JP2014196868A - Cascade refrigeration system - Google Patents

Abstract

[PROBLEMS] To use a refrigerant composition having a low global warming potential (GWP) and being gentle to the earth, capable of achieving a low temperature of -80 ° C, and having excellent refrigeration capacity and other performance aspects. Provision of dual refrigeration equipment. A dual refrigeration apparatus comprising a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, wherein the refrigerant in the low temperature side refrigeration circuit is condensed by a refrigerant passing through a cascade condenser in the high temperature side refrigerant circuit. As a refrigerant in the side refrigeration circuit, a refrigerant composition containing an azeotropic mixture of ethane (R170) and perfluoroethane (R116) is used, and the perfluoroethane (R116) is used as the refrigerant composition. The problem can be solved by a binary refrigeration apparatus characterized by adding 50% to 60% by mass. [Selection] Figure 1

Description

  The present invention relates to a binary refrigeration apparatus. More specifically, the present invention is a refrigerant composition that has a small global warming potential (hereinafter referred to as GWP) and is friendly to the earth, and is -80 ° C. The present invention relates to a refrigerant composition that can be used as a refrigerant that can achieve low temperatures and has excellent performance in terms of refrigeration capacity and other performances, and a binary refrigeration apparatus that uses the refrigerant composition and that can actually achieve low temperatures.

A low temperature of -80 ° C. can be achieved without using a regulated refrigerant that has a high risk of destroying the ozone layer in the refrigerant used in the past, and it is an alternative to R503 in terms of refrigeration capacity and other performance. A refrigerant composition that can be used as a refrigerant and a binary refrigeration apparatus using the same have been proposed (see Patent Document 1).
This refrigerant composition is an azeotropic mixture (R508A, boiling point-85.7 ° C.) in which 39% by weight of trifluoromethane (R23) having a high specific heat ratio and 61% by weight of hexafluoroethane (R116) having a low specific heat ratio are mixed. Or a mixture of this azeotrope and n-pentane or propane, and the n-pentane or propane is in a proportion of 14% or less with respect to the total weight of trifluoromethane and hexafluoroethane. The refrigerant composition mixed with the above is composed of the refrigerant composition, has a low risk of destroying the ozone layer, can achieve a low temperature of −80 ° C., and can be used as an alternative refrigerant for R503 in terms of refrigeration capacity and other performance.

However, the GWP of R508A and R508B is large as 13200 and 13300, respectively, which is a problem.
Carbon dioxide (R744) is as small as GWP1, but because there is a problem of oil deterioration and sludge generation due to pressure increase and discharge temperature increase, hydrocarbons such as propane, cyclopropane, isobutane and butane are added to carbon dioxide. A mixed refrigerant in which about 30 to 70% of the whole is mixed and a refrigeration cycle apparatus using the mixed refrigerant (see Patent Document 2) have been proposed.
Also, a mixed refrigerant in which isobutane is 40 to 60% and the balance is trifluoromethane (R23) (see Patent Document 3), and a mixed refrigerant in which 65% or more of propane is mixed with a mixture of difluoromethane and pentafluoroethane (Patent Document 4). Have been proposed).

Japanese Patent No. 3244296 JP 2005-15633 A Japanese Patent No. 5009530 Japanese Patent No. 4085897

In the prior art, hydrocarbons such as propane are flammable, and there is a risk of explosion because 30 to 70% of the total refrigerant is mixed.
An object of the present invention is to solve the conventional problems, a refrigerant composition having a small GWP, which is friendly to the earth, has a high COP, does not cause oil deterioration and sludge, and uses n-pentane or propane as an oil carrier. As a result, oil can be returned to the compressor without using an oil separator, there is no danger of explosion, a low temperature of -80 ° C can be achieved, and excellent performance in terms of refrigeration capacity and other performances An object of the present invention is to provide a binary refrigeration apparatus that uses a refrigerant composition that can be used as a refrigerant and that can actually achieve a low temperature.

