U.S. patent application number 10/695212 was filed with the patent office on 2004-05-13 for fluorinated alkene refrigerant compositions.
This patent application is currently assigned to Honeywell International, Inc.. Invention is credited to Singh, Rajiv R., Thomas, Raymond H..
Application Number | 20040089839 10/695212 |
Document ID | / |
Family ID | 34549972 |
Filed Date | 2004-05-13 |
United States Patent
Application |
20040089839 |
Kind Code |
A1 |
Thomas, Raymond H. ; et
al. |
May 13, 2004 |
Fluorinated alkene refrigerant compositions
Abstract
Liquid compositions for use in compression refrigeration,
air-conditioning and heat pump systems in which a fluoroalkene
containing from 3 to 4 carbon atoms and at least 1 but no more than
2 double bonds is combined with an effective amount to provide
lubrication of an essentially miscible organic lubricant comprised
of carbon, hydrogen and oxygen and having a ratio of oxygen to
carbon effective to provide a degree of miscibility with said
fluoroalkene so that when up to five weight percent of lubricant is
added to said fluoroalkene the refrigerant has one liquid phase at
at least one temperature between -40 and +70.degree. C. Methods for
producing refrigeration and heating with the fluoroalkenes, alone
or in combination with the disclosed lubricants, are also
disclosed.
Inventors: |
Thomas, Raymond H.;
(Pendelton, NY) ; Singh, Rajiv R.; (Getzville,
NY) |
Correspondence
Address: |
COLLEEN D. SZUCH, ESQ. CHIEF INTELLECTUAL
PROPERTY COUNSEL - SPECIALITY CHEMICALS
HONEYWELL INTERNATIONAL
101 COLUMBIA ROAD, BUILDING MEYER 5
MORRISTOWN,
NJ
07962-2245
US
|
Assignee: |
Honeywell International,
Inc.
Morristown
NJ
|
Family ID: |
34549972 |
Appl. No.: |
10/695212 |
Filed: |
October 27, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60421263 |
Oct 25, 2002 |
|
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60421435 |
Oct 25, 2002 |
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Current U.S.
Class: |
252/67 |
Current CPC
Class: |
C10M 2211/0225 20130101;
C10M 105/38 20130101; C10M 171/008 20130101; C10M 107/34 20130101;
C09K 2205/126 20130101; C10M 111/04 20130101; C10N 2020/101
20200501; C10M 2207/2895 20130101; C10M 2209/1095 20130101; C10M
2211/063 20130101; C09K 2205/24 20130101; C10M 2209/1033 20130101;
C10M 111/02 20130101; C10M 2207/2835 20130101; C09K 5/045 20130101;
C10N 2040/30 20130101 |
Class at
Publication: |
252/067 |
International
Class: |
F25D 001/00 |
Claims
What is claimed is:
1. A liquid composition for use in compression refrigeration,
air-conditioning and heat pump systems comprising: (A) a
fluoroalkene containing from 3 to 4 carbon atoms and at least 1 but
no more than 2 double bonds; and (B) an effective amount to provide
lubrication of an essentially miscible organic lubricant comprised
of carbon, hydrogen and oxygen and having a ratio of oxygen to
carbon effective to provide a degree of miscibility with said
fluoroalkene so that when up to five weight percent of lubricant is
added to said fluoroalkene the mixture has one liquid phase at at
least one temperature between -40 and +70.degree. C.
2. The composition of claim 1, wherein the mixture has one liquid
phase when up to five weight percent of lubricant is added to said
fluoroalkene.
3. The composition of claim 2, wherein the mixture has one liquid
phase when up to 20 weight percent of lubricant is added to said
fluoroalkene.
4. The composition of claim 3, wherein the mixture has one liquid
phase in all proportions of fluoroalkene and lubricant.
5. The composition of claim 1, wherein the mixture has one liquid
phase over essentially the entire temperature range.
6. The composition of claim 1, wherein said lubricant is selected
from the group consisting of polyalkylene glycol, polyalkylene
glycol ester and polyol ester lubricants for compressor
refrigeration, air-conditioning and heat pump systems.
7. The composition of claim 1, wherein said fluoroalkene has the
structure: XCF.sub.ZR.sub.3-Zwherein X is a C.sub.2 or a C.sub.3
unsaturated, substituted or unsubstituted alkyl radical, R is
independently selected from the group consisting of Cl, Br, I or H,
and z is 1 to 3.
8. The composition of claim 7, wherein said fluoroalkene has the
structure: 2wherein each R is independently Cl, F, Br, I or H; R'
is (CR.sub.2).sub.nY; Y is CRF.sub.2; and n is 0 or 1.
9. The composition of claim 8, wherein said fluoroalkene is
1,3,3,3-tetrafluoropropene or 3,3,3-trifluoropropene.
10. The composition of claim 1, wherein said organic lubricant is a
polyalkylene glycol.
11. The composition of claim 10, wherein said polyalkylene glycol
has at least one terminal hydroxyl group.
12. The composition of claim 11, wherein both terminal groups of
said polyalkylene glycol are hydroxyl groups.
13. The composition of claim 10, wherein said polyalkylene glycol
has at least one alkyl terminal group.
