant concentrations of chlorofluorocarbon refrigerants in the atmosphere might contribute to global warming (the so-called greenhouse effect). It is desirable, therefore, to use refrigerants which have relatively short atmospheric lifetimes as a result of their ability to react with other atmospheric constituents such as hydroxyl radicals.
Replacements for some of the chlorofluorocarbon refrigerants presently in use have already been developed. These replacement refrigerants tend to comprise selected hydrofluoroalkanes, i.e. compounds which contain only carbon, hydrogen and fluorine atoms in their structure. Thus, refrigerant R-12 is generally being replaced by 1,1,1,2-tetrafluoroethane (R-134a).
Although suitable replacement refrigerants are available, there is always a need for new refrigerants having a low or zero ozone depletion potential that are capable of replacing the chlorofluorocarbon refrigerants presently in use such as R-502. Furthermore, very real benefits could be realised by a new replacement refrigerant having a higher refrigeration capacity than the replacement refrigerants known in the art.
The present invention provides a non-azeotropic refrigerant composition comprising a mixture of compounds having low or zero ozone depletion potentials which can be used in the low temperature refrigeration applications currently satisfied by refrigerant R-502. The non-azeotropic refrigerant composition of the invention can exhibit an advantageously high refrigeration capacity.
According to the present invention there is provided a non-azeotropic (zeotropic
REFERENCES:
patent: 4943388 (1990-07-01), Shankland et al.
patent: 5169873 (1992-12-01), Behme et al.
patent: 5277834 (1994-01-01), Bivens et al.
patent: 5458798 (1995-10-01), Lunger et al.
patent: 5736062 (1998-04-01), Basile et al.
patent: 5736063 (1998-04-01), Richard et al.
Corr Stuart
Morrison James David
Murphy Frederick Thomas
Powell Richard Llewellyn
Imperial Chemical Industries plc
Skane Christine
LandOfFree
Non-azeotropic refrigerant composition of CO.sub.2, R-125, R-143 does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Non-azeotropic refrigerant composition of CO.sub.2, R-125, R-143, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Non-azeotropic refrigerant composition of CO.sub.2, R-125, R-143 will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-576879