  As a result of intensive research conducted by the inventors to solve the above problems, for example, ethane (R170) having a global warming potential (GWP) of 3 and a global warming potential (GWP) as a refrigerant sealed in a low-temperature refrigerant circuit. A refrigerant composition comprising an azeotropic mixture of 12200 perfluoroethane (R116) or an azeotropic mixture of 20% by mass or less of carbon dioxide (R744) having a global warming potential (GWP) of 1, 1,1,1,2,3-pentafluoropentene having a global warming potential (GWP) of 6 as a refrigerant sealed in the high-temperature side refrigerant circuit using a mixture of n-pentane or propane of a fixed quantity or less A mixture of a refrigerant composition containing HFO-1234ze) having a global warming potential (GWP) of 1500 or less and a predetermined amount or less of n-pentane. It found that can solve the problem by, and accomplished the present invention.

The invention according to claim 1 for solving the above-mentioned problem comprises a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, and condenses the refrigerant in the low temperature side refrigeration circuit through the cascade capacitor in the high temperature side refrigerant circuit. In a binary refrigeration system that uses a refrigerant,
A refrigerant composition containing an azeotropic mixture obtained by mixing ethane (R170) and perfluoroethane (R116) is used as the refrigerant in the low-temperature refrigeration circuit,
It is a binary refrigeration apparatus characterized by adding 50% to 60% by mass of the perfluoroethane (R116) to the refrigerant composition.

The invention according to claim 2 includes a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, and condenses the refrigerant in the low temperature side refrigeration circuit by the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit. In
As a refrigerant in the low temperature side refrigeration circuit, a refrigerant composition containing ethane (R170) and carbon dioxide (R744) is used,
In the binary refrigeration apparatus, 20% by mass or less of the carbon dioxide (R744) is added to the refrigerant composition.

The invention according to claim 3 includes a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, and condenses the refrigerant in the low temperature side refrigeration circuit with the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit. In
As a refrigerant in the low temperature side refrigeration circuit, a refrigerant composition containing an azeotropic mixture of ethane (R170) and perfluoroethane (R116) and carbon dioxide (R744) is used.
The perfluoroethane (R116) is 50% by mass to 60% by mass with respect to the refrigerant composition,
In the binary refrigeration apparatus, 20% by mass or less of the carbon dioxide (R744) is added to the refrigerant composition.

  According to a fourth aspect of the present invention, in the binary refrigeration apparatus according to any one of the first to third aspects, n-pentane or propane is used as the oil carrier with respect to the total mass of the refrigerant composition. It contains in the ratio of the mass% or less.

The invention according to claim 5 includes a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, and performs condensation of the refrigerant in the low temperature side refrigeration circuit by the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit. In
As refrigerant in the high-temperature side refrigeration circuit, refrigerants of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,3-trifluoroethane (R143a) Binary refrigeration characterized by adding a non-azeotropic mixture comprising a group or a fluorinated hydrocarbon mixed refrigerant containing 1,1,1,2,3-pentafluoropentene (HFO-1234ze) to the refrigerant group Device.

  According to a sixth aspect of the present invention, in the binary refrigeration apparatus according to the fifth aspect, the refrigerant in the high-temperature side refrigeration circuit is replaced with 1,1,1,2,3-pentafluoropentene (HFO-1234ze) in the previous period. A fluorinated hydrocarbon mixed refrigerant containing 1,1,1,2-tetrafluoropentene (HFO-1234yf) is added.

  The invention according to claim 7 is the binary refrigeration apparatus according to claim 5, wherein n-pentane is used as an oil carrier for the refrigerant in the high-temperature side refrigeration circuit with respect to the total mass of the fluorinated hydrocarbon mixed refrigerant. It contains in the ratio of the mass% or less.

