Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF INVENTION
REFRIGERANT COMPOSITIONS COMPRISING
1-ETHOXY-1,1, 2,2,3,3,4,4,4-NONAFLUOROBUTANE AND A
HYDROFLUOROCARBON AND USES THEREOF
CROSS REFERENCES) TO RELATED APPLICATIONS)
This application claims the priority benefit of U.S. Provisional
Application 60/536,819, filed January 14, 2004, and U.S. Provisional
Application 60/537,453, filed January 15, 2004, and U.S. Provisional
Application 60/549,978, filed March 4, 2004, and U.S. Provisional
Application 60/575,037, filed May 26, 2004, and U.S. Provisional
Application 60/584,785, filed June 29, 2004.
BACKGROUND OF THE INVENTION
1. Field of the Invention.
The present invention relates to fluoroether compositions for
use in refrigeration and air conditioning apparatus comprising fluoroether
and at least one hydrofluorocarbon. Further, the present invention relates
to these compositions for use in refrigeration and air-conditioning
apparatus employing a centrifugal compressor. The compositions of the
present invention may be azeotropic or near azeotropic in nature and are
useful in processes for producing refrigeration or heat or as heat transfer
fluids.
2. Description of Related Art.
The refrigeration industry has been working for the past few
decades to find replacement refrigerants for the ozone depleting
chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) being
phased out as a result of the Montreal Protocol. The solution for most
refrigerant producers has been the commercialization of
hydrofluorocarbon (HFC) refrigerants. The new HFC refrigerants, HFC-
134a being the most widely used at this time, have zero ozone depletion
potential and thus are not affected by the current regulatory phase out as
a result of the Montreal Protocol.
Further environmental regulations may ultimately cause global
phase out of certain HFC refrigerants. Currently, the automobile industry
is facing regulations relating to global warming potential for refrigerants
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used in mobile air-conditioning. Therefore, there is a great current need
to identify new refrigerants with reduced global warming potential for the
automobile air-conditioning market. Should the regulations be more
broadly applied in the future, an even greater need will be felt for
refrigerants that can be used in all areas of the refrigeration and air-
conditioning industry.
Currently proposed replacement refrigerants for HFC-134a
include HFC-152a, pure hydrocarbons such as butane or propane, or
"natural" refrigerants such as COZ or ammonia. Many of these suggested
replacements are toxic, flammable, and/or have low energy efficiency.
Therefore, new alternatives are constantly being sought.
The object of the present invention is to provide novel
refrigerant compositions and heat transfer fluids that provide unique
characteristics to meet the demands of low or zero ozone depletion
potential and lower global warming potential as compared to current
refrigerants.
BRIEF SUMMARY OF THE INVENTION
The present invention relates to refrigerant and heat transfer fluid
compositions selected from the group consisting of:
C4F90C2H5 and 1,1,3-trifluoropropane;
C4F90C2H5 and 1,4-difluorobutane;
C4F90C2H5 and 1,3-difluoro-2-methylpropane;
C4F90C2H5 and 1,2-difluoropentane;
C4F90C2H5 and 1,1,1-trifluorohexane; and
C4F90C2H5 and 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene.
The present invention further relates to the above listed
compositions specifically suitable for use in refrigeration or air
conditioning
apparatus employing a centrifugal compressor.
The present invention further relates to the above listed
compositions specifically suitable for use in refrigeration or air
conditioning
apparatus employing a multi-stage, preferably a two-stage, centrifugal
compressor.
The present invention further relates to the above listed
compositions specifically suitable for use in refrigeration or air
conditioning
apparatus employing a single pass/single slab heat exchanger.
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The present invention further relates to azeotropic or near
azeotropic refrigerant compositions. These compositions are useful in
refrigeration or air conditioning apparatus. The compositions are also
useful in refrigeration or air conditioning apparatus employing a centrifugal
compressor.
The present invention further relates to processes for producing
refrigeration, heat, and transfer of heat from a heat source to a heat sink
using the present inventive compositions.
DETAILED DESCRIPTION OF THE INVENTION
The compositions disclosed herein comprise fluoroether and at
least one of hydrofluorocarbon (HFC).
The fluoroether of the present invention comprises C4F9OC2H5.
This fluoroether compound may comprise a mixture of several isomers
including CF3CF2CF2CF20C2H5 (1-ethoxy-1,1,2,2,3,3,4,4,4-
nonafluorobutane, Cas reg no. 163702-05-4) and (CF3)2CFCF20C2H5 (2-
(ethoxydifluoromethyl)-1,1,1,2,3,3,3-heptafluoropropane, Cas reg no.
163702-06-5). C4F90C2H5 is available commercially from 3MT"" (St. Paul,
Minnesota).
The hydrofluorocarbons of the present invention comprise
compounds containing hydrogen, fluorine and carbon. These
hydrofluorocarbons may be represented by the formula CXH~x+2-yFy or
CXH2x_yFy, In the formulas, x may equal 3 to 8 and y may equal 1-17. The
hydrofluorocarbons may be straight chain, branched chain or cyclic;
saturated or unsaturated compounds having from about 3 to 8 carbon
atoms. Representative hydrofluorocarbons are listed in Table 1.
TABLE 1
Compound Chemical FormulaChemical Name CAS Reg.
No.
Hydrofluorocarbons
HFC-245ca CHFzCFzCH2F 1,1,2,2,3-pentafluoropropane679-86-7
HFC-245fa CFsCH2CHFz 1,1,1,3,3-pentafluoropropane460-73-1
HFC-263fa CHFzCH2CHzF 1,1,3-trifluoropropane24270-67-5
HFC-272fa CHZFCHzCH2F 1,3-difluoropropane 462-39-5
HFC-338mpy CHFzCF(CFs)CHFz2-(difluoromethyl)-1,1,1,2,3,3-65781-21-7
hexafluoro ro ape
HFC-338pcc CHFzCFzCFzCHFz 1,1,2,2,3,3,4,4-octafluorobutane377-36-6
HFC-356mcf CFsCFzCHzCH2F 1,1,1,2,2,4-hexafluorobutane161791-33-9
HFC-365mfc CFsCHzCF2CHs 1,1,1,3,3-pentafluorobutane406-58-6
1 1
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HFC-392p CFzHCHzCHzCHa 1,1-difluorobutane 2358-38-5
HFC-392qqz (CHzF)zCHCHs 1,3-difluoro-2-methylpropane62126-93-6
HFC-392qy CHzFCF(CHs)z 1,2-difluoro-2-methylpropane62126-92-5
HFC-392qe CHZFCHFCHZCHa 1,2-difluorobutane 686-65-7
HFC-392qfe CHzFCH2CHFCHs 1,3-difluorobutane 691-42-9
HFC-392qff CHzFCHzCHaCHzF 1,4-difluorobutane 372-90-7
HFC-392see CHsCHFCHFCHa 2,3-difluorobutane 666-21-7
HFC-42-11mmyc(CFa)zCFCFzCHFz1,1,1,2,3,3,4,4-octafluoro-2-1960-20-9
trifluorometh I butane
HFC-42-11p CHFzCFzCF2CF2CFs1,1,1,2,2,3,3,4,4,5,5-375-61-1
undecafluoro entane
HFC-43-10meeCFsCHFCHFCFzCFs1,1,1,2,2,3,4,5,5,5-decafluoropentane138495-42-8
HFC-43-10mfCFsCHaCFaCF2CFs1,1,1,2,2,3,3,5,5,5-decafluoropentane755-45-3
HFC-449mmzf(CFg)zCHCHzCFa 1,1,1,4,4,4-hexafluoro-2-367-53-3
trifluorometh I butane
HFC-4-10-3mCF3 (CHz)sCHs 1,1,1-trifluoropentane402-82-6
HFC-4-10-3mfszCFsCHzCH(CHs)z 1,1,1-trifluoro-3-methylbutane406-49-5
HFC-4-11-2pCHFz(CHz)sCHs 1,1-difluoropentane 62127-40-6
HFC-4-11-2qeCHzFCHF(CHz)zCHa1,2-difluoropentane 62126-94-7
HFC-4-11-2scCHsCFzCH2CHzCHs2,2-difluoropentane 371-65-3
HFC-5-12-3mCFs(CHz)aCHs 1,1,1-trifluorohexane 17337-12-1
HFC-52-13p CHFzCF2CFZCFzCF2CFs1,1,1,2,2,3,3,4,4,5,5,6,6-355-37-3
tridecafluorohexane
HFC-54-11mmzf(CFs)zCHCHzCFzCFs1,1,1,2,2,5,5,5-octafluoro-4-90278-01-6
trifluorometh I entane
HFC-C354cc c-CFzCFzCH2CHz-1,1,2,2,-tetrafluorocyclobutane374-12-9
PFBE CFs(CFz)sCH=CHz3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene19430-93-4
or erfluorobut leth
lene
The compounds listed in Table 1 are available commercially or
may be prepared by processes known in the art. The compositions of the
present invention may be prepared by any convenient method to combine
the desired amounts of the individual components. A preferred method is
to weigh the desired component amounts and thereafter combine the
components in an appropriate vessel. Agitation may be used, if desired.
