JPH0655940B2 - Mixed refrigerant - Google Patents

Description

The present invention relates to a working medium for a vapor compression refrigeration cycle, which cools or heats a fluid by utilizing the state changes of substances such as pressurized liquefaction and depressurized vaporization. The present invention relates to a mixed refrigerant used, and more particularly, to a mixed refrigerant used for air conditioning equipment used for air conditioning.

[Prior Art] A vapor compression refrigeration cycle is widely applied to air conditioning equipment, refrigerators, hot water supply equipment, and the like, and is put to practical use.

As a working medium used in such a compression refrigeration cycle, various working media centered on a CFC-based refrigerant have been developed and put into practical use.

A typical example is a working medium containing a methane- or ethane-based halogenated hydrocarbon as a single component.
1, R12, R13, R14, R22 and the like, and in the ethane system, R113, R114, R115 and the like are used according to the purpose.

Among them, R22 (monochlorodifluoromethane) is widely used as a refrigerant in air conditioning equipment used for air conditioning.

Since R22 can obtain a large refrigerating capacity with a compressor of the same size as R12 (dichlorodifluoromethane) which is generally used in refrigerators, dehumidifiers, etc., the device can be downsized.

Further, the suction pressure is higher than the atmospheric pressure even at the evaporation temperature of −40 ° C., which is an advantage, and is widely put to practical use as a refrigerant that is chemically stable and has good thermodynamic properties.

In addition, a non-azeotropic mixed refrigerant has recently been studied because of an attempt to supplement the characteristics that cannot be satisfied by a single refrigerant by mixing and using the refrigerants.
By mixing 3B1 (monobromotrifluoromethane), a heat pump cooling and heating device has been commercialized, which is devised to increase the heating capacity over R22 (Showa 6).
(See Denpa Shimbun, dated August 30, 0).

Since the above-mentioned mixed refrigerant has been developed with an emphasis on improving the heating capacity over the R22 single refrigerant, the current situation is that attention is not paid to the coefficient of performance (Showa 5).
(See page 29-30 of the 4th academic conference of the Japan Refrigeration Society.)

[Problems to be Solved by the Invention] An object of the present invention is to be further superior to R22, namely R
It is intended to provide a working medium for a heat pump cooling / heating machine which has a larger heating capacity and a higher coefficient of performance than that of No. 22, and can be downsized and improved in efficiency of a conventional air conditioner.

[Means for Solving the Problems] The inventors of the present invention have studied many chlorofluorocarbon-based refrigerants in order to achieve the above-described object of the present invention, and as a result, the object of the present invention is to make R22 as a main component. In contrast, R143a (1,1,1-trifluoroethane), which is another fluorocarbon refrigerant that is chemically stable and has excellent thermodynamic characteristics, is mixed, and the mixing ratio is preferably The molar fraction of 1,1,1-trifluoroethane in the mixed refrigerant is 0.
It has been found to be achieved with a mixed refrigerant for heat pump air conditioners that is 25 to 0.45.

EXAMPLES Next, the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to these examples without departing from the gist of the present invention.

FIG. 1 is an outline of a vapor compression refrigeration cycle in which the mixed refrigerant (working medium) of the present invention was tested.

(1) is a working medium compressor, (2) is a water-cooled double-tube condenser, (3) is a liquid receiver, (4) is a pressure reducing expansion valve, and (5).
Is an evaporator, (6) is a brine tank for heat absorption source, (7) is an accumulator, and (8) and (8 ') are piping for heat radiation source water.

In such a vapor compression refrigeration cycle, the working medium is compressed by the compressor (1) and then guided to the condenser (2) to give heat to the radiant heat source water to be condensed. In this example, the inlet and outlet temperatures of the heat radiation source water were made substantially constant, and the condenser capacity was calculated by the product of the inlet and outlet temperature difference, the flow rate, and the specific heat for comparison.

The condensed working medium is stored in the liquid receiver (3), regulated by the decompression expansion valve, then guided to the evaporator (5), and absorbs heat from the heat absorption source brine tank (6) to evaporate, The cycle of being sucked into the compressor (1) again via the accumulator (7) is repeated. The brine tank for the heat absorption source has a built-in heater for heating, which is configured so that the input power is controlled in proportion to the capacity of the evaporator and the temperature inside the tank is kept constant so that a comparative test can be performed. There is.

Table 1 shows the results of the vapor compression refrigeration cycle having the configuration shown in FIG.

As a test condition, in the mixed refrigerant of the present invention, R143
The temperature of the hot water at the inlet and outlet of the condenser and the temperature of the brine tank for the heat sink of the evaporator are kept substantially constant and the expansion for decompression is performed when the mixed refrigerant in which the mixing ratio of a is changed and the refrigerant of R22 alone is used. This is a comparison of the compressor input, condenser capacity, and coefficient of performance, with the valve inlet liquid refrigerant temperature and the accumulator inlet refrigerant temperature being approximately the same. Example 1 is a case where the mole fraction of R143a in the mixed refrigerant of the present invention is 0.4. .

In Example 2, the mole fraction of R143a is 0.35, and in Example 3, the mole fraction of R143a is 0.25. The comparative example is a case where the refrigerant is R22 alone.

FIG. 2 shows the condenser performance and the coefficient of performance of Examples 1 to 3 and Comparative Example using the mole fraction of R143a as a parameter.

From this figure, the molar fraction of R143a is 0.25 to 0.4.
It was found that there was a maximum value in which the coefficient of performance (COPh) was higher than that of R22 in the range of 5, and the peak thereof was at the molar fraction of R143a of 0.35.

On the other hand, the peak of the condenser capacity is when the molar fraction of R143a is 0.35, and the condenser capacity is in the range of 0.25 to 0.45 of the molar fraction of R143a where the above coefficient of performance is higher than that of R22. It is larger than R22.

When the mole fraction of R143a was 0.35, the coefficient of performance improvement was 2.4% and the condenser capacity improvement was 7% compared to R22.

[Effects of the Invention] The mixed refrigerant of the present invention in which R143a is appropriately mixed with R22 as a working medium for a heat pump air conditioner using a vapor compression refrigeration cycle has only a condenser capacity as compared with R22 which is widely used at present. In addition, the coefficient of performance can be improved and the heat pump air conditioner can be made smaller and more efficient.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a vapor compression refrigeration cycle using the mixed refrigerant (working medium) of the present invention, and FIG. 2 is R2.
It is explanatory drawing which shows the characteristic change by R143a mole fraction in a 2 / R143a type | system | group mixed refrigerant. (1) ... Compressor of working medium, (2) ... Water-cooled double-tube condenser, (3) ... Liquid receiver, (4) ... Expansion valve for decompression, (5) ... Evaporator , (6) …… Brine tank for heat absorption source, (7) …… Akymulator, (8), (8 ′) …… Pipe for heat radiation source water.

Claims (2)

[Claims] 1. A mixed refrigerant comprising monochlorodifluoromethane as a main component and 1,1,1-trifluoroethane mixed therein. 2. The mixed refrigerant according to claim 1, wherein the molar fraction of 1,1,1-trifluoroethane in the mixed refrigerant is 0.25 to 0.45.