The invention according to claim 1 of the present invention includes a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, and performs condensation of the refrigerant in the low temperature side refrigeration circuit by the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit. In the original refrigeration system,
A refrigerant composition containing an azeotropic mixture obtained by mixing ethane (R170) and perfluoroethane (R116) is used as the refrigerant in the low-temperature refrigeration circuit,
The perfluoroethane (R116) is a binary refrigeration apparatus characterized by adding 50% or more and 60% by mass or less of the refrigerant composition,
Using an azeotropic mixture of ethane (R170) with a global warming potential (GWP) of 3 and perfluoroethane (R116) with a global warming potential (GWP) of 12200, the boiling point of ethane (R170) with a GWP of 3 Perfluoroethane (R116) with a GWP of 12200 is as low as -78.1 ° C, and the boiling point of the azeotrope is as low as -88.8 ° C. ) The GWP is less than half that of a single case, so it is gentle to the earth, can achieve a low temperature of -80 ° C, has no danger of explosion, and has outstanding performance in terms of refrigerating capacity and other performance. Play.

The invention according to claim 2 of the present invention includes a high-temperature side refrigeration circuit and a low-temperature side refrigeration circuit, and condenses the refrigerant in the low-temperature side refrigeration circuit by the refrigerant passing through the cascade condenser in the high-temperature side refrigerant circuit. In the original refrigeration system,
As a refrigerant in the low temperature side refrigeration circuit, a refrigerant composition containing ethane (R170) and carbon dioxide (R744) is used,
The carbon dioxide (R744) is a binary refrigeration apparatus characterized by adding 20% by mass or less to the refrigerant composition,
The boiling point of ethane (R170) with a GWP of 3 is as low as -88.6 ° C, the boiling point of perfluoroethane (R116) with a GWP of 12200 is as low as -78.1 ° C, and the boiling point of the azeotrope is -88. It is as low as 8 ° C, and GWP is less than half that of perfluoroethane (R116) alone, so it is gentle to the earth, can achieve a low temperature of -80 ° C, has excellent refrigeration capacity and other performance aspects, Since the amount of carbon dioxide (R744) added is as small as 20% by mass or less, the discharge pressure and temperature are not increased, so COP does not decrease, oil deterioration and sludge do not occur, and there is a risk of explosion. There is a remarkable effect of not.

The invention according to claim 3 includes a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, and condenses the refrigerant in the low temperature side refrigeration circuit with the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit. In
As a refrigerant in the low temperature side refrigeration circuit, a refrigerant composition containing an azeotropic mixture of ethane (R170) and perfluoroethane (R116) and carbon dioxide (R744) is used.
The perfluoroethane (R116) is 50% by mass to 60% by mass with respect to the refrigerant composition,
The carbon dioxide (R744) is a binary refrigeration apparatus characterized by adding 20% by mass or less to the refrigerant composition,
Using an azeotropic mixture of ethane (R170) with a global warming potential (GWP) of 3 and perfluoroethane (R116) with a global warming potential (GWP) of 12200, the boiling point of ethane (R170) with a GWP of 3 Perfluoroethane (R116) with a GWP of 12200 is as low as -78.1 ° C, and the boiling point of the azeotrope is as low as -88.8 ° C. ) GWP is less than half that of a single case, so it is gentle to the earth, can achieve a low temperature of -80 ° C, has no danger of explosion, has excellent refrigeration capacity and other performance aspects, and has carbon dioxide ( Since the amount of R744) added is as small as 20% by mass or less, the discharge pressure and temperature are not increased, so COP does not decrease, oil deterioration and sludge do not occur, and there is no risk of explosion It exhibits the remarkable effect that.

According to a fourth aspect of the present invention, in the binary refrigeration apparatus according to any one of the first to third aspects, n-pentane or propane is used as the oil carrier with respect to the total mass of the refrigerant composition. It is characterized by containing at a ratio of mass% or less,
Since n-pentane or propane acts as an oil carrier, the oil can be returned to the compressor without using an oil separator, and the amount of n-pentane added is as small as 14% by mass or less, so there is a risk of explosion. There is a remarkable effect of not.