Compositions of the present invention have no ozone depletion
potential and low global warming potential . For example, lightly
fluorinated hydrofluorocarbons and fluoroethers, alone or in mixtures will
have global warming potentials lower than many HFC refrigerants
currently in use.
The refrigerant or heat transfer compositions of the present
invention are selected from the group consisting of
C4F90C2H5 and 1,1,3-trifluoropropane;
C4F90C2H5 and 1,4-difluorobutane;
C4F90C2H5 and 1,3-difluoro-2-methylpropane;
C4F90C2H5 and 1,2-difluoropentane;
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C4F90C2H5 and 1,1,1-trifluorohexane; and
C4F90C2H5 and 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene.
The refrigerant or heat transfer compositions of the present
invention may further comprise other compounds from Table 1 combined
Wlth C4FgOC2H5,
The refrigerant or heat transfer compositions of the present
invention may be azeotropic or near azeotropic compositions. An
azeotropic composition is a liquid admixture of two or more substances
that has a constant boiling point that may be above or below the boiling
points of the individual components. As such an azeotropic composition
will not fractionate within the refrigeration or air conditioning system
during
operation, which may reduce efficiency of the system. Additionally, an
azeotropic composition will not fractionate upon leakage from the
refrigeration or air conditioning system. In the situation where one
component of a mixture is flammable, fractionation during leakage could
lead to a flammable composition either within the system or outside of the
system.
A near azeotropic composition is a substantially constant
boiling, liquid admixture of two or more substances that behaves
essentially as a single substance. One way to characterize a near
azeotropic composition is that the vapor produced by partial evaporation
or distillation of the liquid has substantially the same composition as the
liquid from which it was evaporated or distilled, that is, the admixture
distills/refluxes without substantial composition change. Another way to
characterize a near azeotropic composition is that the bubble point vapor
pressure and the dew point vapor pressure of the composition at a
particular temperature are substantially the same. Herein, a composition
is near azeotropic if, after 50 weight percent of the composition is
removed, such as by evaporation or boiling off, the difference in vapor
pressure between the original composition and the composition remaining
after 50 weight percent of the original composition has been removed is
less than about 10 percent.
The azeotropic refrigerant compositions of the present
invention are listed in Table 2.
TABLE 2
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Azeotrope Azeotrope
Component Component B Concentration BP C
A
Wt% A Wt%
B
C4FgOC2H5 HFC-263fa 21.4 78.6 44.2
C4F90C2H5 HFC-392qff 77.4 22.6 74.2
C4F9OC2H5 HFC-4-11-2qe 61.4 38.6 72.5
C4F9OC2H5 HFC-5-12-3m 56.6 43.4 72.2
The near azeotropic refrigerant compositions and concentration
ranges of the present invention are listed in Table 3.
TABLE 3
Near Azeotroaic Concentration
Range
Compounds (A/B) wt% A/wt% B
C4F90C2H5/H FC-263fa 1-63/99-37
C4F90C~H~/HFC-392qqz 1-99/99-1
C4F90C~H5/HFC-392qff 1-99/99-1
C4F90C2H5/H FC-4-11-2qe 1-99/99-1
C4F90C2H5/HFC-5-12-3m 1-99/99-1
C4F90C2H5/PFBE 1-99/99-1
Additional compounds from the list in Table 1 may be added to
the binary compositions of the present invention to form ternary or higher
order compositions.
The azeotropic or near azeotropic compositions of the present
invention may further comprise about 0.01 weight percent to about 5
weight percent of a thermal stabilizer such as nitromethane.
The compositions of the present invention may further
comprise an ultra-violet (UV) dye and optionally a solubilizing agent. The
UV dye is a useful component for detecting leaks of the refrigerant
composition by permitting one observe the fluorescence of the dye in in
the refrigerant or heat transfer fluid composition at a leak point in or the
vicinity of refrigeration or air-conditioning apparatus. One may obserce
the fluorosence of the dye under an ultra-violet light. Solubilizing agents
may be needed due to poor solubility of such UV dyes in some
refrigerants.
By "ultra-violet" dye is meant a UV fluorescent composition that
absorbs light in the ultra-violet or "near" ultra-violet region of the
electromagnetic spectrum. The fluorescence produced by the UV
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fluorescent dye under illumination by a UV light that emits radiation with
wavelength anywhere from 10 nanometer to 750 nanometer may be
detected. Therefore, if refrigerant containing such a UV fluorescent dye is
leaking from a given point in a refrigeration or air conditioning apparatus,
the fluorescence can be detected at the leak point. Such UV fluorescent
dyes include but are not limited to naphthalimides, perylenes, coumarins,
anthracenes, phenanthracenes, xanthenes, thioxanthenes,
naphthoxanthenes, fluoresceins, and derivatives or combinations thereof.
Solubilizing agents of the present invention comprise at least
one compound selected from the group consisting of hydrocarbons,
hydrocarbon ethers, polyoxyalkylene glycol ethers, amides, nitrites,
ketones, chlorocarbons, esters, lactones, aryl ethers, fluoroethers and
1,1,1-trifluoroalkanes.
Hydrocarbon solubilizing agents of the present invention r
comprise hydrocarbons including straight chained, branched chain or
cyclic alkanes or alkenes containing 5 or fewer carbon atoms and only
hydrogen with no other functional groups. Representative hydrocarbon
solubilizing agents comprise propane, propylene, cyclopropane, n-butane,
isobutane, and n-pentane. It should be noted that if the refrigerant is a
hydrocarbon, then the solubilizing agent may not be the same
hydrocarbon.
Hydrocarbon ether solubilizing agents of the present invention
comprise ethers containing only carbon, hydrogen and oxygen, such as
dimethyl ether (DME).
