JPH0959612A - Mixed working fluid containing trifluoroiodomethane and refrigeration cycle equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mixed working fluid substantially nondepletive to the ozonosphere, substantially free from an action of global warming, difficultly combustible and capable of being used as it is in a conventional refrigeration cycle equipment. SOLUTION: This mixed working fluid comprises 15-80wt.% trifluoroiodomethane, at least either of 20-55wt.% difluoromethane and 65wt.% or below 1,1-difluroethane and a radical chain inhibitor.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mixed working fluid containing trifluoroiodomethane, combustible fluorinated hydrocarbons and a radical chain inhibitor, and a refrigeration cycle for air conditioners, refrigerators, refrigerators and the like using the same. Regarding the device.

[0002]

2. Description of the Related Art Conventionally, a refrigeration cycle apparatus such as an air conditioner, a refrigerator, a refrigerator, etc. has a compressor, a four-way valve, a condenser, a throttle device such as a capillary tube and an expansion valve, an evaporator, an accumulator, etc., if necessary. By connecting and circulating a refrigerant in the inside, cooling or heating is performed. In these refrigeration cycle apparatuses, halogenated hydrocarbons derived from methane or ethane, which are called fluorocarbons (hereinafter referred to as R ○○ or R ○○○), are known as refrigerants.

In air conditioners, refrigerators, etc., the condensing temperature is usually about 50 ° C. and the evaporating temperature is about 0 ° C. Among them, chlorodifluoromethane (CHClF ₂ , R22, boiling point -40.8 ° C) is an air conditioner,
It has been widely used as a refrigerant for refrigerators, refrigerators, etc., but in recent years, the depletion of CFCs due to CFCs has become a global environmental problem, and since it has the ozone depletion potential for stratosphere, it has already been used and produced by the Montreal International Convention. The amount regulation has been decided, and in the future its use /
There is a move to abolish production. In order to have almost no effect on the stratospheric ozone layer, it is required that chlorine is not contained in the molecular structure, and as a possibility, chlorine-free fluorohydrocarbons are alternative refrigerants. Is proposed as.

[0004]

However, the refrigerants of fluorohydrocarbons have the same global warming potential (hereinafter referred to as GWP), which shows the effect on global warming, which is another environmental problem, as much as R22. It is said that there is an influence of.
1994 IPCC (Intergovermental Panelon Cli
mate Change, Climate Change Intergovernmental Panel)
When the GWP of carbon dioxide (CO ₂ ) is set to 1, the comparison value for 100 years on the horizontal axis at the time of integration is that G22 of R22 is 1700,
Among fluorohydrocarbons not containing chlorine, GWP of difluoromethane (CH ₂ F ₂ , R32, boiling point −52 ° C.) is 58.
0, GWP of pentafluoroethane (CF ₃ -CHF _2, R125, boiling point -48 ° C.) is GWP of 3200,1,1,1- trifluoroethane (CF ₃ -CH _3, R143a, boiling point -48 ° C.) is 4400,1,1,1,2- tetrafluoroethane GWP of _{(CF 3 -CH 2 F, R134a} , boiling point -27 ° C.)
Is 1300, 1,1-difluoroethane (CHF ₂ —CH ₃ , R
GWP of 152a, boiling point -25 ° C) is 140. Here, R32 and R152a have a relatively small GWP and can be greatly improved as compared with R22, but they have flammability, and to use them as refrigerants, in a refrigeration cycle device such as an air conditioner, a refrigerator, a refrigerator, etc. In some cases, explosion-proof measures are necessary, and if such measures are taken, the equipment cost becomes excessive and the usability becomes poor.

The present invention has been tested in view of the above-mentioned problems, and has almost no effect on the stratospheric ozone layer, and may have a small effect on global warming.
The present invention provides an alternative working fluid of No. 2, and in the present invention, a mixed working fluid containing chlorine-free trifluoroiodomethane and a combustible but small GWP fluorohydrocarbon and a radical chain inhibitor is provided. It is a proposal.

[0006]

[Means for Solving the Problems] Here, trifluoroiodomethane (CF ₃ I, boiling point −22.7 ° C.), which is also called as iodotrifluoromethane or trifluoromethyl iodide, is referred to as 1 carbon atom and 3 It has almost no ozone depletion ability because it is composed of only fluorine atoms and 1 iodine atoms and does not contain chlorine in its molecular structure. The GWP of trifluoroiodomethane is considerably smaller than that of fluorohydrocarbons and almost equal to carbon dioxide (CO ₂ ). Moreover, trifluoroiodomethane has been attracting attention as a nonflammable substance having a negative catalytic effect, and can reduce the flammability of fluorohydrocarbons and make them nonflammable depending on the amount mixed.

