JPH075881B2 - Working medium mixture - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel working medium mixture that can be used in refrigerators, heat pumps and the like.

[Prior Art] Air-conditioning, refrigeration and refrigeration equipment (refrigeration cycle / heat pump cycle), waste heat recovery power generation (Rankine cycle), heat exchange equipment (heat pipe), etc. have been put to practical use or tested and developed. The working media used in these devices are water, hydrocarbons such as propane and butane, trichlorofluoromethane (R11) and chlorodifluoromethane (R22).
CFCs such as, and ammonia are known.

[Problems to be solved by the invention] CFCs are less toxic, non-flammable and chemically stable, and various CFCs with different standard boiling points are easily available. Has been done to. The present invention newly provides CFCs having a high heat recovery efficiency, in particular, a freezer, a refrigerator, a cooling / heating equipment, a hot water supply equipment or a heat pump system for the purpose of recovering waste heat.

[Means for Solving the Problems] The present invention relates to a working medium mixture containing trifluoroethane and pentafluoroethane (hereinafter abbreviated as R125) as essential components. In the present invention, trifluoroethane includes 1,1,2-trifluoroethane (R1
43) and 1,1,1-trifluoroethane (R143a) are known as two types of isomers, with R143a being preferred. In the following description, an example in which R143a R125 is mixed and used is shown.

Hereinafter, the present invention will be described in detail with reference to FIG. 1 showing a flow sheet of a refrigeration cycle system using the working medium mixture of the present invention (hereinafter, simply referred to as a working medium). In FIG. 1, 1 is a compressor, 2 is a condenser, 3 and 3'are load fluid pipes, 4 is a pressure reducing device, 5 is an evaporator, and 6 and 6'are heat source fluid pipes.

In the refrigeration cycle system shown in FIG. 1, the working medium is compressed by the compressor 1 and then guided to the condenser 2 where it is cooled and condensed by the load fluid introduced from the pipe 3. On the other hand, the load fluid is inversely heated in the condenser 2 and supplied to the load heating through the pipe 3 '. Next, the condensed working medium is decompressed by the decompression device 4, guided to the evaporator 5, heated in the evaporator 5 by the heat source fluid introduced from the pipe 6 and discharged from the pipe 6 ', and then again. The compressor 1 is sucked and the above cycle is repeated. On the other hand, the heat source fluid is inversely cooled in the evaporator 5 and is cooled by the pipe 6 '.

FIGS. 2 and 3 show the cycle of the working medium mixture in the refrigeration cycle system shown in FIG. 1 plotted on the pressure-enthalpy diagram. When saturated vapor of the working medium is adiabatically compressed, the wet state is shown in FIG. 2 and the dry state is shown in FIG.

The change of the working medium by the compressor of FIG. 1 is shown in FIGS.
Change from 8 to 9 or 13 to 14 in the figure, change of working medium by the condenser is 9 → 10 → 11 or 14 → 15 → 16 →
For 17 changes, the change of working medium by decompressor changes from 11 to 12
Alternatively, a change of 17 to 18 and a change of working medium by the evaporator correspond to changes of 12 to 8 or 18 to 13, respectively.

As the operating conditions of the refrigeration cycle system of FIG. 1 using the working medium mixture of the present invention, the evaporation end temperature of the working medium in the evaporator (the temperature of reference numeral 7 or 13; hereinafter referred to as evaporation temperature) and the working medium in the condenser are The temperature at the start of condensation (the temperature of code 9 or 15; hereinafter referred to as the condensation temperature) was set.

Table 1 shows the coefficient of performance, the refrigerating capacity per unit volume of the compressor, the evaporator inlet / outlet temperature, and the condenser inlet / outlet temperature in the upper air refrigeration cycle system using the working medium of the present invention.

As can be seen from the table, in the refrigeration cycle using the refrigerant of the present invention in which the mixed molar ratio of R143a and R125 is in the range of about 20:80 to 80:20, the coefficient of performance was used for R143a and R125 respectively. It can be seen that the refrigerating capacity is greatly improved without much lowering than in the case, and it is also greatly improved compared to the currently commonly used dichlorodifluoromethane (R12). Furthermore, when the molar ratio of R143a and R125 is in the range of about 40:60 to 60:40, the heat exchanger (evaporator or condenser) inlet / outlet temperatures are equal and an azeotropic mixture is formed. An improvement of about 6 to 8% is observed as compared with the case where R143a and R125 are used alone.

The working medium mixture of the present invention is particularly effective when applied to a refrigerating cycle for the purpose of air conditioning, refrigeration and refrigeration in low to medium temperature and high temperature fields, but also as a working medium for various other heat recovery technologies such as Rankine cycle. It can also be used. The working medium mixture of the present invention has excellent thermal stability and does not require a stabilizer under normal use conditions, but when it is necessary to improve heat stability due to severe use conditions, dimethyl phosphite is used. , A phosphite compound such as diisopropyl phosphite and diphenyl phosphite, or a thiophosphite compound, a phosphine sulfide compound such as triphenoxyphosphine sulfide and trimethylphosphine sulfide, and a stabilizer such as other glycidyl ethers as a working medium. A small amount of about 1 part by weight may be added to 100 parts by weight. The working medium mixture of the present invention is flammable when used alone R143
Since a non-flammable R125 is mixed with a, it can be rendered non-flammable.

EFFECT OF THE INVENTION The working medium mixture of the present invention can be made non-combustible, and without lowering the coefficient of performance, that is, the refrigeration cycle efficiency,
It has excellent freezing capacity and heating capacity, compared to the individual components before mixing,
Significant improvement is observed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a flow chart of a refrigeration cycle for explaining one embodiment of the present invention, and FIGS. 2 and 3 are pressure charts of a cycle using a R143a / R125 mixed system as a working medium. -Drawing on the enthalpy diagram.

Claims (2)

[Claims] 1. A working medium mixture comprising 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.