JP2545879B2 - Coolant - Google Patents

Description

TECHNICAL FIELD The present invention relates to a working fluid of a refrigerator, a so-called refrigerant.

2. Description of the Related Art Conventional technology and its problems Conventionally, as refrigerants, chlorofluorohydrocarbons, fluorohydrocarbons, azeotropic compositions thereof, and compositions having compositions in the vicinity thereof are known. These are called CFCs or CFC-based refrigerants, and currently dichlorodifluoromethane (hereinafter CFC-12), chlorodifluoromethane (CFC-22), etc. are mainly used. However, in recent years, it has been pointed out that, when released into the atmosphere, certain types of CFCs destroy the ozone layer in the stratosphere, and as a result, have a serious adverse effect on the earth's ecosystem including humankind. It is hard to say that such a point has been scientifically proven, but the trend is that regarding fluorocarbons, which have a high possibility of ozone depletion, by international agreement,
It is in the direction of controlling the use and production. One of the CFCs that is subject to control is CFC-12. With the spread of refrigeration and air-conditioning equipment, the control of the use and production of CFCs, whose demand is increasing every year, has a great impact on the current social mechanism including the living environment. Therefore, the development of a refrigerant having excellent refrigeration performance, particularly a coefficient of performance, has become an urgent issue. Difluoromethane (CFC-32) is considered as a CFC that does not have a risk of depleting the ozone layer, but its disadvantage is its low coefficient of performance.

Here, the coefficient of performance is indicated by the ratio of refrigerating capacity / compression work. The coefficient of performance corresponds to the efficiency of the refrigerant because the refrigerating capacity is the amount of heat per unit time taken by the object to be cooled and the compression work is the amount of work of power for operating the refrigerator per unit time. It is a thing.

Means for Solving Problems The present inventor has conducted various studies in order to obtain a new refrigerant that has an excellent coefficient of performance and has a small effect on the ozone layer even when it is discharged into the atmosphere.

As a result, it was found that a refrigerant showing a high coefficient of performance can be obtained when difluoromethane (CFC-32) is mixed with tetrafluoroethane at a specific ratio.

That is, the present invention is difluoromethane 65-1 wt%
And 1,1,1,2-tetrafluoroethane of 35 to 99% by weight.

The refrigerant composition of the present invention comprises 65 to 1% by weight of difluoromethane.
And 1,1,1,2-tetrafluoroethane (CFC-134a) 35
The blending ratio of difluoromethane and tetrafluoroethane in the above range provides a refrigerant exhibiting a high coefficient of performance.

Effects and Effects of the Invention The composition of the present invention is a non-azeotropic composition. In general, for single compounds and azeotropic compositions, the evaporation temperature in the evaporator is constant because evaporation takes place under constant pressure, but for non-azeotropic compositions, the temperature is low at the evaporator inlet and It becomes hot at the exit. On the other hand, the fluid to be cooled is flowed so as to exchange heat with the flow of the refrigerant in the evaporator in a countercurrent direction, so that even if the evaporation temperature of the refrigerant is constant, there is a temperature gradient along the flow. That is, in the evaporator, the temperature difference between the refrigerant and the fluid to be cooled becomes smaller as the fluid to be cooled advances. When the non-azeotropic composition refrigerant according to the present invention is used, the temperature gradient of the fluid to be cooled in the evaporator can be approximated, and the refrigeration efficiency, that is, the coefficient of performance can be increased.

Examples Examples and comparative examples will be shown below to further clarify the features of the present invention.

Examples 1 to 5 and Comparative Example 1 Freon-32 and Freon-134a were mixed at various ratios (weight ratios) shown in Table 1 to prepare refrigerants.

Table 1 Freon-32 Freon-134a Comparative Example 1 100 0 Example 1 60 40 Example 2 40 60 Example 3 20 80 Example 4 5 95 Example 5 1 99 1 Refrigerant in a condenser in a 1-hp refrigerator The condensation start temperature of 50 ℃, the temperature of the refrigerant at the evaporator inlet is 0
C., the degree of superheat of the evaporator was 5.degree. C., and the operation was performed using the refrigerant having the composition shown in Table 1. Table 2 shows (I) of each refrigerant
Maximum evaporation temperature [℃], (II) Refrigerant capacity [kcal / m ³ ], (I
II) Performance coefficient and (IV) Compressor discharge temperature [° C] are shown.

In addition, Table 2 also shows the results when only Freon-32 was used (Comparative Example 1).

Table 2 (I) (II) (III) (IV) Comparative Example 1 0.0 1210 3.85 101.0 Example 1 3.1 1030 4.34 84.5 Example 2 5.3 917 4.73 76.4 Example 3 5.8 743 4.96 68.6 Example 4 2.6 532 4.53 63.3 Example 5 0.6 459 4.24 62.0 FIG. 1 is a graph showing the relationship between the composition ratio of freon-32 and freon-134a and the coefficient of performance.

From the results shown in Table 2 and FIG. 1, the excellent properties of the refrigerant of the present invention are clear.

[Brief description of drawings]

 FIG. 1 is a graph showing the performance of the refrigerant of the present invention.

Claims (1)

(57) [Claims] 1. Difluoromethane 65 to 1% by weight and 1,1,1,2
A refrigerant consisting of 35 to 99% by weight of tetrafluoroethane.