Therefore, trifluoroiodomethane is mixed with difluoromethane (R32) and 1,1-difluoroethane (R152a) and the composition range is specified to form a mixture having a boiling point equivalent to that of R22.
In addition, by making it incombustible, it can be used as an alternative refrigerant for R22. Also, trifluoroiodomethane is only difluoromethane (R32),
It is mixed with 1,1-difluoroethane (R152a) only, and made incombustible by specifying the composition range.
It can be used as an alternative refrigerant. Further, this refrigerant can contribute to the stabilization of trifluoroiodomethane by including a radical chain inhibitor.

Therefore, the present invention is a mixed working fluid containing trifluoroiodomethane containing no chlorine and fluorohydrocarbons which are combustible but have a small GWP, and the fluorohydrocarbons are difluoromethane (R32). Or 1,1-difluoroethane (R152a), or both.

The present invention also stabilizes trifluoroiodomethane by including a radical chain inhibitor.

Further, the composition range of trifluoroiodomethane is specified so as to be flame retarded as a mixture.

Further, the present invention specifies the composition range of the mixture of trifluoroiodomethane and fluorohydrocarbons so that the vapor pressure of the mixture becomes substantially equal to R22.

Further, the present invention is a refrigeration cycle apparatus using these mixed working fluids.

Further, according to the present invention, an accumulator in a refrigerating cycle such as an air conditioner using these mixed working fluids is arranged outside the room.

The present invention provides a combination of the above-mentioned refrigerants as a refrigerant and chlorine-free trifluoroiodomethane and ODP.
It is possible to make almost no influence on the stratospheric ozone layer by using a mixture of fluorocarbons having a value of 0, and the ODP in the specified composition range is also expected to be 0. is there.

Furthermore, such a mixture is considerably smaller than the GWP of fluorohydrocarbons, and almost no carbon dioxide (C
O ₂ ), which may have the same level as trifluoroiodomethane, and difluoromethane (R
32) and 1,1-difluoroethane (R152a), or a mixture of both, so that a refrigerant obtained by mixing them has almost no effect on global warming.

Further, the present invention is stabilized by adding a radical chain inhibitor. In other words, trifluoroiodomethane may decompose due to the release of iodine due to the incorporation of active molecules such as oxygen, but the trifluoromethane radical generated at that time and the chain decomposition reaction by the iodine radical or ion may occur. By stopping, it can be stably used for a long period of time.

Further, since trifluoroiodomethane is a nonflammable substance having a negative catalytic effect, difluoromethane (R32) or 1,1-difluoroethane (R152a) is used.
By further limiting the composition range of the mixture with and to the flame retardant range, it can be used in a normal refrigeration cycle apparatus.

Further, according to the present invention, when R32, which has a lower boiling point than R22, and R152a, which has a higher boiling point than R22, and trifluoroiodomethane are mixed, the refrigeration cycle of an air conditioner or the like is specified by specifying the composition range. It has the same vapor pressure as R22 at the operating temperature of the equipment of about 0 to about 50 ° C, and it can be expected to have the same refrigerating capacity as R22. It is possible to provide a possible refrigerant.

The present invention also relates to R which has a lower boiling point than R22.
When 32 and only trifluoroiodomethane having a higher boiling point than R22 are mixed, the boiling point is lower than R22,
The operating temperature of a refrigeration cycle device such as an air conditioner is approximately 0
At about 50 ° C, although it has a partially higher vapor pressure than R22, it has the same refrigeration capacity and coefficient of performance, so R2
This makes it possible to provide a refrigerant that can be used even in the current equipment using No.2.

The present invention also relates to R which has a higher boiling point than R22.
When only 152a and trifluoroiodomethane are mixed, the boiling point is higher than that of R22, and the temperature is about 0 to about 50 ° C., which is the use temperature of a refrigeration cycle device such as an air conditioner.
Although it has a lower vapor pressure than R22 and is inferior in refrigerating capacity, it has a coefficient of performance equal to or higher than that of R22, so that it is possible to provide a refrigerant that can be used in existing equipment using R22 or R134a.

Further, the mixed refrigerant has a boiling point difference of about 30.
Since it is a mixture of difluoromethane (R32), 1,1-difluoroethane (R152a), and trifluoroiodomethane within deg, it becomes a near-azeotropic non-azeotropic mixture, and a small temperature gradient is generated in the condensation process and the evaporation process. Therefore, by constructing a Lorentz cycle in which the temperature difference with a heat source fluid such as air is close, a refrigeration cycle apparatus having a higher coefficient of performance (COP) than R22, which should be substituted, can be constructed.

Further, according to the present invention, since the accumulator of the refrigerating cycle such as the air conditioner is arranged on the outdoor side, the composition separation of the gas phase and the liquid phase occurs in the accumulator,
The concentration of flammable R32 and R152a increases, and even if it leaks from the device, it is released into the atmosphere, and the danger of explosion can be avoided.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The mixed working fluid of the present invention comprises trifluoroiodomethane and difluoromethane (R32) or 1,1.
-Contains a refrigerant containing either or both of difluoroethane (R152a).