Polyoxyalkylene glycol ether solubilizing agents of the present
invention are represented by the formula R~[(OR2)XOR3]y, wherein: x is an
integer from 1-3; y is an integer from 1-4; R~ is selected from hydrogen
and aliphatic hydrocarbon radicals having 1 to 6 carbon atoms and y
bonding sites; R2 is selected from aliphatic hydrocarbylene radicals having
from 2 to 4 carbon atoms; R3 is selected from hydrogen and aliphatic and
alicyclic hydrocarbon radicals having from 1 to 6 carbon atoms; at least
one of R~ and R3 is said hydrocarbon radical; and wherein said
polyoxyalkylene glycol ethers have a molecular weight of from about 100
to about 300 atomic mass units. In the present polyoxyalkylene glycol
ether solubilizing agents represented by R~[(OR2)XOR3]y: x is preferably 1-
2; y is preferably 1; R~ and R3 are preferably independently selected from
hydrogen and aliphatic hydrocarbon radicals having 1 to 4 carbon atoms;
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R2 is preferably selected from aliphatic hydrocarbylene radicals having
from 2 or 3 carbon atoms, most preferably 3 carbon atoms; the
polyoxyalkylene glycol ether molecular weight is preferably from about 100
to about 250 atomic mass units, most preferably from about 125 to about
250 atomic mass units. The R~ and R3 hydrocarbon radicals having 1 to 6
carbon atoms may be linear, branched or cyclic. Representative R~ and
R3 hydrocarbon radicals include methyl, ethyl, propyl, isopropyl, butyl,
isobutyl, sec-butyl, tern-butyl, pentyl, isopentyl, neopentyl, tern-pentyl,
cyclopentyl, and cyclohexyl. Where free hydroxyl radicals on the present
polyoxyalkylene glycol ether solubilizing agents may be incompatible with
certain compression refrigeration apparatus materials of construction (e.g.
Mylar~), R~ and R3 are preferably aliphatic hydrocarbon radicals having 1
to 4 carbon atoms, most preferably 1 carbon atom. The R2 aliphatic
hydrocarbylene radicals having from 2 to 4 carbon atoms form repeating
oxyalkylene radicals - (OR2)X - that include oxyethylene radicals,
oxypropylene radicals, and oxybutylene radicals. The oxyalkylene radical
comprising R2 in one polyoxyalkylene glycol ether solubilizing agent
molecule may be the same, or one molecule may contain different R2
oxyalkylene groups. The present polyoxyalkylene glycol ether solubilizing
agents preferably comprise at least one oxypropylene radical. Where R~
is an aliphatic or alicyclic hydrocarbon radical having 1 to 6 carbon atoms
and y bonding sites, the radical may be linear, branched or cyclic.
Representative R' aliphatic hydrocarbon radicals having two bonding sites
include, for example, an ethylene radical, a propylene radical, a butylene
radical, a pentylene radical, a hexylene radical, a cycloperitylene radical
and a cyclohexylene radical. Representative R~ aliphatic hydrocarbon
radicals having three or four bonding sites include residues derived from
polyalcohols, such as trimethylolpropane, glycerin, pentaerythritol, 1,2,3-
trihydroxycyclohexane and 1,3,5-trihydroxycyclohexane, by removing their
hydroxyl radicals.
Representative polyoxyalkylene glycol ether solubilizing agents
include but are not limited to: CH30CH2CH(CH3)O(H or CH3) (propylene
glycol methyl (or dimethyl) ether), CH30[CH2CH(CH3)O]2(H or CH3)
(dipropylene glycol methyl (or dimethyl) ether), CH30[CH2CH(CH3)O]3(H
or CH3) (tripropylene glycol methyl (or dimethyl) ether),
C2H50CH2CH(CH3)O(H or C2H5) (propylene glycol ethyl (or diethyl) ether),
C2H50[CH2CH(CH3)O]2(H or C2H5) (dipropylene glycol ethyl (or diethyl)
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ether), C2H50[CH2CH(CH3)O]3(H or C2H5) (tripropylene glycol ethyl (or
diethyl) ether), C3H70CH2CH(CH3)O(H or C3H7) (propylene glycol n-propyl
(or di-n-propyl) ether), C3H70[CH2CH(CH3)O]2(H or C3H7) (dipropylene
glycol n-propyl (or di-n-propyl) ether) , C3H70[CH2CH(CH3)O]3(H or C3H~)
(tripropylene glycol n-propyl (or di-n-propyl) ether), C4H90CH2CH(CH3)OH
(propylene glycol n-butyl ether), C4H90[CH2CH(CH3)O]2(H or C4H9)
(dipropylene glycol n-butyl (or di-n-butyl) ether), C4H90[CH2CH(CH3)O]3(H
or C4H9) (tripropylene glycol n-butyl (or di-n-butyl) ether),
(CH3)3COCH2CH(CH3)OH (propylene glycol t-butyl ether),
(CH3)3C0[CH2CH(CH3)O]2(H or (CH3)3) (dipropylene glycol t-butyl (or di-t-
butyl) ether), (CH3)3C0[CH2CH(CH3)O]3(H or (CH3)3) (tripropylene glycol t-
butyl (or di-t-butyl) ether), C5H~~OCH2CH(CH3)OH (propylene glycol n-
pentyl ether), C4H90CHZCH(C2H5)OH (butylene glycol n-butyl ether),
C4H90[CH2CH(C2H5)O]2H (dibutylene glycol n-butyl ether),
trimethylolpropane tri-n-butyl ether (C2H5C(CH2O(CH2)3CH3)3) and
trimethylolpropane di-n-butyl ether (C2H5C(CH2OC(CH2)3CH3)2CH2OH).
Amide solubilizing agents of the present invention comprise
those represented by the formulae R~CONR2R3 and cyclo-[R4CON(R5)-],
wherein R~, R2, R3 and R5 are independently selected from aliphatic and
alicyclic hydrocarbon radicals having from 1 to 12 carbon atoms; R~ is
selected from aliphatic hydrocarbylene radicals having from 3 to 12 carbon
atoms; and wherein said amides have a molecular weight of from about
100 to about 300 atomic mass units. The molecular weight of said amides
is preferably from about 160 to about 250 atomic mass units. R~, R2, R3
and R5 may optionally include substituted hydrocarbon radicals, that is,
radicals containing non-hydrocarbon substituents selected from halogens
(e.g., fluorine, chlorine) and alkoxides (e.g. methoxy). R~, R2, R3 and R5
may optionally include heteroatom-substituted hydrocarbon radicals, that
is, radicals, which contain the atoms nitrogen (aza-), oxygen (oxa-) or
sulfur (thia-) in a radical chain otherwise composed of carbon atoms. In
general, no more than three non-hydrocarbon substituents and
heteroatoms, and preferably no more than one, will be present for each 10
carbon atoms in R~-3, and the presence of any such non-hydrocarbon
substituents and heteroatoms must be considered in applying the
aforementioned molecular weight limitations. Preferred amide solubilizing
agents consist of carbon, hydrogen, nitrogen and oxygen. Representative
R~, R2, R3 and R5 aliphatic and alicyclic hydrocarbon radicals include
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methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl,
pentyl,
isopentyl, neopentyl, tern pentyl, cyclopentyl, cyclohexyl, heptyl, octyl,
nonyl, decyl, undecyl, dodecyl and their configurational isomers. A
preferred embodiment of amide solubilizing agents are those wherein R4
in the aforementioned formula cyclo-[R4CON(R5)-] may be represented by
the hydrocarbylene radical (CR6R')n, in other words, the formula: cyclo-
[(CR6R')nCON(R5)-] wherein: the previously-stated values for molecular
weight apply; n is an integer from 3 to 5; R5 is a saturated hydrocarbon
radical containing 1 to 12 carbon atoms; R6 and R' are independently
selected (for each n) by the rules previously offered defining R~-3. In the
lactams represented by the formula: cyclo-[(CR6R')nCON(R5)-], all R6 and
R' are preferably hydrogen, or contain a single saturated hydrocarbon
radical among the n methylene units, and R5 is a saturated hydrocarbon
radical containing 3 to 12 carbon atoms. For example, 1-(saturated
hydrocarbon radical)-5-methylpyrrolidin-2-ones.
