JPH0517744A - Working fluid - Google Patents

Abstract

PURPOSE:To provide a working fluid comprising fluoro compounds such as difluoromethane and trifluoroethane in specific amounts, respectively, further reduced in the affection of the fluoro compounds on the ozone layer of the stratosphere, and capable of being used as a substitute for R22. CONSTITUTION:The objective working fluid comprises a mixture of three kinds of Freon gases consisting of (A) difluoromethane (R32), (B) trifluoroethane [e.g. 1,1,1-trifluoroethane (R/43a)], and (C) dichlorotrifluoroethane [e.g. 2,2- dichloro-1,1,1trifluoroethane (R/23)]. The mixture exists e.g. in a gas-liquid saturation state (having substantially the same vapor pressure as R22) within a region surrounded by the saturated gas phase line (the upper side) and the saturated liquid phase line (the lower side) of the gas-liquid equilibrium line 1 (corresponding to R22 at 0 deg.C) in a constant concentration under a constant pressure and by the saturated gas phase line (the points A1-C1) and the saturated liquid phase line (the points D1-F1) of a gas liquid equilibrium line 2 (corresponding to R22 at 50 deg.C. This mixture comprises <=90wt.% (preferably <=85wt.%) of the component A, <=95wt.% of the component B and 5-65 wt.% (preferably 5-85wt.%) of the component C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working fluid used in heat pump devices such as air conditioners and refrigerators.

[0002]

2. Description of the Related Art Conventionally, heat pumps for air conditioners, refrigerators, etc.
In the device, CFCs (hereinafter R ○
Halogenated hydrocarbon water called ◯ or R ○○○)
The element is known and its usage temperature is the condensation temperature and / or
Or when the evaporation temperature is in the range of about 0 to about 50 ° C
Used. Among them, chlorodifluoromethane (CHClF
₂, R22) are home air conditioners, building air conditioners and large
Widely used as a working fluid for refrigerators and the like.

[0003]

However, in recent years, the depletion of the stratospheric ozone layer due to CFCs has become a global environmental problem, and regarding CFCs (hereinafter referred to as "specific CFCs") that have great ozone depletion potential in the stratosphere, The amount of use and the amount of production have already been regulated by international treaties, and there is a movement to abolish the use and production of specified CFCs in the future. By the way, R22 has a very small ozone depletion coefficient (stratospheric ozone depletion capacity when the stratospheric ozone depletion capacity of trichlorofluoromethane (CCl ₃ F) is set to 1, hereinafter referred to as ODP), which is as small as 0.05, not a specific CFC. However, it is expected that the usage amount will increase in the future, and now that the refrigeration / air-conditioning equipment has spread widely, it is expected that the increase in the usage amount and the production amount of R22 will greatly affect the living environment of humankind. Therefore, there is a strong demand for early development of a working fluid that is a substitute for R22, which has a small ozone depletion ability in the stratosphere but is said to have some depletion ability.

The present invention has been tried in view of the above-mentioned problems, and has a smaller influence on the stratospheric ozone layer.
22 to provide an alternative working fluid.

[0005]

In order to solve the above problems, the present invention provides at least difluoromethane (CH
₂ F ₂ ), trifluoroethane (C ₂ H ₃ F ₃ ), and dichlorotrifluoroethane (C ₂ HCl ₂ F ₃ ), including three types of CFCs, and 0 to approximately 90% by weight of difluoromethane and 0 of trifluoroethane. To about 95% by weight and dichlorotrifluoroethane of about 5 to about 65% by weight, particularly, difluoromethane 0 to about 8% by weight.
A composition range of 5% by weight, trifluoroethane 0 to approximately 95% by weight, and dichlorotrifluoroethane approximately 5 to approximately 60% by weight is preferable.

[0006]

According to the present invention, the working fluid can be treated with difluoromethane (ODP = ODP), which is a CFC having almost no ozone depleting ability and containing no chlorine in its molecular structure.
0) and trifluoroethane (ODP = 0), and dichlorotrifluoroethane (OD) which is a CFC containing both chlorine and hydrogen in the molecular structure with extremely low ozone depletion potential.
By using a mixture of P = 0.02), the influence on the stratospheric ozone layer can be made smaller than that of R22. In particular, difluoromethane and trifluoroethane are flammable, but dichlorotrifluoroethane is non-flammable. Therefore, by mixing dichlorotrifluoroethane, the flammability can be reduced, and as in the present invention, This is the first time that a composition range as an alternative to R22 has been specified.

Further, according to the present invention, by setting the above composition range, the vapor pressure of R22 is about the same as that of R22 at about 0 to about 50 ° C., which is the use temperature of heat pump devices such as air conditioners and refrigerators. Alternatively, it is possible to provide a working fluid that can be used in existing equipment. Therefore, the ODP in the above combination and composition range is also 0.
It is expected to be 001 to 0.013, which is an extremely promising working fluid as an alternative to R22. Further, since such a mixture becomes a non-azeotropic mixture and has a temperature gradient in the condensation process and the evaporation process, a coefficient of performance higher than that of R22 can be expected by constructing a Lorentz cycle in which the temperature difference with the heat source fluid is close. Is.