14. The composition of claim 13, wherein at least one terminal
alkyl group of said polyalkylene glycol contains at least one
heteroatom.
15. The composition of claim 14, wherein said polyalkylene glycol
has at least one fluoroalkyl terminal group.
16. The composition of claim 1, wherein said organic lubricant is a
polyalkylene glycol ester.
17. The composition of claim 1, further comprising an amount of
hydrocarbon lubricant essentially miscible with said fluoroalkene
and said organic lubricant.
18. The composition of claim 17, further comprising a surfactant
for solubilizing said hydrocarbon lubricant with said organic
lubricant, in an amount effective to form an essentially miscible
blend.
19. A method for producing refrigeration which comprises condensing
a refrigerant composition comprising a fluoroalkene containing from
3 to 4 carbon atoms and at least 1 but no more than 2 double bonds,
and thereafter evaporating said refrigerant composition in the
vicinity of a body to be cooled.
20. The method of claim 19, wherein said fluoroalkene has the
structure: XCF.sub.ZR.sub.3-Zwherein X is a C.sub.2 or a C.sub.3
unsaturated, substituted or unsubstituted alkyl radical, R is
independently selected from the group consisting of Cl, Br, I or H,
and z is 1 to 3.
21. The method of claim 20, wherein said fluoroalkene has the
structure: 3wherein each R is independently Cl, F, Br, I or H; R'
is (CR.sub.2).sub.nY; Y is CRF.sub.2; and n is 0 or1.
22. The method of claim 21, wherein said fluoroalkene is
1,3,3,3-tetrafluoropropene or 3,3,3-trifluoropropene.
23. The method of claim 19, wherein said refrigeration method is
performed in a compression refrigeration system.
24. The method of claim 19, wherein said refrigeration method is
performed in an air-conditioning system.
25. The method of claim 19, wherein an organic lubricant is added
to said refrigerant in an amount effective to provide lubrication
comprised of carbon, hydrogen and oxygen and having a ratio of
oxygen to carbon effective to provide a degree of miscibility with
said fluoroalkene so that when up to five weight percent of
lubricant is added to said fluoroalkene the refrigerant has one
liquid phase at at least one temperature between -40 and
+70.degree. C.
26. The method of claim 25, wherein the refrigerant has one liquid
phase when up to 20 weight percent of lubricant is added to said
fluoroalkene.
27. The method of claim 26, wherein the refrigerant has one liquid
phase in all proportions of fluoroalkene and lubricant.
28. The method of claim 25, wherein the refrigerant has one liquid
phase over essentially the entire temperature range.
29. The method of claim 25, wherein said lubricant is selected from
the group consisting of polyalkylene glycol, polyalkylene glycol
ester and polyol ester lubricants for compressor refrigeration and
air-conditioning systems.
30. The method of claim 25, wherein there is further added to said
refrigerant an amount of a hydrocarbon lubricant essentially
miscible with said fluoroalkene and said organic lubricant.
31. The method of claim 30, wherein there is further added to said
refrigerant a surfactant for solubilizing said hydrocarbon
lubricant with said fluoroalkene and said organic lubricant in an
amount effective to form an essentially miscible blend.
32. A method for producing heating which comprises condensing a
fluoroalkene composition containing from 3 to 4 carbon atoms and at
least 1 but no more than 2 double bonds in the vicinity of a body
to be heated and thereafter evaporating said fluoroalkene
composition.
33. The method of claim 32, wherein said fluoroalkene has the
structure: XCF.sub.ZR.sub.3-Zwherein X is a C.sub.2 or a C.sub.3
unsaturated, substituted or unsubstituted alkyl radical, R is
independently selected from the group consisting of Cl, Br, I or H,
and z is 1 to 3.
34. The method of claim 33, wherein said fluoroalkene has the
structure: 4wherein each R is independently Cl, F, Br, I or H; R'
is (CR.sub.2).sub.nY; Y is CRF.sub.2; and n is 0 or1.
35. The method of claim 34, wherein said fluoroalkene is
1,3,3,3-tetrafluoropropene or 3,3,3-trifluoropropene.
36. The method of claim 32, wherein an organic lubricant is added
to said fluoroalkene composition in an amount effective to provide
lubrication comprised of carbon, hydrogen and oxygen and having a
ratio of oxygen to carbon effective to provide a degree of
miscibility with said fluoroalkene composition so that when up to
five weight percent of lubricant is added to said fluoroalkene
composition, said composition has one liquid phase at at least one
temperature between -40 and +70.degree. C.
37. The method of claim 36, wherein the fluoroalkene composition
has one liquid phase when up to 20 weight percent of lubricant is
added thereto.
38. The method of claim 37, wherein the fluoroalkene composition
has one liquid phase in all proportions of fluoroalkene composition
and lubricant.
39. The method of claim 36, wherein the fluoroalkene composition
has one liquid phase over essentially the entire temperature
range.
40. The method of claim 36, wherein said lubricant is selected from
the group consisting of polyalkylene glycol, polyalkylene glycol
ester and polyol ester lubricants for compressor refrigeration and
air-conditioning systems.
