JPH03168288A - Working fluid - Google Patents

Abstract

PURPOSE:To provide a working fluid reduced in the affection thereof on the ozone layer of the stratosphere and employed as a substitute of dichlorodifluoromethane (R12) by containing trifluoromethane, chlorodifluoromethane and tetrafluoroethane in a specific ratio. CONSTITUTION:The objective working fluid contains at least three kinds of freons comprising (A) <=25wt.% (preferably <=15wt.%) of trifluoromethane (R23), (B) <=45wt.% (preferably <=35wt.%) of chlorodifluoromethane (R22) and (C) 55-95wt.% (preferably 65-95wt.%) of 1,1,2,2-tetrafluoroethane (R134). The working fluid is employed in freezers, heat pumps, etc.

Description

[Detailed Description of the Invention] Industrial Application Field of the Invention 1 Conventional technology related to working fluids used in refrigerators, heat pumps, etc. A halogenated hydrocarbon called R○○ or R○○○ is known, and its usage temperature ranges from 0 to 50% condensation temperature and/or evaporation temperature.
Among them, dichlorodifluoromethane (CCleF2, R12) is widely used as a working fluid in refrigeration kites, car air conditioners, large refrigerators, etc. However, the problem that the invention aims to solve has recently changed due to fluorocarbons. Depletion of the stratospheric ozone layer has become a global environmental problem, and international treaties have already regulated the amount of fluorocarbons used and produced (hereinafter referred to as specified fluorocarbons), which have a large ability to deplete the stratospheric ozone. Furthermore, there is a movement to abolish the use and production of specific CFCs in the future.Now, R12 is the ozone depletion coefficient (trichlorofluoromethane (CCl$F)).
The stratospheric ozone depletion potential (hereinafter referred to as ODP) is 1. 0 specified fluorocarbons, and is now widely used in refrigeration and air conditioning equipment.
Reducing the amount of R12 used and produced will have a tremendous impact on the human living environment.1 Therefore, its ability to deplete stratospheric ozone is small, and there is a strong demand for the early development of a working fluid that can replace R12. There is.

Invention 1 This invention was tried in view of the above-mentioned problems, and provides a working fluid that has a small influence on the stratospheric ozone layer and can be used as an alternative to I, X, and Rl2.

Means for Solving the Problems The present invention is an attempt to solve the above-mentioned problems.
a) and at least three types of fluorocarbons, including tetrafluoroethane (C2H2F4), trifluoromethane 0 to 2
5% by weight Chlorodifluoromethane 0 to 45% by weight Tetrafluoroethane is characterized by a composition range of 55 to 95% by weight, especially trifluoromethane 0 to 15% by weight Chlorodifluoromethane θ to 35% by weight
Although a composition range of 65% to 95% by weight of tetrafluoroethane is desirable, it is possible to use the working fluid of the present invention with trifluorofluorocarbons, which are fluorocarbons that do not contain chlorine in their molecular structure and have little ability to deplete ozone. lomethane (O D P = 0) and tetrafluoroethane (O D P = O), and chlorodifluoromethane (ODP = 0.
By forming a mixture of at least three of 05),
It is possible to make the influence on the stratospheric ozone layer much smaller than that of RI2.The present invention also reduces the operating temperature of refrigerators, heat bombs, etc. by using the above-mentioned range. It is possible to provide a working fluid that has a vapor pressure similar to that of R12 at ~50°C and can be used in current equipment as an alternative to R12, especially ODP in the above combinations and ranges. is O-0.02, making it an extremely promising working fluid as an alternative to R12.