In general, CFCs having a stratospheric ozone depletion ability tend to have a great effect on global warming as the ODP value increases. However, the working fluid according to the present invention includes only CFCs having an extremely small ODP. Since it is composed of a mixture of three or more kinds, it is estimated that the effect of global warming is similar to R22 or less than R22, and it is possible to reduce the contribution to global warming, which has become a global problem recently. It is possible.

[0009]

Embodiments of the working fluid according to the present invention will be described below with reference to the drawings. FIG. 1 shows difluoromethane (R32), 1,1,1-trifluoroethane (R14).
3a), the equilibrium state of a working fluid composed of a mixture of three freons of 2,2-dichloro-1,1,1-trifluoroethane (R123) at a constant temperature and a constant pressure, using triangular coordinates. It is shown. In this triangular coordinate, single substances are arranged counterclockwise starting from the upper vertex at each vertex of the triangle in descending order of boiling 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 apex of the triangular coordinate on the side opposite to the side. In FIG. 1, 1 indicates a temperature of 0 ° C. and a pressure of 4.044 k.
It is a vapor-liquid equilibrium line of the mixture at g / cm ² G, and this temperature / pressure corresponds to the saturated state of R22. The upper line of the vapor-liquid equilibrium line (corresponding to R22 0 ° C.) 1 represents the saturated vapor phase line, and the lower line of the vapor-liquid equilibrium line (R22 0 ° C. equivalent) 1 represents the saturated liquid phase line. The vapor-liquid equilibrium state is reached in the range that is set. In addition, 2 is temperature 50 ℃, pressure 18.782
It is a vapor-liquid equilibrium line of the mixture at kg / cm ² G, and this temperature / pressure also corresponds to the saturated state of R22. As can be seen from the figure, R32, R143a, and R123 are 0 to about 90% by weight, 0 to about 95% by weight, and about 5 to about 65%, respectively.
The composition range such that the weight percent is obtained is desirable because it has a vapor pressure almost equal to that of R22 at a use temperature of approximately 0 to approximately 50 ° C. Furthermore, the composition range in which R32, R143a, and R123 are 0 to about 85% by weight, 0 to about 95% by weight, and about 5 to about 60% by weight, respectively, should be used at all temperatures between 0 ° C and 50 ° C. Is particularly desirable because it has a vapor pressure almost equal to that of R22.

The composition of the working fluid at points A ₁ to F ₁ in FIG. 1 is shown in (Table 1).

[0011]

[Table 1]

Point A₁~ Point C₁Is the vapor-liquid equilibrium line (R2250
On the saturated vapor phase line of 2) ₁~ Point F₁Is vapor-liquid equilibrium
It is on the saturated liquid line of line 2 (equivalent to R22 50 ° C), and both
Gas-liquid equilibrium line (equivalent to R220 ° C) 1 saturated vapor phase line and gas
Liquid equilibrium line (equivalent to R220 ° C) 1 saturated liquidus line
Since it is in the sandwiched range, the temperature is 0 ° C and the pressure is 4.04.
4 kg / cm²At G (corresponding to the saturated state of R22)
Becomes vapor-liquid equilibrium. Therefore, the set shown in (Table 1)
Working fluid with composition of R22 at 0 ℃ ・ 50 ℃
Saturated state or vapor-liquid equilibrium state under the condition of saturated vapor pressure
Realized at the same temperature at operating temperatures of about 0 to about 50 ° C.
By operating at the saturated vapor pressure of R22 in
It is possible to obtain the condensation temperature and evaporation temperature that are almost equal to 2.
It will be.

Although only the points on the gas-liquid equilibrium line (R22 at 50 ° C.) 2 are described here, points inside the points A ₁ to F ₁ , that is, temperature 0 ° C. and pressure 4.044 k.
g / cm ² G, temperature 50 ° C, pressure 18.782 kg /
By similarly operating a working fluid having a composition in a vapor-liquid equilibrium state at cm ² G (both corresponding to the saturated state of R22), a condensation temperature substantially equal to R22 at a use temperature of approximately 0 to approximately 50 ° C. -It is possible to obtain the evaporation temperature.

FIG. 2 shows the equilibrium state of a working fluid composed of a mixture of three freons of R32, R143a and 1,2-dichlorotrifluoroethane (R123a) at a constant temperature and a constant pressure by using triangular coordinates. Is shown. In FIG. 2, 3 indicates a temperature of 0 ° C. and a pressure of 4.0.
4 is a vapor-liquid equilibrium line of the mixture at 44 kg / cm ² G, and 4 is a temperature of 50 ° C. and a pressure of 18.782 kg / c.
3 is a vapor-liquid equilibrium line of the mixture at m ² G. In this case, R32, R143a and R123a are 0 to
About 90% by weight, 0 to about 95% by weight, about 5 to about 65% by weight
The composition range such that R2, R143a and R123 is desirable because it has a vapor pressure almost equal to that of R22.
Composition ranges in which a is 0 to about 85% by weight, 0 to about 95% by weight, and about 5 to about 60% by weight are particularly desirable.