41. The method of claim 36, wherein there is further added to said
fluoroalkene composition an amount of a hydrocarbon lubricant
essentially miscible with said fluoroalkene and said organic
lubricant.
42. The method of claim 41, wherein there is further added to said
fluoroalkene composition a surfactant for solubilizing said
hydrocarbon lubricant with said fluoroalkene and said organic
lubricant in an amount effective to form an essentially miscible
blend.
Description
RELATED APPLICATIONS
[0001] The present application is related to and claims the
priority benefit of U.S. Provisional Application Nos. 60/421,263,
and 60/421,435, each of which was filed on Oct. 25, 2002 and each
of which is incorporated herein by reference. The present
application is also related to and incorporates by reference each
of the following concurrently filed U.S. Patent Applications:
Attorney Docket Number H0004412 (26,269) entitled "COMPOSITIONS
CONTAINING FLUORINE SUBSTITUTED OLEFINS," by Singh et al. and
Attorney Docket Number H0003789 (26,267) entitled "PROCESS FOR
PRODUCING FLUOROPROPENES," by Tung et al.
FIELD OF THE INVENTION
[0002] The present invention relates to compositions used as
refrigeration fluids in compression refrigeration, air-conditioning
and heat pump systems.
BACKGROUND OF THE INVENTION
[0003] The use of chlorine-containing refrigerants, such as
chlorofluorocarbons (CFC's), hydrochlorofluorocarbons (HCF's) and
the like, as refrigerants in air-conditioning and refrigeration
systems has become disfavored because of the ozone-depleting
properties associated with such compounds. As a result, it has
become desirable to retrofit chlorine-containing refrigeration
systems by replacing chlorine-containing refrigerants with
non-chlorine-containing refrigerant compounds that will not deplete
the ozone layer, such as hydrofluorocarbons (HFC's).
[0004] In order for any of the replacement materials to be useful
in connection with refrigeration compositions, the materials must
be compatible with the lubricant utilized in the compressor.
Unfortunately, many non-chlorine-containing refrigeration fluids,
including HFC's, are relatively insoluble and/or immiscible in the
types of lubricants used traditionally with CFC's and HFC's,
including, for example, mineral oils, alkylbenzenes or
poly(alpha-olefins). In order for a refrigeration fluid-lubricant
combination to work efficiently within a compression refrigeration,
air-conditioning or heat pump system, the lubricant must be
sufficiently soluble in the refrigeration liquid over a wide range
of operating temperatures. Such solubility lowers the viscosity of
the lubricant and allows it to flow more easily throughout the
system. In the absence of such solubility, lubricants tend to
become lodged in the coils of the compression refrigeration,
air-conditioning or heat pump system evaporator, as well as other
parts of the system, and thus reduce the system efficiency.
[0005] Polyalkylene glycol, esterified polyalkylene glycol, and
polyol ester lubricating oils have been developed as misicible
lubricants for HFC refrigeration liquids. Polyalkylene glycol
refrigeration lubricants are disclosed by U.S. Pat. Nos. 4,755,316;
4,971,712, and 4,975,212. Polyalkylene glycol esters are disclosed
by U.S. Pat. No. 5,008,028. The polyalkylene glycol and
polyalkylene glycol ester lubricating oils are disclosed as being
misicible in fluoroalkanes containing one or two carbon atoms and
no double bonds.
[0006] Consequently fluorocarbon-based fluids have found widespread
use in industry for refrigeration system applications, including
air-conditioning systems and heat pump applications as well, all of
which involve compression refrigeration. Compression refrigeration
generally involves changing the refrigerant from the liquid to the
vapor phase through heat adsorption at a lower pressure and then
from the vapor to the liquid phase through heat removal at an
elevated pressure.
[0007] While the primary purpose of refrigeration is to remove
energy at low temperature, the primary purpose of a heat pump is to
add energy at higher temperature. Heat pumps are considered reverse
cycle systems because for heating, the operation of the condenser
is interchanged with that of the refrigeration evaporator.
[0008] The art is continually seeking new fluorocarbon and
hydrofluorocarbon-based pure fluids that offer alternatives for
refrigeration and heat pump applications. Applicants have come to
appreciate that fluoro-olefin-based materials (fluoroalkenes) are
of particular interest because they have characteristics that make
them environmentally safer substitutes for the presently used
fluoroalkanes (HFC's), that despite being safe for the ozone layer
are suspected of causing global warming.
[0009] Applicant has also come to recognize that refrigeration
composition substitutes for HFC's in many cases preferably possess
certain performance properties to be considered acceptable
substitutes, including acceptable refrigeration characteristics,
chemical stability, low toxicity, non-flammability, lubricant
compatibility and efficiency in use. The latter characteristic is
important in many refrigeration systems, air-conditioning systems
and heat pump applications, especially when a loss in refrigeration
thermodynamic performance or energy efficiency may have secondary
environmental impacts through increased fossil fuel usage arising
from an increased demand for electrical energy. Furthermore, it
would be advantageous for HFC refrigeration composition substitutes
to not require major engineering changes to conventional vapor
compression technology and lubricant systems currently used with
HFC refrigeration liquids.
