KR960009238B1 - Refrigerant composition - Google Patents

Abstract

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Description

Refrigerant composition

1 and 2 is a refrigerant circuit,

3 is a diagram showing the flammable area of R12b due to the composition of R142b, R2l and air;

4 shows the flammable region of R142b due to the composition of R142b, R22 and air;

* Explanation of symbols for main parts of the drawings

1 Compressor 3

4: evaporator 6: gas-liquid separator

9: middle heat exchanger

The present invention relates to a refrigerant composition which is used in a refrigerating device and which has no risk of destroying the ozone layer.

There are many R12 (dichlorodifluoromethane) and R500 (azeotropic mixture of R12 and R152a (1, 1-difluoroethane)) also used as a refrigerant | coolant of a conventional refrigerator. The chemical formula of R12 is CC1 ₂ F _2. The boiling point is -29.5 ° C at atmospheric pressure, and the boiling point of R500 is -33.45 ° C, which is most suitable for a normal refrigerant device. Again, even though the suction temperature in the compressor is relatively high, the discharge temperature is not high enough to cause oil deposits in the compressor. Again, R12 has good compatibility with the oil in the compressor and also serves to return oil in the refrigerant circuit to the compressor.

However, each of these refrigerants reaches the ozone layer above the earth so as to be released into the atmosphere by its high ozone depletion potential, and destroys the ozone layer. It is understood that the destruction of the ozone layer is caused by the chlorine group (C1) in the refrigerant.

Thus, refrigerants which do not contain this chlorine group, for example R125 (pentafluoroethane, CHF ₂ CH ₃ ) or R134a (l, 1, 1, 2-tetrafluoroethane, CH 2 FCF 3) or R 23 (trifluoromethane, CF ₃ H) is considered as their alternative refrigerant. The boiling point of R125 is -48 ° C at atmospheric pressure, the boiling point of R134a is -26 ° C, and the boiling point of R23 is -82.05 ° C.

R22 (chlorodifluoromethane, CClF ₂ H) or R142b (1-chloro-1, 1-difluoroethane, C ₂ ClF ₂ F ₃ ) contains a chlorine group (Cl) Since it has (H), there is no risk of destroying the ozone layer since it is decomposed before reaching the ozone layer. The boiling point of this R22 is -40.75 degreeC at atmospheric pressure, and the boiling point of R142b is -9.8 degreeC.

These are also described in the preceding specification of US Pat. No. 4,048,403. Several mixed examples are shown which do not destroy the ozone layer using these refrigerants.

The above-mentioned US patent specification shows some examples of exhibiting a refrigerant capacity equivalent to that of R12 (dichlorodifluoromethane) described above by mixing a plurality of refrigerants which do not destroy the ozone layer, and do not contain chlorine group (C1). In addition, the above-mentioned R125 and others, and as the refrigerant containing the chlorine group (C1) and the hydrogen group (H), mixing by R22 or R142 guitar is indicated.

However, such a refrigerant mixture as shown in the prior art causes the inconvenience described below. That is, the refrigerants containing no chlorine group (Cl), R125, R134a and R23 is extremely poor compatibility with the oil of the compressor of the refrigeration cycle. This is because compatibility with oil is due to the presence of chlorine group (Cl). R22 and R142b also contain a chlorine group (Cl) but have poor compatibility with oil. (Furthermore, R134a dissolves in a certain range in certain oils, as described later).

If the oil in the compressor does not dissolve in the refrigerant, two-phase separation (separation of oil and refrigerant) occurs in the evaporator of the refrigerant circuit, and there is a risk that the moving parts may slip on the bearings of the compressor without returning oil to the compressor. .

R22 cannot suppress an increase in the discharge temperature unless the suction temperature of the compressor is significantly lowered, but the discharge temperature drops by mixing R142b. That is, R142b does not fall even if the suction temperature is relatively high.

In addition, R142b is incombustible by mixing with R22 which is combustible, and stability can be improved. 4 shows the flammability of R142b, R22, and air mixed droplets, in which the diagonal line indicates the flammable area and the other part shows the nonflammable area. That is, by mixing 10% by weight or more of R22, the flammable region of R142b can be avoided.

However, if, for example, the coolant leaks from the refrigerant circuit at low ambient temperatures (e.g., 0 ° C or less), most of R22 with low boiling point evaporates and radiates first, and only R142b with high boiling point alone or flammable Is dissolved in and remains in the compressor oil. Therefore, if the temperature rises again due to the increase in the ambient temperature or close to a blowpipe for repair, etc., only flammable R142b is made of gas and there is a risk of explosion.