Further, the mixed refrigerant described above is stabilized by adding a radical chain inhibitor. In other words, trifluoroiodomethane may decompose due to the release of iodine due to the incorporation of active molecules such as oxygen, but the trifluoromethane radical generated at that time and the chain decomposition reaction by the iodine radical or ion may occur. By stopping, it can be stably used for a long period of time. Specifically, compounds having a hindered phenol structure, an arylamine structure, a hindered piperidine structure, a thioether structure, and a phosphite structure can be used alone or in combination. For example, as the hindered phenol structure, 2,6-ditertiary butyl-4-methylphenol, 2,4,6-tritertiary butylphenol, alkylphenol such as styrenated phenol or a derivative having the structure, 2, 2'-methylenebis (4-methyl-6-tert-butylphenol),
4,4'-isopropylidene-bisphenol, 4,
Monoalkylenedialkylphenols such as 4′-butylidene-bis (6-tert-butyl-3-methyl) phenol, 1,1-bis- (4-oxyphenyl) cyclohexane and derivatives having the structure, 2,6-bis ( 2'-hydroxy-3'-tert-butyl-5'-
Dialkylenetrialkylphenols such as methylbenzyl) -4-methylphenol and its derivatives, 2,2 ′
Typical examples include bisphenol monosulfide such as -thiobis- (4-methyl-6-tert-butylphenol), 4,4'-thiobis- (3-methyl-6-tertialbutylphenol) and derivatives having the structure. Can be given as. As the arylamine structure,
Phenyl-α-naphthylamine, phenyl-β-naphthylamine, N, N′-diphenyl-p-phenylenediamine, N, N′-di-β-naphthyl-p-phenylenediamine, N-cyclohexyl-N′-phenyl-p -Phenylenediamine, p-hydroxy-diphenylamine, p-hydroxyphenyl-β-naphthylamine,
Examples include 2,2,4-trimethyl-1,2-dihydroquinoline and derivatives. Further, as thioethers, thiobis (β-naphthol), mercaptobenzothiazole, mercaptobenzimidazole, dodecyl mercaptan, etc. and derivatives, and as phosphites, triphenylphosphite, tri-2-ethylhexylphosphite, trinonylphenylphosphite, etc. The organic phosphite compound and the like are used.

Besides these compounds, compounds used for the purpose of radical chain inhibitors can be used. They are,
They may be used singly or in a mixture of two or more, and the amount may be about several wt% with respect to the lubricating oil to be used, and depending on the selection of the compound, 1 wt% or less may provide a sufficient effect. The criteria for selection are those having good compatibility or good solubility in lubricating oils, such as compounds having a hindered phenol structure such as 2,6-di-tert-butyl-4-methylphenol, or compounds containing these compounds and triphenylphosphine. Combinations with organic phosphite compounds such as fight were suitable.

Here, difluoromethane (R32) and 1,
1-Difluoroethane (R152a) is a combustible substance, and according to the cited document, “Reduction of Freon Refrigerant Emissions and Alternative Technology” edited by the Japan Refrigeration Association (March 1, 1994), page 81, R32 in air Combustion range of 13.3 to 29.3
vol%, the combustion range of R152a is 3.7 to 21.8v
ol%. The combustion range of the mixed refrigerant in the case of mixing an ordinary inert gas with this combustible substance is calculated by the method described on page 79 of the same document, and conversely, the composition of the inert gas for making the mixed refrigerant incombustible. Percentages are also calculated. The composition range where the combustion range disappears is calculated as a composition ratio in which the lower combustion limit and the upper combustion limit match. That is, when a normal inert gas is mixed with R32, the composition ratio of the inert gas is approximately 94% by weight or more, and when mixed with R152a, the composition ratio of the inert gas is approximately 98% by weight or more. It can be seen that the mixed refrigerant can be made incombustible. However, when it is considered as a normal inert gas as described above, about 95% by weight or more is required. However, when trifluoroiodomethane is used, it has a strong negative catalytic action on combustion by iodine and fluorine, especially iodine. Therefore, the incombustibility effect can be obtained from approximately 10% by weight to 20% by weight or more.

The flammability test was carried out as follows as a simple burning test method.

First, as the first method, the volume is 75.6 m.
1 test tube or graduated cylinder of 325 ml in volume is used, the opening is installed at the bottom, the container is filled with a mixed gas of a predetermined concentration and sufficiently diffused, and then the opening is matched immediately after opening. Ignited by The combustion was determined by determining the combustion concentration when the flame reached the entire container from the lower opening, that is, the upper part of the container. By this method, a mixed gas composition having no combustion concentration was made nonflammable. As a verification of this method, when the combustion range of a single combustible gas was measured, the lower limit was ± 0.1 vol% and the upper limit was ± 0.4 vo
The experiment was performed after confirming that the agreement was within the range of 1%.

