JPH0433989A - Cooling medium - Google Patents

Abstract

PURPOSE:To provide a cooling medium not decomposing the ozone layer, having excellent thermal stability and flame safety and compatible with polyglycol oil, etc., by employing a mixture of 1,1,2,2-tetrafluoroethane and 1,1,2- trifluoroethane. CONSTITUTION:The objective cooling medium comprises a mixture of (A) 1,1,2,2- tetreafluoroethane (R-134) and (B) 1,1,2-trifluoroethane (R-143) preferably in a molar ratio of 99-4:1-96. The compounding ratio of the components A:B preferably 60-30:40-70 when prominence is given to the achievement coefficient of cooling cycles, 4-20:96-80 for the air conditioning of high temperature circumstances such as cab coolers or 99-80:1-20 for room air conditioners, car air conditioners or electric refrigerators.

Description

[Detailed description of the invention] Industrial applications The present invention relates to refrigerants.

BACKGROUND ART Conventionally, as working fluids or refrigerants, chlorofluorocarbons, fluorocarbons, azeotropic compositions thereof, and compositions in the vicinity thereof have been known. Of these,
Currently, the working fluids for refrigerators include R-110 (dichlorofluoromethane), R-12 (dichlorodifluoromethane), and R-114 (1,2-dichloro-1,1,2,2
-tetrafluoroethane), R-22 (chlorodifluoromethane), etc. are mainly used. however,
In recent years, it has been pointed out that certain types of chlorofluorocarbons that do not contain hydrogen can deplete the stratospheric ozone layer when released into the atmosphere, resulting in serious adverse effects on the earth's ecosystems, including humans. ing. Therefore, the use and production of these hydrogen-free chlorofluorocarbons, which have a high possibility of destroying the stratospheric ozone layer, has been restricted by international agreements.

As the hydrogen-free chlorofluorocarbon that is subject to restrictions, R-11, which is widely used as described above,
Examples include R-12 and R-114.

Restrictions on the use and production of these refrigerants, whose demand is increasing every year with the spread of refrigeration and air-conditioning equipment, have a large impact on the current social structure as a whole, including the living environment. Therefore, there is an urgent need to develop a new refrigerant that has no or very low risk of causing the problem of stratospheric ozone depletion.

Means for Solving the Problems The inventor of the present invention sought to find a refrigerant suitable for refrigerators, and of course, developed a new refrigerant that would not affect the ozone layer in the stratosphere even if released into the atmosphere. Get the refrigerant (,
I have conducted various research. As a result, it was found that a mixture of 1,1.2.2-tetrafluoroethane and 1,1.2-)lifluoroethane meets the requirements for the purpose.

That is, the present invention relates to a refrigerant consisting of a mixture of 1,1,2,2-tetrafluoroethane and 1,1,2-trifluoroethane.

The main physical properties of 1,1,2,2-tetrafluoroethane (hereinafter referred to as R-134) used in the present invention are as follows.

Boiling point -19.8℃ Critical temperature 119℃ Molecule j1 102. 032 Flammability
On the other hand, the main physical properties of 1,2,2-trifluoroethane (hereinafter referred to as R-143) used in combination with R-134 are as follows.

Boiling point: 5°C Critical temperature: 158°C Molecular weight: 84.041 Flammability Yes In the present invention, the mixing ratio of R-134 and R-143 is generally the former: the latter = 9 in 100 moles of the refrigerant mixture.
It is preferable to set it as 9-4:1-96. R-134:
More specifically, when focusing on the coefficient of performance of the refrigeration cycle, the mixing ratio of R-143 is 60-30:40-7.
It is more preferable to set it to 0, and in the case of air conditioning applications in high-temperature environments such as cab coolers, it is 4 to 20: 96 to
80 is more preferable, and for use in room coolers, car coolers, electric refrigerators, etc., it is 99 to 99.
It is preferable to set it as 80:1-20. From the viewpoint of non-flammability, the proportion of R-134 in 100 moles of mixed refrigerant should be 7.
It is desirable that the amount is 0 mole or more. R-143 has good compatibility with certain synthetic lubricating oils, whereas R-1
No. 34 has poor compatibility. Therefore, R-1 with excellent compatibility
By incorporating at least 1% of 43, the oil return characteristics in the refrigeration cycle are greatly improved, and as a result, the situation where lubricating oil accumulates on the low temperature side and seizes the sliding parts of the compressor is prevented. In addition to preventing this, gas leaks can be easily found by looking at the oil leaks. On the other hand, refrigerant 100
If the ratio of R-143 in moles exceeds 96 moles, the vapor pressure of the mixed refrigerant will become too low, and the low pressure side pressure of the refrigeration cycle will always be below atmospheric pressure. If there is a place where air can get mixed in, air can enter the system, and combined with the fact that the mixed gas has a flammable composition ratio, if sparks are generated from the built-in motor etc., an explosion can occur. There is a risk of causing