An object of the present invention is to solve various problems of such prior art.

Claim 1 Claim 1 of Claim 1 consists of the refrigerant composition which consists of a refrigerant | coolant which does not contain a chlorine group by formula, and dichloro monofluoromethane.

The refrigerant according to claim 1 is selected from the group consisting of pentafluoroethane, l, 1, 2, 2-tetrafluoroethane and trifluoromethane.

The invention according to claim 3, which contains a chlorine group and a hydrogen group, is selected from the group having a poor compatibility with the compressor oil, and a single or a plurality of refrigerants, dichloromonofluoromethane, 1, 1, 1, 2-tetra. The refrigerant composition is composed of a refrigerant selected from fluoroethane.

The refrigerant containing the chlorine group and the hydrogen group according to claim 3 is any one or both of chlorofluoromethane, 1-chloro-1 and 1-difluoroethane.

Again, in the refrigerant composition according to claim 3, dichloromonofluoromethane is 5 wt% or more and 20 wt% or less of 1-chloro-1 and 1-difluoroethane.

The refrigerant composition of claim 5 is composed of chlorodifluoromethane, 1-chloro-1, 1-difluoroethane and dichloromonofluoromethane.

The refrigerant composition of claim 5 is composed of 70% by weight of chlorofluoromethane, 25% by weight of 1-chloro-1 and 1-difluoroethane, and 5% by weight of dichloromonofluoromethane.

Again, the refrigerant composition according to claim 3 is used in a refrigerating device in which alkylbenzene series oil is used as the compressor oil, and chlorodifluoromethane, 1-chloro-1, 1-difluoroethane and 1, 1, 1 And 2-tetrafluoroethane.

Again, the refrigerant composition of claim 8 is incorporated within the limits in which 1, 1, 1, 2-tetrafluoroethane is dissolved in compressor oil.

The refrigerant composition of claim 8 is composed of 70% by weight of chlorodifluoromethane, 25% by weight of 1-chloro-1 and 1-difluoroethane, and 1, 1, 1, 2-tetrafluoroethane. It is comprised as 5 weight%.

R21 (dichloromonofluoromethane, CHCl ₂ F) has a chlorine group (Cl), but also has a hydrogen group (H), so there is no risk of destroying the ozone layer since it is active decomposed before rising to the ozone layer. In addition, since the refrigerant cycle of the refrigerant cycle has a very good compatibility with oil, it is mixed with R125, R134a, R23, R22, or R142b, which is poor in compatibility, and the oil in the refrigerant circuit is dissolved therein and returned to the compressor. The boiling point of is + 8.95 ℃ at atmospheric pressure, so it functions to cool the compressor by evaporation in the compressor.

In addition, R21 is mixed with R142b, and as shown in FIG. 3, a non-combustible region of R142b (parts other than indicated by diagonal lines in the drawing) can be made in the same manner as in R22. Therefore, even after the refrigerant extraction as described above occurs and R22 dissipates, R21 also remains in the refrigerant circuit at the same time as R142b, so that the composition of the remaining refrigerant can be prevented by nonflammability.

This explosion-proof effect is achieved by increasing the weight ratio of R21 to R142b. Since the boiling point of R21 is high, if excessively added, the required cooling temperature cannot be obtained. According to the experiment, R21 is not less than 5% by weight and less than 20% by weight of R142b. Mixing avoids the risk of explosion without compromising refrigerant capacity.

Applicant's new research shows that the highest stability is achieved and the rate at which the desired freezing temperature (at least -40 ° C or lower) is required in the freezer is obtained, with 70% by weight of R22 and 25% of R142b. It was derived that% and R21 were 5% by weight.

In addition, since R134a also dissolves in the alkylbenzene series oil within a predetermined range, the function of oil return can be exhibited in the same manner as R21.

According to the experiment, in particular, the evaporation temperature at atmospheric pressure could be -30 ° C or lower by setting 70 wt% of R22, 25 wt% of R142b, and 5 wt% of R134a.

Next, in the drawings, an embodiment will be described. FIG. 1 is a refrigerant circuit diagram of a normal refrigeration cycle. (1) is a compressor driven by an electric motor, (2) is an evaporator, (3) is a capillary tube, and (4) is an evaporator, and these are connected sequentially. The refrigerant circuit is filled with a refrigerant which does not contain chlorine group (Cl) in the chemical formula, for example a refrigerant mixture of R125 and R21. The composition is 90 weight% of R125 and 10 weight% of R21.

