JPH1180719A - Working fluid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a working fluid free or almost free from danger causing disruption problem of ozone layer by using heptafluorolpropane. SOLUTION: This working fluid is obtained by using heptafluoropropane [e.g. CHF2 CF2 CF3 (HCFC-227ca) or CF3 CHFCF3 (HCFC-227ea)]. When high stabilization is required under severe use conditions, a stabilizer (e.g. propylene oxide or dimethyl phosphite) is preferably added in an amount of 0.01-5% based on the weight of the working fluid to the working fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a working fluid used in a refrigerator, a heat pump and the like.

[0002]

2. Description of the Related Art Conventionally, as working fluids or refrigerants, chlorofluorohydrocarbons, fluorohydrocarbons, azeotropic compositions thereof, and compositions having compositions in the vicinity thereof have been known. These are called chlorofluorocarbons or chlorofluorocarbon-based refrigerants. Currently, trichlorofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), and the like are mainly used as working fluids for refrigerators.

However, in recent years, when released into the atmosphere, certain types of chlorofluorocarbons destroy the stratospheric ozone layer,
As a result, it has been pointed out that it has serious adverse effects on ecosystems on earth, including humans. Therefore, the use and production of CFCs, which are highly likely to deplete the ozone layer, have been restricted by international agreements. One type of restricted Freon is Freon-11 and Freon-12, which are widely used as described above.

[0004] With the spread of refrigeration and air-conditioning equipment, the use and production restrictions of Freon, whose demand is increasing every year, have a great effect on the present social system including the living environment. Therefore, there is an urgent need to develop a new refrigerant having no or low risk of causing ozone depletion.

[0005]

The present inventor has conducted various studies to obtain a new refrigerant which has little or no effect on the ozone layer even when released into the atmosphere. As a result, they have found that heptafluoropropane has requirements meeting its purpose. Also,
It has also been found that heptafluoropropane has excellent properties as a working fluid for a heat pump.

That is, the present invention relates to a working fluid comprising heptafluoropropane.

The heptafluoropropane used in the present invention includes CHF ₂ CF ₂ CF ₃ (hereinafter referred to as CFC-227ca) and CF ₃ CHFCF ₃ (hereinafter referred to as CFC-227ea). These may be used alone or in combination. In the following, unless otherwise required, both are represented by CFC-227ca.

The main physical properties of CFC-227ca used in the present invention are as follows.

Boiling point -18.3 ° C Critical temperature 102.7 ° C Critical pressure 32.4kg / cm ² · a Molecular weight 170

In the present invention, a stabilizer can be used in combination with Freon-227ca, if necessary. That is, when a high degree of stability is required under severe use conditions,
A stabilizer can be added in an amount of about 0.01 to 5% by weight of the working fluid.

As the stabilizer, propylene oxide, 1,1,
Epoxides such as 2-butylene oxide and glycidol; phosphites such as dimethyl phosphite, diisopropyl phosphite and diphenyl phosphite; thiophosphites such as trilauryl trithiophosphite; triphenoxy phosphine sulfide and trimethyl phosphine sulfide Phosphine sulfides; boron compounds such as boric acid, triethyl borate, triphenyl borate, phenylboronic acid and diphenylboronic acid; phenols such as 2,6-di-tert-butylparacresol; nitroalkanes such as nitromethane and nitroethane Acrylates such as methyl acrylate and ethyl acrylate; other dioxane, te
rt butanol, pentaerythritol, paraisopropenyl toluene; and the like can be added.

[0012] In the present invention, within a range of up to 50% by weight of CFC-227ca, CFC-227ca and the boiling point of ± 50 ° C.
Other compounds having a boiling point within the range can be mixed. Such compounds include Freon-22, 32, 124, 12
Examples thereof include fluorocarbons such as 5, 134a, 142b, 143a, and 152a; ethers such as pentafluorodimethyl ether; and amines such as perfluoroethylamine.

[0013]

The CFC-227ca used in the present invention is relatively easily decomposable and does not contain chlorine and bromine atoms which affect the ozone layer. Absent.

Further, since CFC-227ca has low solubility in a high molecular compound, it can be used as it is without changing the material in existing refrigeration equipment and the like.

Further, since CFC-227ca is nonflammable,
In ordinary refrigeration equipment, it can be used as it is.

Further, the CFC-227ca of the present invention is useful not only as a refrigerant but also as a working fluid for a heat pump or the like.

[0017]

The following examples are provided to further clarify the features of the present invention.

Example 1 In a one-horsepower refrigerator using Freon-227ca as a refrigerant, (I) the condensation temperature [° C.] and (II) the evaporation temperature [° C.] of the refrigerant in the condenser are shown in Table 1. The operation was performed with the degree of supercooling of the condenser set to 0 ° C.

Table 1 shows (III) evaporation pressure [kg / cm ² ], (IV) condensation pressure [kg / cm ² ], (V) refrigerating capacity [kcal / m ³ ] and (VI) discharge under each condition. Indicates the gas temperature.

Comparative Example 1 A refrigerator was operated in the same manner as in Example 1 except that CFC-11 was used instead of CFC-227ca. The results are shown in Table 1.

[0021]

TABLE 1 evaporation temperature condensation temperature evaporation pressure condensation pressure refrigerating capacity discharge gas ^{℃ ℃ kg / cm 2 · a} kg / cm 2 · a Kcal / m 3 Temperature ℃ Example 1 5 40 2.57 7.58 404 40. 0 Comparative Example 1 5 40 0.51 1.77 115 52.0

Example 2 The procedure of Example 1 was repeated except that the operating conditions were partially changed.
The refrigerator was operated. Table 2 shows the results.

Comparative Examples 3 and 4 A refrigerator was operated in the same manner as in Example 2 except that CFC-11 was used instead of CFC-227ca. The results are also shown in Table 2.

[0024]

TABLE 2 evaporation temperature condensation temperature evaporation pressure condensation pressure refrigerating capacity discharge gas ^{℃ ℃ kg / cm 2 · a} kg / cm 2 · a Kcal / m 3 Temperature ℃ Example 2 5 50 2.14 9.87 287 50. 0 Comparative Example 2 5 50 0.41 2.39 87 64.7

From the results shown in Tables 1 and 2, it is clear that the working fluid according to the present invention exhibits an excellent refrigeration capacity as compared with the conventional working fluid.

Claims (2)

[Claims] 1. A working fluid comprising heptafluoropropane. 2. A refrigerator using heptafluoropropane as a refrigerant.