JPWO2015140875A1 - Refrigeration equipment - Google Patents

Abstract

The refrigeration apparatus 100 is a refrigeration apparatus 100 that uses a refrigerant including HFO1123 refrigerant, and includes a first compressor 1, an intermediate heat exchanger 8, a second compressor 2, a condenser 3, and a subcool heat exchanger. 4, the expansion valve 6, and the evaporator 7 are sequentially connected to the main refrigerant circuit, and between the subcool heat exchanger 4 and the expansion valve 6, and the intermediate heat exchanger is connected via the subexpansion valve 5. 8 and a bypass refrigerant circuit 10 connected between the second compressor 2.

Description

  The present invention relates to a refrigeration apparatus.

  As a conventional refrigeration apparatus, for example, a two-stage compression refrigeration apparatus shown in the following Patent Document 1 is known as one that is used for applications in which the evaporation temperature is −40 ° C. or lower. In the conventional two-stage compression refrigeration apparatus, generally, an R22 refrigerant or an R404A refrigerant is used.

JP-A-3-217762 (page 3, FIG. 1)

  However, since the R22 refrigerant and the R404A refrigerant have a high global warming potential (GWP), it is desirable to refrain from using them from the viewpoint of preventing global warming.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a refrigerant that can be used in applications where the evaporation temperature is -40 ° C or lower and has a low global warming potential. The refrigeration apparatus used is obtained.

  The refrigeration apparatus according to the present invention is a refrigeration apparatus that uses a refrigerant including HFO1123 refrigerant, and includes a first compressor, an intermediate heat exchanger, a second compressor, a condenser, a subcool heat exchanger, A main refrigerant circuit in which an expansion valve and an evaporator are connected in sequence; a branch from between the subcool heat exchanger and the expansion valve; and the intermediate heat exchanger and the second compression through the subexpansion valve A bypass refrigerant circuit connected to the machine.

  According to the present invention, it is possible to obtain a refrigeration apparatus that uses a refrigerant having a low global warming potential and that can be used in applications where the evaporation temperature is −40 ° C. or lower.

It is the schematic which shows an example of the refrigerant circuit of the freezing apparatus which concerns on Embodiment 1 of this invention. It is a schematic diagram explaining the refrigerating cycle of the freezing apparatus shown in FIG. It is a graph which shows the relationship between the ratio of the R32 refrigerant | coolant in the mixed refrigerant | coolant of HFO1123 refrigerant | coolant, and R32 refrigerant | coolant, and its boiling point. It is a graph which shows the relationship between the ratio of R32 refrigerant | coolant in the mixed refrigerant | coolant of HFO1123 refrigerant | coolant, and R32 refrigerant | coolant, and its GWP. It is a graph which shows the relationship between the ratio of the HFO1234yf refrigerant | coolant in the mixed refrigerant | coolant of HFO1123 refrigerant | coolant, and HFO1234yf refrigerant | coolant, and its boiling point. It is a graph which shows the relationship between the ratio of the HFO1234yf refrigerant | coolant in the mixed refrigerant | coolant of HFO1123 refrigerant | coolant, and HFO1234yf refrigerant | coolant, and its GWP.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof is omitted or simplified as appropriate. Further, the size and arrangement of the configurations shown in the drawings can be appropriately changed within the scope of the present invention.

Embodiment 1 FIG.
As shown in FIG. 1, the refrigeration apparatus 100 according to this embodiment includes a first compressor 1, an intermediate heat exchanger 8, a second compressor 2, a condenser 3, and a subcool heat exchanger 4. The main refrigerant circuit has an expansion valve 6 and an evaporator 7 connected in order. Further, the refrigeration apparatus 100 branches from between the subcool heat exchanger 4 and the expansion valve 6, and is a bypass connected between the intermediate heat exchanger 8 and the second compressor 2 via the subexpansion valve 5. A refrigerant circuit 10 is provided.

  The refrigeration apparatus 100 according to this embodiment is applied to, for example, an ultra-low temperature refrigerator whose inside temperature is −40 ° C. or lower. The first compressor 1 and the second compressor 2 may be separate compressors each housed in a casing, or the first compressor 1 and the second compressor 2 are combined into one casing. The compressor may be housed and integrally formed.