As another embodiment of the refrigerant to be charged, a refrigerant mixture of R134a and R21 is considered. The composition is similarly 90% by weight of R134a and 10% by weight of R21.

As another example, a refrigerant mixture of R23 and R21 is considered. The composition is similarly 90% by weight of R23 and 10% by weight of R21.

The operation of the refrigerant in the refrigerant circuit in FIG. 1 will be described.

The high temperature, high pressure gas-like refrigerant mixture discharged from the compressor (1) flows into the condenser (2), radiates heat, depressurizes it into the capillary tube (3), enters the evaporator (4), and evaporates from there to exert cooling capacity. Then, it returns to the compressor 1. Since R21 has a high boiling point as mentioned above, it returns to the compressor 1 in the state which melt | dissolved the oil of the compressor 1 in it, and evaporates in the compressor 1, and cools it. As a result, the oil in the refrigerant circuit is returned to the compressor 1 and the discharge refrigerant temperature of the compressor 1 can be lowered.

Since the cooling temperature obtained by the evaporator 4 differs according to the refrigerant | coolant used, it is good to select it according to a use purpose. For example, a combination of R125 and R21, or a combination of R134a and R21 in a typical domestic refrigerator freezer requires a freezing temperature of about -20 ℃ to -40 ℃, and the combination of R23 and R21 freeze around -80 ℃ Used in super-temperature freezers that require temperature.

Here, since the boiling point of R21 is high, when the mixing ratio is excessively large, the required cooling temperature in the evaporator 4 cannot be obtained. On the contrary, when the mixing ratio is excessively small, the function of oil return becomes impossible. According to the experiment, in any case, R21 is most preferably 5% by weight to 15% by weight, and preferably 10% by weight.

As another refrigerant to be applied to the refrigerant circuit of FIG. 1, a refrigerant mixture of R22 and R21 is considered. The composition is also 90% by weight R22 and 10% by weight R21. In addition, the refrigerant mixture of R142b and R21 can be charged. The composition is 90 weight% of R142b and 10 weight% of R21. In order to obtain the required freezing temperature with these combinations, the most suitable composition was similarly 5% to 15% by weight of R21, preferably 10% by weight. Moreover, since R142b is combustible, it can be kept in a nonflammable area by mixing with R21.

Next, the example in the case where the refrigerant mixture of R22, R142b, and R21 is used in FIG. 2 is demonstrated. 2 is a refrigerant circuit of the refrigerant cycle in the case where the refrigerant mixture of R22, R142b and R21 is used. In addition, the same code | symbol as FIG. 1 shows the same thing. The discharge side pipe 5 of the compressor 1 is connected to the condenser 2, and the condenser 2 is connected to the gas-liquid separator 6. The liquid pipe 7 from the gas-liquid separator 6 is connected to the capillary tube 8, and the capillary tube 8 is connected to the intermediate heat exchanger 9. The gas phase pipe 10 from the gas-liquid separator 6 passes through the inside of the intermediate heat exchanger 9 and is connected to the capillary tube 11, and the capillary tube 11 is connected to the evaporator 4. The pipe 12 from the intermediate heat exchanger 9 and the pipe 13 from the evaporator 4 join at the connection point P and are connected to the suction side pipe 14 of the compressor 1.

The refrigerant circuit of FIG. 2 is filled with a refrigerant, not azeotropic mixture of R22, R142b, and R21. Next, the operation will be described. The high-temperature, high-pressure gas-shaped refrigerant mixture discharged from the compactor 1 flows into the condenser 2 to radiate heat, and most of R142b and R21 therein liquefy and enter the gas-liquid separator 6. Thus, the liquid R142b and R21 are separated into the liquid phase pipe 7 and still, the gas R22 is separated into the gas phase pipe 10. R142b and R21 introduced into the liquid pipe 7 are depressurized into the capillary tube 8 and flow into the intermediate heat exchanger 9, and R142b evaporates there. Meanwhile, R22 introduced into the gas phase pipe 10 is cooled by condensation by R142b evaporating therein in the course of passing through the intermediate heat exchanger 9, and decompressed by the capillary tube 11 to the evaporator 4. Flows in and evaporates there to cool the surroundings. R142b and R21 from the intermediate heat exchanger (9) pass through the pipe (12) and R22 exiting the evaporator (4) through the pipe (13), contained at the junction P, and again composed of a mixture of R22, R142b and R21. Return to the compressor (1).

