U.S. patent application number 15/948530 was filed with the patent office on 2018-12-20 for hydrofluorocarbon/trifluoroiodomethane/hydrocarbons refrigerant compositions.
The applicant listed for this patent is HONEYWELL INTERNATIONAL INC.. Invention is credited to RAJIV R. SINGH, I, MARK W. SPATZ, RAYMOND H. THOMAS, ELIZABET DEL CARMEN VERA BECERRA, DAVID P. WILSON, SAMUEL F. YANA MOTTA.
Application Number | 20180362820 15/948530 |
Document ID | / |
Family ID | 40640930 |
Filed Date | 2018-12-20 |
United States Patent
Application |
20180362820 |
Kind Code |
A1 |
SPATZ; MARK W. ; et
al. |
December 20, 2018 |
HYDROFLUOROCARBON/TRIFLUOROIODOMETHANE/HYDROCARBONS REFRIGERANT
COMPOSITIONS
Abstract
A composition comprising from about 40 weight percent to about
99.9 weight percent of at least one C.sub.1-c.sub.5
hydrofluorocarbon, from about 0.1 weight percent to about 50 weight
percent of CF3I, and from about 0.1 weight percent to about 10
weight percent of at least one C.sub.1-c.sub.6 hydrocarbon and the
use of these composition for in methods of the recharging of
refrigeration systems.
Inventors: |
SPATZ; MARK W.; (East
Amherst, NY) ; THOMAS; RAYMOND H.; (Pendleton,
NY) ; SINGH, I; RAJIV R.; (Getzville, NY) ;
YANA MOTTA; SAMUEL F.; (Amherst, NY) ; WILSON; DAVID
P.; (East Amherst, NY) ; VERA BECERRA; ELIZABET DEL
CARMEN; (Amherst, NY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HONEYWELL INTERNATIONAL INC. |
MORRIS PLAINS |
NJ |
US |
|
|
Family ID: |
40640930 |
Appl. No.: |
15/948530 |
Filed: |
April 9, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11941228 |
Nov 16, 2007 |
9938442 |
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15948530 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2040/30 20130101;
C10N 2020/103 20200501; C10N 2020/101 20200501; C09K 5/045
20130101; C10M 171/008 20130101; C10M 2203/06 20130101; C09K
2205/12 20130101; C09K 2205/122 20130101; C10M 2203/10 20130101;
C10N 2020/101 20200501; C10N 2020/101 20200501; C10N 2020/103
20200501 |
International
Class: |
C09K 5/04 20060101
C09K005/04; C10M 171/00 20060101 C10M171/00 |
Claims
1. A composition comprising: (a) from about 40 weight percent to
about 99.8 weight percent of at least one C.sub.1-C5
hydrofluorocarbon; (b) from about 0.1 weight percent to about 50
weight percent of CF.sub.3I; and (c) from about 0.1 weight percent
to about 10 weight percent of at least one C.sub.1-C6
hydrocarbon.
2. The composition of claim 1 wherein the at least one C.sub.1-C5
hydrofluorocarbon is present in an amount of from about 72 weight
percent to about 99.8 weight percent.
3. The composition of claim 1 wherein the CF.sub.3I is present in
an amount of from about 0.1 weight percent to about 20 weight
percent.
4. The composition of claim 1 wherein the at least one C.sub.1-C6
hydrocarbon is present in an amount of from about 0.1 weight
percent to about 8 weight percent.
5. The composition of claim 1 wherein the at least one C.sub.1-C5
hydrofluorocarbon is present in an amount of from about 72 weight
percent to about 99.8 weight percent; the CF.sub.3I is present in
an amount of from about 0.1 weight percent to about 20 weight
percent; and the at least one C.sub.1-C6 hydrocarbon is present in
an amount of from about 0.1 weight percent to about 8 weight
percent.
6. (canceled)
7. The composition of claim 1 wherein the CF.sub.3I is present in
an amount of from about 0.1 weight percent to about 10 weight
percent.
8. (canceled)
9. (canceled)
10. The composition of claim 1 wherein the at least one
C.sub.1-C.sub.5 hydrofluorocarbon comprises consists essentially of
difluoromethane, and 1,1-1,2-,2-p-entafluoro-ethane.