  Next, operation | movement of the freezing apparatus 100 is demonstrated using FIG. 1 and FIG. In the following description, high pressure, intermediate pressure, or low pressure represents the relative relationship of pressure in the refrigerant circuit. The same applies to the temperature. The high temperature or the low temperature represents a relative relationship of the temperature in the refrigerant circuit.

  The high-temperature and high-pressure gas refrigerant E discharged from the second compressor 2 flows into the condenser 3. In the condenser 3, heat exchange is performed between the refrigerant flowing in the condenser 3 and the condensation side heat source outside the condenser 3. The refrigerant F that has been subjected to heat exchange and has flowed out of the condenser 3 is cooled by the subcool heat exchanger 4. The refrigerant G cooled and flowing out from the subcool heat exchanger 4 is branched into a main refrigerant flowing into the expansion valve 6 and a branch refrigerant flowing into the sub expansion valve 5.

  The main refrigerant that has flowed into the expansion valve 6 is decompressed to a low pressure. The refrigerant J that has been decompressed to a low pressure and has flowed out of the expansion valve 6 flows into the evaporator 7. In the evaporator 7, heat exchange is performed between the refrigerant flowing in the evaporator 7 and the evaporation side heat source outside the evaporator 7. The refrigerant A that has exchanged heat and has flowed out of the evaporator 7 is sucked into the first compressor 1 and compressed. The intermediate-pressure refrigerant B discharged from the first compressor 1 is cooled by the intermediate heat exchanger 8. The refrigerant C that has been cooled and has flowed out of the intermediate heat exchanger 8 merges with the refrigerant I that has passed through the bypass refrigerant circuit 10.

  The branched refrigerant that has flowed into the sub expansion valve 5 is reduced to an intermediate pressure. The refrigerant H decompressed to an intermediate pressure by the sub expansion valve 5 is heat-exchanged with the refrigerant F flowing out of the condenser 3 in the subcool heat exchanger 4. The refrigerant I that exchanges heat with the refrigerant F and flows out of the subcool heat exchanger 4 joins the refrigerant C cooled by the intermediate heat exchanger 8. The refrigerant D merged as described above is sucked into the second compressor 2 and compressed.

  The refrigerant used in the refrigeration apparatus 100 configured as described above preferably has a low global warming potential (GWP) from the viewpoint of preventing global warming. Furthermore, since the refrigeration apparatus 100 according to this embodiment is used in an environment where the evaporation temperature is −40 ° C. or lower, a refrigerant having a low boiling point is suitable. Therefore, in the refrigeration apparatus 100 according to this embodiment, a refrigerant including the HFO1123 refrigerant is used.

  As shown in Table 1 below, the HFO1123 refrigerant used in this embodiment has a global warming potential of 0 and a boiling point of −51 ° C. Therefore, since the HFO1123 refrigerant has a low global warming potential and a low boiling point, it is suitable as a refrigerant used in an environment where the evaporation temperature is −40 ° C. or lower.

Note that the R22 refrigerant and the R404A refrigerant have a higher boiling point and a higher global warming potential than the HFO1123 refrigerant, and thus are not suitable for use in the refrigeration apparatus 100 according to this embodiment.
Although the R32 refrigerant has a lower boiling point than the HFO1123 refrigerant, it has a high global warming potential, so it is not suitable for use in the refrigeration apparatus 100 according to this embodiment.
The CO2 refrigerant has a triple point of −56.6 ° C. and becomes solid (dry ice) at −56.6 ° C. or lower, and is not suitable for use in the refrigeration apparatus 100 according to this embodiment.
Since the HFO1234yf refrigerant has a boiling point of −29.4 ° C., it is not suitable for use in an environment where the evaporation temperature is −40 ° C. or lower.

  Since the HFO1123 refrigerant has a low global warming potential and a low boiling point as described above, it is suitable as a refrigerant used in an environment where the evaporation temperature is −40 ° C. or lower. However, the HFO1123 refrigerant is still inferior in efficiency compared with the R32 refrigerant or the HFO1234yf refrigerant, and when the HFO1123 refrigerant is used alone, a disproportionation reaction (self-decomposition reaction) may occur. is there. Therefore, in this embodiment, the HFO1123 refrigerant is used by mixing with other refrigerants.