As a second method, the same container is installed with the opening on the top, the mixed gas of a predetermined concentration is filled in the container and sufficiently diffused, and then the opening is matched by a match immediately after opening. I ignited. The combustion was determined by determining the combustion concentration when the flame reached the entire container from the upper opening, that is, the lower part of the container. By this method, a mixed gas composition having no combustion concentration was made flame-retardant.

Non-flammable trifluoroiodomethane and flammable difluoromethane (R32), 1,1-difluoroethane (R152a), difluoromethane (R32)
When a mixed gas of 1,1-difluoroethane (R152a) was mixed, the concentration of trifluoroiodomethane was increased to approximately 2.5 vol by increasing the mixing amount of trifluoroiodomethane in any flammable gas. %, That is, approximately 7 to 9% by weight, becomes flame retardant, and approximately 5 vol%,
That is, it was found that the composition became nonflammable from about 14 to 17% by weight. The reason why trifluoroiodomethane can obtain the incombustibility effect from such a low mixture concentration is that the negative catalytic effect on the combustion of iodine or fluorine in the molecule works as described above.

Next, trifluoroiodomethane and difluoromethane (R32) or 1,1-difluoroethane (R
Examples of the composition range specified so that the vapor pressure of the mixed refrigerant containing one or both of 152a) is approximately equal to R22 will be described with reference to the vapor pressure diagram.

FIG. 1 shows difluoromethane (CH ₂ F ₂ , R 3
2, boiling point -52 ° C), 1,1-difluoroethane (CHF ₂
-CH _3, R152a, boiling point -25 ° C.), trifluoroiodomethane (CF ₃ I, the DPT refrigerant constituted by a mixture of the boiling point -22.7 ℃), triangular equilibrium at a constant temperature and constant pressure It is shown using coordinates. In the triangular coordinates, a single substance is arranged at each vertex of the triangle in the order of lower boiling point in a counterclockwise direction from the upper vertex as a base point, and the composition ratio (weight ratio) of each component at a certain point on the coordinate plane Is represented by the ratio of the distance between the point and each side of the triangle. At this time, the distance between the point and the side of the triangle corresponds to the composition ratio of the substance described at the vertex of the triangular coordinates on the side opposite to the side.

In FIG. 1, 1L and 1V are temperatures of 0 ° C.
It is a vapor-liquid equilibrium line of the mixture at a pressure of 0.498 MPa, and this temperature / pressure corresponds to a saturated state of R22 at a temperature of 0 ° C. Upper vapor-liquid equilibrium line (equivalent to R220 ° C)
1 V represents a saturated vapor phase line, and the lower gas-liquid equilibrium line (corresponding to R220 of 0 ° C.) 1 L represents a saturated liquid phase line, and a vapor-liquid equilibrium state is established in a range sandwiched by these lines. 2L and 2V are
It is a vapor-liquid equilibrium line of the saturated liquidus line 2L and the saturated vapor phase line 2V of the mixture at a temperature of 50 ° C and a pressure of 1.943 MPa, and this temperature / pressure also corresponds to the saturated state of R22 at a temperature of 50 ° C.

The points in FIG. 1 correspond to the gas phase composition (subscript V) and the liquid phase composition (subscript L) in the composition pairs A to E of the mixed refrigerant shown in (Table 1).

[0036]

[Table 1]

Point A_L~ Point C_LIs the vapor-liquid equilibrium line (R220 ° C
Equivalent) 1 A on the saturated liquidus line 1 L, point A _V~ Point C_VIs vapor-liquid equilibrium
Line D (corresponding to R220 0 ° C) 1 on saturated vapor line 1V, point D_L
~ E_LIs a saturated liquid of gas-liquid equilibrium line (R22 50 ° C equivalent) 2
Point D on phase line 2L_V~ E_VIs the vapor-liquid equilibrium line (R22 50 ° C
Equivalent) 2 on the saturated vapor line 2V. Gas-liquid equilibrium line (R2
Saturated liquidus line 1L of 1) and vapor-liquid equilibrium line (R
2 2L equivalent to the saturated liquidus line 2L of 2
Gas-liquid equilibrium line (equivalent to R220 ° C) 1 saturated vapor phase line 1V
Is the vapor-liquid equilibrium line (R22 equivalent to 50 ° C) 2 saturated vapor phase line
The composition of R32 is shifted to a value larger than 2V. Obedience
Therefore, the set shown in the liquid phase composition or the gas phase composition of (Table 1)
The product has a saturated vapor pressure of R22 at 0 ° C or 50 ° C.
A saturation state is realized under the condition of. Also, for example, point D_V~
E_VIs a saturated vapor phase of vapor-liquid equilibrium line (R22 50 ° C equivalent) 2
It is on the line 2V and has a vapor-liquid equilibrium line (R22 0 ° C phase).
1) saturated vapor phase line 1V and vapor-liquid equilibrium line (R220 0 ° C)
Equivalent) It is in the range sandwiched by both lines of 1 saturated liquid phase line 1L
Therefore, the temperature is 0 ° C and the pressure is 0.498 MPa (for R22
(Equivalent to the saturated state), the gas-liquid equilibrium state is reached and the temperature
50 ° C, pressure 1.943 MPa (in the saturated state of R22,
In this case), a saturated vapor phase equilibrium state is reached.