11. (canceled)
12. The composition of claim 1 wherein the at least one
C.sub.1-C.sub.5 hydrofluorocarbon is a combination of
1,1,1,2,2-pentafluoroethane; 1,1,1-trifluoroethane; and
1,1,1,2-tetrafluoroethane.
13. The composition of claim 1 wherein the at least one
C.sub.1-C.sub.5 hydrofluorocarbon is a combination of
difluoromethane; 1,1,1,2,2-pentafluoroethane; and
1,1,1,2-tetrafluoroethane.
14. (canceled)
15. The composition of claim 1 wherein the at least one
C.sub.1-C.sub.6 hydrocarbon comprises isobutane.
16. (canceled)
17. (canceled)
18. The composition of claim 1 further comprising a lubricant.
19. The composition of claim 18 wherein said lubricant comprises a
mineral oil, hydrocarbon oil, alkyl oil, alkyl benzene oil,
paraffinic oil, or combinations thereof.
20. The composition of claim 18 wherein said lubricant is present
in an amount of from about 0.1 to about 99.9 weight percent based
on the weight of the composition.
21. The composition of claim 19 wherein said lubricant comprises a
mineral oil or alkyl benzene oil.
22. The composition of claim 20 wherein said lubricant comprises a
mineral oil or alkyl benzene oil.
23. A method of recharging a refrigeration system comprising the
steps of: providing a refrigeration system from which a
chlorine-containing refrigerant has been substantially removed; and
introducing the composition of claim 1 into said refrigeration
system.
24. (canceled)
25. (canceled)
26. (canceled)
27. (canceled)
28. (canceled)
29. (canceled)
30. (canceled)
31. (canceled)
32. (canceled)
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. application Ser. No.
11/941,228, filed Nov. 16, 2007 (now pending) the entirety of which
is herein incorporated by reference.
BACKGROUND OF THE INVENTION
Field of Invention
[0002] The invention relates generally to hydrofluorocarbon
compositions. More particularly, the invention relates to blends of
one or more hydrofluorocarbons, trifluoroiodomethane (CF.sub.3I)
and hydrocarbons, as well as methods for using these compositions
in applications such as the recharging of refrigeration systems.
and for its use in replacing a chlorofluorocarbon or
hydrochlorofluorocarbon in a refrigeration system.
Description of the Related Art
[0003] Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons
(HCFCs), such as dichlorofluoromethane (R-12),
monochlorodifluoromethane (R-22), and azeotropic mixtures of
monochlorodifluoromethane and chloropentafluoroethane (R-115)
(known as R-502), have conventionally been used as refrigerants in
heating and cooling systems. However, the use of
chlorine-containing refrigerants, such as chlorofluorocarbons
(CFC's), hydrochlorofluorocarbons (HCFC'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.
[0004] New compounds have been developed as alternatives to CFCs
and HCFCs. Hydrofluorocarbons (HFCs) and hydrofluorocarbon blends
are of particular interest as such alternatives because they have
properties that are similar to chlorofluorocarbons, including
similar refrigeration characteristics, i.e. a vapor pressure that
is plus or minus 20 percent of the reference refrigerant at the
same temperature, chemical stability, low toxicity,
non-flammability, efficiency in-use and low temperature glides.
Unlike CFCs and HCFCs, HFCs do not damage the ozone layer, and thus
are considered environmentally friendly. Moreover, HFCs generally
possess a good efficiency in-use which is important, for example,
in air conditioning and refrigeration where a loss in refrigerant
thermodynamic performance or energy efficiency may have secondary
environmental impacts through increased fossil fuel usage arising
from an increased demand for electrical energy.
[0005] Some HFCs are known to be exceptional refrigerants,
including, but not limited to, difluoromethane (R-32),
1,1,1,2,2-pentafluoroethane (R-125), 1,1,1-trifluoroethane
(R-143a), 1,1,1,2-tetrafluoroethane (R-134a), and
1,1-difluoroethane (R-152a). Certain blends of two or more of these
HFCs can also be used to achieve particular thermodynamic
properties. Common HFC blends include an azeotrope-like blend of
R-143a and R-125 (known as R-507A), a non-azeotropic blend of
R-125, R-143a, and R-134a (known as R-404A), a non-azeotropic blend
of R-32 and R-125 (known as R-410A), and a non-azeotropic blend of
R-32, R-125, and R-134a (known as R-407C). These alternative
refrigerants are available commercially from various sources
including Honeywell, DuPont, Atochem and ICI.