The invention according to claim 5 of the present invention includes a high-temperature side refrigeration circuit and a low-temperature side refrigeration circuit, and condenses the refrigerant in the low-temperature side refrigeration circuit by the refrigerant passing through the cascade condenser in the high-temperature side refrigerant circuit. In the original refrigeration system,
As refrigerant in the high-temperature side refrigeration circuit, refrigerants of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,3-trifluoroethane (R143a) Binary refrigeration characterized by adding a non-azeotropic mixture comprising a group or a fluorinated hydrocarbon mixed refrigerant containing 1,1,1,2,3-pentafluoropentene (HFO-1234ze) to the refrigerant group Device,
1,1,1,2,3-pentafluoropentene (HFO-1234ze), difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetra with a global warming potential (GWP) of 6 Since the mixed refrigerant containing fluorocarbon such as fluoroethane (R134a) has a GWP of 1500 or less, the GWP is small and friendly to the earth, the discharge pressure and the discharge temperature are not increased, the COP is not lowered, and the oil There is a remarkable effect that it does not cause deterioration and sludge and there is no danger of explosion.

The invention according to claim 6 of the present invention is the refrigerant composition according to claim 5, wherein 1,1,1,2 instead of 1,1,1,2,3-pentafluoropentene (HFO-1234ze). -Tetrafluoropentene (HFO-1234yf) is used,
Even if it uses HFO-1234yf instead of HFO-1234ze, there exists the further remarkable effect that the same effect as the refrigerant composition of Claim 5 can be acquired.

The invention described in claim 7 is characterized in that in the refrigerant composition of claim 5 or 6, n-pentane is further mixed at a ratio of 6% by mass or less with respect to the total mass of the refrigerant composition. Is what
Since n-pentane acts as an oil carrier, oil can be returned to the compressor without using an oil separator, and since the amount of n-pentane added is as small as 6% by mass or less, there is no risk of explosion. There is a further remarkable effect.

FIG. 1 is a refrigerant circuit diagram of a binary refrigeration apparatus in which the refrigerant composition of the present invention is enclosed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a refrigerant circuit diagram of a binary refrigeration apparatus in which the refrigerant composition of the present invention is enclosed. S1 shows a high temperature side refrigerant cycle, and S2 shows a low temperature side refrigerant cycle.

  The discharge side pipe 2 of the compressor 1 constituting the high temperature side refrigerant cycle S1 is connected to the auxiliary condenser 3, and the auxiliary condenser 3 constitutes the oil cooler 4, the auxiliary condenser 5, and the low temperature side refrigerant cycle S2 of the compressor 1. The compressor 6 is connected to the cascade condenser 11 through the oil cooler 7, the condenser 8, the dryer 9, and the capillary tube 10 in order, and is connected to the compressor 1 through the liquid receiver 12 through the suction side pipe 13. . Reference numeral 14 denotes a cooling fan for the condensers 3, 5 and 8.

  The discharge side pipe 15 of the compressor 6 in the low temperature side refrigerant cycle S2 is connected to the oil separator 16, and the separated compressor oil is returned to the compressor 6 through the return pipe 17. On the other hand, the refrigerant flows into the pipe 18 and exchanges heat with the suction-side heat exchanger 19, passes through the pipe 20 in the cascade condenser 11, condenses, and enters the inlet pipe 23 through the dryer 21 and the capillary tube 22. Further, the refrigerant flows into the evaporator 24, exits from the outlet pipe 25, passes through the suction side heat exchanger 19, and returns to the compressor 6 from the suction side pipe 26 of the compressor 6. An expansion tank 27 is connected to the suction side pipe 26 via a capillary tube 28.