Representative amide solubilizing agents include but are not
limited to: 1-octylpyrrolidin-2-one, 1-decylpyrrolidin-2-one, 1-octyl-5-
methylpyrrolidin-2-one, 1-butylcaprolactam, 1-cyclohexylpyrrolidin-2-one,
1-butyl-5-methylpiperid-2-one, 1-pentyl-5-methylpiperid-2-one, 1-
hexylcaprolactam, 1-hexyl-5-methylpyrrolidin-2-one, 5-methyl-1-
pentylpiperid-2-one, 1,3-dimethylpiperid-2-one, 1-methylcaprolactam, 1-
butyl-pyrrolidin-2-one, 1,5-dimethylpiperid-2-one, 1-decyl-5-
methylpyrrolidin-2-one, 1-dodecylpyrrolid-2-one, N,N-dibutylformamide
and N,N-diisopropylacetamide.
Ketone solubilizing agents of the present invention comprise
ketones represented by the formula R~COR2, wherein R~ and R2 are
independently selected from aliphatic, alicyclic and aryl hydrocarbon
radicals having from 1 to 12 carbon atoms, and wherein said ketones have
a molecular weight of from about 70 to about 300 atomic mass units. R~
and R2 in said ketones are preferably independently selected from
aliphatic and alicyclic hydrocarbon radicals having 1 to 9 carbon atoms.
The molecular weight of said ketones is preferably from about 100 to 200
atomic mass units. R~ and RZ may together form a hydrocarbylene radical
connected. and forming a five, six, or seven-membered ring cyclic ketone,
for example, cyclopentanone, cyclohexanone, and cycloheptanone. R~
and RZ may optionally include substituted hydrocarbon radicals, that is,
radicals containing non-hydrocarbon substituents selected from halogens
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(e.g., fluorine, chlorine) and alkoxides (e.g. methoxy). R~ and R2 may
optionally include heteroatom-substituted hydrocarbon radicals, that is,
radicals, which contain the atoms nitrogen (aza-), oxygen (keto-, oxa-) or
sulfur (thia-) in a radical chain otherwise composed of carbon atoms. In
general, no more than three non-hydrocarbon substituents and
heteroatoms, and preferably no more than one, will be present for each 10
carbon atoms in R~ and R2, and the presence of any such non-
hydrocarbon substituents and heteroatoms must be considered in applying
the aforementioned molecular weight limitations. Representative R~ and
R2 aliphatic, alicyclic and aryl hydrocarbon radicals in the general formula
R~COR2 include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl,
tern butyl, pentyl, isopentyl, neopentyl, tent-pentyl, cyclopentyl,
cyclohexyl,
heptyl, octyl, nonyl, decyl, undecyl, dodecyl and their configurational
isomers, as well as phenyl, benzyl, cumenyl, mesityl, tolyl, xylyl and
phenethyl.
Representative ketone solubilizing agents include but are not
limited to: 2-butanone, 2-pentanone, acetophenone, butyrophenone,
hexanophenone, cyclohexanone, cycloheptanone, 2-heptanone, 3-
heptanone, 5-methyl-2-hexanone, 2-octanone, 3-octanone, diisobutyl
ketone, 4-ethylcyclohexanone, 2-nonanone, 5-nonanone, 2-decanone, 4-
decanone, 2-decalone, 2-tridecanone, dihexyl ketone and dicyclohexyl
ketone.
Nitrite solubilizing agents of the present invention comprise
nitrites represented by the formula RCN, wherein R~ is selected from
aliphatic, alicyclic or aryl hydrocarbon radicals having from 5 to 12 carbon
atoms, and wherein said nitrites have a molecular weight of from about 90
to about 200 atomic mass units. R~ in said nitrite solubilizing agents is
preferably selected from aliphatic and alicyclic hydrocarbon radicals
having 8 to 10 carbon atoms. The molecular weight of said nitrite
solubilizing agents is preferably from about 120 to about 140 atomic mass
units. R~ may optionally include substituted hydrocarbon radicals, that is,
radicals containing non-hydrocarbon substituents selected from halogens
(e.g., fluorine, chlorine) and alkoxides (e.g. methoxy). R~ may optionally
include heteroatom-substituted hydrocarbon radicals, that is, radicals,
which contain the atoms nitrogen (aza-), oxygen (keto-, oxa-) or sulfur
(this-) in a radical chain otherwise composed of carbon atoms. In general,
no more than three non-hydrocarbon substituents and heteroatoms, and
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preferably no more than one, will be present for each 10 carbon atoms in
R~, and the presence of any such non-hydrocarbon substituents and
heteroatoms must be considered in applying the aforementioned
molecular weight limitations. Representative R~ aliphatic, alicyclic and aryl
hydrocarbon radicals in the general formula RCN include pentyl,
isopentyl, neopentyl, tent-pentyl, cyclopentyl, cyclohexyl, heptyl, octyl,
nonyl, decyl, undecyl, dodecyl and their configurational isomers, as well as
phenyl, benzyl, cumenyl, mesityl, tolyl, xylyl and phenethyl.
Representative nitrite solubilizing agents include but are not limited to: 1-
cyanopentane, 2,2-dimethyl-4-cyanopentane, 1-cyanohexane, 1-
cyanoheptane, 1-cyanooctane, 2-cyanooctane, 1-cyanononane, 1-
cyanodecane, 2-cyanodecane, 1-cyanoundecane and 1-cyanododecane.
Chlorocarbon solubilizing agents of the present invention
comprise chlorocarbons represented by the formula RCIX, wherein; x is
selected from the integers 1 or 2; R is selected from aliphatic and alicyclic
hydrocarbon radicals having 1 to 12 carbon atoms; and wherein said
chlorocarbons have a molecular weight of from about 100 to about 200
atomic mass units. The molecular weight of said chlorocarbon solubilizing
agents is preferably from about 120 to 150 atomic mass units.
Representative R aliphatic and alicyclic hydrocarbon radicals in the
general formula RCIX include methyl, ethyl, propyl, isopropyl, butyl,
isobutyl, sec-butyl, tert butyl, pentyl, isopentyl, neopentyl, tent pentyl,
cyclopentyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl and
their configurational isomers.
Representative chlorocarbon solubilizing agents include but are
not limited to: 3-(chloromethyl)pentane, 3-chloro-3-methylpentane, 1-
chlorohexane, 1,6-dichlorohexane, 1-chloroheptane, 1-chlorooctane, 1-
chlorononane, 1-chlorodecane, and 1,1,1-trichlorodecane.
Ester solubilizing agents of the present invention comprise
esters represented by the general formula R~C02R2, wherein R~ and R2
are independently selected from linear and cyclic, saturated and
unsaturated, alkyl and aryl radicals. Preferred esters consist essentially of
the elements C, H and O, have a molecular weight of from about 80 to
about 550 atomic mass units.
Representative esters include but are not limited to:
(CH3)2CHCH200C(CH2)2~.OCOCH2CH(CH3)2 (diisobutyl dibasic ester),
ethyl hexanoate, ethyl heptanoate, n-butyl propionate, n-propyl propionate,
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ethyl benzoate, di-n-propyl phthalate, benzoic acid ethoxyethyl ester,
dipropyl carbonate, "Exxate 700" (a commercial C~ alkyl acetate), "Exxate
800" (a commercial C$ alkyl acetate), dibutyl phthalate, and tert-butyl
acetate.
Lactone solubilizing agents of the present invention comprise
lactones represented by structures [A], [B], and [C]:
0
0 0
R2 ~ R2.e R ~
,~nR$ R1 , O R2 O
R3 R5R6 R~ R3 R4 Rs 5 R3 R4 R~ 5
[A] [B] [C]
These lactones contain the functional group -C02- in a ring of six (A), or
preferably five atoms (B), wherein for structures [A] and [B], R1 through R$
are independently selected from hydrogen or linear, branched, cyclic,
bicyclic, saturated and unsaturated hydrocarbyl radicals. Each R1 though
R$ may be connected forming a ring with another R1 through R8. The
lactone may have an exocyclic alkylidene group as in structure [C],
wherein R1 through R6 are independently selected from hydrogen or linear,
branched, cyclic, bicyclic, saturated and unsaturated hydrocarbyl radicals.