[0010] Flammability is another important property for many
applications. That is, it is considered either important or
essential in many applications, including particularly in heat
transfer applications, to use compositions which are non-flammable.
Thus, it is frequently beneficial to use in such compositions
compounds which are nonflammable. As used herein, the term
"nonflammable" refers to compounds or compositions which are
determined to be nonflammable in accordance with ASTM standard
E-681, dated 2002, which is incorporated herein by reference.
Unfortunately, many HFC's which might otherwise be desirable for
used in refrigerant compositions are not nonflammable. For example,
the fluoroalkane difluoroethane (HFC-152a) and the fluoroalkene
1,1,1-trifluoropropene (HFO-1243zf) are each flammable and
therefore not viable for use in many applications.
[0011] Higher fluoroalkenes, that is fluorine-substituted alkenes
having at least five carbon atoms, have been suggested for use as
refrigerants. Smutry, U.S. Pat. No. 4,788,352 is directed to
production of fluorinated C.sub.5 to C.sub.8 compounds having at
least some degree of unsaturation. The Smutny patent identifies
such higher olefins as being known to have utility as refrigerants,
pesticides, dielectric fluids, heat transfer fluids, solvents, and
intermediates in various chemical reactions.
[0012] While the fluorinated olefins described in Smutny may have
some level of effectiveness in heat transfer applications, it is
believed that such compounds may also have certain disadvantages.
For example, some of these compounds may tend to attack substrates,
particularly general-purpose plastics such as acrylic resins and
ABS resins. Furthermore, the higher olefinic compounds described in
Smutny may also be undesirable in certain applications because of
the potential level of toxicity of such compounds which may arise
as a result of pesticide activity noted in Smutny. Also, such
compounds may have a boiling point which is too high to make them
useful as a refrigerant in certain applications.
[0013] Applicant have thus come to appreciate a need for
compositions, and particularly fluid transfer compositions that are
potentially useful in numerous applications, including vapor
compression heating and cooling systems and methods, while avoiding
one or more of the disadvantages noted above. Moreover, applicant
has also recognized that in many applications there remains a need
for fluorocarbon and hydrofluorocarbon-based refrigeration liquids
that are environmentally safer than HFC's, possess similar or
better characteristics with respect to at least certain refrigerant
thermodynamic performance properties, and are compatible with
existing lubricant systems.
SUMMARY
[0014] Applicants have found that the above-noted needs, and other
needs, can be satisfied by compositions comprising one or more C3
or C4 fluoroalkenes, preferably compounds having Formula I as
follows:
XCF.sub.ZR.sub.3-Z (I)
[0015] where X is a C.sub.2 or a C.sub.3 unsaturated, substituted
or unsubstituted, alkyl radical, R is independently Cl, Br, I or H,
and z is 1 to 3. The present compositions also preferably include
one or more lubricants in combination with one or more of the
compounds of the present invention.
[0016] The present invention provides also methods and systems
which utilize the heat transfer compositions of the present
invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
the Compositions
[0017] The present invention is directed to compositions comprising
at least one fluoroalkene containing from 3 to 4 carbon atoms and
at least one carbon-carbon double bond. The fluoroalkene compounds
of the present invention are sometimes referred to herein for the
purpose of convenience as hydrofluoro-olefins or "HFOs." Although
it is contemplated that the HFOs of the present invention may
contain two carbon--carbon double bonds, such compounds at the
present time are not considered to be preferred.
[0018] As mentioned above, the present compositions comprise one or
compounds in accordance with Formula I. In preferred embodiments,
the compositions include compounds of Formula II below: 1
[0019] wherein each R is independently Cl, F, Br, I or H; R' is
(CR.sub.2).sub.nY; Y is CRF.sub.2 and n is 0 or 1. In highly
preferred embodiments, Y is CF.sub.3, n is 0 and at least one of
the remaining R's is F.
[0020] Applicant believes that, in general, the compounds of the
above identified Formulas I and II are generally effective and
exhibit utility in heat transfer applications in general and in
compression refrigerant compositions in particular. However, it has
been surprisingly and unexpectedly found that certain of the
compounds having a structure in accordance with the formulas
described above exhibit a highly desirable low level of toxicity
compared to other of such compounds. As can be readily appreciated,
this discovery is of potentially enormous advantage and benefit for
the formulation of not only refrigerant compositions, but also any
and all compositions which would otherwise contain relatively toxic
compounds satisfying the formulas described above. More
particularly, it is believed that a relatively low toxicity level
is associated with compounds of Formula II, preferably wherein Y is
CF.sub.3, wherein at least one R on the unsaturated terminal carbon
is H, and at least one of the remaining R's is F. It is believed
also that all structural, geometric and stereoisomers of such
compounds are effective and of beneficially low toxicity.
[0021] In highly preferred embodiments, especially embodiments
which comprise the low toxicity compounds described above, n is
zero. Thus, in certain preferred embodiments the compositions of
the present invention comprise one or more compounds selected from
the group consisting of trifluorpropene (HFC -1243),
tetrafluoropropenes (HFO-1234), pentafluoropropenes (HFO-1225) and
combinations of these. The trans-1234 isomer has a boiling point of
approximately -19.degree. C. and the cis isomer has a boiling point
of approximately +9.degree. C. The trans isomer is particularly
useful as a refrigerant and as an aersol propellent.