  The high temperature side refrigerant cycle S1 includes difluoromethane (R32) / pentafluoroethane (R125) / 1,1,1,2-tetrafluoroethane (R134a) azeotrope (R407D) or pentafluoroethane (R125) / 1, 1,1-trifluoroethane (R143a) / 1,1,1,2-tetrafluoroethane (R134a) azeotrope (R404A), or global warming potential (GWP) of 1500 or less As a refrigerant composition, a refrigerant group of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,3-trifluoroethane (R143a), 1,1,1,2,3-pentafluoropentene (HFO-1234ze, GWP6, boiling point) Mixed refrigerant containing fluorinated hydrocarbon mixed refrigerant containing 9 ° C.) is sealed. The boiling point is about −40 ° C. at atmospheric pressure, and this mixed refrigerant is condensed in the condensers 3, 5 and 8, depressurized in the capillary tube 10, flows into the cascade condenser 11 and evaporates. Here, the cascade capacitor 11 is about −36 ° C.

The boiling point of ethane (R170) with a GWP of 3 is as low as -88.6 ° C, the boiling point of perfluoroethane (R116) with a GWP of 12200 is as low as -78.1 ° C, and the boiling point of the azeotrope is -88. As low as 8 ° C.
In the low-temperature side refrigerant cycle S2, a mixed refrigerant (GWP5119, 45% by mass of ethane (R170) having a GWP of 3, 42% by mass of perfluoroethane (R116) having a GWP of 12200 and 13% by mass of carbon dioxide (R744) is mixed. A refrigerant composition in which n-pentane is mixed with a boiling point of −85 ° C. or lower) is enclosed. Here, n-pentane is mixed and composed at a ratio of 14% by mass or less (in this example, 6.4% by mass) with respect to the total mass of the mixed refrigerant. As a result, a considerably low-temperature refrigerant composition having a boiling point of −85 ° C. or lower is enclosed. The refrigerant and compressor oil discharged from the compressor 6 flows into the oil separator 16. Therefore, it is separated into a gas phase portion and a liquid phase portion, and most of the oil is in the liquid phase, so that it can be returned to the compressor 6 through the return pipe 17. The gas-phase refrigerant and oil pass through the pipe 18 and exchange heat with the suction-side heat exchanger 19, and are further cooled and condensed by evaporation of the refrigerant in the high-temperature side refrigerant cycle S1 in the cascade condenser 11. Thereafter, the pressure is reduced in the capillary tube 22 and then flows into the evaporator 24 to evaporate. The evaporator 24 is attached to a wall surface of a freezer (not shown) in a heat exchange relationship to cool the inside of the refrigerator. Here, the evaporation temperature in the evaporator 24 reaches −85 ° C. or lower.

  In the binary refrigeration apparatus configured as described above, the refrigerant composition enclosed in the low-temperature side refrigerant cycle S2 has a boiling point of about −85 ° C. or less, and thus is sufficiently refrigeration capacity as an alternative refrigerant for R508A and R508B. Can be demonstrated.

  Furthermore, although the refrigerant composition has poor compatibility with oil, it can be solved by mixing n-pentane in an amount of 14% by weight or less. That is, although n-pentane has a high boiling point of + 36.07 ° C., it has good compatibility with the compressor oil. By mixing n-pentane in the range of 14% by weight, the oil is dissolved in n-pentane. In this state, the compressor can be returned to the compressor, and adverse effects such as locking due to the oil rising of the compressor can be prevented. As a result, the oil can be returned to the compressor 6 without particularly separating the oil completely by the oil separator 16. Here, since n-pentane has a high boiling point, if it is mixed too much, the evaporation temperature rises and the desired low temperature cannot be obtained, but by mixing n-pentane at a ratio of 14% by weight or less, The oil can be returned to the compressor without increasing the evaporation temperature and maintaining n-pentane in the non-combustible region.

  Thus, according to the binary refrigeration apparatus of the present embodiment, the oil return is good and a low temperature of about −85 ° C. or less can be achieved in the evaporator without risk of explosion or the like. It can be put to practical use as a medical freezer such as blood cold storage without using a refrigerant.