[0006] Each of these HFCs or HFC blends can serve as a replacement
for one or more CFCs or HCFCs. For example, R-134a can serve as
replacement of R-12 in refrigeration and air conditioning
applications such as chillers; R-404A and R-507A can serve as
replacements for R-502 in most refrigeration applications,
including high, medium and low evaporation temperature systems;
R410A can serve as replacement of R-22 in new air conditioning and
refrigeration equipment: and R-407C can serve as a replacement for
R-22 in various air-conditioning applications, as well as in most
refrigeration systems including chillers. The use of
chlorine-containing refrigerants, such as chlorofluorocarbons
(CFC's), hydrochlorofluorocarbons (HCFC'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 refrigerants that will not deplete the
ozone layer, such as hydrofluorocarbons (HFC's). In order for
replacement materials to be useful in connection with refrigeration
compositions, the materials must be compatible with a lubricant
utilized in the compressor.
[0007] However, widespread commercial use of these and other HFC
refrigerants has been hindered by the lack of commercially adequate
lubricants. Refrigeration system designers are interested in how
the lubricant behaves in the system so that they can design piping
and other components to best manage lubricant return to the
compressor. The behavior of a refrigerant on a lubricant entering
the system can affect film characteristics on heat transfer
surfaces, and thus energy efficiency performance. Generally, the
first property considered is miscibility of the lubricant with the
liquid refrigerant. 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 mineral oils. In order for a
refrigeration fluid-mineral oil combination to work efficiently
within a compression refrigeration, air-conditioning or heat pump
system, the mineral oil must be sufficiently soluble in the
refrigeration liquid over a wide range of operating temperatures.
Such solubility lowers the viscosity of the mineral oil and allows
it to flow more easily throughout the system. In the absence of
such solubility, mineral oils 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. 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.
[0008] The HFC refrigerants that are replacing HCFC refrigerants
have a different influence on lubricants, which affects both
compressor durability and system performance. Specifically, mineral
oil or alkyl benzenes, which have been used with conventional
refrigerants such as R-12, R-502 and R-22, are immiscible with HFCs
and must therefore be replaced with polyol ester (POE) or other
synthetic lubricants. However, majordevelopment considerations for
the synthetic lubricants remain, including miscibility, solubility,
stability, electrical properties, lubricity and retrofitting
requirements.
[0009] Since HFC are generally immiscible in conventional
lubricants, retrofitting refrigeration or air conditioning systems
with HFC refrigerants typically requires the drainage of as much of
the lubricant oil as possible before introducing the new
refrigerants with synthetic lubricants. This process often involves
removing the compressor from the system so that the lubricant can
be adequately drained. For these and other reasons, it would be
highly desirable to retrofit a CFC or HCFC system with HFC without
having to remove the system's lubricant. By not needing to replace
the existent oil, such a retrofit would become a simple "drop-in"
operation. That is, the existent refrigerant would be replaced with
a new refrigerant without any further change in, or disassembly of,
the system hardware.
[0010] U.S. Pat. No. 5,611,210 teaches fluoroiodocarbon blends with
an additive selected from the group consisting of: alcohols,
esters, ethers, fluoroethers, hydrocarbons, hydrofluorocarbons, and
perfluorocarbons with boiling points between -150.degree. C. and
+2000.degree. C. U.S. Pat. No. 7,208,098 discloses a lubricating
composition for compression refrigeration containing a blend of a
polyol ester and an alkylbenzene, however, CF3I is not taught. U.S.
patent application 20050233934 teaches azeotrope-like compositions
comprising tetrafluoropropene and trifluoroiodomethane and uses
thereof, including use in refrigerant compositions, and
refrigeration systems. U.S. 2006/0116310A1, U.S. Pat. No. 7,083,743
and WO 94/20588 show combinations of halocarbons and
fluoroiodocarbons. US2003/0062508A1, U.S. Pat. No. 2,004,006, U.S.
Pat. No. 2,005,015 and U.S. Pat. No. 6,428,720 show combinations of
halocarbons and hydrocarbons.