[0022] It is even more preferred that the compounds of the present
invention are the tetrafluoroprpoene and pentafluoropropene
compounds in which the unsaturated terminal carbon has not more
than one F substituent, specifically: 1, 3, 3, 3-tetrafluoropropene
(HFO-1234ze); 2, 3, 3, 3-tetrafluoropropene (HFO-1234yf); and
1,2,3,3,3-pentafluoropropene (HFO-1225ye), and any and all
stereoisomers of each of these. It has been discovered that such
compounds have a very acute low toxicity level, as measured by
inhalation exposure to mice and rats. On the other hand, it has
been found that a relatively high degree of toxicity may be
associated with certain compounds adaptable for use with the
present compositions, namely, those compounds which have more than
one F on the terminal unsaturated carbon, or which do not have at
least one H on the terminal unsaturated carbon. For example, it has
been discovered that 1,1,3,3,3-pentafluoropropene (HFO-1225zc)
exhibits an unacceptably high degree of toxicity, as measured by
inhalation exposure to mice and rats.
[0023] The preferred compounds of the present invention, namely,
HFO-1225 and HFO-1234 are known materials and are listed in
Chemical Abstracts databases. HFO-1225 is commercially available,
for example from Syntex Chemical Co. Futhermore, methods are
described generally in the patent literature for producing
fluoroalkenes. For example the production of fluoropropenes such as
CF.sub.3CH=CH.sub.2 by catalytic vapor phase fluorination of
various saturated and unsaturated halogen-containing C.sub.3
compounds is described in U.S. Pat. Nos. 2,889,379; 4,798,818 and
4,465,786, each of which is incorporated herein by reference. U.S.
Pat. No. 5,532,419, which is also incorporated herein by reference,
discloses a vapor phase catalytic process for the preparation of
fluoroalkene using a chloro- or bromo-halofluorocarbon and H. EP
974,571, also incorporated herein by reference, discloses the
preparation of 1,1,1,3-tetrafluoro-pro- pene by contacting
1,1,1,3,3-pentafluoropropane (HFC-245fa) in the vapor phase with a
chromium-based catalyst at elevated temperature, or in the liquid
phase with an alcoholic solution of KOH, NaOH, Ca(OH).sub.2 or
Mg(OH).sub.2. In addition, methods for producing compounds in
accordance with the present invention are described generally in
connection with concurrently filed United States Patent Application
entitled "Process for Producing Fluorpropenes" bearing attorney
docket number (H0003789 (26,267USA)), which is also incorporated
herein by reference.
[0024] The present compositions are believed to possess properties
that are advantageous for a number of important reasons. For
example, applicants believe, based at least in part on mathematical
modeling, that the fluoroolefins of the present invention will not
have a substantial negative affect on atmospheric chemistry, being
negligible contributors to ozone depletion in comparison to some
other halogenated species. The preferred compositions of the
present invention thus have the advantage of not contributing
substantially to ozone depletion. The preferred compositions also
do not contribute substantially to global warming compared to many
of the hydrofluoroalkanes presently in use.
[0025] Although it is contemplated that the compositions of the
present invention may include the compounds of the present
invention in widely ranging amounts, it is generally preferred that
refrigerant compositions of the present invention comprise
compound(s) in accordance with Formula I, and even more preferably
Formula II, in an amount that is at least about 50% by weight, and
even more preferably at least about 70% by weight, of the
composition. For preferred compositions for use as blowing agents
in accordance with the present invention, compound(s) in accordance
with Formula I, and even more preferably Formula II, are present in
an amount that is at least about 5% by weight, and even more
preferably at least about 15% by weight, of the composition.
[0026] The compositions of the present invention may include other
components for the purpose of enhancing or providing certain
functionality to the composition, or in some cases to reduce the
cost of the composition. For example, refrigerant compositions
according to the present invention, especially those used in vapor
compression systems, include a lubricant, generally in amounts of
from about 30 to about 50 percent by weight of the composition.
Furthermore, the present compositions may also include a
compatibilzer, such as propane, for the purpose of aiding
compatibility and/or solubility of the lubricant. Such
compatibilizers, including propane, butanes and pentanes, are
preferably present in amounts of from about 0.5 to about 5 percent
by weight of the composition. Combinations of surfactants and
solubilizing agents may also be added to the present compositions
to aid oil solubility, as disclosed by U.S. Pat. No. 6,516,837, the
disclosure of which is incorporated by reference. Commonly used
refrigeration lubricants such as Polyol Esters (POEs), Poly
Alkylene Glycols (PAGs) and esterified Poly Alkylene Glycols that
are used in refrigeration machinery with hydrofluorocarbon (HFC)
refrigerants may be used with the refrigerant compositions of the
present invention.
METHODS AND SYSTEMS
[0027] The compositions of the present invention are useful in
connection with numerous methods and systems, including as heat
transfer fluids in methods and systems for transferring heat, such
as refrigerants used in refrigeration, air conditioning and heat
pump systems.