  In addition, n-pentane is commercially available, and is easily available and practical when used in a freezer or the like.

  In addition, although the present Example demonstrated by the mixture of the mixed refrigerant | coolant which mixed 20 mass% or less of carbon dioxide (R744), and n-pentane, even if it mixes in the same ratio instead of n-pentane, the same effect Is obtained. That is, propane has good compatibility with the compressor oil. By mixing 14% by weight of propane, the propane can be returned to the compressor 6 in a state where the oil is dissolved in the propane. It is possible to prevent bad effects such as locking due to rising. Here, propane has little influence on the evaporation temperature, but because it is flammable, there is a risk of explosion and there is a difficulty in handling. However, by setting the mixing ratio of propane to 14% by mass or less, propane can be maintained in an incombustible region, and there is no concern about explosion.

  The description of the above embodiment is for explaining the present invention, and does not limit the invention described in the claims or reduce the scope. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention in detail, unless it deviates from the main point of this invention, it is not limited to these Examples.

Example 1
The refrigerant circuit of the binary refrigeration apparatus shown in FIG. 1 is encapsulated with the following refrigerant composition of the present invention, and the internal temperature of the binary refrigeration apparatus and the evaporator 24 inlet and outlet temperatures are measured. The cooling capacity was evaluated.
Low temperature side refrigerant composition:
A refrigerant composition comprising ethane (R170) mixed with 60% by mass of perfluoroethane (R116) (azeotropic mixture) and 6.0% by mass of n-pentane with respect to the entire refrigerant composition.
High temperature side refrigerant composition:
Difluoromethane (R32) / pentafluoroethane (R125) / 1,1,1,2-tetrafluoroethane (R134a) azeotrope (R407D) or pentafluoroethane (R125) / 1,1,1-trifluoroethane ( R143a) / 1,1,1,2-tetrafluoroethane (R134a) azeotrope (R404A), or difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane ( R134a), 1,1,3-trifluoroethane (R143a) refrigerant group includes 1,1,1,2,3-pentafluoropentene (HFO-1234ze (E), GWP6, boiling point −19 ° C.). Fluorohydrocarbon mixed refrigerant or fluorinated hydrocarbon mixed containing 1,1,1,2-tetrafluoropentene (HFO-1234yf) Mixed refrigerant with combined refrigerant added.

(Example 2)
A cooling capacity is measured by operating in the same manner as in Example 1 except that the following refrigerant composition is used as the low-temperature side refrigerant composition, and measuring the internal temperature of the binary refrigeration apparatus and the inlet and outlet temperatures of the evaporator 24. Evaluated.
Low temperature side refrigerant composition:
A refrigerant composition in which ethane (R170) is mixed with 20% by mass or less of carbon dioxide (R744) and 8.7% by mass of n-pentane with respect to the whole refrigerant composition.

(Example 3)
A cooling capacity is measured by operating in the same manner as in Example 1 except that the following refrigerant composition is used as the low-temperature side refrigerant composition, and measuring the internal temperature of the binary refrigeration apparatus and the inlet and outlet temperatures of the evaporator 24. Evaluated.
Low temperature side refrigerant composition:
A refrigerant composition obtained by mixing 20% by mass or less of carbon dioxide (R744) and 13.0% by mass of n-pentane with respect to the whole refrigerant composition in perfluoroethane (R116).

Example 4
A cooling capacity is measured by operating in the same manner as in Example 1 except that the following refrigerant composition is used as the low-temperature side refrigerant composition, and measuring the internal temperature of the binary refrigeration apparatus and the inlet and outlet temperatures of the evaporator 24. And COP were evaluated.
Low temperature side refrigerant composition:
A refrigerant composition in which ethane (R170) is mixed with 50% by mass of perfluoroethane (R116), 15.0% by mass of carbon dioxide (R744), and 6.4% by mass of n-pentane with respect to the entire refrigerant composition.