[0011] Accordingly, there exists a need and an opportunity to
resolve this solubility problem so that the refrigeration industry
may retrofit systems without costly and time-consuming flushing to
entirely remove conventional lubricants. Applicants have discovered
that the miscibility of HFCs in conventional lubricants can be
greatly increased by blending the HFCs with CF3I
(trifluoroiodomethane) and hydrocarbons (HC). It has been
unexpectedly found that HFCs blended with CF3I and HCs are
generally more miscible in common lubricant oils than blends of
HFCs alone. By utilizing such HFC/CF3I/HC blends, CFC or HCFC
systems can be retrofitted without having to drain or replace the
system's lubricants. In addition, it has been found that certain
blends of HFCs, CF3I and HCs generally retain the thermodynamic
properties that are important for refrigerants.
DESCRIPTION OF THE INVENTION
[0012] The invention provides a composition comprising (a) from
about 40 weight percent to about 99.8 weight percent of at least
one C1-C5 hydrofluorocarbon; (b) from about 0.1 weight percent to
about 50 weight percent of CF3I; and (c) from about 0.1 weight
percent to about 10 weight percent of at least one C1-C6
hydrocarbon.
[0013] The invention further provides a method of recharging a
refrigeration system comprising the steps of (a) providing a
refrigeration system from which a chlorine-containing refrigerant
has been substantially removed; and (b) introducing a composition
comprising (a) from about 40 weight percent to about 99.8 weight
percent of at least one C1-C5 hydrofluorocarbon; (b) from about 0.1
weight percent to about 50 weight percent of CF3I; and (c) from
about 0.1 weight percent to about 10 weight percent of at least one
C1-C6 hydrocarbon into the system.
[0014] The invention also provides a method of recharging a
refrigeration system comprising the steps of (a) providing a
refrigeration system having at least one chlorine-containing
refrigerant and at least one lubricant; substantially removing said
chlorine-containing refrigerants while substantially retaining said
lubricant; and (c) introducing a composition comprising (a) from
about 40 weight percent to about 99.8 weight percent of at least
one C1-C5 hydrofluorocarbon; (b) from about 0.1 weight percent to
about 50 weight percent of CF3I; and (c) from about 0.1 weight
percent to about 10 weight percent of at least one C1-C6
hydrocarbon into the system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a plot of data from Example 1.
[0016] FIG. 2 is a representation of a typical commercial
refrigeration system.
[0017] FIG. 3 illustrates an immiscible refrigerant/oil combination
behavior in the liquid receiver.
[0018] The present invention is directed to compositions comprising
a hydrofluorocarbon, a hydrocarbon, and CF3I as a solubilizing
agent, and the use of these compositions in applications such as
the recharging of refrigeration systems. The compositions of the
present invention may also be utilized as aerosol propellants, heat
transfer media, gaseous dielectrics, fire-extinguishing agents,
foam blowing agents, solvents, as well as in numerous other
applications. As used herein, the term "solubilizing agent" refers
to a substance that increases the solubility of one or more
hydrofluorocarbons, one or more hydrocarbons, and one or more
lubricants. In certain preferred embodiments of the invention,
compositions are provided that comprise at least one HFC, at least
one HC and an effective amount of CF3I as a solubilizing agent. As
used herein, the term "effective amount" with respect to
solubilizing agents refers to an amount of the CF3I solubilizing
agent effective to dissolve a sufficient amount of the HFC and HC
in a lubricant such that the diluted lubricant can be transported
through the system back to a compressor.
[0019] The least one C1-C5 hydrofluorocarbon component comprises
from about 40 weight percent to about 99.8 weight percent,
preferably from about 72 weight percent to about 99.8 weight
percent, and more preferably from about 85 weight percent to about
99.8 weight percent based on the weight of the overall composition.
The CF3I component comprises from about 0.1 weight percent to about
50 weight percent, preferably from about 0.1 weight percent to
about 20 weight percent, and more preferably from about 0.1 weight
percent to about 10 weight percent based on the weight of the
overall composition. The at least one C1-C6 hydrocarbon component
comprises from about 0.1
[0020] weight percent to about 10 weight percent, preferably from
about 0.1 weight percent to about 8 weight percent, and more
preferably from about 0.1 weight percent to about 5 weight percent
based on the weight of the overall composition.