Each R1 though R6 may be connected forming a ring with another R1
through R6. The lactone solubilizing agents have a molecular weight
range of from about 80 to about 300 atomic mass units, preferred from
about 80 to about 200 atomic mass units.
Representative lactone solubilizing agents include but are not
limited to the compounds listed in Table 4.
TABLE 4
Additive Molecular StructureMolecular Molecular
Formula Weight
(amu)
(E Z)-3-ethylidene-5-methyl-O
dihydro-furan-2-one C~H~oO~ 126
(E Z)-3-propylidene-5-methyl-O
O
dihydro-furan-2-one CsH~~02 140
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(E Z)-3-butylidene-5-methyl-O O
dihydro-furan-2-one CsH~aOz 154
(E Z)-3-pentylidene-5-methyl-O
O
dihydro-furan-2-one C~oH~sOz 168
(E Z)-3-Hexylidene-5-methyl-O
O
dihydro-furan-2-one C11HieOz 182
(E Z)-3-Heptylidene-5-methyl-O
O
dihydro-furan-2-one C~zHzoOz 196
(E Z)-3-octylidene-5-methyl-0 0
dihydro-furan-2-one C~sHzzOz 210
(E Z)-3-nonylidene-5-methyl-o
dihydro-furan-2-one C~qHpqOp 224
(E Z)-3-decylidene-5-methyl-o 0
dihydro-furan-2-one CisHzsOz 238
(E,Z)-3-(3,5,5-trimethylhexylidene)-0 0
5-methyl-dihydrofuran-2-one C~aHzaOz 224
~
(E,Z)-3-cyclohexylmethylidene-5-o 0
methyl-dihydrofuran-2-one C~zHisOz 194
gamma-octalactone o 0
CgH9qOz 142
gamma-nonalactone o 0
C9H~sOz 156
gamma-decalactone 0
CIOH~gOp 170
gamma-undecalactoneo
CHzoOz 184
gamma-dodecalactoneo
C~zHzzOz 198
3-hexyldihydro-furan-2-one
o C10H~BO2 17~
3-heptyldihydro-furan-2-oneo
CHzoOz 184
o
cis-3-ethyl-5-methyl-dihydro-furan-o
2-one C~HizOz ~ 128
o
cis-(3-propyl-5-methyl)-dihydro-O
furan-2-one CeHlaOz 142
O
cis-(3-butyl-5-methyl)-dihydro-
furan-2-one CeH~sOz 156
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cis-(3-pentyl-5-methyl)-dihydro-
furan-2-one CloHieOz 170
0
cis-3-hexyl-5-methyl-dihydro-furan-
2-one CilHzoOz 184
0
cis-3-heptyl-5-methyl-dihydro-
furan-2-one CizHzzOz 198
0
cis-3-octyl-5-methyl-dihydro-furan-
2-one o C13Hz40z 212
cis-3-(3,5,5-trimethylhexyl)-5-
methyl-dihydro-furan-2-oneo Ci4HzsOz 226
cis-3-cyclohexylmethyl-5-methyl-o
dihydro-furan-2-one CizHzoOz 196
5-methyl-5-hexyl-dihydro-furan-2-O
one CllHzoOz 184
o
", ~~~i~
5-methyl-5-octyl-dihydro-furan-2-O
one CaaHzaOz 212
O
Hexahydro-isobenzofuran-1-oneH O
CBHizOz 140
O
H
delta-decalactone
Ci0H1802
O O
delta-undecalactone
CllHzoOz 184
0 0
delta-dodecalactone
CizHzzOz 198
0 0
mixture of 4-hexyl-dihydrofuran-2-o
one and 3-hexyl-dihydro-furan-2- CloHisOz 170
one o
0
Lactone solubilizing agents generally have a kinematic
viscosity of less than about 7 centistokes at 40°C. For instance, gamma-
undecalactone has kinematic viscosity of 5.4 centistokes and cis-(3-hexyl-
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5-methyl)dihydrofuran-2-one has viscosity of 4.5 centistokes both at
40°C.
Lactone solubilizing agents may be available commercially or prepared by
methods as described in U. S. provisional patent application 10/910,495
(inventors being P. J. Fagan and C. J. Brandenburg), filed August 3, 2004,
incorporated herein by reference.
Aryl ether solubilizing agents of the present invention further
comprise aryl ethers represented by the formula R~OR2, wherein: R' is
selected from aryl hydrocarbon radicals having from 6 to 12 carbon atoms;
R2 is selected from aliphatic hydrocarbon radicals having from 1 to 4
carbon atoms; and wherein said aryl ethers have a molecular weight of
from about 100 to about 150 atomic mass units. Representative R' aryl
radicals in the general formula R~OR2 include phenyl, biphenyl, cumenyl,
mesityl, tolyl, xylyl, naphthyl and pyridyl. Representative R2 aliphatic
hydrocarbon radicals in the general formula R~OR2 include methyl, ethyl,
propyl, isopropyl, butyl, isobutyl, sec-butyl and tart-butyl. Representative
aromatic ether solubilizing agents include but are not limited to: methyl
phenyl ether (anisole), 1,3-dimethyoxybenzene, ethyl phenyl ether and
butyl phenyl ether.
Fluoroether solubilizing agents of the present invention
comprise those represented by the general formula R~OCF2CF2H, wherein
R~ is selected from aliphatic and alicyclic hydrocarbon radicals having from
about 5 to about 15 carbon atoms, preferably primary, linear, saturated,
alkyl radicals. Representative fluoroether solubilizing agents include but
are not limited to: C$H~~OCF2CF2H and C6H~30CF2CF2H. It should be
noted that if the refrigerant is a fluoroether, then the solubilizing agent
may
not be the same fluoroether.
1,1,1-Trifluoroalkane solubilizing agents of the present
invention comprise 1,1,1-trifluoroalkanes represented by the general
formula CF3R~, wherein R~ is selected from aliphatic and alicyclic
hydrocarbon radicals having from about 5 to about 15 carbon atoms,
preferably primary, linear, saturated, alkyl radicals. Representative 1,1,1-
trifluoroalkane solubilizing agents include but are not limited to: 1,1,1-
trifluorohexane and 1,1,1-trifluorododecane.
Solubilizing agents of the present invention may be present as
a single compound, or may be present as a mixture of more than one
solubilizing agent. Mixtures of solubilizing agents may contain two
solubilizing agents from the same class of compounds, say two lactones,
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or two solubilizing agents from two different classes, such as a lactone
and a polyoxyalkylene glycol ether.
In the present compositions comprising refrigerant and UV
fluorescent dye, from about 0.001 weight percent to about 1.0 weight
percent of the composition is UV dye, preferably from about 0.005 weight
percent to about 0.5 weight percent, and most preferably from 0.01 weight
percent to about 0.25 weight percent.
Solubility of these UV fluorescent dyes in refrigerants may be
poor. Therefore, methods for introducing these dyes into the refrigeration
or air conditioning apparatus have been awkward, costly and time
consuming. US patent no. RE 36,951 describes a method, which utilizes a
dye powder, solid pellet or slurry of dye that may be inserted into a
component of the refrigeration or air conditioning apparatus. As refrigerant
and lubricant are circulated through the apparatus, the dye is dissolved or
dispersed and carried throughout the apparatus. Numerous other methods
for introducing dye into a refrigeration or air conditioning apparatus are
described in the literature.
Ideally, the UV fluorescent dye could be dissolved in the
refrigerant itself thereby not requiring any specialized method for
introduction to the refrigeration or air conditioning apparatus. The present
invention relates to compositions including UV fluorescent dye, which may
be introduced into the system directly in the refrigerant. The inventive
compositions will allow the storage and transport of dye-containing
refrigerant even at low temperatures while maintaining the dye in solution.
