JPH03170584A - Working fluid - Google Patents

Abstract

PURPOSE:To obtain a working fluid which scarcely affects the ozonosphere and serves as an R22 substitute by mixing trifluoromethane, tetrafluoroethane, and difluoroethane. CONSTITUTION:A working fluid containing at least three hydrofluorocarbons, i.e., 5-50wt.% trifluoromethane, at most 95wt.% tetrafluoroethane, and at most 90wt.% difluoroethane. As the working fluid, particularly those comprising 10-40wt.% trifluoromethane, at most 85wt.% tetrafluoroethane, and at most 85wt.% difluoroethane are preferably used. The working fluid having a composition in the above-mentioned range has a vapor pressure comparable to that of R22 at about 0-50 deg.C, which is the service temperature of a heat pump of, e.g. an air conditioner or a refrigerator, and it can be employed as an R22 substitute in machinery now in use.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention (i. Conventional technology related to working fluids used in heat pump devices such as air conditioners and refrigerators) Fluorocarbons (hereinafter referred to as R○○ or R○
Halogenated hydrocarbons known as )
Although CFCs are widely used as working fluids in home air conditioners, building air conditioners, and large refrigerators, the problem that the invention attempts to solve remains the same. Regarding fluorocarbons (hereinafter referred to as specified fluorocarbons), which have a limited ability to deplete stratospheric ozone, international treaties have already regulated the use and production of fluorocarbons. There is a movement to abolish R22. Now, R22 has an ozone depletion coefficient (trichlorofluoromethane
) is 0. 05, and although it is not a specified CFC, usage is expected to increase in the future.Now that refrigeration and air conditioning equipment has become widespread, R2
Although it is expected that an increase in the amount of use and production of R22 will have a greater impact on the living environment of humankind, it is therefore expected that R22 has a small ability to deplete the abyssal ozone. There is also a strong demand for the early development of alternative working fluids.

Companion of the present invention C This was tried in view of the above-mentioned problems, and the I. x R2
The present invention provides an alternative working fluid to 2.

Means for Solving the Problems The present invention solves the above-mentioned problems.At least, trifluoromethane (CHF*), tetrafluoroethane (C2H2F-), and difluoroethane (CzHaF2) are used.
(Includes three types of fluorocarbons, trifluoromethane, approximately 5~
It is characterized by a composition range of approximately 50% by weight, tetrafluoroethane from 0 to approximately 95% by weight, difluoroethane from 0 to approximately 90% by weight, particularly trifluoromethane from approximately 1% to approximately 40% by weight, tetrafluoroethane from 0 to approximately 90% by weight. A range of about 85% by weight difluoroethane from 0 to about 85% by weight 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 =
O), tetrafluoroethane (ODPO) and difluoroethane (ODP=0), the effect on the stratospheric ozone layer is even smaller than that of R22, and it is possible to almost eliminate it. In addition, by setting the above-mentioned 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 bomb devices such as air conditioners and refrigerators.
This makes it possible to provide a working fluid that can be used in current equipment as an alternative to AR22. Therefore, the ODP in the above combination and set range is also expected to be O, h,
It is an extremely promising working fluid as an alternative to R22.a Such a mixture becomes a non-azeotropic mixture and has a temperature gradient in the condensation and evaporation processes.A Lorenz cycle in which the temperature difference between the heat source fluid and the heat source fluid is kept close is used. In general, fluorocarbons 41, which have the ability to deplete stratospheric ozone, can be expected to have a higher coefficient of performance than R22.
The effect of global warming tends to increase as the ODP value increases.The working fluid according to the present invention has an OD
The global warming effect caused by a mixture of three or more types of fluorocarbons with P of 0 is estimated to be on the same level as R22 or less than R22, which has recently become a worldwide problem. However, the present invention is particularly directed to a mixture containing three or more types of fluorocarbons, including trifluoromethane. Because trifluoromethane has a low critical temperature (25.7℃) and a high vapor pressure, it can be used alone for air conditioners and air conditioners with operating temperatures of approximately 0 to approximately 50℃.
This mixture cannot be used in heat pump devices such as refrigerators.It is still commercially available, and by making such a mixture, it is possible to construct a working fluid that can be a practical substitute for R22. Examples of working fluids according to the present invention will be explained below with reference to figures.
l, 2-tetrafluoroethane (R 1 3
4 a) Working fluid Q composed of a mixture of three types of fluorocarbons: 1,l-difluoroethane (R152a)
An equilibrium state at a constant temperature and constant pressure is shown using triangular coordinates. The ratio (weight ratio) of each precept at a certain point on the coordinate plane is expressed as the ratio of the distance between the point and each side of the triangle. This corresponds to the composition ratio of the substance written at the vertex of the triangular coordinates on the side opposite the side.
This is the vapor-liquid equilibrium line of the mixture at cm R G, and this temperature and pressure correspond to the saturated state of R22. The upper line of the vapor-liquid equilibrium line (R22, equivalent to 0℃) l represents the saturated gas phase wind. The line below the vapor-liquid equilibrium line (R22, equivalent to 0℃) l represents the saturated liquidus line, and the line sandwiched between these lines In the range 21, temperature is 50℃ and pressure is 18.
This is the vapor-liquid equilibrium line of the mixture at 782 kg/cm'G, and this temperature and pressure also correspond to the saturated state of R22.