At the same temperature as R22, the composition on the saturated vapor phase line V is vaporized at a pressure higher than that of R22 and liquefied at the same pressure as R22. The composition on the saturated liquidus line L is vaporized at the same temperature as R22 at the same pressure as R22 and liquefied at a pressure lower than R22. The composition in the area between these two lines vaporizes at a pressure higher than R22 and liquefies at a pressure lower than R22 at the same temperature as R22. That is, the composition in the area between the vapor-liquid equilibrium lines 2 at 50 ° C. is 5
At 0 ° C, the gas phase changes to a liquid phase at a pressure lower than R22, and at the same pressure as R22, a gas phase higher than 50 ° C condenses and changes to a liquid phase lower than 50 ° C. The composition in the area between the vapor-liquid equilibrium line 1 at 0 ° C changes from the liquid phase to the vapor phase at a pressure higher than R22 at 0 ° C, and the liquid phase lower than 0 ° C evaporates at the same pressure as R22. Then, the gas phase changes to a temperature higher than 0 ° C. That is, the composition between the saturated liquid phase line 1L of the gas-liquid parallel line 1 or the saturated liquid phase line 2L of the gas-liquid parallel line 2 and the saturated gas phase line 1V of the gas-liquid equilibrium line 1 is R22 at a temperature of 0 ° C. It has almost the same evaporation pressure and a temperature of 50
Since it has almost the same condensation pressure as R22 at ℃,
Suitable for air conditioners, refrigerators, refrigerators, etc.

Here, only the points on the gas-liquid equilibrium line (corresponding to R220 ° C.) 1 or the gas-liquid equilibrium line (corresponding to R2250 ° C.) 2 are described, but the points inside the composition pairs A to E, that is, Temperature 0 ° C, pressure 0.498 MPa or temperature 50 ° C, pressure 1.943 MPa (both R22
(Corresponding to the saturated state of the
It is possible to obtain a condensation temperature / evaporation temperature almost equal to R22 at a use temperature of about 0 to about 50 ° C.

As can be seen from the figure, R32, R152a
And trifluoroiodomethane are each about 20 to about 6
A composition range of 0% by weight, 0 to about 65% by weight, and 0 to about 80% by weight is desirable because it has a vapor pressure almost equal to that of R22 at a use temperature of about 0 to about 50 ° C. Further, R32, R152a and trifluoroiodomethane are each approximately 20 to approximately 50% by weight, 0 to approximately 65% by weight,
The composition range of 0 to about 80% by weight is 0 ° C and 50%.
It is particularly desirable because it has a vapor pressure almost equal to R22 at all utilization temperatures between ° C.

Further, the mixed refrigerant composed of the three components of R32, R152a and trifluoroiodomethane is combustible with R32 in a mixture having a small composition ratio of trifluoroiodomethane when the gas phase refrigerant leaks from the device, for example. It can be seen from Table 1 that the total composition of R152a only increases in concentration by about 5% by weight. A mixture containing 10% by weight or more of trifluoroiodomethane has a composition of combustible components of 90% by weight or less and is inflammable. Therefore, as a composition of the mixed refrigerant, 15% by weight or more of trifluoroiodomethane is used. It is desirable that the mixture contains In the mixture containing a large proportion of trifluoroiodomethane, the total composition of flammable R32 and R152a has a higher concentration, but there is no fear of flammability due to a large proportion of trifluoroiodomethane. Therefore, R32, R152a and trifluoroiodomethane are each approximately 20 to approximately 55% by weight, 0 to approximately 65% by weight,
The composition range of about 15 to about 80% by weight is R32
And R152a are desirable because they eliminate the flammability of trifluoromethane.

The GWP of the R32 / R152a mixture is 1
Since it is 40 (R152a) to 580 (R32), a mixed refrigerant obtained by mixing trifluoroiodomethane, which has almost negligible GWP, is R32 / R152a.
The composition range of the mixture is about 20% by weight (R32 is about 20
Wt%) to approximately 85 wt% (R32 is 55 wt% and R15
2a is 30% by weight) G corresponding to 120 to 360
The WP can be reduced and the impact on global warming
It can be reduced to about 1/5 or less as compared with WP of 1700.

In this case, R15 is added to R32 at a constant 40% by weight.
When the 2a / trifluoroiodomethane mixture is mixed, the composition is on a straight line parallel to the side opposite to R32 in FIG. In this case, R32, R152a and trifluoroiodomethane are 40% by weight and 0-60 respectively.
The composition range such that the weight percent is 0 to 60 weight percent is about 0.
It is desirable because it has a vapor pressure almost equal to that of R22 at a use temperature of about 50 ° C. Furthermore, R32, R152a
And 40% by weight of trifluoroiodomethane,
The composition range of 0 to 45% by weight and 15 to 60% by weight is desirable because the flammability of R32 and R152a is eliminated by the incombustibility of trifluoromethane.