[0028] The preferred heat transfer methods generally comprise
providing a composition of the present invention and causing heat
to be transferred to or from the composition by changing the phase
of the composition. For example, the present methods provide
cooling by absorbing heat from a fluid or article, preferably by
condensing a refrigerant comprising the present compositions and
thereafter evaporating the refrigerant in the vicinity of the body
or fluid to be cooled. In many of such processes, the step of
compressing the refrigerant vapor, usually with a rotary compressor
or similar equipment, is also included as part of the refrigeration
cycle. Such a step is then sometimes followed by an intermediate
cooling step to remove at least a portion of the heat added to the
refrigerant composition of the present invention by the compression
step. This intermediate cooling step is then preferably followed by
a nominally isoenthalpic reduction of the pressure of the cooled,
high pressure refrigerant vapor to cause at least a portion of the
vapor to condense to a relatively cold liquid phase. In such
embodiments, it is this reduced temperature refrigerant liquid
which is then vaporized by heat transferred from the body or fluid
to be cooled.
[0029] In another process embodiment of the invention, the
compositions of the invention may be used in a method for producing
heating which comprises condensing a refrigerant comprising the
compositions in the vicinity of a liquid or body to be heated and
thereafter evaporating the refrigerant. Such methods, as mentioned
hereinbefore, frequently are reverse cycles to the refrigeration
cycle described above.
[0030] According to one aspect of the present invention, a method
for producing refrigeration is provided by condensing a
fluoroalkene containing from 2 to 5 carbon atoms and at least 1 but
no more than 2 double bonds and thereafter evaporating the
fluoroalkene in the vicinity of a body to be cooled. Fluoroalkenes
containing 3 carbon atoms and 1 double bond are preferred.
[0031] Because heat pump systems are simply the reverse of
refrigeration systems, according to another aspect of the present
invention, a method is provided for producing heating by condensing
a fluoroalkene containing from 2 to 5 carbon atoms and at least 1
but no more than 2 double bonds in the vicinity of a body to be
heated and thereby evaporating the fluoroalkene. Again,
fluoroalkenes containing 3 carbon atoms and 1 double bond are
preferred.
[0032] It has also been discovered that the fluoroalkenes of the
present invention are misicible with existing polyalkylene glycol,
polyalkylene glycol ester and polyol ester lubricating oils.
Therefore, according to another aspect of the present invention, a
liquid composition is provided for use in compression
refrigeration, air-conditioning and heat pump systems in which a
fluoroalkene containing from 2 to 5 carbon atoms and at least 1 but
no more than 2 double bonds is combined with a sufficient amount to
provide lubrication of an essentially miscible organic lubricant
selected from polyalkylene glycol, polyalkylene glycol ester and
polyol ester lubricants for compression refrigeration,
air-conditioning and heat pump systems. In certain preferred
embodiments, the lubricants of this invention are organic compounds
which are comprised of carbon, hydrogen and oxygen with a ratio of
oxygen to carbon sufficient to provide a degree of miscibility with
the fluoroalkene such the when about 1 to 5 weight percent of the
lubricant is added to the refrigerant fluid the mixture has one
liquid phase. Preferably, the mixture has one liquid phase when 1
to 20 weight percent of the lubricant is present in the mixture.
Most preferably, the mixture is one liquid phase in all proportions
of the components of mixture. This solubility or miscibility
preferably exists at at least one temperature from about
-40.degree. C. and 70.degree. C, and more preferably over
essentially the entire temperature range.
[0033] As used herein the term "refrigeration system" refers to any
system or apparatus, or any part or portion of such a system or
apparatus, which employs a refrigeration liquid or refrigerant to
provide cooling. Such refrigeration systems include, for example,
air-conditioners, electric refrigerators, chillers, transport
refrigeration systems, commercial refrigeration systems, and the
like.
[0034] The present invention substitutes HFO's for HFC's, which,
despite being safe for the ozone layer, are suspected of
contributing to global warming. At least certain of the preferred
HFO's according to the present invention have physical
characteristics that allow for their substitution for HFC's with
only a minimum of equipment changes.
[0035] The polyalkylene glycol lubricants suitable for use with the
present invention typically containing from about 5 to 50
oxylakylene repeating units that contain from 1 to 5 carbon atoms.
The polyalkylene glycol can be straight chain or branched and can
be a homopolymer or co-polymer of 2, 3 or more oxyethylene,
oxypropylene, oxybutylene or oxypentylene groups or combinations
thereof in any proportions. Preferred polyalkylene glycols contain
at least 50% oxypropylene groups. Compositions according to the
present invention may contain one or more polyalkylene glycols as
the lubricant, one or more polyalkylene glycol esters as the
lubricant, one or more polyol esters as the lubricant, or a mixture
of one of more polyalkylene glycols, one or more polyalkylene
glycol esters and one or more polyol esters. Vinyl ethers are also
useful in this invention.
[0036] Suitable polyalkylene glycols include the polyalkylene
glycols of U.S. Pat. No. 4, 971,712 and the polyalkylene glycol
having hydroxy groups at each terminus disclosed by U.S. Pat. No.