In addition, such a mixture becomes a non-azeotropic mixture, and a higher performance coefficient than R12 is expected by constructing a Lorenz cycle in which the temperature difference with the heat extraction source fluid is close to each other with a temperature gradient in the condensation process and evaporation process. Even if it is possible, the present invention is particularly applicable to a mixture of three or more types of fluorocarbons including trifluoromethane. Trifluoromethane ζ has a low critical temperature (25.7°C) and a high vapor pressure, so it cannot be used alone. U% cannot be used in refrigerators, heat pumps, etc. where the temperature ranges from 0 to 50℃. By mixing the third fluorocarbon, it is possible to make the vapor pressure of the mixture almost equivalent to R12 and to obtain a working fluid with a small ODP. An example will be explained using a diagram. Figure 1 ζ Trifluoromethane (R23), chlorodifluoromethane (R22), 1, l, 2.2
- A working fluid composed of a mixture of three types of fluorocarbons, such as tetrafluoroethane (R134) α The equilibrium state at constant temperature and constant pressure is shown using triangular coordinates. In this triangular coordinate, U is each vertex of a triangle. The single substances are arranged counterclockwise from the upper vertex as the base point in descending order of boiling point, and the ratio (weight ratio) of each precept at a certain point on the coordinate plane is given by the point and each side of the triangle. In this case, the distance between the point and the side of the triangle {upper corresponds to the composition ratio of the substance marked at the vertex of the triangular coordinates on the side opposite the side. This is the vapor-liquid equilibrium line of the mixture at a temperature of 0°C and a pressure of 2.1 1 6 kg/cm2G, and this temperature and pressure are R12
The line above the vapor-liquid equilibrium line (R12 corresponds to 0°C) is the saturated vapor phase vapor-liquid equilibrium line (Rl2
The line below 1 (equivalent to 0℃) represents the saturated liquidus line, and the area between these lines is in a state of vapor-liquid equilibrium.
This is the vapor-liquid equilibrium line of the mixture in gG, and this temperature and pressure also correspond to the saturated state of Rl2.4 If R23 is used alone, the critical temperature will be exceeded at 50℃Q.Saturation can be achieved by forming such a mixture. It can be used in refrigerators, heat pumps, etc. whose operating temperature is O to 50℃.As you can see from the figure, R23, R22, and R134 are each O to 2
5% by weight, 0 to 45% by weight, 55 to 95% by weight (upper R at usage temperature of 0 to 50℃)
It is desirable that L~=R23, R22 and Rl34 are each O~15 because they have a vapor pressure almost equal to that of 12.
Weight: 0 to 35 weight % 65 to 95 weight %. Surrounded! ．． It is particularly desirable because it has nearly the same vapor pressure as R12 at all operating temperatures between 0°C and 50°C.1 Particularly in the above-mentioned combinations and combinations, ODP in certain ranges is between 0 and 0. Table 1 shows the set of working fluids and ODP at points A1 to F1 in FIG. Points A1 to Ct are the vapor-liquid equilibrium line (
R12 (equivalent to 50℃) 2 on the saturated gas phase line &ζ Point Fl
is on the saturated liquid line of the vapor-liquid equilibrium line (Rl2 equivalent to 50°C) 2, and also on the saturated vapor line and the vapor-liquid equilibrium line (R
12 (equivalent to 0°C) The board must be in the range between the lines of the saturated liquidus line of l. 1 1 6
kg/cm"G (corresponding to the saturated state of Rl 2), there is a vapor-liquid equilibrium state. Also, point DI and point E1 are on the saturated liquid line of the vapor-liquid equilibrium line (R12, equivalent to 0°C) 1, and the gas-liquid Keep the temperature within the range between the saturated vapor line of equilibrium line (Rl2, equivalent to 50°C) 2 and the saturated liquidus line of vapor-liquid equilibrium line (Rl2, equivalent to 50°C) 2.
℃・Pressure 11. At 373 kg/cm''G (corresponding to the saturated state of R12), there is a gas-liquid equilibrium state.
Realizes a saturated state or a vapor-liquid equilibrium state under the condition of R12's saturated vapor pressure at 50°C l- At a usage temperature of 0 to 50°C, by operating at R12's saturated vapor pressure at the same temperature, it is almost equal to R12. Although it is possible to obtain the condensation temperature and evaporation temperature, here we only explain points on the vapor-liquid equilibrium line (R120℃ equivalent) 1 or the vapor-liquid equilibrium line (R12 equivalent to 50℃) 2. The structure inside A1 to point F1 has a temperature of 0°C and a pressure of 2. By performing the same operation for a working fluid that has a composition that is in a vapor-liquid equilibrium state at 116 kg/cm"G and a temperature of 50 ° C. and a pressure of 11.373 kg/cm"G (both correspond to the saturated state of R12), It is possible to obtain condensation and evaporation temperatures that are approximately equal to Rl2 at a usage temperature of 0 to 50°C.

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. Such a mixture becomes a non-azeotropic mixture and has a temperature gradient in the condensation process and the evaporation process. By creating 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 performance coefficient than R12 can be expected. It is.

Effects of the InventionAs is clear from the above explanation, the present invention (including upper trifluoromethane) uses three types of working fluids: fluorocarbons that do not contain chlorine in their molecular structure, and fluorocarbons that contain both chlorine and hydrogen in their molecular structure. From the above, it is possible to identify which mixtures are effective and by specifying the range of composition. (1) It is possible to expand the range of selection of Q working fluids in order to make the influence on the stratospheric ozone layer much smaller than that of R12. Demo (2) L.Rl has a vapor pressure similar to R12 at the operating temperature of equipment that cannot be used with trifluoromethane alone.
Although it can be used with current equipment as an alternative to (3) Rl
Even if it has an effect such as being able to expect a higher performance coefficient than 2.

[Brief explanation of the drawing]

Figure 1! Working fluid Q composed of a mixture of three types of fluorocarbons is a diagram showing the equilibrium state at constant temperature and constant pressure using triangular coordinates. 1... Vapor-liquid equilibrium line (R1 equivalent to 20°C), 2... Vapor-liquid equilibrium line (R12 equivalent to 50°C).

Claims (2)

[Claims] (1) Trifluoromethane 25% by weight or less, chlorodifluoromethane 45% by weight or less, tetrafluoroethane 5
A working fluid containing at least three types of fluorocarbons in an amount of 5 to 95% by weight. (2) Trifluoromethane 15% by weight or less, chlorodifluoromethane 35% by weight or less, tetrafluoroethane 6
A working fluid containing at least three types of fluorocarbons in an amount of 5 to 95% by weight.