Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
  • C09K5/02—Materials undergoing a change of physical state when used
  • C09K5/04—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa
  • C09K5/041—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems
  • C09K5/044—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems comprising halogenated compounds
  • C09K5/045—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for compression-type refrigeration systems comprising halogenated compounds containing only fluorine as halogen
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2205/00—Aspects relating to compounds used in compression type refrigeration systems
  • C09K2205/10—Components
  • C09K2205/106—Carbon dioxide
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K2205/00—Aspects relating to compounds used in compression type refrigeration systems
  • C09K2205/34—The mixture being non-azeotropic

Definitions

• 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 bromotrifluoromethane (R-13B1).
• Heat transfer devices of the mechanical compression type such as refrigerators, freezers, heat pumps and air conditioning systems are well known.
• 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.
• the properties preferred of a refrigerant include low toxicity, non-flammability, non-corrosivity, high stability and freedom from objectionable odour.
• chlorofluorocarbon refrigerants such as bromotrifluoromethane (refrigerant R-13B1), trichlorofluoromethane (refrigerant R-ll), 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-13B1 has been widely used in low temperature refrigeration applications.
• 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-13B1.
• non-azeotropic (zeotropic) refrigerant composition comprising:
• the zeotropic refrigerant composition of the invention comprises three separate components.
• the first component (component (A)) is carbon dioxide (C0 2 ) which exhibits a low temperature refrigeration action subliming at around -78.5°C.
• the second component (component (B)) is difluoromethane (R-32) which has a boiling point of around -51.6°C.
• the third component (component (C)) is pentafluoroethane (R-125) which has a boiling point of around -48.5°C.
• a preferred refrigerant composition of the invention in terms of its suitability as a replacement for refrigerant R-13B1 is one comprising from 2 to 15 Z by weight C0 2 , from 25 to 50 Z by weight R-32 and from 40 to 65 Z by weight R-125.
• a particularly preferred refrigerant composition of the invention in terms of its suitability as a replacement for refrigerant R-13B1 is one comprising from 5 to 12 Z by weight, more particularly from 8 to 12 Z by weight, C0 2> from 35 to 50 Z by weight, more particularly from 40 to 50 Z by weight, R-32 and from 40 to 55 Z by weight, more particularly from 40 to 50 Z by weight, R-125.
• An especially preferred refrigerant composition of the invention is one comprising about 10 Z by weight C0 2 , about 43 Z by weight R-32 and about 47 Z by weight R-125.
• the refrigerant composition of the invention may also be combined with one or more hydrocarbon compounds in an amount which is sufficient to allow the composition to transport a mineral oil or alkyl benzene type lubricant around a refrigeration circuit and return it to the compressor.
• inexpensive lubricants based on mineral oils or alkyl benzenes may be used to lubricate the compressor.
• Suitable hydrocarbons for use with the refrigerant composition of the invention are those containing from 2 to 6 carbon atoms, with hydrocarbons containing from 3 to 5 carbon atoms being preferred. Propane and pentane are particularly preferred hydrocarbons, with pentane being especially preferred. Where a hydrocarbon is combined with the refrigerant composition of the invention, it will preferably be present in an amount of from 1 to 10 Z by weight on the total weight of the refrigerant composition.
• the refrigerant composition of the invention may also be used in combination with the types of lubricants which have been specially developed for use with hydrofluorocarbon based refrigerants.
• lubricants include those comprising a polyoxyalkylene glycol base oil.
• Suitable polyoxyalkylene glycols include hydroxyl group initiated polyoxyalkylene glycols, e.g. ethylene and/or propylene oxide oligomers/polymers initiated on mono- or polyhydric alcohols such as methanol, butanol, pentaerythritol and glycerol.
• Such polyoxyalkylene glycols may also be end-capped with suitable terminal groups such as alkyl, e.g. methyl groups.
• lubricants which have been developed for use with hydrofluorocarbon based refrigerants and which may be used in combination with the present refrigerant compositions are those comprising a neopentyl polyol ester base oil derived from the reaction of at least one neopentyl polyol and at least one aliphatic carboxylic acid or an esterifiable derivative thereof.
• Suitable neopentyl polyols for the formation of the ester base oil include pentaerythritol, polypentaerythritols such as di- and tripentaerythritol, trimethylol alkanes such as trimethylol ethane and trimethylol propane, and neopentyl glycol.
• the esters may be formed with linear and/or branched aliphatic carboxylic acids, such as linear and/or branched alkanoic acids. Preferred acids are selected from the C 5 _ 8 , particularly the C 5 _ 7 , linear alkanoic acids and the C 5 _ 10 , particularly the C 5 _ 9 , branched alkanoic acids.
• a minor proportion of an aliphatic polycarboxylic acid may also be used in the synthesis of the ester in order to increase the viscosity thereof.
• the amount of the carboxylic acid(s) which is used in the synthesis will be sufficient to esterify all of the hydroxyl groups contained in the polyol, although residual hydroxyl functionality may be acceptable.
• the zeotropic refrigerant composition of the present invention may be used to provide the desired cooling in heat transfer devices such as low temperature refrigeration systems by a method which involves condensing the refrigerant composition and thereafter evaporating it in a heat exchange relationship with a heat transfer fluid to be cooled.
• the refrigerant composition of the invention may be employed as a replacement for refrigerant R-13B1 in low temperature refrigeration applications.
• a composition comprising 10 Z by weight C0 2 , 43 Z by weight R-32 and 47 Z by weight R-125.
• composition comprising 10 Z by weight C0 2 , 45 Z by weight R-32 and 45 Z by weight R-125.
• composition comprising 5 Z by weight C0 2 , 45.6 Z by weight R-32 and 49.4 Z by weight R-125.
• a composition comprising 10 Z by weight C0 2 , 36 Z by weight R-32 and 54 Z by weight R-125.
• a composition comprising 10 Z by weight C0 2 , 27 Z by weight R-32 and 63 Z by weight R-125.
• the performance parameters of the refrigerant compositions which are presented in Table 1, i.e. condenser pressure, evaporator pressure, discharge temperature, refrigeration capacity (by which is meant the cooling duty achieved per unit swept volume of the compressor), coefficient of performance (COP) (by which is meant the ratio of cooling duty (refrigeration effect) achieved to mechanical energy supplied to the compressor), and the glides in the evaporator and condenser (the temperature range over which the refrigerant composition boils in the evaporator and condenses in the condenser), are all art recognised parameters.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Thermal Sciences (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)

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• 1995
  • 1995-08-18 GB GBGB9516921.5A patent/GB9516921D0/en active Pending
• 1996
  • 1996-08-12 EP EP96927757A patent/EP0845021A1/de not_active Ceased
  • 1996-08-12 JP JP9509032A patent/JPH11511192A/ja active Pending
  • 1996-08-12 AU AU67463/96A patent/AU6746396A/en not_active Abandoned
  • 1996-08-12 CA CA 2227917 patent/CA2227917A1/en not_active Abandoned
  • 1996-08-12 WO PCT/GB1996/001960 patent/WO1997007181A1/en not_active Ceased

Non-Patent Citations (1)

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