4,755,316. The disclosures of both patents are incorporated herein
by reference.
[0037] While suitable polyalkylene glycols include glycols
terminating at each end with a hydroxyl group, other suitable HFO
lubricants include polyalkylene glycols in which either or both
terminal hydroxyl group is capped. The hydroxyl group may be capped
with alkyl groups containing from 1 to 10 carbon atoms, 1 to 10
carbon atom alkyl groups containing heteroatoms such as nitrogen,
the fluoroalkyl groups described by U.S. Pat. No. 4,975,212, the
disclosure of which is incorporated herein by reference, and the
like. When both polyalkylene glycol hydroxyl groups are end capped,
the same type or a combination of two different types of terminal
capping groups can be used.
[0038] Either or both hydroxyl groups can also be capped by forming
the ester thereof with a carboxylic acid as disclosed by U.S. Pat.
No. 5,008,028, the disclosure of which is also incorporated herein
by reference. The lubricating oils of this patent are referred to
as polyol esters and polyalkylene glycol esters. The carboxylic
acid can also be fluorinated. When both ends of the polyalkylene
glycol are capped, either or both ends may be capped with an ester,
or one end may be capped with an ester and the other not capped or
capped with one of the aforementioned alkyl, heteroalkyl or
fluoroalkyl groups.
[0039] Commercially available polyalkylene glycol lubricants
include Goodwrench Refrigeration Oil for HFC-134a systems from
General Motors and MOPAR-56 from Daimler-Chrysler, which is a
polyalkylene glycol that is bis-capped by acetyl groups.
Commercially available polyalkylene glycol esters include Mobil EAL
22 cc available from Exxon-Mobil and Solest 120 available from CPI
Engineering Services, Inc. A wide variety of polyalkylene glycol
lubricants are also available from Dow Chemical.
[0040] In preferred embodiments, the lubricants of this invention
have viscosities of from about 1 to 1000 centistokes at about
37.degree. C., more preferably in the range of from about 10 to
about 200 centistokes at about 37.degree. C. and even more
preferably of from about 30 to about 150 centistokes.
[0041] In addition to the HFO refrigerant and lubricant,
compositions according to the present invention can include other
additives or materials of the type used in refrigeration,
air-conditioning and heat pump compositions to enhance their
performance. For example, the compositions can also include extreme
pressure and anti-wear additives, oxidation and thermal stability
improvers, pour and floc point depressants, anti-foaming agents,
other lubricants soluble in HFO's, and the like. Examples of such
additives are disclosed in U.S. Pat. No. 5,254,280, the disclosure
of which is incorporated herein by reference. Compositions of the
present invention can thus further include a quantity of mineral
oil lubricant that would not otherwise be misicible or soluble with
the HFO but is at least partially misicible or partially soluble
when added to the HFO in combination with a polyalkylene glycol,
polyalkylene glycol ester or polyol ester. Typically, this is a
quantity up to about 5-20 weight %. A surfactant may also be added
to compatibilize the mineral oil with the polyalkylene glycol,
polyalkylene glycol ester or polyol ester and the HFO, as disclosed
in U.S. Pat. No. 6,516,837, the disclosure of which is incorporated
herein by reference.
[0042] Any of a wide range of methods for introducing the
refrigeration compositions of the present invention to a
compression refrigeration, air-conditioning or heat pump system can
be used from the present invention. For example, one method
comprises attaching a refrigerant container to the low-pressure
side of a refrigeration system and turning on the refrigeration
system compressor to pull the refrigeration composition into the
system. In such embodiments, the refrigerant container may be
placed on a scale such that the amount of refrigeration composition
entering the system can be monitored. When a desired amount of
refrigeration composition has been introduced into the system,
charging is stopped. Alternatively, a wide range of charging tools,
known to those skilled in the art, are commercially available.
Accordingly, in light of the above disclosure, those of skill in
the art will be readily able to introduce the HFO refrigerant and
refrigeration compositions of the present invention into
compression refrigeration, air-conditioning and heat pump systems
without undue experimentation.
EXAMPLES
[0043] The following examples are provided for the purpose of
illustrating the present invention but without limiting the scope
thereof.
EXAMPLE 1
[0044] The coefficient of performance (COP) is a universally
accepted measure of refrigerant performance, especially useful in
representing the relative thermodynamic efficiency of a refrigerant
in a specific heating or cooling cycle involving evaporation or
condensation of the refrigerant. In refrigeration engineering, this
term expresses the ratio of useful refrigeration to the energy
applied by the compressor in compressing the vapor. The capacity of
a refrigerant represents the volumetric efficiency of the
refrigerant and provides some measure of the capability of a
compressor to pump quantities of heat for a given volumetric flow
rate of refrigerant. In other words, given a specific compressor, a
refrigerant with a higher capacity will deliver more cooling or
heating power. One means for estimating COP of a refrigerant at
specific operating conditions is from the thermodynamic properties
of the refrigerant using standard refrigeration cycle analysis
techniques (see for example, R. C. Downing, FLUOROCARBON
REFRIGERANTS HANDBOOK, Chapter 3, Prentice-Hall, 1988).