If R23 is used alone, the critical temperature will be exceeded at 50°C α.By forming such a mixture, a saturated state will exist, and it can be used in heat pump devices such as air conditioners and refrigerators with operating temperatures of approximately 0 to approximately 50°C. It is possible to do so. As you can see from the figure, R23,
R134a and R152a are each about 5 to about 50% by weight. 0 to approximately 95% by weight Above the composition range ζ such that 0 to approximately 90% by weight R at a usage temperature of approximately 0 to approximately 50°C
Desirable because it has almost the same vapor pressure as 22 (1 Sara G,:, R23, R134a and R152a each exceed about 1O to about 40% by weight, 0 to about 90% by weight, 0 to about 85%)
It is particularly desirable to have a vapor pressure approximately equal to that of R22 at all operating temperatures between 0°C and 50°C (from point A+ to point F1 in Figure 1). The working fluid composition is shown in Table 9. Points A1 to C1 are the vapor-liquid equilibrium line (R22
Points D1 to F+ are on the saturated liquidus line of the vapor-liquid equilibrium line (equivalent to R22 5Ot) 2, and both are on the saturated vapor phase line of the vapor-liquid equilibrium line (equivalent to R220°C) l. Since it is in the range between both the saturated liquidus line and the vapor-liquid equilibrium line (R22 0℃ equivalent) 1, the temperature is 0℃ and the pressure is 4.044 kg/cm'G (R22 Therefore, the working fluid having the structure shown in Table 1 is 0℃・
By realizing a saturated state or a vapor-liquid equilibrium state under the condition of the saturated vapor pressure of R22 at 50 tons, and operating at the saturated vapor pressure of R22 at the same temperature at a usage temperature of about 0 to about 5oC, it is almost equal to R22. This makes it possible to obtain the condensation temperature and evaporation temperature.

