JPH0192286A - Working medium mixture - Google Patents

Abstract

PURPOSE:To provide a novel nonflammable working medium mixture capable of enhancing both freezing and heating abilities without lowering freezing cycle- heat pump cycle efficiencies, comprising, as the essential components, trifluoroethane and pentafluoroethane. CONSTITUTION:The objective mixture comprising, as the essential components, trifluoroethane and pentafluoroethane in the molar ratio: 20/80-80/20. In case enhancement of thermal stability is needed for use under severe conditions, it is suggested that 100pts.wt. of this medium be incorporated with ca. 1pt.wt. of a stabilizer such as (thio)phosphite compound (e.g., dimethyl phosphite), phosphine sulfide compound (e.g., triphenoxyphosphine sulfide) or glycidyl ether.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel working medium mixture that can be used in refrigerators, heat pumps, etc.

[Prior Art] Air conditioning, freezing and refrigeration equipment (refrigeration cycle/heat pump cycle), waste heat recovery power generation (Rankine cycle), heat exchange equipment (Heatvibe), etc. have been put into practical use or tested and developed. Working media used in these devices include water, hydrocarbons such as propane and butane, trichlorofluoromethane (R11), and chlorodifluoromethane (R11).
CFCs such as 22) or ammonia are known.

[Problems to be solved by the invention] Fluorocarbons have low toxicity, are non-flammable, and are chemically stable, and various kinds of fluorocarbons with different standard boiling points are easily available, so research on evaluating them as working media has been active. is being carried out. The present invention provides novel fluorocarbons that have high heat recovery efficiency, particularly for freezers, refrigerators, air conditioning equipment, hot water supply equipment, or heat pump systems for the purpose of waste heat recovery.

[Means for Solving the Problems] The present invention relates to a working medium mixture characterized by containing trifluoroethane and pentafluoroethane (hereinafter abbreviated as R125) as essential components. Trifluoroethane in the present invention includes 1.1.2-trifluoroethane (R143) and 1), i-trifluoroethane (
Two isomers of R143a) are known;
43a is preferred. In the following explanation, R14
3a An example of mixed use of R125 is shown.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIG. 1, which shows a flow sheet of a refrigeration cycle system using the working medium mixture of the present invention (hereinafter sometimes simply referred to as working medium). In FIG. 1, 1 is a compressor, 2 is a condenser, 3.3' is a load fluid piping, 4 is a pressure reducing device, 5 is an evaporator, and 6.6' is a heat source fluid piping.

In the refrigeration cycle system shown in FIG. 1, a working medium is compressed by a compressor 1 and then led to a condenser 2, where it is cooled and condensed by a load fluid introduced through a pipe 3. On the other hand, the load fluid is reversely heated in the condenser 2 and passed through the pipe 3' for load heating. Next, the condensed working medium is depressurized by the pressure reducing device 4, and then led to the evaporator 5, where it is heated by the heat source fluid introduced from the pipe 6 and discharged from the pipe 6', and then heated again. It is sucked into the compressor 1 and the above cycle is repeated. On the other hand, the heat source fluid is reversely cooled in the evaporator 5 and is provided for cooling through the tube 6'.

2 and 3 are pressure-enthalpy diagrams showing the cycle of the working medium mixture in the refrigeration cycle system shown in FIG. 1. When saturated vapor as a working medium is adiabatically compressed, a wet state is shown in Fig. 2, and a dry state is shown in Fig. 3.

Changes in the working medium caused by the compressor in Figure 1 are shown in Figures 2 and 3.
The change in the working medium due to the condenser is 9-10-11-4 or 14→15-16-17, and the change in the working medium due to the pressure reducing device is 11. to 12 or 17 to 18, the change in the working medium by the evaporator corresponds to a change from 12 to 8 or from 18 to 13, respectively.

The operating conditions of the refrigeration cycle system shown in FIG. 1 using the working medium mixture of the present invention are the evaporation path temperature of the working medium in the evaporator (temperature 7 or 13, hereinafter referred to as evaporation temperature) and the working medium in the condenser. temperature at the beginning of condensation (temperature numbered 9 or 15; hereinafter referred to as condensation temperature)
It was set.

Table 1 shows the coefficient of performance, refrigeration capacity per unit volume of compressor, evaporator inlet/outlet temperature, and condenser inlet/outlet temperature in the above-mentioned refrigeration cycle system using the working fluid of the present invention.

As can be understood from the table, in a refrigeration cycle using the refrigerant of the present invention in which the mixing molar ratio of R143a and R125 is in the range of about 20:80 to 80:20, the coefficient of performance is R1.
43a and R125, the refrigeration capacity is greatly improved without much deterioration compared to when used alone,
It can be seen that this is greatly improved compared to dichlorodifluoromethane (R12), which is currently commonly used. Furthermore, the molar ratio of R143a and R125 is about 40.
: In the range of 60 to 60:40, the temperature at the inlet and outlet of the heat exchanger (evaporator or condenser) is equal to form an azeotropic mixture, and the refrigerating capacity at that time is greater than when R143a and R125 are used alone. An improvement of approximately 6-8% is observed.

The working medium mixture of the present invention is particularly effective in refrigeration cycle applications for air conditioning, refrigeration and refrigeration in low to medium and high temperature fields, but can also be used as a working medium for various other heat recovery techniques such as the Rankine cycle. You can also use The working medium mixture of the present invention has excellent thermal stability and does not require stabilizers under normal conditions of use;
When it is necessary to improve thermal stability due to harsh usage conditions, phosphite compounds such as dimethyl phosphite, diisopropyl phosphite, diphenyl phosphite, etc.
Alternatively, a small amount of about 1 part by weight of a thiophosphite compound, a phosphine sulfide compound such as triphenoxyphosphine sulfide or trimethylphosphine sulfide, or other stabilizers such as glycidyl ethers is added to 100 parts by weight of the working medium. do it. The working medium mixture of the invention is R14 which is flammable when used alone.
Since RI25, which is nonflammable, is mixed with 3a, it is possible to make it nonflammable.

[Effects of the Invention] The working medium mixture of the present invention can be made non-flammable, and has a high coefficient of performance without reducing the coefficient of performance, that is, the refrigeration cycle efficiency.
It has excellent freezing and heating ability, compared to single ingredients before mixing.
Significant improvement is observed.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet of a refrigeration cycle for explaining one embodiment of the present invention, and FIGS. 2 and 3 are R143a/
R] is a pressure-enthalpy diagram showing a cycle using a 25 mixture system as a working medium. Figure 1 Mouth Dream 2 Difficulty Figure 3 Enthalpy Enthalpy.

Claims (1)

[Claims] 1. A working medium mixture characterized by containing trifluoroethane and pentafluoroethane as essential components. 2. The working medium mixture according to claim 1, wherein the mixing molar ratio of trifluoroethane and pentafluoroethane is 20:80 to 80:20.