[0021] Preferred HFCs for use with the present invention include,
but are not limited to, C1-C5 hydrofluorocarbons and blends
thereof. These include difluoromethane (R-32);
1,1,1,2,2-pentafluoroethane (HFC-125); 1,1,1-trifluoroethane
(R-143A); 1,1,1,2-tetrafluoroethane (R134A); 1,1-difluoroethane
(R-152A); and combinations thereof. Useful blends are commercially
available as R-404A which is a blend of 1,1-difluoroethane
(R-152A), 1,1,1,2-tetrafluoroethane (R134A) and
1,1,1-trifluoroethane (R-143A); R-507A which is a blend of
1,1,1,2-tetrafluoroethane (R134A) and 1,1,1,2,2-pentafluoroethane
(HFC-125); R410A which is a blend of difluoromethane (R-32) and
1,1,1,2,2-pentafluoroethane (HFC-125); R-407C which is a blend of
1,1,1,2-tetrafluoroethane (R134A), 1,1,1,2,2-pentafluoroethane
(HFC-125) and difluoromethane (R-32); R-407A which is a blend of
difluoromethane (R-32), pentafluoroethane (HFC-125) and
1,1,1,2-tetrafluoroethane (R134A); and combinations thereof.
[0022] Useful hydrocarbons include wherein the at least one C1-C6
hydrocarbon comprises methane, ethane, propane, propene, propyne,
cyclopropane, 2,2-dimethylpropane, butane, isobutane,
2-methylbutane, pentane, isopentane, 3-methylpentane, hexane,
cyclohexane, isohexane, and combinations thereof.
[0023] The composition of the present invention are particularly
miscible in lubricating oils such as mineral oil, hydrocarbon oil,
alkyl oil, alkyl benzene oil, white or paraffinic oil, and mixtures
thereof. Useful mineral oils include paraffins (i.e. straight-chain
and branched-carbon-chain, saturated hydrocarbons), naphthenes
(i.e. cyclic paraffins) and aromatics (i.e. unsaturated, cyclic
hydrocarbons containing one or more rings characterized by
alternating double bonds). The mineral oils useful for the present
invention include those commonly known as "synthetic oils" in the
field of compression refrigeration lubrication. Synthetic oils
comprise alkylaryls (i.e. linear and branched alkyl alkylbenzenes),
synthetic paraffins and napthenes, and poly(alphaolefins).
Commercially available mineral oils include Witco LP 250 from
Witco, Zerol 300 from Shrieve Chemical, Sunisco 3GS from Witco, and
Calumet R015 from Calumet. Other useful mineral oils are
commercially available as BVM 100 N (paraffinic mineral oil sold by
BVA Oils), Suniso.RTM. 3GS (napthenic mineral oil sold by Crompton
Co.), Sontex.RTM. 372LT (napthenic mineral oil sold by Pennzoil),
Calumet.RTM. RO-30 (napthenic mineral oil sold by Calument
Lubricants), Zerol.RTM. 75 and Zerol.RTM. 150 (linear alkylbenzenes
sold by Shrieve Chemicals) and HAB 22 (branched alkylbenzene sold
by Nippon Oil). The chemical compositions and uses of these oils
are well known (see e.g. "Fluorocarbon Refrigerants Handbook" by
Ralph C. Downing, Prentice Hall, 1998, pp. 206-270).
[0024] For systems utilizing an HFC and a lubricant, the lubricant
and/or HFC may be added to the system as a mixture, provided that
the HFC and lubricant are miscible with each other. Therefore,
according to certain embodiments of the present invention,
compositions are provided comprising an HFC/CF3I/HC blend and at
least one lubricant, wherein said lubricant is present in an amount
of from about 0.1 to about 99.9 weight percent, and preferably from
about 0.2 to about 90 weight percent, based on the total weight of
the composition. The compositions of the present invention may
further include any of a variety of optional additives including
other lubricants, stabilizers, metal passivators, corrosion
inhibitors, flammability suppressants, and the like.
Examples
[0025] The following non-limiting examples serve to illustrate the
invention examples.
Example 1: Performance
[0026] This example demonstrates the thermodynamic properties of a
HFC/CF3I blend. Testing was performed in a refrigeration machine
under typical operating conditions using a refrigerant test mixture
and mineral oil (Nu-Calgon C-3 Refrigeration Oil). The test mixture
composition was 89 wt. % of HFC (R404A) and 11 wt. % of CF3I.
