JPH05117651A - Working fluid - Google Patents

Abstract

PURPOSE:To provide a working fluid which hardly affects the ozone layer in the stratosphere and can substitute for R22. CONSTITUTION:A working fluid comprising about 60 to about 85wt.%, pref. about 65 to about 85wt.%, pentafluoroethane (C2HF5), 0 to about 10wt.%, pref. 0 to about 6wt.%, propane (C3H8), and about 10 to about 35wt.%, pref. about 10 to about 30wt.%, chlorotetrafluoroethane (C2HClF4).

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 the 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) is a home air conditioner, building air conditioner or large
Widely used as a working fluid for refrigerators and the like.

[0003]

However, in recent years, the depletion of the stratospheric ozone layer by 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 production has 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 trichlorofluoromethane (CCl ₃ F) has a stratospheric ozone depletion capacity of 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 become widespread, the increase in the usage amount and the production amount of R22 will have a great influence on the human living environment. Therefore, there is a strong demand for early development of a working fluid that substitutes 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 propane (C₃H₈) And chlorotetrafluoro
Ethane (C₂HClF_Four) Containing three types of CFCs
Tafluoroethane about 60 to about 85% by weight, propane 0
About 10% by weight, about 10 to about chlorotetrafluoroethane
The composition range is 35% by weight.
In particular, pentafluoroethane approximately 65 to approximately 85 weight
%, Propane 0 to 6% by weight, chlorotetrafluoroethane
The composition range of about 15 to about 30% by weight is desirable.
It

[0006]

Operation: Propane (boiling point-42.1 ° C) as a single refrigerant having a boiling point almost the same as R22 (boiling point-40.8 ° C)
However, propane is flammable and can be made almost incombustible by setting the composition range of the mixture to 0 to about 10% by weight, and more preferably set to 0 to about 6% by weight to make it almost incombustible. It has been known.

According to the present invention, the combination of the above-mentioned components makes the working fluid pentafluoroethane (OD) which is a CFC containing no chlorine in its molecular structure and having almost no ozone depletion ability.
P = 0), propane (ODP = 0), and chlorotetrafluoroethane (ODP), which is a CFC containing both chlorine and hydrogen in its molecular structure and having an extremely low ozone depletion ability.
= 0.02), the influence on the stratospheric ozone layer can be made smaller than that of R22. In particular, propane is flammable, but pentafluoroethane and chlorotetrafluoroethane are non-flammable, and the composition range of propane was limited, so by mixing pentafluoroethane and chlorotetrafluoroethane, flammability was reduced. This is the first time that a composition range as an alternative to R22 is specified as in the present invention.

Further, the present invention has the above composition range so that it has a vapor pressure similar to that of R22 at about 0 to about 50 ° C., which is a use temperature of a heat pump device such as an air conditioner / refrigerator. 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 0.0
It is expected to be 02 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 from 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, but the working fluid according to the present invention is composed only of 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.

[0010]

Embodiments of the working fluid according to the present invention will be described below with reference to the drawings.

FIG. 1 shows pentafluoroethane (R12
5), propane (R290), 2-chloro-1,1,
FIG. 3 shows the equilibrium state of a working fluid composed of a mixture of three types of freons of 1,2-tetrafluoroethane (R124) at constant temperature and constant pressure by using triangular coordinates. In this triangular coordinate, a single substance is arranged at each vertex of the triangle counterclockwise from the upper vertex in the ascending order of the boiling points, 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.
It is a vapor-liquid equilibrium line of the mixture at ℃ and pressure of 4.044 kg / cm ² G, and this temperature and pressure correspond 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 liquidus line. The vapor-liquid equilibrium state will be reached in the range. 2 is temperature 50
It is a vapor-liquid equilibrium line of the mixture at a temperature of 18.782 kg / cm ² G and a temperature and pressure corresponding to the saturated state of R22. When R23 is used alone, it exceeds the critical temperature at 50 ° C, but due to such a mixture, a saturated state exists, and the heat pump device such as an air conditioner / refrigerator having a use temperature of about 0 to about 50 ° C is used. It is possible to use. As can be seen from the figure, when the composition range of R290 is limited to 0 to approximately 10% by weight, R125, R290 and R124 are approximately 60% respectively.
To about 85% by weight, 0 to about 10% by weight, and about 10 to about 35% by weight have a vapor pressure almost equal to that of R22 at a use temperature of about 0 to about 50 ° C. It is desirable because it becomes nonflammable. Further, when the composition range of R290 is limited to 0 to about 6% by weight, R125, R290 and R124 become about 65 to about 80% by weight, 0 to about 6% by weight, and about 15 to about 30% by weight, respectively. The composition range is
It has a vapor pressure almost equal to that of R22 at all use temperatures between 0 ° C. and 50 ° C. and is almost nonflammable, which is particularly desirable.

