JPH03170589A - Working fluid - Google Patents

Abstract

PURPOSE:To obtain a working fluid which does not affect the ozonosphere and has an improved coefficient of performance by mixing trifluoromethane, trifluoroethane, and difluoroethane. CONSTITUTION:At most 50wt.% trifluoromethane is mixed with at most 80wt.% trifluoroethane and 20-90wt.% difluoroethane.

Description

[Detailed description of the invention] Industrial application field of the present invention (Part 1) Conventional technology related to working fluid used in heat pump devices such as air conditioners and refrigerators Conventional technology As a working fluid in heat pump devices such as air conditioners and refrigerators Freon (hereinafter referred to as R○○ or R○○
Halogenated hydrocarbons called halogenated hydrocarbons (denoted as ○) are known, and are usually used at a condensation temperature and/or evaporation temperature range of approximately 0 to approximately 50°C. Among them, chlorodifluoromethane (CHCIFa, R22) is known. Although it is widely used as a working fluid in home air conditioners, building air conditioners, and large refrigerators, it is still a problem that the invention attempts to solve. The use and production of fluorocarbons (hereinafter referred to as specified fluorocarbons), whose ability to deplete stratospheric ozone is limited, has already been regulated by international treaties. There is a movement to abolish the ozone depletion coefficient (trichlorofluoromethane (CCIsF)).
) has a stratospheric ozone depletion potential of 9 (hereinafter referred to as ODP) of 0. 05, and although it is not a specified CFC, usage is expected to increase in the future.
It is expected that an increase in the amount of use and production of No. 22 will have a greater impact on the living environment of humankind. Therefore, there is a strong demand for the early development of a working fluid that can replace R22, which has a small ability to deplete stratospheric ozone.

The present invention was tried in view of the above-mentioned problems, and provides a working fluid that has little effect on the stratospheric ozone layer (＼ R22).

Means for Solving the Problems The present invention solves the above-mentioned problems by using at least L trifluoromethanes (CHFs) and trifluoroethane (C
Contains three types of fluorocarbons: ++HsF*) and difluoroethane (C2HJF2) Trifluoromethane O ~ approx. 50
It is characterized by a composition range of 0 to approximately 80% by weight of trifluoroethane and approximately 20 to approximately 90% by weight of difluoroethane, particularly trifluoromethane O.
A range of about 40% by weight of trifluoroethane, 0 to about 80% by weight of difluoroethane, and about 20% to about 85% by weight of difluoroethane is desirable.

Effect of the present invention By using the above-mentioned combination, the working fluid has almost no ozone depletion ability\trifluoromethane (O D P =
0 ), trifluoroethane (O D P =0)
By forming a mixture of R22 and difluoroethane (○DP=0), the effect on the stratospheric ozone layer is even smaller than that of R22, and it is possible to almost eliminate it. By making the assembly range L, it has a vapor pressure comparable to that of R22 at temperatures of approximately 0 to approximately 50 degrees Celsius, which is the operating temperature of heat pump devices such as air conditioners and refrigerators.A working fluid that can be used in current equipment as an alternative to R22. This makes it possible to provide the following.

Therefore, ODP in the above combinations and ranges is also O
If it is predicted that it will be a very promising working fluid as a replacement for R22, such a mixture will be a non-azeotropic mixture, and will have a temperature gradient in the condensation process and evaporation process. By using a Lorrenck cycle with a high ODP level, a higher coefficient of performance can be expected than R22. The working fluid according to the present invention is composed of a mixture of three or more only fluorocarbons with a DP of 0. The present invention also makes it possible to reduce the contribution to global warming, which is estimated to be less than 30% and has recently become a worldwide problem. It is a mixture. Because trifluoromethane has a low critical temperature (25.7℃) and a high vapor pressure, it cannot be used alone in heat pump devices such as air conditioners and refrigerators that have operating temperatures of about 0 to about 50℃. force pulling
It is still commercially available at present, and by making such a mixture, it is possible to construct a working fluid that is a practical substitute for R22. This will be explained using figures.