The oil of the compressor 1 circulating in the refrigerant circuit returns to the compressor 1 in a state dissolved in R21. R21 returned to the compressor 1 cools it by evaporating in the compressor 1. Therefore, the temperature of the discharged refrigerant can be further lowered.

In determining the composition of the refrigerant mixture encapsulated in the refrigerant circuit, when R21 is large, the explosion-proof property of R142b is improved, but it is safer, but conversely, the cooling capacity of the evaporator 4 is lowered, and thus cannot be used for practical use of the refrigerating device. It needs to be considered. From this situation, the applicant set this composition to R2l of 5 weight% or more and 15 weight% or less of R142b, and to set the composition of the refrigerant mixture encapsulated in the refrigerant circuit as R22b 57 weight% R142b 38 weight% and R21 5 weight%. . According to this composition, experiments show that the evaporator 4 has a cooling capacity of -40 ° C, and also avoids the risk of explosion.

The higher the ratio of R21 to R142b, the lower the risk of explosion. As a result of further experimental studies, Applicants have derived that a cooling capacity of -40 ° C is obtained in the evaporator 4 even if the ratio of R21 to R142b is increased to 20%. In this case, the composition of the refrigerant mixture encapsulated in the refrigerant circuit was found to be most suitable at 70 wt% of R22, 25 wt% of R142b, and 5 wt% of R21. According to the experiment by this composition, the same -40 degreeC cooling capacity is obtained in the evaporator 4, and also the risk of explosion can be made low again.

The freezing temperature of -40 ° C is obtained to form a refrigerant composition most suitable for a refrigerating device such as a freezer, a refrigerator, or a home freezer.

As the refrigerant to be charged in the refrigerant circuit of FIG. 2, there is a refrigerant that is not azeotropic mixture of R22, R142b, and R134a. Thus, R134a circulates in the refrigerant circuit substantially the same as R21 described above.

At this time, the oil of the compressor 1 in the refrigerant circuit is returned to the compressor 1 in a state in which it is dissolved in R134a. Moreover, since R134a does not dissolve in naphthenic oil, it is necessary to use alkylbenzene oil as the oil of the compressor 1.

Since R134a dissolves only a predetermined amount in the alkylbenzene oil, it is necessary to determine the composition of the refrigerant mixture encapsulated in the refrigerant circuit within the limits in which R134a dissolves in the oil of the compressor 1.

Experimental results show that the mixing ratio of R134a is 5% by weight relative to the total weight of the refrigerant. Therefore, the composition of the refrigerant mixture was 70 wt% of R22, 25 wt% of R142b, and 5 wt% of R134a. According to the experiment by this composition, the evaporation temperature in the middle stage 4 is -30 ° C at atmospheric pressure, and R134a is also dissolved in the oil of the compressor 1, and the expected effect on the oil return function is also achieved. Was obtained.

According to the refrigerant composition of the present invention, there is no risk of destroying the ozone layer, and the oil is returned to the compressor of the refrigerant in the refrigerant circuit by dichloromonofluoromethane (R21) having good compatibility with the compressor oil. You can prevent it. In addition, R21 can correspond to the cooling of the compressor to prevent the occurrence of oil deposits.

When 1-chloro-1 and 1-difluoroethane (R142b) are used again, 1-chloro remaining in the non-combustible region by R21 and remaining even when a refrigerant leaks from the refrigerant circuit under low ambient temperature. Explosion by -1 and 1-difluoroethane (R142b) can be prevented.

In addition, by setting R21 to 5% by weight or more and 20% by weight of R142b, by mixing R21 having a high boiling point, it is possible to suppress the deterioration of the freezing capacity, to secure the required cooling capacity and to avoid the risk of explosion. . In particular, it is frozen by making 70 weight% of chlorodifluoromethane (R22), 25 weight% of 1-chloro-1, 1-difluoroethane (R142b), and 5 weight% of dichloromonofluoromethane (R21). It is possible to configure the refrigerant composition most suitable for the device.

In addition, since R134a also dissolves in the alkylbenzene-based oil in a predetermined range, it can exhibit the same function as R21, in particular 70% by weight of R22, 25% by weight of R142b, and 5% by weight of R134a to exhibit the required oil return function. have.

Claims (1)

50 wt% to 99.9 wt% of a refrigerant selected from the group consisting of pentafluoroethane, 1, 1, 1, 2-tetrafluoroethane and trifluoromethane containing no chlorine group, and 50 dichloromonofluoromethane A refrigerant composition containing from 0% by weight to 0.1% by weight.

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