In the present compositions comprising refrigerant, UV
fluorescent dye and solubilizing agent, from about 1 to about 50 weight
percent, preferably from about 2 to about 25 weight percent, and most
preferably from about 5 to about 15 weight percent of the combined
composition is solubilizing agent in the refrigerant. In the compositions of
the present invention the UV fluorescent dye is present in a concentration
from about 0.001 weight percent to about 1.0 weight percent in the
refrigerant, preferably from 0.005 weight percent to about 0.5 weight
percent, and most preferably from 0.01 weight percent to about 0.25
weight percent.
Optionally, commonly used refrigeration system additives may
optionally be added, as desired, to compositions of the present invention
in order to enhance performance and system stability. These additives
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are known within the field of refrigeration, and include, but are not limited
to, anti wear agents, extreme pressure lubricants, corrosion and oxidation
inhibitors, metal surface deactivators, free radical scavengers, and foam
control agents,. In general, these additives are present in the inventive
compositions in small amounts relative to the overall composition.
Typically concentrations of from less than about 0.1 weight percent to as
much as about 3 weight percent of each additive are used. These
additives are selected on the basis of the individual system requirements.
These additives include members of the triaryl phosphate family of EP
(extreme pressure) lubricity additives, such as butylated triphenyl
phosphates (BTP~P), or other alkylated triaryl phosphate esters, e.g. Syn-
0-Ad 8478 from Akzo Chemicals, tricrecyl phosphates and related
compounds. Additionally, the metal dialkyl dithiophosphates (e.g, zinc
dialkyl dithiophosphate (or ZDDP), Lubrizol 1375 and other members of
this family of chemicals may be used in compositions of the present
invention. Other antiwear additives include natural product oils and
asymmetrical polyhydroxyl lubrication additives, such as Synergol TMS
(International Lubricants). Similarly, stabilizers such as anti oxidants, free
radical scavengers, and water scavengers may be employed.
Compounds in this category can include, but are not limited to, butylated
hydroxy toluene (BHT) and epoxides.
Solubilizing agents such as ketones may have an objectionable
odor, which can be masked by addition of an odor masking agent or
fragrance. Typical examples of odor masking agents or fragrances may
include Evergreen, Fresh Lemon, Cherry, Cinnamon, Peppermint, Floral
or Orange Peel or sold by Intercontinental Fragrance, as well as d-
limonene and pinene. Such odor masking agents may be used at
concentrations of from about 0.001 % to as much as about 15% by weight
based on the combined weight of odor masking agent and solubilizing
agent.
The present invention further relates to a method of using the
refrigerant or heat transfer fluid compositions further comprising ultraviolet
fluorescent dye, and optionally, solubilizing agent, in refrigeration or air
conditioning apparatus. The method comprises introducing the refrigerant
or heat transfer fluid composition into the refrigeration or air conditioning
apparatus. This may be done by dissolving the UV fluorescent dye in the
refrigerant or heat transfer fluid composition in the presence of a
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solubilizing agent and introducing the combination into the apparatus.
Alternatively, this may be done by combining solubilizing agent and and
UV fluorescent dye and introducing said combination into refrigeration or
air conditioning apparatus containing refrigerant and/or heat transfer fluid.
The resulting composition is may be used in the refrigeration or air
conditioning apparatus.
The present invention further relates to a method of using the
refrigerant or heat transfer fluid compositions comprising ultraviolet
fluorescent dye to detect leaks. The presence of the dye in the
compostions allows for detection of leaking refrigerant in the refrigeration
or air conditioning apparatus. Leak detection helps to address, resolve or
prevent inefficient operation of the apparatus or system or equipment
failure. Leak detection also helps one contain chemicals used in the
operation of the apparatus.
The method comprises providing the composition comprising
refrigerant, ultra-violet fluorescent dye as described herein, and optionally,
a solubilizing agent as described herein, to refrigeration and air
conditioning apparatus and employing a sutiable means for detecting the
UV fluorescent dye-containing refrigerant. Suitable means for detecting
the dye include, but are not limited to, ultra-violet lamp, often referred to
as
a "black light" or "blue light". Such ultra-violet lamps are commercially
available from numerous sources specifically designed for this purpose.
Once the ultra-violet fluorescent dye containing composition has been
introduced to the refrigeration or air conditioning apparatus and has been
allowed to circulate throughout the system, a leak can be found by shining
said ultra-violet lamp on the apparatus and observing the fluorescence of
the dye in the vicinity of any leak point.
The present invention further relates to a method of using the
compositions of the present invention for producing refrigeration or heat,
wherein the method comprises producing refrigeration by evaporating said
composition in the vicinity of a body to be cooled and thereafter
condensing said composition; or producing heat by condensing the said
composition in the vicinity of the body to be heated and thereafter
evaporating said composition.
Mechanical refrigeration is primarily an application of
thermodynamics wherein a cooling medium, such as a refrigerant, goes
through a cycle so that it can be recovered for reuse. Commonly used
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cycles include vapor-compression, absorption, steam-jet or steam-ejector,
and air.
Vapor-compression refrigeration systems include an
evaporator, a compressor, a condenser, and an expansion device. A
vapor-compression cycle re-uses refrigerant in multiple steps producing a
cooling effect in one step and a heating effect in a different step. The
cycle can be described simply as follows. Liquid refrigerant enters an
evaporator through an expansion device, and the liquid refrigerant boils in
the evaporator at a low temperature to form a gas and produce cooling.
The low-pressure gas enters a compressor where the gas is compressed
to raise its pressure and temperature. The higher-pressure (compressed)
gaseous refrigerant then enters the condenser in which the refrigerant
condenses and discharges its heat to the environment. The refrigerant
returns to the expansion device through which the liquid expands from the
higher-pressure level in the condenser to the low-pressure level in the
evaporator, thus repeating the cycle.
There are various types of compressors that may be used in
refrigeration applications. Compressors can be generally classified as
reciprocating, rotary, jet, centrifugal, scroll, screw or axial-flow,
depending
on the mechanical means to compress the fluid, or as positive-
displacement (e.g., reciprocating, scroll or screw) or dynamic (e.g.,
centrifugal or jet), depending on how the mechanical elements act on the
fluid to be compressed.
Either positive displacement or dynamic compressors may be
used in the present inventive process. A centrifugal type compressor is
the preferred equipment for the present refrigerant compositions.
A centrifugal compressor uses rotating elements to accelerate
the refrigerant radially, and typically includes an impeller and difFuser
housed in a casing. Centrifugal compressors usually take fluid in at an
impeller eye, or central inlet of a circulating impeller, and accelerate it
radially outward. Some static pressure rise occurs in the impeller, but
most of the pressure rise occurs in the diffuser section of the casing,
where velocity is converted to static pressure. Each impeller-diffuser set is
a stage of the compressor. Centrifugal compressors are built with from 1
to 12 or more stages, depending on the final pressure desired and the
volume of refrigerant to be handled.
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The pressure ratio, or compression ratio, of a compressor is the
ratio of absolute discharge pressure to the absolute inlet pressure.
Pressure delivered by a centrifugal compressor is practically constant over
a relatively wide range of capacities.
Positive displacement compressors draw vapor into a chamber,
and the chamber decreases in volume to compress the vapor. After being
compressed, the vapor is forced from the chamber by further decreasing
the volume of the chamber to zero or nearly zero. A positive displacement
compressor can build up a pressure, which is limited only by the
volumetric efficiency and the strength of the parts to withstand the
pressure.
Unlike a positive displacement compressor, a centrifugal
compressor depends entirely on the centrifugal force of the high-speed
impeller to compress the vapor passing through the impeller. There is no
positive displacement, but rather what is called dynamic-compression.
The pressure a centrifugal compressor can develop depends
on the tip speed of the impeller. Tip speed is the speed of the impeller
measured at its tip and is related to the diameter of the impeller and its
revolutions per minute. The capacity of the centrifugal compressor is
determined by the size of the passages through the impeller. This makes
the size of the compressor more dependent on the pressure required than
the capacity.