(Comparative Example 1)
Operation was carried out in the same manner as in Example 1 except that only ethane (R170) was used as the low-temperature refrigerant composition, and a refrigerant composition in which 9.77% by mass of n-pentane was mixed with the whole refrigerant composition was used. The cooling capacity was evaluated by measuring the internal temperature of the binary refrigeration system and the inlet and outlet temperatures of the evaporator 24.

(Comparative Example 2)
As in Example 1, except that only perfluoroethane (R116) was used as the low-temperature side refrigerant composition, and a refrigerant composition in which 14.0% by mass of n-pentane was mixed with the whole refrigerant composition was used. The cooling capacity was evaluated by measuring the internal temperature of the binary refrigeration unit and the inlet and outlet temperatures of the evaporator 24.

In Example 1, by mixing perfluoroethane (R116) with ethane (R170), the cooling performance was improved by the azeotropic effect. The effect is obtained when the mass% of perfluoroethane (R116) is 50% or more and 60% or less, and the mass% of perfluoroethane (R116) is 15.3%, 35.4%, 52.6%. 59.7%, compared with the result of Comparative Example 1, the temperature at the inlet and outlet of the evaporator 24 is lowered, and the internal refrigeration unit temperature is -0.5 ° C, -1.2 ° C. , -1.7 ° C and -1.8 ° C. The maximum temperature drop at that time was about -2.0 ° C. For example, when the internal temperature of the binary refrigeration apparatus of Comparative Example 1 is −85 ° C., it is about −85.5 ° C., −86.2 ° C., −86.7 ° C., −86.8 ° C., and the maximum at that time The temperature drop was about -87.0 ° C.
In Example 2, the cooling performance was improved by mixing ethane (R170) with carbon dioxide (R744) due to its high heat transfer effect. The effect is that, when the mass% of carbon dioxide (R744) is 20% or less, the inlet and outlet temperatures of the evaporator 24 are lowered compared to the result of Comparative Example 1, and the internal temperature of the binary refrigeration system is It decreased by about -0.9 ° C. The maximum decrease temperature at that time was about -1.0 ° C.
In Example 3, by mixing carbon dioxide (R744) with perfluoroethane (R116), the cooling performance was improved by its high heat transfer effect and the effect estimated to be azeotropic. The effect is that when the mass% of carbon dioxide (R744) is 20% or less, the temperature at the inlet and outlet of the evaporator 24 is lowered compared to the result of Comparative Example 2, and the internal temperature of the binary refrigeration system is It decreased by about -4.4 ° C. The maximum temperature drop at that time was about -4.5 ° C.
In Example 4, as demonstrated in Examples 1 to 3, the cooling performance was further improved by the azeotropic effect and the high heat transfer effect of carbon dioxide (R744). The effect is that, when the mass% of carbon dioxide (R744) is 20% or less, the inlet and outlet temperatures of the evaporator 24 are lowered compared to the result of Comparative Example 1, and the internal temperature of the binary refrigeration system is -2.3 degree C. The maximum decrease temperature at that time was about -2.5 ° C. In the form of Example 4, the flammability that is the characteristic of ethane (R170) can be suppressed by mixing perfluoroethane (R116) and carbon dioxide (R744). Further, since perfluoroethane (R116) has a high GWP value, the GWP value can be suppressed by mixing ethane (R170) and carbon dioxide (R744). In addition, since perfluoroethane (R116) has a low specific heat ratio, an increase in discharge temperature in the high-pressure characteristics of carbon dioxide (R744) can be suppressed. Therefore, the form of Example 4 is considered to satisfy the object of the present invention.