The composition of the working fluid at points A ₂ to F ₂ in FIG. 2 is shown in (Table 2).

[0016]

[Table 2]

Point A₂~ Point C₂Is the vapor-liquid equilibrium line (R2250
On the saturated vapor phase line of 4) ₂~ Point F₂Is vapor-liquid equilibrium
Line (R22 50 ° C equivalent) is on the saturated liquidus line 4 and
The saturated liquidus of the vapor-liquid equilibrium line (corresponding to R220 ° C) 3 and
Both lines of saturated liquidus of vapor-liquid equilibrium line (R220 equivalent to 0 ° C) 3
The temperature is 0 ° C and the pressure is 4.0 because it is in the range sandwiched by
44 kg / cm²G (corresponding to saturation of R22) odor
The gas-liquid equilibrium state. Therefore, as shown in (Table 2)
The working fluid having the composition is R22 at 0 ° C / 50 ° C.
State or vapor-liquid equilibrium state under the condition of saturated vapor pressure
And the same temperature at operating temperatures of approximately 0 to approximately 50 ° C.
By operating at the saturated vapor pressure of R22 at
It is possible to obtain condensation temperature and evaporation temperature almost equal to 22.
It will be.

Although only the point on the vapor-liquid equilibrium line (R22 at 50 ° C.) 4 is described here, the point inside the points A ₂ to F ₂ , that is, temperature 0 ° C. and pressure 4.044 k.
g / cm ² G, temperature 50 ° C, pressure 18.782 kg /
By similarly operating a working fluid having a composition in a vapor-liquid equilibrium state at cm ² G (both corresponding to the saturated state of R22), a condensation temperature substantially equal to R22 at a use temperature of approximately 0 to approximately 50 ° C. -It is possible to obtain the evaporation temperature.

In the above embodiments, the working fluid is composed of a mixture of three types of freons, but it is of course possible to form the working fluid by a mixture of four or more types of freon including structural isomers. , In this case, difluoromethane 0 to approximately 90% by weight, trifluoroethane 0 to approximately 95% by weight, dichlorotrifluoroethane approximately 5 to approximately 65%
The composition range such that the weight percent is obtained is desirable because it has a vapor pressure almost equal to that of R22 at a use temperature of approximately 0 to approximately 50 ° C. Furthermore, 0 to approximately 85% by weight of difluoromethane,
The composition range such that trifluoroethane is 0 to about 95% by weight and dichlorotrifluoroethane is about 5 to about 60% by weight is R2 at all use temperatures between 0 ° C and 50 ° C.
It is particularly desirable because it has a vapor pressure almost equal to 2. Especially, ODP in the above-mentioned combination and composition range is also 0.00
It is expected to be 1 to 0.013 and is a very promising working fluid as an alternative to R22. Further, since such a mixture becomes a non-azeotropic mixture and has a temperature gradient in the condensation process and the evaporation process, a coefficient of performance higher than that of R22 can be expected by constructing a Lorentz cycle in which the temperature difference with the heat source fluid is close. Is.

[0020]

EFFECTS OF THE INVENTION As is clear from the above description, according to the present invention, the working fluid contains two types of CFCs containing no chlorine in the molecular structure and chlorine and hydrogen in the molecular structure, and has an ozone depletion ability. (1) Expanding the range of choice of working fluid that makes the influence on the stratospheric ozone layer even smaller than R22 by defining a composition range consisting of three or more types of CFCs with extremely small It is possible. (2) Dichlorotrifluoroethane was selected as one of the CFCs containing both chlorine and hydrogen in the molecular structure and having an extremely low ozone depletion ability, so it was selected as two CFCs containing no chlorine in the molecular structure. The flammability of difluoromethane and trifluoroethane can be reduced. (3) It has a vapor pressure similar to that of R22 at the operating temperature of the equipment, and can be used in existing equipment as an alternative to R22. (4) Utilizing the property of the temperature gradient of the non-azeotropic mixture, R2
A coefficient of performance higher than 2 can be expected. And so on.

[Brief description of drawings]

FIG. 1 is a triangular coordinate diagram showing an equilibrium state of a working fluid composed of a mixture of three types of CFCs at a constant temperature and a constant pressure.

FIG. 2 is a triangular coordinate diagram showing an equilibrium state of a working fluid composed of a mixture of three types of freons at a constant temperature and a constant pressure.

[Explanation of symbols]

1 vapor-liquid equilibrium line (R220 equivalent to 0 ° C) 2 Gas-liquid equilibrium line (R22 50 ° C equivalent) 3 Gas-liquid equilibrium line (R220 equivalent to 0 ° C) 4 Gas-liquid equilibrium line (R22 50 ° C equivalent)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Minor Tagashi, the inventor             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (2)

[Claims] 1. A working fluid containing at least three types of CFCs in an amount of 90% by weight or less of difluoromethane, 95% by weight or less of trifluoroethane, and 5 to 65% by weight or less of dichlorotrifluoroethane. 2. A working fluid comprising 85% by weight or less of difluoromethane, 95% by weight or less of trifluoroethane, and 5 to 60% by weight or less of dichlorotrifluoroethane.