JPH05117649A - 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 10 to about 55wt.%, pref. about 10 to about 45wt.%, trifluoromethane (CHF3), 0 to about 90wt.% tetrafluoroethane (C2B2F4), and 0 to about 90wt.%, pref. 0 to about 85wt.%, 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 trifluoromethane (CHF
₃) And tetrafluoroethane (C₂H₂F_Four) And Chlorotet
Rafluoroethane (C ₂HClF_Four) Three types of CFCs
Including, about 10 to about 55 wt% trifluoromethane, Tet
Lafluoroethane 0-about 90% by weight, chlorotetraflu
The composition range of 0-90% by weight of oroethane
It is a characteristic, especially trifluoromethane approximately 10
~ About 45% by weight, tetrafluoroethane 0 to about 90% by weight
%, Chlorotetrafluoroethane 0 to approximately 85% by weight
The range is desirable.

[0006]

According to the present invention, trifluoromethane (ODP = ODF), which is a CFC containing no chlorine in its molecular structure and having almost no ozone depletion ability, is used as a working fluid by the above combination.
0) and tetrafluoroethane (ODP = 0), and a mixture of chlorotetrafluoroethane (ODP = 0.02), which is a CFC containing both chlorine and hydrogen in the molecular structure and having an extremely small ozone depletion ability. This makes it possible to make the influence on the stratospheric ozone layer smaller than that of R22. In particular, since trifluoromethane, tetrafluoroethane, and chlorotetrafluoroethane are nonflammable, the mixture can also be made nonflammable by mixing them, and the composition range as an alternative to R22 as in the present invention is set. This is the first time I have identified.

The present invention is in particular a mixture of three or more freons, including trifluoromethane. Since trifluoromethane has a low critical temperature (25.7 ° C) and a high vapor pressure, it cannot be used alone in heat pump devices such as air conditioners and refrigerators having operating temperatures of approximately 0 to approximately 50 ° C. It is commercially available, and by using such a mixture, it becomes possible to construct a working fluid that is a practical substitute for R22.

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 0 to
It is expected to be 0.018, 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 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 trifluoromethane (R23),
1,1,1,2-Tetrafluoroethane (R134
a), the equilibrium state at a constant temperature and a constant pressure of a working fluid composed of a mixture of three types of CFCs of 2-chloro-1,1,1,2-tetrafluoroethane (R124) is determined using triangular coordinates. It is shown. In this triangular coordinate, a single substance is arranged counterclockwise from the upper apex 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 It is a vapor-liquid equilibrium line of the mixture, 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. 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. 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 you can see, R23, R134a
And R124 are in the range of about 10 to about 55% by weight, 0 to about 90% by weight, and 0 to about 90% by weight, respectively. Desirable because it has Furthermore, R23, R
The composition range such that 134a and R124 are approximately 10 to approximately 45% by weight, 0 to approximately 90% by weight, and 0 to approximately 85% by weight, respectively, is approximately the same as R22 at all use temperatures between 0 ° C and 50 ° C. It is particularly desirable because it has comparable vapor pressure.

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 that the working fluid composed of a mixture of three fluorocarbons R23, 1,1,2,2-tetrafluoroethane (R134) and R124 has a constant temperature.
The equilibrium state at a constant pressure is shown using triangular coordinates. In FIG. 2, 3 indicates a temperature of 0 ° C. and a pressure of 4.04.
Is a vapor-liquid equilibrium line of the mixture at 4 kg / cm ² G,
Further, 4 is a temperature of 50 ° C. and a pressure of 18.782 kg / cm ²
3 is a vapor-liquid equilibrium line of the mixture in G. In this case,
R23, R134 and R124 are each approximately 10 to approximately 5
A composition range of 5% by weight, 0 to about 90% by weight, and 0 to about 90% by weight is desirable because it has a vapor pressure almost equal to that of R22, and R23, R134, and R124 are each about 15 to about 45% by weight. %, 0 to about 85% by weight, 0 to about 8
A composition range of 5% 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.

FIG. 3 shows R23, R134a, 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. 3, 5 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 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) 5 is the saturated vapor phase line, and the vapor-liquid equilibrium line (corresponding to R22 0 ° C) 5
The lower line represents the saturated liquidus line, and a gas-liquid equilibrium state is reached in the range sandwiched by the two lines. 6 is temperature 5
This is a vapor-liquid equilibrium line of the mixture at 0 ° C. and a pressure of 18.782 kg / cm ² G, and this temperature and pressure also correspond 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, R23, R134a, and R124a are each approximately 1
The composition range of 0 to about 55% by weight, 0 to about 90% by weight, and 0 to about 90% 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. Furthermore, the composition range such that R23, R134a and R124a are about 10 to about 45% by weight, 0 to about 90% by weight and 0 to about 85% 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 ₃ to F ₃ in FIG. 3 is shown in (Table 3).