A stabilizer can be used in combination with the refrigerant of the present invention, if necessary. That is, when a high degree of stability is required under harsh usage conditions, epoxides such as propylene oxide, 1,2-butylene oxide, and glycidol; phosphors such as dimethyl phosphite, diisopropylphosphite, and diphenyl phosphite are phytes; thiophosphites such as trilauryl trithiophosphite; phosphine sulfides such as triphenoxyphosphine sulfide and trimethylphosphine sulfide; boron such as boric acid, triethylborate, triphenylborate, phenylboronic acid, and diphenylboronic acid Compounds; Phenols such as 2,6-di-tert-butyl para-cresol; Nitroalkanes such as nitromethane and nitroethane; Acrylic acid esters such as methyl acrylate and ethyl acrylate; Other dioxane, tert-butanol, pentaerythritol, A stabilizer such as barisopropenyltoluene may be added in an amount of about 0.01 to 5% of the weight of the working fluid.

Further, other compounds may be mixed with the mixture of the present invention within a range that does not impair the purpose or effect of the present invention. Examples of such compounds include ethers such as dimethyl ether and pentafluorodimethyl ether; amines such as perfluoroethylamine; and LPG.

Effects of the Invention The mixed refrigerant according to the present invention has each component that is easily decomposed and does not contain chlorine atoms, which have a strong ability to destroy the ozone layer, so there is no risk of causing the problem of depletion of the ozone layer in the stratosphere.

Furthermore, as is clear from Table 1 below, the refrigerant according to the present invention is superior to R-114, which is currently used as a refrigerant for cab coolers, in terms of coefficient of performance and cooling ability, and the discharge gas temperature Performance is also well balanced.

Further, since the refrigerant according to the present invention has low solubility in high molecular compounds, it can be used as is without changing the materials in existing refrigerators.

Furthermore, although the refrigerant of the present invention has excellent thermal stability and is nonflammable or slightly flammable, under normal usage conditions there is no place where the vapor pressure is below atmospheric pressure, so there is no risk of gas leakage. However, air does not enter the system, and therefore, the refrigerant and air do not mix in a flammable ratio, so it is highly safe.

Furthermore, the refrigerant according to the invention is not compatible with mineral oils, but is compatible with certain synthetic oils (eg, polyglycol oils).

EXAMPLES Examples will be shown below to further clarify the features of the present invention.

Example 1 In a 1 horsepower refrigerator using R-143 and/or R-134 as a refrigerant, the evaporation temperature of the refrigerant in the condenser was 5°C, the condensation temperature was 75°C, and the degree of superheat was 5°C.
℃, and the condenser supercooling degree was 2℃.

Table 1 shows refrigerant composition (mol%), (I) coefficient of performance and (
II) Shows the relationship between refrigeration capacity [kcal/hr].

Note that Table 1 also shows the results when R-114 was used for comparison.

Table 1 2.78 2.95 3.06 3.13 3.16 3.15 3.11 2.93 2.79 2.62 1.72 From the results shown in Table 1, The refrigerant according to the present invention It is clear that it has certain characteristics.

(Hereafter Up)

Claims (1)

[Claims] (1) 1,1,2,2-tetrafluoroethane and 1
, 1,2-trifluoroethane.