Figure (trifluoromethane (R23), 1, 1
．． Using triangular coordinates, the equilibrium state at constant temperature and constant pressure for a working fluid treated with a mixture of three types of fluorocarbons, 1-1 difluoroethane (R143a) and 1,1 difluoroethane (R152a), is shown. In this triangular coordinate system, a single substance is placed at each vertex of the triangle in the order of decreasing boiling point, starting from the upper vertex, and in order of decreasing boiling point. ratio(
It is expressed as 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 (weight ratio) (upper) is expressed as the ratio of the distance between the point and each side of the triangle. Corresponds to the composition ratio of the substance.In the figure, 1 (upper temperature, 0°C, pressure 4.
This is the vapor-liquid equilibrium line of the mixture at 0 4 4 kg/cm2G, and this temperature and pressure correspond to the saturated state of R22. Equilibrium line (R22 equivalent to 0℃) ■
The lower line represents the saturated liquidus line, and the area between these lines is in a vapor-liquid equilibrium state. In addition, 2 (y) is the vapor-liquid equilibrium line of the mixture at a temperature of 50°C and a pressure of 18.782 kg/cm2G, and this temperature and pressure also correspond to the saturated state of R22. When R23 is used alone, 5
Q that exceeds the critical temperature at 0°C By forming such a mixture, a saturated state exists and the temperature is about 0 to about 5
It can be used in heat pump devices such as air conditioners and refrigerators that have an operating temperature of 0°C. As can be seen from the figure, E, R23, Rl43a and R152a each have a weight of 0 to approximately 50% and 9%. 0 to approximately 80% by weight, approximately 20 to approximately 90% by weight (approximately 0 to approximately 50℃)
It is desirable because it has almost the same vapor pressure as R22 at the usage temperature of R22. Furthermore, R23, R143a and Rl5
2a is O to about 40% by weight, respectively. 0 to approximately 80% by weight Approximately 20 to approximately 85% by weight
It is particularly desirable because it has a vapor pressure approximately equal to R22 at all operating temperatures between 50°C and 50°C. The working fluid combinations at points A1 to F1 in the figure are shown in the table. Points A1 to C1 are vapor-liquid equilibrium lines (equivalent to R2250°C)
On the saturated vapor phase line of 2, points D1 to F+ are on the vapor liquid equilibrium line (R
22 is on the saturated liquidus line of 2 (equivalent to 50°C), and both are on the saturated gas phase line of the vapor-liquid equilibrium line (R22 equivalent to 0°C) l and the saturated liquidus line of the vapor-liquid equilibrium line (equivalent to R22 0°C) l. Since it is within the range between the lines, the temperature is 0°C and the pressure is 4.
At 044 kg/cm2G (corresponding to the saturated state of R22), a gas-liquid equilibrium state is reached. Therefore, a working fluid having the composition shown in Table 1 (R at 0°C and 50°C)
By realizing a saturated state or a vapor-liquid equilibrium state under the condition of the saturated vapor pressure of R22, and operating at the saturated vapor pressure of R22 at the operating temperature of approximately 0 to approximately 50°C, the condensation temperature is approximately equal to that of R22.・It is possible to obtain the evaporation temperature here (Friend Vapor-Liquid Equilibrium Line (R22)
(equivalent to 50°C) 2 Points inside points A1 to F1, that is, the plate Temperature 0°C, pressure 4.0 4 4 kg/cm2G and temperature 50°C, pressure 18.7 8 2kg/cm”G (both R22
By performing the same operation for a working fluid that has a gas-liquid equilibrium state (corresponding to the saturated state of
It is possible to obtain condensation and evaporation temperatures almost equal to R22 at a usage temperature of approximately 0 to approximately 50°C.

In this embodiment, the working fluid is constituted by a mixture of three types of fluorocarbons.Of course, it is also possible to constitute the working fluid by a mixture of four or more types of fluorocarbons, including structural isomers. In particular, in the combination and assembly range described above, the DP is also expected to be 0, making it an extremely promising working fluid as an alternative to R22. In addition, such a mixture becomes a non-azeotropic mixture and has a temperature gradient in the condensation process and evaporation process. By constructing a Lorenz cycle in which the temperature difference between the heat source fluid and the heat source fluid is close to each other, a higher coefficient of performance than R22 can be expected. It is something.

Effects of the Invention As is clear from the above explanation, the present invention uses a trifluoromethane-containing working fluid as a mixture of three or more types of fluorocarbons that do not contain chlorine in their molecular structure, and specifies the range of their composition. By doing this, (1) it is possible to expand the range of selection of working fluids that have even less influence on the stratospheric ozone layer than R22, and (2) it is possible to expand the range of choices for working fluids that have almost no effect on the stratospheric ozone layer. It has a vapor pressure similar to that of R22 at the usage temperature L,,R
(3) Utilizing the temperature gradient properties of non-azeotropic mixtures, R2 can be used as an alternative to R22.
Even if it has the effect that a performance coefficient higher than 2 can be expected.

[Brief explanation of the drawing]

The figure is constructed by a mixture of three types of fluorocarbons...
Vapor-liquid equilibrium line (R'22 0℃ equivalent), - Vapor-liquid equilibrium line (
R22 equivalent to 50°C).

Claims (2)

[Claims] (1) Trifluoromethane 50% by weight or less, trifluoroethane 80% by weight or less, difluoroethane 20-90%
A working fluid containing at least three types of fluorocarbons in an amount of not more than % by weight. (2) Trifluoromethane 40% by weight or less, trifluoroethane 80% by weight or less, difluoroethane 20-85%
% by weight or less.