Because of its high-speed operation, a centrifugal compressor
is fundamentally a high volume, low-pressure machine. A centrifugal
compressor works best with a low-pressure refrigerant, such as
trichlorofluoromethane (CFC-11 ) or 1,2,2-trichlorotrifluoroethane (CFC-
113).
Large centrifugal compressors typically operate at 3000 to
7000 revolutions per minute (rpm). Small turbine centrifugal compressors
are designed for high speeds, from about 40,000 to about 70,000 (rpm),
and have small impeller sizes, typically less than 0.15 meters.
A multi-stage impeller may be used in a centrifugal compressor
to improve compressor efFiciency thus requiring less power in use. For a
two-stage system, in operation, the discharge of the first stage impeller
goes to the suction intake of a second impeller. Both impellers may
operate by use of a single shaft (or axle). Each stage can build up a
compression ratio of about 4 to 1; that is, the absolute discharge pressure
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can be four times the absolute suction pressure. An example of a two-
stage centrifugal compressor system, in this case for automotive
applications, is described in US 5,065,990, incorporated herein by
reference.
The compositions of the present invention suitable for use in a
refrigeration or air conditioning apparatus employing a centrifugal
compressorare selected from the group consisting of:
C4F90C2H5 and 1,1,3-trifluoropropane;
C4F90C2H5 and 1,4-difluorobutane;
C4F90C2H5 and 1,3-difluoro-2-methylpropane;
C4F90C2H5 and 1,2-difluoropentane;
C4F90C2H5 and 1,1,1-trifluorohexane; and
C4F90C2H5 and 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene.
These above-listed compositions are also suitable for use in two-stage or
multiple centrifugal compressor apparatus.
The compositions of the present invention may be used in
stationary air-conditioning, heat pumps or mobile air-conditioning and
refrigeration systems. Stationary air conditioning and heat pump
applications include window, ductless, ducted, packaged terminal, chillers
and commercial, including packaged rooftop. Refrigeration applications
include domestic or home refrigerators and freezers, ice machines, self
contained coolers and freezers, walk-in coolers and freezers and transport
refrigeration systems.
The compositions of the present invention may additionally be
used in air-conditioning, heating and refrigeration systems that employ fin
and tube heat exchangers, microchannel heat exchangers and vertical or
horizontal single pass tube or plate type heat exchangers.
Conventional microchannel heat exchangers may not be ideal
for the low pressure refrigerant compositions of the present invention. The
low operating pressure and density result in high flow velocities and high
frictional losses in all components. In these cases, the evaporator design
may be modified. Rather than several microchannel slabs connected in
series (with respect to the refrigerant path) a single slab/single pass heat
exchanger arrangement may be used. Therefore, a preferred heat
exchanger for the low pressure refrigerants of the present invention is a
single slab/single pass heat exchanger.
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In addition to two-stage compressor apparatus, the following
compositions of the present invention are also suitable for use in
refrigeration or air conditioning apparatus employing a single
slab/single pass heat exchanger:C4F90C2H5 and 1,1,3-
trifluoropropane;
C4F90C2H5 and 1,4-difluorobutane;
C4F90C2H5 and 1,3-difluoro-2-methylpropane;
C4F90C2H5 and 1,2-difluoropentane;
C4F90C2H5 and 1,1,1-trifluorohexane; and
C4F90CZH5 and 3,3,4,4,5,5,6,6,6-nonafluoro-1-hexene.
The compositions of the present invention are particularly
useful in small turbine centrifugal compressors, which can be used in auto
and window air conditioning or heat pump as well as other applications.
These high efficiency miniature centrifugal compressors may be driven by
an electric motor and can therefore be operated independently of the
engine speed. A constant compressor speed allows the system to provide
a relatively constant cooling capacity at all engine speeds. This provides
an opportunity for efficiency improvements especially at higher engine
speeds as compared to a conventional R-134a automobile air-conditioning
system. When the cycling operation of conventional systems at high
driving speeds is taken into account, the advantage of these low pressure
systems becomes even greater.
Some of the low pressure refrigerant fluids of the present
invention may be suitable as drop-in replacements for CFC-113 in existing
centrifugal equipment.
The present invention relates to a process for producing
refrigeration comprising evaporating the compositions of the present
invention in the vicinity of a body to be cooled, and thereafter condensing
said compositions.
The present invention further relates to a process for producing
heat comprising condensing the compositions of the present invention in
the vicinity of a body to be heated, and thereafter evaporating said
compositions.
The present invention further relates to a process for transfer of
heat from a heat source to a heat sink wherein the compositions of the
present invention serve as heat transfer fluids. Said process for heat
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transfer comprises transferring the compositions of the present invention
from a heat source to a heat'sink.
Heat transfer fluids are utilized to transfer, move or remove
heat from one space, location, object or body to a different space, location,
object or body by radiation, conduction, or convection. A heat transfer
fluid may function as a secondary coolant by providing means of transfer
for cooling (or heating) from a remote refrigeration (or heating) system. In
some systems, the heat transfer fluid may remain in a constant state
throughout the transfer process (i.e., not evaporate or condense).
Alternatively, evaporative cooling processes may utilize heat transfer fluids
as well.
A heat source may be defined as any space, location, object or
body from which it is desirable to transfer, move or remove heat.
Examples of heat sources may be spaces (open or enclosed) requiring
refrigeration or cooling, such as refrigerator or freezer cases in a
supermarket, building spaces requiring air conditioning, or the passenger
compartment of an automobile requiring air conditioning. A heat sink may
be defined as any space, location, object or body capable of absorbing
heat. A vapor compression refrigeration system is one example of such a
heat sink.
EXAMPLES
FXL\MPI F 1
Impact of Vapor Leakage
A vessel is charged with an initial composition at a specified
temperature, and the initial vapor pressure of the composition is
measured. The composition is allowed to leak from the vessel, while the
temperature is held constant, until 50 weight percent of the initial
composition is removed, at which time the vapor pressure of the
composition remaining in the vessel is measured. The results are
summarized in Table 4 below.