The present invention relates to a binary refrigeration apparatus comprising a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, wherein the refrigerant in the low temperature side refrigeration circuit is condensed by the refrigerant passing through a cascade condenser in the high temperature side refrigerant circuit. As a refrigerant in the side refrigeration circuit, a refrigerant composition containing an azeotropic mixture of ethane (R170) and perfluoroethane (R116) is used, and the perfluoroethane (R116) is used as the refrigerant composition. 50% or more and 60% by mass or less is added,
Using an azeotropic mixture of ethane (R170) with a global warming potential (GWP) of 3 and perfluoroethane (R116) with a global warming potential (GWP) of 12200, the boiling point of ethane (R170) with a GWP of 3 Perfluoroethane (R116) with a GWP of 12200 is as low as -78.1 ° C, and the boiling point of the azeotrope is as low as -88.8 ° C. ) The GWP is less than half that of a single case, so it is gentle to the earth, can achieve a low temperature of -80 ° C, has no danger of explosion, and has outstanding performance in terms of refrigerating capacity and other performance. Therefore, the industrial utility value is high.

S1 High temperature side refrigerant cycle S2 Low temperature side refrigerant cycle 1, 6 Compressor 11 Cascade condenser 24 Evaporator

Claims (7)

In a binary refrigeration apparatus comprising a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, wherein the refrigerant in the low temperature side refrigeration circuit is condensed by the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit,
A refrigerant composition containing an azeotropic mixture obtained by mixing ethane (R170) and perfluoroethane (R116) is used as the refrigerant in the low-temperature refrigeration circuit,
A binary refrigeration apparatus, wherein the perfluoroethane (R116) is added in an amount of 50% to 60% by mass with respect to the refrigerant composition. In a binary refrigeration apparatus comprising a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, wherein the refrigerant in the low temperature side refrigeration circuit is condensed by the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit,
As a refrigerant in the low temperature side refrigeration circuit, a refrigerant composition containing ethane (R170) and carbon dioxide (R744) is used,
The binary refrigeration apparatus characterized by adding 20% by mass or less of the carbon dioxide (R744) to the refrigerant composition. In a binary refrigeration apparatus comprising a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, wherein the refrigerant in the low temperature side refrigeration circuit is condensed by the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit,
As a refrigerant in the low temperature side refrigeration circuit, a refrigerant composition containing an azeotropic mixture of ethane (R170) and perfluoroethane (R116) and carbon dioxide (R744) is used.
The perfluoroethane (R116) is 50% by mass to 60% by mass with respect to the refrigerant composition,
The binary refrigeration apparatus characterized by adding 20% by mass or less of the carbon dioxide (R744) to the refrigerant composition. As an oil carrier, n-pentane or propane is contained at a ratio of 14% by mass or less with respect to the total mass of the refrigerant composition.
The binary refrigeration apparatus according to any one of claims 1 to 3. In a binary refrigeration apparatus comprising a high temperature side refrigeration circuit and a low temperature side refrigeration circuit, wherein the refrigerant in the low temperature side refrigeration circuit is condensed by the refrigerant passing through the cascade condenser in the high temperature side refrigerant circuit,
As refrigerant in the high-temperature side refrigeration circuit, refrigerants of difluoromethane (R32), pentafluoroethane (R125), 1,1,1,2-tetrafluoroethane (R134a), 1,1,3-trifluoroethane (R143a) Binary refrigeration characterized by adding a non-azeotropic mixture comprising a group or a fluorinated hydrocarbon mixed refrigerant containing 1,1,1,2,3-pentafluoropentene (HFO-1234ze) to the refrigerant group apparatus.   As a refrigerant in the high temperature side refrigeration circuit, fluorine containing 1,1,1,2-tetrafluoropentene (HFO-1234yf) instead of 1,1,1,2,3-pentafluoropentene (HFO-1234ze) in the previous period. 6. A binary refrigeration apparatus according to claim 5, wherein a mixed hydrocarbon refrigerant is added. The refrigerant in the high temperature side refrigeration circuit contains n-pentane as an oil carrier in a ratio of 6% by mass or less based on the total mass of the fluorinated hydrocarbon mixed refrigerant.
The binary refrigeration apparatus according to claim 5.

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