Testing was performed using a setup similar to the unit described
in Report DOE/CE/23810-71 "Study of Lubricant Circulation in HVAC
Systems," March 1995-April 1996 by Frank R Biancardi et. al.
(prepared for Air Conditioning and Refrigeration Technology
Institute Under ARTI/MCLR Project No. 665-53100), which is
incorporated herein by reference. In this case, a commercial
refrigeration system equipment was employed using a commercially
available condensing unit and an evaporator for a walk-in
freezer/cooler. The following is a detailed description of the
equipment:
[0027] The condensing unit was as manufactured by Keeprite
Refrigeration, Brantford, Ontario Model K350L2 outdoor, air cooled,
low temperature, R-22 condensing unit equipped with a 2DF-0300
Copeland compressor, a fin-and-tube coil, and a demand cooling
system for low temperature operation. It also has a suction
accumulator, an oil separator, a receiver, a two-valve head
pressure control system, and other standard operating controls. The
evaporator was as manufactured by Keeprite Refrigeration. A Model
KUCB204DED electric defrost, low profile DX fed evaporator with
electric defrost heaters and a Sporlan distributor and TXV.
Capacity was rated as 17,340 BTUH @-20.degree. F. SST, 10 degree
TD, and 3,200 CFM air flow. The evaporator was installed in an
environmentally controlled chamber that served as the walk-in
freezer/cooler. The condenser unit was installed in another chamber
to control temperature. Instrumentation was added to the system to
measure refrigerant mass flow rate, refrigerant pressure and
temperature before and after each component, air temperature and
flow in/out of evaporator and condenser, and power to condensing
unit and evaporator. Tests were run at two typical freezer
temperatures (0.degree. F.), and a range of ambient temperatures
from 55.degree. F. to 95.degree. F. It should be noted that the
refrigerant temperatures were typically 15.degree. F. to 20.degree.
F. lower than the chamber temperatures. Table 1 shows performance
results compared to R-22. R404A shows slightly higher capacity (Q)
and lower efficiency (COP) as compared to R-22, but these values
are expected due to their inherent thermodynamic properties. It is
also showed a blend composed of 89% R404A and 11% of CF3I by
weight. For this case, both capacity and COP do not change
significantly respect of pure R404A. Therefore, addition of CF3I
does not affect the system performance of an HFC-type fluid.
TABLE-US-00001 TABLE 1 Test Results (Box temperature of 0.degree.
F.) Outdoor R22 R404A R404A/CF3I Temperature Q COP Q COP Q COP
(.degree. F.) Tons -- BTU/h Rel -- Rel BTU/h Rel -- Rel 55 1.56
1.41 19791.7 105% 1.374 97% 19747. 105% 1.40 99% 75 1.49 1.37
18767.2 105% 1.288 94% 17996. 100% 1.25 91% 95 1.37 1.18 16308 100%
1.047 89% 15619. 95% 1.02 86%
Example 2: "Oil Pump-Out" Tests
[0028] This example demonstrates that an HFC/CF.sub.3I blend has
better oil return properties in a refrigeration system as compared
to R-404A without CF.sub.3I. These tests utilized the same
equipment as described in Example 1, with the following
modifications: The oil separator located at the discharge of the
compressor was by-passed, so the compressor oil level reflects
actual oil movement to and from the system. The suction line was
properly sized for this unit (11/8'').
[0029] An oil level was added to the compressor, so oil migration
from and to the compressor could be tracked. A high-pressure piston
pump was used to inject oil extracted from the compressor sump into
the compressor discharge line. This gave us the ability to simulate
oil pump out conditions as described in Biancardi's report. These
tests consisted in injecting 375 cc of oil, previously extracted
from the compressor pump, and observing the oil level. This type of
test is known as a "pump-out" test and simulates oil leaving the
compressor during the startup of a system, as described in
Biancardi's report above. For reference, oil return tests were
performed using refrigerant (R-22) and mineral oil which is a
refrigerant/oil combination commonly found in the industry. Oil
return was considered satisfactory when the oil level showed a
recovery similar to the one recorded for R22. By recovering this
amount, the compressor had enough oil to satisfy its lubrication
needs and, thus, to extend compressor reliability. By observing the
oil level in the compressor sump versus time (see plots of actual
data in FIG. 1), it was observed that the final oil level with the
test mixture is almost identical to the one obtained with R22, and
significantly better than the one obtained with pure R-404A. This
figure shows the oil level recorded with R404A never recovers. This
example demonstrates that with the test mixture, the oil return in
the system is enhanced over R-404A, the leading R-22 alternate
refrigerant, without any significant effect on Capacity or COP (as
showed in Table 1).