Here, only the points on the vapor-liquid equilibrium line (R22, equivalent to 50°C) 2 are explained (top) The hole inside point A+ to point F1 Temperature 0°C, pressure 4.0 4 4 k
g/cm2G and temperature 50℃/pressure 18.782kg
/cm"G (both correspond to the saturated state of R22) By performing the same operation on a working fluid that has a gas-liquid equilibrium state, it becomes almost equal to R22 at a usage temperature of about 0 to about 50 degrees Celsius. If it is possible to obtain the condensation temperature and evaporation temperature, see Figure 2 C. R23, 1. 1, 2. 2-
Although the working fluid Q is composed of a mixture of three types of fluorocarbons, tetrafluoroethane (R134) and R152a, the equilibrium state at a constant temperature and constant pressure is shown using triangular coordinates.In these triangular coordinates, atmospheric pressure The standard boiling point of R152a is lower than that of R134.
Even if a single substance is arranged in the order of 152a, it will be 31 in Figure 2.Temperature 0℃・Pressure 4. 044kg/cm”
It is the vapor-liquid equilibrium line of the mixture at 41. Temperature 50°C and pressure 18. The vapor-liquid equilibrium line of the mixture at 782 kg/cm'G In this case, G; LR23
, R134 and R152a each in an amount of about 10 to about 50% by weight. A certain range of assembly force such that O~approximately 90% by weight, O~approximately 90% by weight<. Particularly desirable is a composition range bar in which R23, Rl34 and R152a are respectively about 15 to about 40% by weight, O to about 85% by weight, and 0 to about 85% by weight. Table 2 shows the composition of the working fluid at points A2 to F2 in FIG. Point A2 to point C2 is the vapor-liquid equilibrium line (R22
Points D2 to F2 are on the saturated liquidus line of the vapor-liquid equilibrium line (R22, equivalent to 50°C) 4, and both are on the saturated vapor line of the vapor-liquid equilibrium line (R22, equivalent to 50°C) 3. It must be within the range between the phase line and the saturated liquid phase line (equivalent to R22 0℃) 3.Temperature 0℃・Pressure 4.044 kg/cm"G (equivalent to a saturated state of
Achieve a saturated state or a vapor-liquid equilibrium state under the condition of the saturated vapor pressure of R22 at 0°C. At a usage temperature of about 0 to about 50°C, by operating at the saturated vapor pressure of R22 at the same temperature, If it is possible to obtain equal condensation and evaporation temperatures, here we explain only the points on the vapor-liquid equilibrium line (R22, equivalent to 50°C) 4, which are inside points A2 to F2. Sunawa board Temperature 0°C/Pressure 4.0 4 4
kg/cm2G and temperature 50℃/pressure 1 8.7 8
By performing the same operation on a working fluid that has a gas-liquid equilibrium state at 2 kg/cm2G (both correspond to the saturated state of R22), condensation approximately equal to that of R22 can be obtained at a usage temperature of approximately 0 to approximately 50°C. This makes it possible to obtain temperature and evaporation temperature.

In the above embodiments, the working fluid is constituted by a mixture of three types of fluorocarbons.It is of course possible to configure the working fluid by a mixture of four or more types of fluorocarbons, including structural isomers. In the case, trifluoromethane approximately 5 to approximately 50% by weight tetrafluoroethane 0 to approximately 95% by weight
Weight % Difluoroethane O to approximately 90% by weight (with R
It is desirable because it has almost the same vapor pressure as 22. Furthermore, trifluoromethane approximately 10 to approximately 40% by weight, tetrafluoroethane 0 to approximately 85% by weight, and difluoroethane 0 to approximately 85% by weight.
The composition range is approximately 85% by weight {0℃ and 50℃
It is particularly desirable because it has almost the same vapor pressure as R22 at all operating temperatures between (℃) ○DP is also expected to be 0 especially in the above-mentioned combinations and ranges tt R2
This is a very promising working fluid as an alternative to 2. In addition, such a mixture becomes a non-azeotropic mixture, and 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 is expected. Effects of the Invention As is clear from the above explanation, the working fluid containing trifluoromethane is a mixture of three or more types of fluorocarbons that do not contain chlorine in their molecular structure.
By specifying the range of the composition, it is possible to (1) expand the range of selection of working fluids that have even less influence on the bottom ozone layer than R22, and have almost no effect;

(2) Trifluoromethane alone has a vapor pressure similar to that of R22 at the operating temperature of equipment where it cannot be used.
It can be used in current equipment as an alternative to .22.

(3) Taking advantage of the temperature gradient properties of non-azeotropic mixtures, R2
Even if it has the effect of being able to expect a higher precept coefficient than 2.

[Brief explanation of the drawing]

Figures 1 to 2 (Table) A mixture of three types of fluorocarbons is present. 1, 3... Vapor-liquid equilibrium line (R22 equivalent to 0°C), 2
, 4 Vapor-liquid equilibrium line (equivalent to R2 2 5 O°C).

Claims (2)

[Claims] (1) Trifluoromethane 5-50% by weight or less, tetrafluoroethane 95% by weight or less, difluoroethane 90%
A working fluid containing at least three types of fluorocarbons in an amount of not more than % by weight. (2) Trifluoromethane 10-40% by weight or less Tetrafluoroethane 85% by weight or less, difluoroethane 85%
% by weight or less.