(Table 2) shows that 40% by weight is constant for R32.
It is an ideal refrigeration performance of a three-component system in which a 152a / trifluoroiodomethane mixture is mixed. The conditions are the case where the condensation average temperature is 50 ° C., the evaporation average temperature is 0 ° C., the condenser outlet supercooling degree is 0 deg, and the evaporator outlet superheat degree is 0 deg.

[0045]

[Table 2]

As can be seen from (Table 2), R32 and R152 in the composition range for making the vapor pressure equivalent to R22.
The three-component system in which a and trifluoroiodomethane are 40% by weight, 0 to 60% by weight, and 0 to 60% by weight, respectively, shows almost the same characteristics as R22. Especially, the three-component system in which R32 is 40% by weight, R152a is 20 to 40% by weight, and trifluoroiodomethane is 20 to 40% by weight, all of the refrigerating capacity, the coefficient of performance, and the vapor pressure are almost R.
It shows the same characteristics as No. 22. The composition of flammable components at that time is 6
Even if R32 or R152a having a low boiling point of 0 to 80% by weight leaks from the device and its concentration is slightly increased, the flammability of R32 or R152a can be eliminated by the incombustibility of trifluoromethane. In addition, the temperature gradient in the condensation process and the evaporation process is 10 deg or less, and a near azeotropic mixture is formed. By utilizing this temperature gradient in reverse to construct a Lorentz cycle in which the temperature difference with the heat source fluid is close, a higher coefficient of performance can be expected than in (Table 2).

Further, in the case of a mixed refrigerant of two kinds consisting only of trifluoroiodomethane and difluoromethane (R32), the composition range for making the vapor pressure equivalent to that of R22 is:
The range on the side connecting the trifluoroiodomethane and R32 in the triangular coordinates in FIG. 1 is preferable. In this case, it is desirable that the composition range is such that trifluoroiodomethane and R32 are approximately 60 to approximately 80% by weight and approximately 20 to approximately 40% by weight, respectively. Further, if the vapor pressure is allowed to rise higher than that of R22, it is desirable that the composition range is such that trifluoroiodomethane and R32 are approximately 45 to approximately 80% by weight and approximately 20 to approximately 55% by weight, respectively. Even if the low boiling point R32 leaks from the device, for example, even if the composition of R32 at that time is 55% by weight or more, it does not fall within the combustion range.
The inflammability of can be eliminated by the incombustibility of trifluoromethane.

The GWP of R32 alone is smaller than 580 and R22, and the mixed refrigerant obtained by mixing trifluoroiodomethane, which has almost negligible GWP, is R32.
Corresponding to about 20 to about 55% by weight of the composition range of 120 to
The GWP can be reduced to 320, and the effect on global warming can be greatly reduced as compared with R22. Therefore, a binary system consisting only of trifluoroiodomethane and difluoromethane (R32) is also a useful alternative to R22.

Table 3 shows the ideal refrigerating performance of a binary system consisting only of R32 and trifluoroiodomethane. The conditions are that the condensation average temperature is 50 ° C and the evaporation average temperature is 0.
C., the supercooling degree at the condenser outlet is 0 deg, and the superheat degree at the evaporator outlet is 0 deg.

[0050]

[Table 3]

As can be seen from (Table 3), the two-component system in which trifluoroiodomethane and R32 are only about 45 to about 80% by weight and about 20 to about 55% by weight, respectively, trifluoroiodomethane is about 45 to about 50% by weight. 60% by weight and R32
In the range of 40 to 55% by weight, the refrigerating capacity and the vapor pressure are higher than those of R22, but trifluoroiodomethane, which is a composition range for making the vapor pressure equal to that of R22, is 60 to 80% by weight, When R32 is in the range of 20 to 40% by weight, almost the same properties as R22 are exhibited.
Particularly, the two-component system consisting of 70% by weight of trifluoroiodomethane and 30% by weight of difluoromethane (R32) has both higher refrigerating capacity and coefficient of performance than R22. Even if R32 having a low boiling point leaks from the device, for example, the composition of R32 at that time does not fall within the combustion range, and the flammability of R32 can be eliminated by the incombustibility of trifluoromethane. In addition, the temperature gradient in the condensation process and the evaporation process is 10 deg or less, and a near azeotropic mixture is formed. By utilizing this temperature gradient in reverse, by configuring a Lorenz cycle in which the temperature difference with the heat source fluid is close,
A higher coefficient of performance can be expected than in (Table 3).

