JPH03170583A - Working fluid - Google Patents

Abstract

PURPOSE:To obtain a working fluid which scarcely affects the ozonosphere and serves as an R22 substitute by mixing pentafluoroethane, trifluoroethane, and difluoroethane. CONSTITUTION:A working fluid containing at least three hydrofluorocarbons, i.e., at most 85wt.% pentafluoroethane, at most 80wt.% trifluoroethane, and 15-35wt.% difluoroethane. As the working fluid, particularly those comprising at most 80wt.% pentafluoroethane, at most 80wt.% trifluoroethane, and 20-30wt.% 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 the Invention The present invention relates to a working fluid used in heat pump devices such as air conditioners and refrigerators.

Conventional technology has been around for a long time.In heat pump devices such as air conditioners and refrigerators, fluorocarbons (hereinafter referred to as R○○ or R○
Halogenated hydrocarbons called as )
Although it is widely used as a working fluid in home air conditioners, building air conditioners, large refrigerators, etc., the problem that the invention is trying to solve has changed.In recent years, the depletion of the stratospheric ozone layer by fluorocarbons has become a global environmental problem. The amount of use and production of fluorocarbons (hereinafter referred to as specified fluorocarbons) has already been regulated by international treaties, and the use and production of specified fluorocarbons will be regulated in the future. There is a movement to abolish production. Now, R22 is the ozone depletion coefficient (trichlorofluoromethane (CC+t
F)'s stratospheric ozone depletion ability (9), where the stratospheric ozone depletion ability is l (hereinafter referred to as ○DP) 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,
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 only a small ability to deplete stratospheric ozone.

The present invention was attempted in view of the above-mentioned problems, and is intended to provide a working fluid that can be used as an alternative to 8R22 and has little effect on the stratospheric ozone layer.

Means for Solving the Problems The present invention aims to solve the above-mentioned problems.
It is characterized by containing three types of fluorocarbons: pentafluoroethane O to approximately 85% by weight, trifluoroethane 0 to approximately 80% by weight, difluoroethane approximately 15 to approximately 35% by weight, and particularly Pentafluoroethane O ~ about 80 weight group Trifluoroethane O ~ about 80 weight group
Weight % A composition range of about 20 to about 30 weight % difluoroethane is desirable.

Effect of the present invention (by the above combination), the working fluid can be converted to pentafluoroethane (ODP = 0), which is a fluorocarbon that does not contain chlorine in its 8-molecular structure and has little ozone depletion ability.
By forming a mixture of trifluoroethane (○DP=0) and difluoroethane (○DP=O), the effect on the stratospheric ozone layer is even smaller than that of R22, and it is possible to almost eliminate it. Amo Mata
By setting the above-mentioned set within a certain range, the present invention can reduce the operating temperature of heat pump devices such as air conditioners and refrigerators from approximately O to
It has a vapor pressure similar to that of R22 at approximately 50℃ L,,R
This makes it possible to provide a working fluid that can be used in current equipment as an alternative to 22. Therefore, the ODP in the above combination and group range is expected to be 0 h R2
This mixture becomes a non-azeotropic mixture and has a temperature gradient in the condensation process and the evaporation process. CFCs can be expected to have a higher coefficient of performance than R22, but they also generally have the ability to deplete stratospheric ozone. A certain force t The working fluid according to the invention is ODP
It is composed of a certain mixture of three or more types of fluorocarbons, where O is the only fluorocarbon, and the global warming effect is estimated to be the same as or less than R22.It is said that the global warming effect has recently become a worldwide problem. This also makes it possible to reduce the contribution of

EXAMPLES Hereinafter, examples of working fluids according to the present invention will be described with reference to the drawings.