[0023]

[Table 3]

Point A₃~ Point C₃Is the vapor-liquid equilibrium line (R2250
On the saturated vapor line of 6) ₃~ Point F₃Is vapor-liquid equilibrium
Line (R22 50 ° C equivalent) is on the saturated liquidus line 6
The vapor-liquid equilibrium line (equivalent to R220 ° C) 5, the saturated vapor phase line, and
Gas-liquid equilibrium line (equivalent to R220 ° C) 5 both saturated liquidus lines
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 3
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 gas-liquid equilibrium line (R22 at 50 ° C.) 6 is described here, the point inside the points A ₃ to F ₃ , 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. 4 shows, using triangular coordinates, the equilibrium state of a working fluid composed of a mixture of three types of freons R23, R134 and R124a at a constant temperature and a constant pressure. In FIG. 4, 7 indicates a temperature of 0 ° C.
-Vapor-liquid equilibrium line of the mixture at a pressure of 4.044 kg / cm ² G, and 8 is a temperature of 50 ° C and a pressure of 18.78
3 is a vapor-liquid equilibrium line of the mixture at ² kg / cm ² G.
In this case, the composition range in which R23, R134, and R124a are approximately 10 to approximately 55% by weight, 0 to approximately 90% by weight, and 0 to approximately 90% by weight, respectively, has a vapor pressure substantially equal to that of R22. Therefore, it is desirable that R23, R134, and R124a are approximately 15 to approximately 45% by weight, and 0 to approximately 8 respectively.
The composition range of 5% by weight, 0 to about 85% by weight,
Especially desirable.

The composition of the working fluid at points A ₄ to F ₄ in FIG. 4 is shown in (Table 4).

[0028]

[Table 4]

Point A_Four~ Point C_FourIs the vapor-liquid equilibrium line (R2250
On the saturated vapor line of 8) _Four~ Point F_FourIs vapor-liquid equilibrium
Line (equivalent to R22 50 ° C) on the saturated liquidus line 8
The vapor-liquid equilibrium line (equivalent to R220 ° C) 7, the saturated vapor line, and
Gas-liquid equilibrium line (R220 equivalent to 0 ° C) 7 both saturated liquidus lines
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 4
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 points on the gas-liquid equilibrium line (R22 at 50 ° C.) 8 are described here, points inside the points A ₄ to F ₄ , 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.

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, trifluoromethane approximately 10 to approximately 55% by weight, tetrafluoroethane 0 to approximately 90% by weight, chlorotetrafluoroethane 0 to
The composition range of about 90% by weight is about 0 to about 50 ° C.
It is desirable because it has a vapor pressure almost equal to that of R22 at the utilization temperature of. Furthermore, trifluoromethane approximately 10 to approximately 45% by weight, tetrafluoroethane 0 to approximately 90% by weight,
A composition range of 0 to about 85% by weight of chlorotetrafluoroethane is particularly desirable because it has a vapor pressure almost equal to that of R22 at all use temperatures between 0 ° C and 50 ° C. OD especially in the above-mentioned combinations and composition ranges
P is also expected to be 0 to 0.018, 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.

[0032]

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-flammable chlorotetrafluoroethane was selected as a CFC with extremely low ozone depletion ability, and non-combustible trifluoromethane and tetrafluoroethane were selected as CFCs with almost no ozone depletion ability. Can be (3) R2 has a vapor pressure similar to that of R22 at the operating temperature of equipment that cannot be used with trifluoromethane alone.
It can be used with existing equipment as an alternative to item 2. (4) Utilizing the property 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.

FIG. 3 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. 4 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 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) 5 Gas-liquid equilibrium line ( R22 0 ° C equivalent) 6 Gas-liquid equilibrium line (R22 50 ° C equivalent) 7 Gas-liquid equilibrium line (R22 0 ° C equivalent) 8 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 types of CFCs in an amount of 10 to 55% by weight of trifluoromethane, 90% by weight or less of tetrafluoroethane, and 90% by weight or less of chlorotetrafluoroethane. 2. A working fluid comprising 10 to 45 wt% or less of trifluoromethane, 90 wt% or less of tetrafluoroethane, and 85 wt% or less of chlorotetrafluoroethane.