Example 3: Miscibility in a Liquid Receiver
[0030] FIG. 2 shows a typical commercial refrigeration system,
which has suction accumulator and a liquid receiver after the
condenser. Also shown in FIG. 3 is an immiscible refrigerant/oil
combination behavior in the liquid receiver where a layer of oil
would form on top of the liquid refrigerant due to its lower
density. A test was developed to test solubilizing additives with
two types of oils: mineral and alkylbenzenic. A liquid receiver was
charged with approximately 3200 g of an HFC blend (R407C) and 39 g
of oil. This blend as formulated is immiscible with oil floating on
top of the liquid refrigerant as shown in FIG. 2. Next, a
solubilizing additive was added until a single-phase was obtained.
Table 2 shows the results obtained for two oils (MO and AB) and two
additives (CF3I and isobutane). It is demonstrated that 48.3% of
CF3I is needed to dissolve the mineral oil, and 38.3% is needed
when AB oil is used.
TABLE-US-00002 TABLE 2 Miscibility Tests with a Liquid Receiver
TEST HFC CF3I OIL AMOUNT HFC/CF3I with mineral oil 51.70% 48.30%
0.63% HFC/CF3I with alkylbenzene oil 61.70% 38.30% 0.69%
Example 4: System Test with HFC/CF3I/HC Blends
[0031] This example demonstrates that an HFC/CF3I/HC blend has
better oil return properties in the liquid receiver of a
refrigeration system as compared to a pure HFC. The intent of this
experiment is to take advantage of the good miscibility of
hydrocarbons but limiting the flammability of the resulting blend
by using CF3I as both flammability suppressant and solubilizing
additive. These tests used the same equipment as described in
Example 1, with the following modifications: Two high-efficiency
coalescent oil separators were added at the discharge of the
compressor, so the stream after them was oil-free (below 50 ppm). A
continuous oil injection system was designed to extract oil from
the compressor sump and inject it at the inlet of the condenser,
after the oil separators and before the liquid receiver (FIG. 3).
This system comprises a high pressure oil pump, a metering valve
and a mass flow meter, so we could impose a desired Oil Circulation
Ratio (OCR), which is a relation by mass between oil and the total
mass flow (refrigerant plus oil). Two sight glasses were added to
the horizontal liquid receiver, so one can visually observe any oil
accumulating or dissolving in the refrigerant. Oil circulation at
the inlet of the liquid receiver was measured directly using the
system and oil flow meters shown in FIG. 3. The OCR at the outlet
of the receiver was measured using an oil separator at the outlet
of the evaporator, which sends the vapor back to the system and the
oil to flow meter. Verification measurements were done by sampling
before and after the liquid receiver to measure directly the amount
of oil passing through. These tests consisted of imposing an OCR of
0.40% (oil by mass) at the inlet of the liquid receiver and
measuring it after. Table 3 shows results for two blends, which
contain a constant fraction of isobutane (5% by mass) and two
different contents of CF3I. The first blend containing 5% of CF3I
and 5% of isobutane did not dissolve enough oil in the refrigerant
as showed by the lower OCR at the outlet and a visual inspection
through the sight glass (oil layer on top of the refrigerant). The
second blend containing 18% of CF3I and 5% of isobutane was
successful in both mass balance and visual inspection (oil
completely dissolved in the refrigerant).
TABLE-US-00003 TABLE 3 OCR % Blends Inlet Outlet 90% HFC, 5% CF3I,
5% isobutane 0.40% 0.38% 77% HFC, 18% CF3I, 5% isobutane 0.40%
0.40%
[0032] Having thus described a few particular embodiments of the
invention, various alterations, modifications, and improvements
will readily occur to those skilled in the art. Such alterations,
modifications, and improvements, as are made obvious by this
disclosure, are intended to be part of this description though not
expressly stated herein, and are intended to be within the spirit
and scope of the invention. Accordingly, the foregoing description
is by way of example only, and not limiting. The invention is
limited only as defined in the following claims and equivalents
thereto.
* * * * *