  In this embodiment, for example, a mixed refrigerant obtained by mixing HFO1123 refrigerant and R32 refrigerant is used. As shown in Table 1, the R32 refrigerant has a lower boiling point than the HFO1123 refrigerant. Therefore, as shown in Table 2 and FIG. 3, the boiling point can be lowered by increasing the mixing ratio (mass ratio) of the R32 refrigerant in the entire mixed refrigerant.

  On the other hand, since the R32 refrigerant has a high GWP, increasing the mixing ratio of the R32 refrigerant increases the GWP as shown in Table 3 and FIG. For example, in this embodiment, since the GWP of the mixed refrigerant is set to 300 or less, the mass ratio of the R32 refrigerant to the entire mixed refrigerant is 43 mass% or less. Further, the mass ratio of the R32 refrigerant to the entire mixed refrigerant is set to 20 mass% or more so as not to cause a disproportionation reaction. Therefore, in the mixed refrigerant of the HFO1123 refrigerant and the R32 refrigerant, the mass ratio of the R32 refrigerant to the whole mixed refrigerant is preferably 20% by mass to 43% by mass.

  In addition, for example, in this embodiment, a mixed refrigerant obtained by mixing HFO1123 refrigerant and HFO1234yf refrigerant is used. As shown in Table 1, the HFO1234yf refrigerant has a boiling point higher than that of the HFO1123 refrigerant. Therefore, as shown in Table 4 and FIG. 5, increasing the mixing ratio of the HFO1234yf refrigerant in the entire mixed refrigerant increases the boiling point. For example, in this embodiment, since the boiling point of the mixed refrigerant is set to −40.8 ° C. or less, the mass ratio of the HFO1234yf refrigerant to the entire mixed refrigerant is 49% by mass or less. As shown in Table 5 and FIG. 6, the HFO1234yf refrigerant has a GWP of 0, so that the GWP is 0 even if the mass ratio of the HFO1234yf refrigerant is increased.

  Further, the mass ratio of the HFO1234yf refrigerant to the entire mixed refrigerant is set to 20 mass% or more so as not to cause a disproportionation reaction. Therefore, in the mixed refrigerant of the HFO1123 refrigerant and the HFO1234yf refrigerant, the mass ratio of the HFO1234yf refrigerant to the whole mixed refrigerant is preferably 20% to 49%.

  As described above, in the refrigeration apparatus 100 according to this embodiment, a refrigerant including the HFO 1123 refrigerant having a low global warming potential and a low boiling point is used. Therefore, the refrigeration apparatus 100 according to this embodiment can be suitably applied to uses in which the evaporation temperature is −40 ° C. or lower, and the environmental load is reduced.

  Furthermore, in this embodiment, it has the 1st compressor 1 and the 2nd compressor 2, and the intermediate heat exchanger 8 is installed between the 1st compressor 1 and the 2nd compressor 2, Moreover, it has a bypass refrigerant circuit 10 branched from between the subcool heat exchanger 4 and the expansion valve 6 and connected between the intermediate heat exchanger 8 and the second compressor 2 via the subexpansion valve 5. It is a configuration.

Therefore, in this embodiment, it can suppress that the temperature of the refrigerant | coolant B discharged from the 1st compressor 1 and the temperature of the refrigerant | coolant E discharged from the 2nd compressor 2 become high.
Because the first compressor 1 compresses the refrigerant to an intermediate pressure lower than the high pressure, the temperature of the refrigerant B discharged from the first compressor 1 is suppressed from increasing.
The refrigerant B discharged from the first compressor 1 is cooled by the intermediate heat exchanger 8. And the refrigerant | coolant C which flowed out from the intermediate heat exchanger 8 merges with the refrigerant | coolant I which passed the bypass refrigerant circuit 10, and is further cooled. Since the second compressor 2 sucks and compresses the refrigerant D thus cooled, the temperature of the refrigerant E discharged from the second compressor 2 is suppressed from increasing.
As described above, in this embodiment, since the temperature of the refrigerant B discharged from the first compressor 1 and the temperature of the refrigerant E discharged from the second compressor 2 are suppressed, the HFO 1123 is suppressed. The risk that the refrigerant including the refrigerant causes a disproportionation reaction is suppressed.
Furthermore, in this embodiment, since the refrigerant temperature is suppressed from increasing on the discharge side of the first compressor 1 and on the suction side and discharge side of the second compressor 2, the first compressor 1 and the first compressor 1 2 The compression efficiency of the compressor 2 is improved.