Furthermore, trifluoroiodomethane and 1,1
In the case of two kinds of mixed refrigerants consisting of only difluoroethane (R152a), both have higher boiling points than R22,
Trifluoroiodomethane and R152 in triangular coordinates in Fig. 1
A range having a vapor pressure equivalent to that of R22 does not appear on the side connecting a and has a vapor pressure lower than that of R22, but by specifying the composition range of trifluoroiodomethane,
The flammability of 152a can be eliminated by the incombustibility of trifluoromethane. In this case, trifluoroiodomethane and R152a are each approximately 35 to approximately 80% by weight,
The composition range is preferably about 20 to about 65% by weight. Even if the low boiling point R152a leaks from the apparatus, for example, the composition of R152a at that time is almost a mixed composition, and the flammability of R152a can be eliminated by the incombustibility of trifluoromethane.

The GWP of R152a alone is 140 and R22.
Smaller than that, and mixed with trifluoroiodomethane, which has almost negligible GWP,
The GWP can be reduced to 30 to 90, which corresponds to approximately 20 to approximately 65% by weight of the composition range of 152a, and the influence on global warming can be made much smaller than that of R22. Therefore, a two-component system consisting only of trifluoroiodomethane and 1,1-difluoroethane (R152a) is also
And useful as an alternative refrigerant, in particular a refrigerator, 1,1,1,2-tetrafluoroethane of the refrigerator or the like (CF ₃ -CH
₂ F, R134a, boiling point -27 ° C), it is about 1/1 compared to 1300 of GWP of R134a.
It can be reduced to 5 or less.

Table 4 shows the ideal refrigerating performance of a two-component system consisting of R152a and trifluoroiodomethane only. The conditions are the case where the condensation average temperature is 50 ° C., the evaporation average temperature is 0 ° C., the condenser outlet supercooling degree is 0 deg, and the evaporator outlet superheat degree is 0 deg.

[0055]

[Table 4]

As can be seen from (Table 4), the binary system consisting only of trifluoroiodomethane and R152a has a temperature gradient of 1 deg or less in the condensation process and the evaporation process, and as a near azeotropic mixture with almost a single refrigerant. Although it can be handled in the same manner and has a low vapor pressure and a low refrigerating capacity, it shows almost the same or better coefficient of performance as R22. In particular, the composition range in which trifluoroiodomethane and R152a are approximately 35 to approximately 80% by weight and approximately 20 to approximately 65% by weight, respectively, is such that even if the low boiling point R152a leaks from the device, for example, The composition is almost 65% by weight or less as it is as a mixed composition, and the inflammability of R152a can be eliminated by the incombustibility of trifluoromethane.

FIG. 2 shows an embodiment of a refrigerating cycle device such as an air conditioner, in which a compressor 3, a four-way valve 4 and an outdoor heat exchanger acting as a condenser or an evaporator are provided inside an integrated casing. 5, the expansion device 6 such as a capillary tube and an expansion valve, the indoor heat exchanger 7 acting as an evaporator and a condenser, the accumulator 8 and the like are connected by pipes, and the outdoor fan 9 connected to the indoor / outdoor shared motor is an outdoor fan. The heat exchanger 5 exchanges heat with the atmosphere, and the indoor fan 10 exchanges heat with the indoor air.

This refrigeration cycle apparatus is equipped with R32 and R15
A mixed working fluid consisting of 2a, trifluoroiodomethane and a radical chain inhibitor is enclosed, and R32 and R1
When 52a and trifluoroiodomethane are circulated in the refrigeration cycle as refrigerants, cooling is performed when the indoor heat exchanger 7 acts as an evaporator, and when the indoor heat exchanger 7 acts as a condenser. Performs a heating action. The radical chain inhibitor is R32 and R15 which circulate as a refrigerant.
By stopping the decomposition reaction of trifluoromethane among 2a and trifluoroiodomethane, it can be stably used for a long period of time.

Here, especially during the heating operation, the refrigerant is compressed by the compressor 3
Liquid back is easy to occur and composition separation of the gas phase and the liquid phase occurs in the accumulator 8. A mixed refrigerant such that R32, R152a, and trifluoroiodomethane are about 20 to about 55% by weight, 0 to about 65% by weight, and about 15 to about 80% by weight, respectively, is R32 which has a low boiling point in the accumulator 8. Although the composition ratio of R152a increases and the maximum gas phase composition of the combustible component becomes about 90% by weight, the combustibility of R32 and R152a is suppressed by the incombustibility of trifluoroiodomethane. Also flammable R32 and R152a
Even if the gas leaks from the device, since the accumulator 8 is arranged on the outside of the room, it is possible to discharge it to the atmosphere, and it is desirable that the danger of explosion can be avoided.
R32 and trifluoroiodomethane are approximately 40 each
~ About 55% by weight, about 45 to about 60% by weight 2
Since the mixed refrigerant composed of the components has an excessive refrigerating capacity, the cylinder volume of the compressor 3 is slightly reduced so that R152a and trifluoroiodomethane are approximately 20 to approximately 65% by weight and approximately 35 to approximately 80% by weight, respectively. Since the mixed refrigerant consisting of two components has a low refrigerating capacity, the cylinder capacity of the compressor 3 is made large so that the refrigerating capacity is equalized and the coefficient of performance is also equal. The outer heat exchanger 5 and the indoor heat exchanger 7 can be used without changing.

