JPH0517755A - Working fluid - Google Patents

Abstract

PURPOSE:To obtain a working fluid, containing fluorocarbons such as pentafluoroethane in a specific proportion, hardly destroying the ozonosphere as a substitutive fluid for R22, usable in the existing equipment, excellent in heat exchange efficiency and useful as heat pump devices such as air conditioners. CONSTITUTION:The objective working fluid containing at least three fluorocarbons of (A) 65-95wt.%, preferably 70-95wt.% pentafluoroethane, (B) 0-30wt.% difluoroethane and (C) 0-35wt.%, preferably 0-25wt.% dichlorotrifluoroethane.

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]

The present invention solves the above problems.
At least pentafluoroethane (C ₂
HF_Five) And difluoroethane (C₂H_FourF₂) And dichloroto
Lifluoroethane (C₂HCl₂F₃) Three types of CFCs
Including about 65 to about 95% by weight of pentafluoroethane,
Difluoroethane 0 to approximately 30% by weight, dichlorotriflu
The composition range of 0 to about 35% by weight of oroethane is specified.
In particular, pentafluoroethane approximately 7
0 to approximately 95% by weight, difluoroethane 0 to approximately 30% by weight
%, Dichlorotrifluoroethane 0 to approximately 25% by weight
The range is desirable.

[0006]

According to the present invention, the combination of the above causes the working fluid to be a pentafluoroethane (OD) which is a CFC having almost no ozone depletion ability and which does not contain chlorine in its molecular structure.
P = 0) and difluoroethane (ODP = 0), and dichlorotrifluoroethane (O), which is a CFC containing both chlorine and hydrogen in the molecular structure with extremely low ozone depletion ability.
By making a mixture of DP = 0.02), it is possible to make the influence on the stratospheric ozone layer smaller than that of R22. In particular, difluoroethane is flammable, but pentafluoroethane and dichlorotrifluoroethane are nonflammable. Therefore, by mixing pentafluoroethane and dichlorotrifluoroethane, the flammability can be reduced. Like R
This is the first time that a composition range of 22 alternatives 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 0 to 0.007, which 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.

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 pentafluoroethane (R125) and 1,1-difluoroethane (R152).
a), the equilibrium state at a constant temperature and a constant pressure of a working fluid composed of a mixture of three freons of 2,2-dichloro-1,1,1-trifluoroethane (R123) is determined using triangular coordinates. It is shown. In this triangular coordinate, a single substance is arranged counterclockwise starting from the upper vertex at each vertex of the triangle in descending order of boiling point,
Composition ratio (weight ratio) of each component at a 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 kg.
/ Cm ² G is a vapor-liquid equilibrium line of the mixture, 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, the composition range in which R125, R152a, and R123 are approximately 70 to approximately 95% by weight, 0 to approximately 30% by weight, and 0 to approximately 30% by weight is approximately 0 to approximately 50 ° C. It is desirable because it has a vapor pressure almost equal to that of R22 at temperature. In addition, R125, R152a and R12
The composition ranges in which 3 is approximately 70 to approximately 95% by weight, 0 to approximately 30% by weight, and 0 to approximately 25% by weight are substantially the same as R22 at all use temperatures between 0 ° C and 50 ° C. It is particularly desirable because it has a vapor pressure.

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
Line (R22 50 ° C equivalent) is on the saturated liquidus line 2
The vapor-liquid equilibrium line (corresponding to R220 ° C) 1 and the saturated vapor line
Both lines of saturated liquidus of vapor-liquid equilibrium line (corresponding to R220 ° C) 1
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, the composition shown in Table 1
Working fluids with
Saturated state or vapor-liquid equilibrium state is realized under the condition of sum vapor pressure.
At the operating temperature of about 0 to about 50 ° C,
By operating at the saturated vapor pressure of R22
It is possible to obtain a condensing temperature / evaporating temperature almost equal to
It is something.

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 R125, R152a, 1,2-
FIG. 3 shows the equilibrium state of a working fluid composed of a mixture of three freons of dichlorotrifluoroethane (R123a) at a constant temperature and a constant pressure by using triangular coordinates. In FIG. 2, 3 indicates a temperature of 0 ° C. and a pressure of 4.
4 is a vapor-liquid equilibrium line of the mixture at 044 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, the composition range such that R125, R152a and R123a are approximately 65 to approximately 95% by weight, 0 to approximately 30% by weight and 0 to approximately 35% by weight, respectively, has a vapor pressure approximately equal to that of R22. Therefore, R125, R152a and R are desirable.
123a is approximately 70 to approximately 95% by weight, and 0 to approximately 30%
A composition range of 0% to approximately 25% by weight is 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, the composition shown in Table 2
Working fluids with
Saturated state or vapor-liquid equilibrium state is realized under the condition of sum vapor pressure.
At the operating temperature of about 0 to about 50 ° C,
By operating at the saturated vapor pressure of R22
It is possible to obtain a condensing temperature / evaporating temperature almost equal to
It is something.

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, the composition range of pentafluoroethane is about 65 to about 95% by weight, difluoroethane is about 0 to about 30% by weight, and dichlorotrifluoroethane is about 0 to about 35% by weight. Is desirable because it has a vapor pressure almost equal to that of R22. Further, the composition range such that pentafluoroethane is approximately 70 to approximately 95% by weight, difluoroethane is approximately 0 to approximately 30% by weight, and dichlorotrifluoroethane is approximately 0 to approximately 25% by weight is used for all applications between 0 ° C and 50 ° C. It is particularly desirable because it has a vapor pressure almost equal to that of R22 at temperature. In particular, the ODP in the above-mentioned combination and composition range is also expected to be 0.0 to 0.007, which is an extremely promising working fluid as a substitute for 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 that contains both chlorine and hydrogen in the molecular structure and has an extremely low ozone depletion capacity, and as one of two CFCs that do not contain chlorine in the molecular structure. Since pentafluoroethane is selected, it is possible to reduce the flammability of difluoroethane selected as one of the two types of CFCs that does not contain chlorine in the molecular structure. (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. 65 to 95% by weight of pentafluoroethane
Hereinafter, a working fluid containing at least three types of CFCs in an amount of 30% by weight or less of difluoroethane and 35% by weight or less of dichlorotrifluoroethane. 2. Pentafluoroethane 70 to 95% by weight
Hereinafter, a working fluid comprising 30% by weight or less of difluoroethane and 25% by weight or less of dichlorotrifluoroethane.