Figure 1 Bentafluoroethane (R125), 1,1
．． 1-trifluoroethane (R143a), 1,l-
A working fluid Q composed of a mixture of three types of fluorocarbons, difluoroethane (R 1 5 2 a), at a constant temperature
An equilibrium state at a constant pressure is shown using triangular coordinates. The ratio (weight ratio) of each part at a point on the plane is expressed as the ratio of the distance between the point and each side of the triangle.In this case, the distance between the point and the side of the triangle is relative to the side. It corresponds to the composition ratio of the substance written at the vertex of the triangular coordinates on the side where the
Pressure 4. This is the vapor-liquid equilibrium line of the mixture at 044 kg/cm"G, and this temperature and pressure correspond to the saturated state of R22. The line above l is the saturated vapor phase line. Line (corresponding to R22 0℃) The lower line of 1 represents the saturated liquidus line, and the range between these lines is in vapor-liquid equilibrium state. 2 is the temperature 50
℃・Pressure 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. As can be seen from the figure, E.Rl25, RI
43a and Rl52a each contain O to approximately 85% by weight. O
R22 at a service temperature of approximately 0 to approximately 50°C.
It is desirable because it has almost the same vapor pressure as 4.
Rl25, R143a and R152a are each from 0 to
Approximately 8o weight 0 to approximately 80% by weight Approximately 20 to approximately 30% by weight
It is particularly desirable because it has a vapor pressure almost equivalent to R22 at all operating temperatures between 0°C and 50°C.

The table shows the combination of working fluids at points A1 to F1 in the figure; Points A1 to C1 are on the saturated gas phase line of the gas-liquid equilibrium line (corresponding to R2250°C) 2; Points D1 to F1 are gas-liquid. Equilibrium line (
The image of the saturated vapor line of the vapor-liquid equilibrium line (R22 equivalent to 0°C) l and the saturated liquidus line of the vapor-liquid equilibrium line (R22 equivalent to 0°C) l. Since it is within the range between the lines, the temperature is 0°C and the pressure is 4.
044kg/cm2G (equivalent to the saturated state of R22)
At this point, there is a gas-liquid equilibrium state. Therefore, the working fluid (above) having the composition shown in Table 1 realizes a saturated state or a vapor-liquid equilibrium state under the conditions of the saturated vapor pressure of R22 at 0°C and 50°C, and the operating temperature is approximately 0 to approximately 50°C. In,
By operating at the saturated vapor pressure of R22 at the same temperature, it is possible to obtain almost the same condensation and evaporation temperatures as R22.
2 (equivalent to 50℃) Force intersection explained only for the points on 2 The temperature O of the area inside the points A1 to F1
℃・Pressure 4.044 kg/cm2G and temperature 50℃・pressure 18.7 8.2 kg/cm"G (both correspond to the saturated state of R22) By operating the fluid in the same manner, it is possible to obtain condensation and evaporation temperatures approximately equal to R22 at a usage temperature of approximately 0 to approximately 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; The ODP in a certain range of combinations and compositions is also expected to be O, making it a very promising working fluid as an alternative to R22. A higher coefficient of performance than R22 can be expected by observing the Lorenz cycle in which the temperature difference with the heat source fluid is made close to that of the heat source fluid.

Effects of the Invention As is clear from the above explanation, the present invention (by making the working fluid a certain mixture of three or more types of fluorocarbons that do not contain chlorine in their molecular structure and specifying the range of the composition) 1) It is possible to expand the range of selection of working fluids that have an even smaller influence on the stratospheric ozone layer than R22, and have almost no effect.

(2) It has a vapor pressure comparable to that of R22 at the operating temperature of the equipment, and can be used in current equipment as an alternative to R22.

(3) Taking advantage of the temperature gradient properties of non-azeotropic mixtures, R2
This has the effect that a higher performance coefficient can be expected than that of 2.

4.

[Brief explanation of the drawing]

Figure (Yo) 1 ・Vapour-liquid equilibrium line (R 2 2 (equivalent to 0℃), 2 ・Vapour-liquid equilibrium line (R2 2 5 (equivalent to 0°C).

Claims (2)

[Claims] (1) Pentafluoroethane 85% by weight or less, trifluoroethane 80% by weight or less, difluoroethane 15-3
A working fluid containing at least three types of fluorocarbons in an amount of 5% by weight or less. (2) Pentafluoroethane 80% by weight or less, trifluoroethane 80% by weight or less, difluoroethane 20-3
A working fluid characterized in that its content is 0% by weight or less.