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

[0013]

[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 (R220 0 ° C) 1 saturated gas phase line and
Both lines of saturated liquidus of vapor-liquid equilibrium line (equivalent 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 (equivalent to R22 saturation) 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 condensation temperature and an evaporation temperature almost equal to
It is something.

Here, only the point on the gas-liquid equilibrium line (corresponding to R22 of 50 ° C.) 2 is explained, but the point 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 gas-liquid equilibrium state at cm ² G (both corresponding to the saturated state of R22), a condensation temperature almost equal to that of R22 at a use temperature of about 0 to about 50 ° C. -It is possible to obtain the evaporation temperature.

FIG. 2 shows R125, R290, 1-chloro-1,1,2,2-tetrafluoroethane (R124
3 is a diagram showing the equilibrium state of a working fluid composed of a mixture of three types of freons of a) at a constant temperature and a constant pressure by using triangular coordinates. In FIG. 2, 3 is a vapor-liquid equilibrium line of the mixture at a temperature of 0 ° C. and a pressure of 4.044 kg / cm ² G, and 4 is a temperature of 50 ° C. and a pressure of 18.
3 is a vapor-liquid equilibrium line of the mixture at 782 kg / cm ² G. In this case, if the composition range of R290 is limited to 0 to approximately 10% by weight, R125, R290 and R124a
Are approximately 60 to approximately 85% by weight, 0 to approximately 10% by weight,
The composition range of R22 is about 10 to about 35% by weight.
It is desirable because it has a vapor pressure almost equal to and becomes almost nonflammable. If the composition range of R290 is limited to 0 to approximately 6% by weight, R125, R290 and R124a are approximately 7% each.
A composition range of 0 to about 85% by weight, 0 to about 6% by weight, and about 15 to about 30% 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).

[0018]

[Table 2]

Point A₂~ Point C₂Is the vapor-liquid equilibrium line (R2250
On the saturated vapor line of 4) ₂~ Point F₂Is vapor-liquid equilibrium
Line (R22 50 ° C equivalent) is on the saturated liquidus line 4 and
And the saturated vapor phase line of vapor-liquid equilibrium line (R220 0 ° C) 3 and
Both lines of saturated liquidus of vapor-liquid equilibrium line (R220 0 ° C equivalent) 3
The temperature is 0 ° C and the pressure is 4.0 because it is in the range sandwiched by
44 kg / cm²G (equivalent to R22 saturation) 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 condensation temperature and an evaporation temperature almost equal to
It is something.

Although only the point on the vapor-liquid equilibrium line (R22 of 50 ° C.) 4 has been described here, the point inside the points A ₂ to F ₂ , that is, the temperature of 0 ° C. and the pressure of 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 gas-liquid equilibrium state at cm ² G (both corresponding to the saturated state of R22), a condensation temperature almost equal to that of R22 at a use temperature of about 0 to about 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, pentafluoroethane approximately 60 to approximately 85% by weight, propane 0 to approximately 1
0% by weight, chlorotetrafluoroethane approximately 10 to approximately 35
The composition range such that the content is wt% 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. and becomes substantially nonflammable. Further, the composition range such that pentafluoroethane is about 65 to about 85% by weight, propane is 0 to about 6% by weight, and chlorotetrafluoroethane is about 15 to about 30% by weight, all composition ranges between 0 ° C and 50 ° C. It has a vapor pressure almost equal to that of R22 at the use temperature and is almost incombustible, which is particularly desirable. In particular, the ODP in the above-mentioned combination and composition range is also expected to be 0.002 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 from the heat source fluid is close. Is.

[0022]

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 an ozone depletion ability containing both chlorine and hydrogen in the molecular structure. It is a mixture consisting of three or more kinds of extremely small one of CFCs, and specifies its composition range,
It has the following effects. (1) It is possible to expand the range of selection of the working fluid that makes the influence on the stratospheric ozone layer smaller than that of R22. (2) Non-combustible pentafluoroethane was selected as a CFC having almost no ozone depletion ability, and non-combustible chlorotetrafluoroethane was selected as a CFC having an extremely small ozone depletion ability. The flammability of propane selected as a class 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 current equipment as an alternative to R22. (4) Utilizing the nature of the temperature gradient of the non-azeotropic mixture, R2
A coefficient of performance higher than 2 can be expected.

[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 freons 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 CFCs at a constant temperature and a constant pressure.

[Explanation of symbols]

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

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

Claims (2)

[Claims] 1. A working fluid containing at least three fluorocarbons, 60 to 85 wt% or less of pentafluoroethane, 10 wt% or less of propane, and 10 to 35 wt% or less of chlorotetrafluoroethane. 2. A working fluid characterized by containing 65 to 85% by weight of pentafluoroethane, 6% by weight or less of propane, and 15 to 30% by weight or less of chlorotetrafluoroethane.