JPH03172384A - Working fluid - Google Patents

Abstract

PURPOSE:To obtain a working fluid, containing trifluoromethane, difluoromethane and difluoroethane at a specific ratio with hardly any influence on the stratospheric ozonosphere and substitutive for chlorodifluoromethane (R22). CONSTITUTION:The objective working fluid containing at least three kinds of fluorocarbons of (A) <=50wt.% (preferably <=40wt.%) trifluoromethane (R23), (B) <=60wt.% (preferably <=50wt.%) difluoromethane (R32) and (C) 40-90wt.% (preferably 50-85wt.%) 1,1-difluoroethane (R152a). The aforementioned working fluid is used for heat pump devices of air conditioners, refrigerators, etc.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a working fluid used in heat pump devices such as air conditioners and refrigerators. Freon (hereinafter referred to as RO○ or R○○
Among them, halogenated hydrocarbons called chlorodifluoromethane (CHCI F2, R22 )
Although it is widely used as a working fluid in home air conditioners, building air conditioners, and large refrigerators, the problem that the invention is trying to solve is only limited. Regarding fluorocarbons (hereinafter referred to as specified fluorocarbons), which have a large ability to deplete stratospheric ozone, the usage and production amounts have already been regulated by international treaties, and furthermore, in the future, the use and production of specified fluorocarbons will be restricted.
Now, there is a movement to abolish production of R22.
The stratospheric ozone depletion capacity (hereinafter referred to as ODP) is as small as 0.05, assuming that the stratospheric ozone depletion capacity of ) is 1, and although it is not a specified CFC, its usage is expected to increase in the future. Although it is expected that the increase in the use and production of the now widely used &R22 will have a greater impact on the living environment of humankind, it is therefore thought that the stratospheric ozone depleting ability is small, but it is said that it has some depleting ability. Although there is a strong demand for the early development of a working fluid to replace R22, none of the fluids that have been tried in view of the above-mentioned problems have a negligible effect on the stratospheric ozone layer. Means for Solving the Problems The present invention solves the above problems by using at least k" trifluoromethanes (CHFs) and difluoromethanes (C
HI! Contains three types of fluorocarbons: F2) and difluoroethane (C2HaF2), trifluoromethane 0 to approximately 50% by weight, difluoromethane 0 to approximately 60% by weight, and difluoroethane approximately 40 to approximately 90% by weight. In particular, a composition range of trifluoromethane 0 to approximately 40% by weight, difluoromethane 0 to approximately 50% by weight, and difluoroethane approximately 50 to approximately 85% by weight is desirable. ,゛Has almost no ozone depletion ability (\Trifluoromethane (ODP), a fluorocarbon that does not contain chlorine in its molecular structure.
= O), difluoromethane (OD P = 0), and difluoroethane (ODP = O), it is possible to make the effect on the stratospheric ozone layer even smaller than R22 and almost eliminate it. Furthermore, by having the above-mentioned composition range, the present invention has a vapor pressure comparable to that of R22 at approximately 0 to approximately 50 degrees Celsius, which is the usage temperature of heat pump devices such as air conditioners and refrigerators, and is an alternative to R22. This makes it possible to provide a working fluid that can be used in current equipment. Therefore, the ODP in the above combination and composition range is expected to be 0.
This mixture is a non-azeotropic mixture and has a temperature gradient in the condensation and evaporation processes. By configuring the cycle, a higher coefficient of performance than R22 can be expected.

In addition, general
It is estimated that the effect of global warming is the same as that of R22 or less than that of R22, which is composed of a mixture of three or more types of fluorocarbons in which O is O. The present invention is particularly applicable to mixtures of three or more types of fluorocarbons, including trifluoromethane. Trifluoromethane has a low critical temperature (25.7°C) and a low vapor pressure. Because of the high Examples Below, examples of working fluids according to the present invention will be explained using figures (trifluoromethane (R23), difluoromethane (R32) , 1. 1-difluoroethane (Rl
For the working fluid composed of a mixture of the three types of fluorocarbons in 52 a), the equilibrium state at a constant temperature and constant pressure is shown using triangular coordinates.In this triangular coordinate, the upper vertex is Single substances are arranged counterclockwise as a base point in descending order of boiling point, and the composition ratio (weight ratio) of each component at a certain point on the coordinate plane (Y) is expressed as the ratio of the distance between the point and each side of the triangle. Also, in this case, the distance method between a point and the side of a triangle corresponds to the composition ratio of the substance written at the vertex of the triangular coordinates on the side opposite the side. k
This is the vapor-liquid equilibrium line of the mixture at g/cm"G, and this temperature and pressure correspond to the saturated state of R22. The line above l is the saturated vapor phase line. Vapor-liquid equilibrium line (equivalent to R220℃). The line below the line (R220℃ equivalent) ■ represents the saturated liquidus line L The range between these two lines is in a state of vapor-liquid equilibrium.Table 2C Temperature 50℃, pressure 18.782k
This is the vapor-liquid equilibrium line of the mixture at g7cm2G, and this temperature and pressure also correspond to the saturated state of R22.