The R32 and R152a fluorohydrocarbon refrigerants have poor compatibility with mineral oils and some synthetic oils used as conventional lubricating oils for compressors, and are discharged together with the refrigerants from the compressors. When the fluorocarbons are used as the refrigerant, ester oil with good compatibility should be used as the lubricating oil for the compressor, because the lubricating oil may not return from the low temperature evaporator to the compressor. desirable.

[0061]

As is apparent from the above description, the present invention has the following features. (1) It is possible to expand the range of selection of refrigerants that have almost no effect on the stratospheric ozone layer. (2) Since such a mixed refrigerant is composed of trifluoroiodomethane, whose global warming potential is almost negligible, and difluoromethane (R32) and 1,1-difluoroethane (R152a), which have a small GWP, the influence on global warming Can be reduced depending on the composition range of trifluoroiodomethane. (3) By containing a radical chain inhibitor, trifluoroiodomethane can be stabilized and stably used for a long period of time. (4) Since trifluoroiodomethane is a nonflammable substance having a negative catalytic effect, by further limiting the composition range of the mixture with R32 and R152a to the flame retardant range,
It can be used for normal refrigeration cycle equipment. (5) Trifluoroiodomethane and R32 and R152a
The mixed refrigerant consisting of, by specifying the composition range,
At a use temperature of a refrigeration cycle device such as an air conditioner, a refrigerator, or a refrigerator, which is approximately 0 to approximately 50 ° C., the vapor pressure is about the same as that of R22, and the same refrigerating capacity and coefficient of performance as R22 can be expected. It can also be used with the current equipment used. (6) The mixed refrigerant composed of trifluoroiodomethane and R32 is partially specified by specifying the composition range at about 0 to about 50 ° C. which is the use temperature of a refrigeration cycle device such as an air conditioner, a refrigerator, or a refrigerator. Although it has a higher vapor pressure than R22, it has the same refrigeration capacity and coefficient of performance,
It can also be used with existing equipment using R22. (7) The mixed refrigerant of trifluoroiodomethane and R152a has a composition range that is higher than that of R22 at about 0 to about 50 ° C., which is the use temperature of a refrigeration cycle device such as an air conditioner, a refrigerator, or a refrigerator. It has a low vapor pressure and a low refrigerating capacity, but the coefficient of performance is equal or higher, so it can be used with existing equipment using R22 or R134a. (8) It is expected that such a mixed refrigerant will be an almost azeotropic non-azeotropic mixture, and by constructing a Lorentz cycle, a higher coefficient of performance than that of R22 can be expected.

[Brief description of drawings]

FIG. 1 is a triangular coordinate diagram of an equilibrium state at a constant temperature and a constant pressure of a refrigerant composed of a mixture of R32, R152a and trifluoroiodomethane.

FIG. 2 is a sectional view showing an embodiment of a refrigeration cycle device to which a mixed working fluid according to the present invention is applied.

[Explanation of symbols]

 1 Gas-liquid equilibrium line (R22 equivalent to 0 ° C) 2 Gas-liquid equilibrium line (R22 equivalent to 50 ° C) V Saturated vapor phase line L Saturated vapor phase line 3 Compressor 4 Four-way valve 5 Outdoor heat exchanger 6 Throttling device 7 Indoor side Heat exchanger 8 Accumulator 9 Outdoor fan 10 Indoor fan

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumakuta Inagaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (6)

[Claims] 1. 15 to 80% by weight of trifluoroiodomethane and 20 to 55% by weight of difluoromethane and 6
A mixed working fluid comprising up to 5% by weight of either or both of 1,1-difluoroethane and a radical chain inhibitor. 2. 15 to 80% by weight of trifluoroiodomethane, 20 to 55% by weight of difluoromethane, 65
The mixed working fluid according to claim 1, further comprising a radical chain inhibitor and three components containing 1% or less by weight of 1,1-difluoroethane. 3. A mixture according to claim 1, which further comprises a radical chain inhibitor and two components containing 45 to 80% by weight of trifluoroiodomethane and 20 to 55% by weight of difluoromethane. Working fluid. 4. A two-component composition containing 35 to 80% by weight of trifluoroiodomethane and 20 to 65% by weight of 1,1-difluoroethane, and a radical chain inhibitor. A mixed working fluid as described. 5. 15 to 80% by weight of trifluoroiodomethane and 20 to 55% by weight of difluoromethane and 6
A refrigeration cycle apparatus characterized by using a mixed working fluid containing one or both of 5% by weight or less of 1,1-difluoroethane and a radical chain inhibitor. 6. The mixed working fluid according to claim 1, wherein at least a compressor, a four-way valve, a condenser, a throttle device, an evaporator and an accumulator are connected by piping, and the accumulator is arranged outside the room. An air conditioner characterized by using.