  Preferably, the first compressor 1 and the second compressor 2 are driven by an inverter. For example, the rotation speeds of the first compressor 1 and the second compressor 2 are controlled so that the temperature of the refrigerant B discharged from the first compressor 1 is 120 ° C. or less. Thus, by controlling the rotation speeds of the first compressor 1 and the second compressor 2 so that the temperature of the refrigerant B does not become too high, the temperature of the refrigerant B becomes higher, and the first compressor 1 And it can prevent that the 2nd compressor 2 fails.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention. That is, the configuration of the above embodiment may be improved as appropriate, or at least a part of the configuration may be replaced with another configuration. Further, the configuration requirements that are not particularly limited with respect to the arrangement are not limited to the arrangement disclosed in the embodiment, and can be arranged at a position where the function can be achieved.

  For example, in the above embodiment, an example in which the R32 refrigerant or the HFO1234yf refrigerant is mixed with the HFO1123 refrigerant has been described, but the RFO refrigerant and the HFO1234yf refrigerant may be mixed with the HFO1123 refrigerant. Further, the HFO1123 refrigerant may be mixed with other refrigerants other than the R32 refrigerant and the HFO1234yf refrigerant.

  In addition, the refrigerant including the HFO1123 refrigerant can be suitably applied not only to the two-stage compression refrigerant circuit described in the above embodiment, but also to a refrigerant circuit whose evaporation temperature is −40 ° C. or lower.

  DESCRIPTION OF SYMBOLS 1 1st compressor, 2nd 2nd compressor, 3 condenser, 4 subcool heat exchanger, 5 subexpansion valve, 6 expansion valve, 7 evaporator, 8 intermediate heat exchanger, 10 bypass refrigerant circuit, 100 refrigeration apparatus.

The refrigeration apparatus according to the present invention is a refrigeration apparatus that uses a mixed refrigerant containing HFO1123 refrigerant, and includes a first compressor, an intermediate heat exchanger, a second compressor, a condenser, and a subcool heat exchanger. A main refrigerant circuit in which an expansion valve and an evaporator are connected in sequence, a branch from between the subcool heat exchanger and the expansion valve, and the intermediate heat exchanger and the second through the subexpansion valve A bypass refrigerant circuit connected to a compressor , wherein the mixed refrigerant includes the HFO1123 refrigerant and the R32 refrigerant, and a mass ratio of the R32 refrigerant to the entire mixed refrigerant is 20% by mass to 43% by mass .

Claims (4)

A refrigeration apparatus that uses refrigerant including HFO1123 refrigerant,
A main refrigerant circuit in which a first compressor, an intermediate heat exchanger, a second compressor, a condenser, a subcool heat exchanger, an expansion valve, and an evaporator are connected in order;
A refrigeration apparatus comprising: a bypass refrigerant circuit branched from between the subcool heat exchanger and the expansion valve and connected between the intermediate heat exchanger and the second compressor via the subexpansion valve .   The refrigeration apparatus according to claim 1, wherein the refrigerant is a mixed refrigerant obtained by mixing the HFO1123 refrigerant with an R32 refrigerant or an HFO1234yf refrigerant. The mixed refrigerant is a mixed refrigerant of the HFO1123 refrigerant and the R32 refrigerant,
The refrigerating apparatus according to claim 2, wherein a mass ratio of the R32 refrigerant to the entire mixed refrigerant is 20 mass% to 43 mass%. The mixed refrigerant is a mixed refrigerant of the HFO1123 refrigerant and the HFO1234yf refrigerant,
The refrigerating apparatus according to claim 2, wherein a mass ratio of the HFO1234yf refrigerant to the entire refrigerant mixture is 20 mass% to 49 mass%.

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