If R23 is used alone, the temperature will exceed the critical temperature at 50℃, but by forming such a mixture, a saturated state will exist, and it can be used in heat pump equipment such as air conditioners and refrigerators with operating temperatures of approximately 0 to approximately 50℃. It is possible to do so.

As can be seen from the figure, R23, R32 and R152a are each 0 to approximately 50% by weight, and 0 to approximately 60% by weight, approximately 40% by weight.
~ approximately 90% by weight composition range (approximately 0~approximately 5%
It is desirable because it has almost the same vapor pressure as R22 at the usage temperature of 0°C ~ Furthermore, R23, R32 and R1
Composition range 1 Table θ such that 52a is 0 to approximately 40% by weight, 0 to approximately 50% by weight, and approximately 50 to approximately 85% by weight, respectively.
Particularly desirable since it has a vapor pressure almost equivalent to R22 at all operating temperatures between ℃ and 50℃.
1- The composition of the working fluid at point F+ is shown in the table. Point A1
- Point C1 is above the saturated gas phase line of the vapor-liquid equilibrium line (corresponding to R2250°C) 2 Point D1 to point F+ are above the vapor-liquid equilibrium line (R2250°C equivalent)
If it is on the saturated liquidus line of 2 (equivalent), the same number 2 vapor-liquid equilibrium line (
The saturated gas phase line and vapor-liquid equilibrium line (R2 equivalent to 220°C)
Temperature 0℃, pressure 4.044kg/cm2G
(corresponding to the saturated state of R22). Therefore, the working fluid having the composition shown in Table 1 (corresponding to the saturated state of R22 at 10°C and 50°C) is in a vapor-liquid equilibrium state. Achieves a gas-liquid equilibrium state of about 0 to about 5
At a usage temperature of 0° C., by operating at the saturated vapor pressure of R22 at the same temperature, it is possible to obtain condensation and evaporation temperatures almost equal to those of R22.

Here, only the points on the vapor-liquid equilibrium line (corresponding to R2250°C) 2 are explained.The point inside point A1-point F1, that is, the cane Temperature 0°C, pressure 4°044 kg/
cm2G and temperature 50℃, pressure 18゜782kg/cm
By performing the same operation on a working fluid having a composition that reaches a vapor-liquid equilibrium state at "G" (both correspond to the saturated state of R22), the condensation temperature and This makes it possible to obtain the evaporation temperature.

In this embodiment, the working fluid is composed of a mixture of three types of fluorocarbons.Of course, the working fluid can also be composed of a mixture of four or more types of fluorocarbons, including structural isomers. The ODP is also expected to be 0 in the combination and composition range.It is a very promising working fluid as an alternative to R22.In addition, such a mixture will be a non-azeotropic mixture and will have a temperature gradient in the condensation and evaporation processes.Heat source fluid By configuring a Lorenz cycle with a temperature difference close to that of R22, a higher coefficient of performance than R22 can be expected. By making the fluid a mixture of three or more types of fluorocarbons that do not contain chlorine in their molecular structure, and by specifying the composition range, (1) the impact on the stratospheric ozone layer is even smaller than that of R22; Although it is possible to expand the range of selection of working fluids, (2) trifluoromethane alone cannot be used because it has a vapor pressure comparable to that of R22 at the operating temperature of the equipment;
(3) Utilizing the temperature gradient properties of non-azeotropic mixtures, R2 can be used as an alternative to R2.
It has the effect of being able to expect a higher coefficient of performance than 2.a

[Brief explanation of the drawing]

Figure (Friend) Composed of a mixture of three types of fluorocarbons 1...
- Vapor-liquid equilibrium line (equivalent to R220°C), 2... Vapor-liquid equilibrium line (equivalent to R2250°C).

Claims (2)

[Claims] (1) A working fluid containing at least three types of fluorocarbons: 50% by weight or less of trifluoromethane, 60% by weight or less of difluoromethane, and 40 to 90% by weight of difluoroethane. (2) A working fluid characterized by containing 40% by weight or less of trifluoromethane, 50% by weight or less of difluoromethane, and 50 to 85% by weight of difluoroethane.