[0045] A refrigeration/air conditioning cycle system is provided
where the condenser temperature is about 150.degree. F. and the
evaporator temperature is about -35.degree. F. under nominally
isentropic compression with a compressor inlet temperature of about
50.degree. F. COP is determined for several compositions of the
present invention over a range of condenser and evaporator
temperatures and reported in Table I below, based upon HFC-134a
having a COP value of 1.00, a capacity value of 1.00 and a
discharge temperature of 175.degree. F.
1TABLE I REFRIGERANT Relative DISCHARGE COMPOSTION Relative COP
CAPACITY TEMPERATURE HFO 1225ye 1.02 0.76 158 HFO trans-1234ze 1.04
0.70 165 HFO cis-1234ze 1.13 0.36 155 HFO 1234yf 0.98 1.10 168
[0046] This example shows that certain of the preferred compounds
for use with the present compositions each have a better energy
efficiency than HFC-134a (1.02, 1.04 and 1.13 compared to 1.00) and
the compressor using the present refrigerant compositions will
produce discharge temperatures (158, 165 and 155 compared to 175),
which is advantageous since such result will likely leading to
reduced maintenance problems.
EXAMPLE 2
[0047] The miscibility of HFO-1225ye and HFO-1234ze with various
refrigeration lubricants is tested. The lubricants tested are
mineral oil (C3), alkyl benzene (Zerol 150), ester oil (Mobil EAL
22 cc and Solest 120), polyalkylene glycol (PAG) oil (Goodwrench
Refrigeration Oil for 134a systems), and a poly(alpha-olefin) oil
(CP-6005-100). For each refrigerant/oil combination, three
compositions are tested, namely 5, 20 and 50 weight percent of
lubricant, with the balance of each being the compound of the
present invention being tested
[0048] The lubricant compositions are placed in heavy-walled glass
tubes. The tubes are evacuated, the refrigerant compound in
accordance with the present invention is added, and the tubes are
then sealed. The tubes are then put into an air bath environmental
chamber, the temperature of which is varied from about -50.degree.
C. to 70.degree. C. At roughly 10.degree. C. intervals, visual
observations of the tube contents are made for the existence of one
or more liquid phases. In a case where more than one liquid phase
is observed, the mixture is reported to be immiscible. In a case
where there is only one liquid phase observed, the mixture is
reported to be miscible. In those cases where two liquid phases
were observed, but with one of the liquid phases occupying only a
very small volume, the mixture is reported to be partially
miscible.
[0049] The polyalkylene glycol and ester oil lubricants were judged
to be miscible in all tested proportions over the entire
temperature range, except that for the HFO-1225ye mixtures with
polyalkylene glycol, the refrigerant mixture was found to be
immiscible over the temperature range of -50.degree. C. to
-30.degree. C. and to be partially miscible over from 20 to
50.degree. C. At 50 weight percent concentration of the PAG in
refrigerant and at 60.degree., the refrigerant/PAG mixture was
miscible. At 70.degree. C., it was miscible from 5 weight percent
lubricant in refrigerant to 50 weight percent lubricant in
refrigerant.
EXAMPLE 3
[0050] The compatibility of the refrigerant compounds and
compositions of the present invention with PAG lubricating oils
while in contact with metals used in refrigeration and air
conditioning systems is tested at 350.degree. C., representing
conditions much more severe than are found in many refrigeration
and air conditioning applications.
[0051] Aluminum, copper and steel coupons are added to heavy walled
glass tubes. Two grams of oil are added to the tubes. The tubes are
then evacuated and one gram of refrigerant is added. The tubes are
put into an oven at 350.degree. F. for one week and visual
observations are made. At the end of the exposure period, the tubes
are removed.
[0052] This procedure was done for the following combinations of
oil and the compound of the present invention:
[0053] a) HFC-1234ze and GM Goodwrench PAG oil
[0054] b) HFC1243zf and GM Goodwrench oil PAG oil
[0055] c) HFC-1234ze and MOPAR-56 PAG oil
[0056] d) HFC-1243zf and MOPAR-56 PAG oil
[0057] e) HFC-1225 ye and MOPAR-56 PAG oil.
[0058] In all cases, there is minimal change in the appearance of
the contents of the tube. This indicates that the refrigerant
compounds and compositions of the present invention are stable in
contact with aluminum, steel and copper found in refrigeration and
air conditioning systems, and the types of lubricating oils that
are likely to be included in such compositions or used with such
compositions in these types of systems.
COMPARATIVE EXAMPLE
[0059] Aluminum, copper and steel coupons are added to a heavy
walled glass tube with mineral oil and CFC-12 and heated for one
week at 350.degree. C., as in Example 3. At the end of the exposure
period, the tube is removed and visual observations are made. The
liquid contents are observed to turn black, indicating there is
severe decomposition of the contents of the tube.
[0060] CFC-12 and mineral oil have heretofore been the combination
of choice in many refrigerant systems and methods. Thus, the
refrigerant compounds and compositions of the present invention
possess significantly better stability with many commonly used
lubricating oils than the widely-used prior art
refrigerant-lubricating oil combination.
* * * * *