TABLE 4
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After 50% After 50%
Compounds Initial Initial Leak Leak Delta
wt% AI wt% B Psia kPa Psia kPa P
C4F90C2H5/HFC-263fa (44.2 °C)
21.4/78.6 14.71 101.42 14.71 101.42 0.0%
10/90 14.62 100.80 14.57 100.46 0.3%
1 /99 14.36 99.01 14.34 98.87 0.1
0/100 14.31 98.66 14.31 98.66 0.0%
40/60 14.55 100.32 14.38 99.15 1.2%
60/40 13.97 96.32 12.92 89.08 7.5%
63/37 13.82 95.29 12.50 86.19 9.6%
100/0 4.80 33.10 4.80 33.10 0.0%
C4F90C2H5/HFC-392qqz
(50 C)
0/100 9.67 66.67 9.67 66.67 0.0%
1 /99 9.66 66.60 9.66 66.60 0.0%
10/90 9.63 66.40 9.62 66.33 0.1
20/80 9.57 65.98 9.56 65.91 0.1
40/60 9.39 64.74 9.33 64.33 0.6%
60/40 9.02 62.19 8.85 61.02 1.9%
80/20 8.25 56.88 7.83 53.99 5.1
90/10 7.47 51.50 6.97 48.06 6.7%
99/1 6.19 42.68 6.07 41.85 1.9%
100/0 5.98 41.23 5.98 41.23 0.0%
C4F90C2H5/HFC-392qff (74.2 °C)
77.4/22.6 14.68 101.22 14.68 101.22 0.0%
90/10 14.50 99.97 14.47 99.77 0.2%
99/1 13.97 96.32 13.95 96.18 0.1
100/0 13.87 95.63 13.87 95.63 0.0%
60/40 14.51 100.04 14.47 99.77 0.3%
40/60 14.12 97.35 14.02 96.67 0.7%
20180 13.65 94.11 13.55 93.42 0.7%
10/90 13.41 92.46 13.34 91.98 0.5%
1 /99 13.18 90.87 13.17 90.80 0.1
0/100 13.16 90.74 13.16 90.74 0.0%
C4F90C2H5/HFC-4-11-2qe (72.5 °C)
61.4/38.6 14.68 101.22 14.68 101.22 0.0%
40/60 14.51 100.04 14.47 99.77 0.3%
20/80 14.14 97.49 14.05 96.87 0.6%
10/90 13.90 95.84 13.83 95.36 0.5%
1 /99 13.65 94.11 13.64 94.05 0.1
0/100 13.62 93.91 13.62 93.91 0.0%
80/20 14.46 99.70 14.40 99.29 0.4%
90/10 14.02 96.67 13.92 95.98 0.7%
99/1 13.25 91.36 13.22 91.15 0.2%
CA 02553276 2006-07-12
WO 2005/067558 PCT/US2005/001509
100/0 13.12 90.46 13.12 90.46 0.0%
C4F90C2H5/HFC-5-12-3m (72.2 °C)
56.6/43.4 14.71 101.42 14.71 101.42 0.0%
40/60 14.59 100.60 14.56 100.39 0.2%
20/80 14.18 97.77 14.07 97.01 0.8%
10/90 13.87 95.63 13.77 94.94 0.7%
1 /99 13.52 93.22 13.51 93.15 0.1
01100 13.48 92.94 13.48 92.94 0.0%
80/20 14.36 99.01 14.27 98.39 0.6%
90/10 13.87 95.63 13.74 94.73 0.9%
99/1 13.11 90.39 13.08 90.18 0.2%
100/0 13.00 89.63 13.00 89.63 0.0%
C4F90C2H5/PFBE C)
(50
0/100 10.80 74.46 10.80 74.46 0.0%
1 /99 10.75 74.12 10.74 74.05 0.1
10/90 10.35 71.36 10.20 70.33 1.4%
20/80 9.89 68.19 9.61 66.26 2.8%
30/70 9.43 65.02 9.04 62.33 4.1
40/60 8.96 61.78 8.50 58.61 5.1
50/50 8.48 58.47 7.99 55.09 5.8%
60/40 7.99 55.09 7.51 51.78 6.0%
70/30 7.50 51.71 7.06 48.68 5.9%
80/20 7.00 48.26 6.66 45.92 4.9%
90/10 6.50 44.82 6.30 43.44 3.1
.
99/1 6.04 41.64 6.01 41.44 0.5%
100/0 5.98 41.23 5.98 41.23 0.0%
The results show the difference in vapor pressure between the original
composition and the composition remaining after 50 weight percent has
been removed is less then about 10 percent for compositions of the
present invention. This indicates compositions of the present invention
are azeotropic or near-azeotropic. Where an azeotrope is present, the
data show compositions of the present invention have an initial vapor
pressure higher than the vapor pressure of either pure component.
EXAMPLE 2
Tip Speed to Develop Pressure
Tip speed can be estimated by making some fundamental
relationships for refrigeration equipment that use centrifugal compressors.
The torque an impeller ideally imparts to a gas is defined as
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WO 2005/067558 PCT/US2005/001509
T = m*(v2*r2-v1 *r1 ) Equation 1
where
T = torque, N*m
m = mass rate of flow, kg/s
v2 = tangential velocity of refrigerant leaving impeller (tip
speed), m/s
r2 = radius of exit impeller, m
v1 = tangential velocity of refrigerant entering impeller, m/s
r1 = radius of inlet of impeller, m
Assuming the refrigerant enters the impeller in an essentially
radial direction, the tangential component of the velocity v1 = 0, therefore
T = m*v2*r2 Equation 2
The power required at the shaft is the product of the torque and
the rotative speed
P = T*w Equation 3
where
P = power, W
w = rotative speed, rez/s
therefore,
P = T*w = m*v2*r2*w Equation 4
At low refrigerant flow rates, the tip speed of the impeller and
the tangential velocity of the refrigerant are nearly identical; therefore
r2*w = v2 Equation 5
and
P = m*v2*v2 Equation 6
Another expression for ideal power is the product of the
mass rate of flow and the isentropic work of compression,
P = m*Hi*(1000J/kJ) Equation 7
where
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Hi = Difference in enthalpy of the refrigerant from a saturated
vapor at the evaporating conditions to saturated condensing conditions,
kJ/kg.
Combining the two expressions Equation 6 and 7
produces,
v2*v2 = 1000*Hi Equation 8
Although Equation 8 is based on some fundamental
assumptions, it provides a good estimate of the tip speed of the impeller
and provides an important way to compare tip speeds of refrigerants.
Table 6 below shows theoretical tip speeds that are calculated
for 1,2,2-trichlorotrifluoroethane (CFC-113) and compositions of the
present invention. The conditions assumed for this comparison are:
Evaporator temperature 40.0°F (4.4°C)
Condenser temperature 110.0°F (43.3°C)
Liquid subcool temperature 10.0°F (5.5°C)
Return gas temperature 75.0°F (23.8°C)
Compressor efFiciency is 70%
These are typical conditions under which small turbine centrifugal
compressors perform.
TABLE 6
V2 rel
Refrigerant C4F90CZH5wt% Hi Hi*0.7Hi*0.7V2 to CFC-
Composition wt% B Btu/IbBtu/lbKJ/Kgm/s 113
CFC-113 10.92 7.6 17.8 133.3nla
C4FgOCZHS
IUS B
HFC-263fa 21.4 78.615.1 10.6 24.6 156.8118%
HFC-392qqz 50.0 50.016.6 11.6 27.0 164.4123%
HFC-392qff 77.4 22.615.26 10.7 24.8 157.6118%
HFC-4-11-2 61.4 38.616.51 11.6 26.9 164.0123%
a
HFC-5-12-3m 56.6 43.416.45 11.5 26.8 163.7123%
PFBE 50.0 50.013.26 9.3 21.6 146.9110%
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The Example shows that compounds of the present invention
have tip speeds within about +/- 30 percent of CFC-113 and would be
effective replacements for CFC-113 with minimal compressor design
changes.
EXAMPLE 3
Performance Data
Table 7 shows the performance of various refrigerants
compared to CFC-113. The data are based on the following conditions.
Evaporator temperature 40.0F (4.4C)
Condenser temperature 110.0F (43.3C)
Subcool temperature 10.0F (5.5C)
Return gas temperature 75.0F (23.8C)
Compressor efficiency is 70%
TABLE 7
ComprCompr
Refrigerantwt% wt%EvapEvapCondCondDischDisch CapacityCapacity
compositionC4F90CZH5B PresPresPresPresTempTemp COPBtu/min ,(~
Psia(kPa)Psia(kPa),(FZ
CFC-113 2.7 19 12.888 156.369.1 4.1814.8 0.26
C4F90CZH5
lus B
HFC-263fa21.4 78.62.9 20 14.096 168.075.6 4.2519.0 0.33
HFC-392qqz50.0 50.01.5 10 7.9 54 150.665.9 4.169.9 0.17
HFC-392qff77.4 22.60.8 5 4.8 33 142.461.3 4.105.5 0.10
HFC-4-11-2qe61.4 38.60.9 6 5.2 36 142.361.3 4.116.1 0.11
HFC-5-12-3m56.6 43.40.9 6 5.2 36 135.557.5 4.025.9 0.10
PFBE 50.0 50.01.2 8 7.2 50 129.754.3 3.938.1 0.14
Data show the compositions of the present invention have evaporator and
condenser pressures similar to CFC-113. Some compositions also have
higher capacity or energy efficiency (COP) than CFC-113.
29
