JP3226247U - Refrigeration equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating apparatus using a non-azeotropic mixed refrigerant of carbon dioxide and HFO gas having a low GWP value, which can maintain conventional working pressure at 3.0 MPa or less and use conventional general-purpose equipment. Provide a device. SOLUTION: In order to reduce the high pressure of the refrigeration circuit to 3.0 MPa or less by cooling, one heat transfer plate is provided inside the casing between the condenser 21 of the refrigeration circuit and the expansion valve on the primary side of the evaporator 25. A heat exchanger in which the heat transfer plate forms a primary side and a secondary side having the same capacity, through which the refrigerant flows, and the heat transfer area of the heat transfer plate is the same on the primary side and the secondary side. It is assumed that a plurality of 22, 24 are connected in series and a pressure reducing valve is arranged in front of the secondary inlet of each heat exchanger. [Selection diagram] Figure 1

Description

  The present invention relates to a refrigerating apparatus, which also uses a non-azeotropic refrigerant mixture of carbon dioxide and HFO gas having a low GWP value.

  In recent years, CFCs have been deteriorating the global environment and causing global warming. Therefore, carbon dioxide having a GWP value of 1 has been used as a refrigerant, and a mixed refrigerant of this carbon dioxide and HFO is used. It has also been used.

  However, even with this mixed refrigerant, the condensed temperature of the refrigerant is low, and therefore the condensed water temperature at normal temperature and the atmospheric temperature are high, and do not fall below 3.0 MPa. Therefore, it cannot be used within the conventional usage standard for general-purpose devices.

  Regarding the invention of the present application, the applicant searched the prior art documents, but could not find any document which is particularly related to the invention of the present application and which seems to be similar.

  The problem to be solved by the present invention is that when a non-azeotropic mixed refrigerant of carbon dioxide and HFO gas having a low GWP value is used, the condensation temperature of the refrigerant is low, so that the pressure becomes high at room temperature. The point is that it cannot be set to 0 Mpa or less, and that there is no apparatus that can maintain the normal pressure at 3.0 Mpa or less and use conventional general-purpose equipment.

  In order to solve the above-mentioned problems, a refrigerating apparatus according to the present invention is a refrigerating apparatus using a non-azeotropic mixed refrigerant in which carbon dioxide and HFO gas having a low GWP value are mixed as a refrigerant. In order to reduce the temperature to 3.0 MPa or less by cooling, one heat transfer plate is provided inside the casing between the condenser of the refrigeration circuit and the expansion valve on the primary side of the evaporator. Circulates, forms a primary side and a secondary side having the same capacity, and the heat transfer area of the heat transfer plate is the same as that of the primary side and the secondary side, and a plurality of heat exchangers are connected in series. It is characterized in that a pressure reducing valve is provided in front of the secondary inlet of each heat exchanger.

  Further, the refrigerating apparatus according to the present invention is characterized in that the heat exchangers described above are connected to each other to form a two-stage evaporation pressure reducing mechanism.

  Further, the refrigerating apparatus according to the present invention is characterized in that the refrigerant is a mixed gas of carbon dioxide having a GWP value of 1 and R1224yd (HFO-1224yd) having a GWP value larger than 0.8.

  Further, the refrigerating apparatus according to the present invention is characterized in that the pressure reducing valve is a capillary tube for adjusting the degree of pressure reduction.

  Further, the refrigerating apparatus according to the present invention is characterized in that the heat exchanger described above is configured to self-evaporate and condense.

  The present invention is constructed as described above. Therefore, in the present invention, a plurality of heat exchangers, each of which has a two-stage configuration, for self-evaporative condensation can suppress the increase in the condensation pressure even if the temperature of the condensation heat source is not completely low. Here, the completely low temperature means a temperature at which the wet steam on the PH diagram can be cooled and condensed within a constant pressure.

It is a refrigeration circuit diagram which implemented this invention. It is a refrigeration circuit diagram at the time of using one heat exchanger. FIG. 3 is a schematic diagram of the PH diagram of FIG. 2.

  This is realized by the configuration shown in the drawings and configured as described in the embodiments.

  Next, a preferred embodiment of the present invention will be described with reference to the drawings. First, a case where one heat exchanger is used will be described with reference to FIG. Reference numeral 20 in the drawing denotes a compressor from which high-pressure and high-temperature refrigerant gas is discharged. Here, as the refrigerant, a non-azeotropic mixed refrigerant of carbon dioxide (GWP value is 1) and R1224yd (HFO-1224yd having a GWP value smaller than 0.8) is used. This mixing ratio is ideally 1: 1 but this ratio is determined by the set temperature.

  The refrigerant is discharged from the compressor 20 (state 2 in the figure), passes through the condenser 21, and flows into the primary side A of the one-stage heat exchanger 22 (state 3 in the figure). Then, there is specific enthalpy heat dissipation by the condenser 21 (h1).

  Here, the first-stage heat exchanger 22 is one in which the inside of the casing is partitioned by one heat transfer plate to form a primary side A and a secondary side B having the same capacity in which the refrigerant flows. The heat transfer area is the same on the primary side A and the secondary side B. In the state of 3 in the figure, after passing through the condenser 21, the temperature is the temperature before flowing into the primary side A of the one-stage heat exchanger 22 (see the PH diagram of FIG. 3).

  The refrigerant flowing into the primary side A of the one-stage heat exchanger 22 and flowing out (concentration enthalpy heat dissipation in the state of 3 to 4 in the figure) (h2). The refrigerant that has passed through the primary side A of the one-stage heat exchanger 22 passes through the pressure reducing valve, specifically, the capillary tube 26, and flows into the secondary side B.

  Before passing through the primary side A, passing through the capillary tube 26, and flowing into the secondary side B (states 4 to 5 in the figure), the pressure is reduced and evaporated.

  The refrigerant that has passed through the secondary side B of the one-stage heat exchanger 22 (states 5 to 5'in the figure) absorbs heat of the evaporation ratio enthalpy (h3). The amount of heat absorbed by the refrigerant when passing through the secondary side B is approximately the same as the amount of heat released from the primary side A.

  The refrigerant (states 5 ′ to 10 in the figure) that passes through the secondary side B, passes through the expansion valve 23, and flows into the evaporator 25 is depressurized and evaporated. The refrigerant that has passed through the evaporator 25 returns to the compressor 20 to form a circuit.

  Here, the condensation-side enthalpy heat dissipation (h2) on the primary side A of the first-stage heat exchanger 22 and the evaporation-specific enthalpy endotherm (h3) on the secondary side B exchange heat with the barter and pass through the expansion valve 23 to pass through the evaporator 25. The evaporation ratio enthalpy becomes 0 on the primary side (state 10 in the figure) flowing into the. That is, although the high pressure of the refrigerant is suppressed, the final cooling capacity is attenuated.

  Therefore, in the present invention, the one-stage heat exchanger 22 and the two-stage heat exchanger 24 are connected in series between the condenser 21 and the expansion valve 23. The two-stage heat exchanger 24 is a self-evaporative condensation heat exchanger having the same configuration as the one-stage heat exchanger 22, and the refrigerant passing through the secondary side B of the one-stage heat exchanger 22 is the primary heat of the two-stage heat exchanger 24. The refrigerant flowing into the side C and passing through the primary side C flows into the secondary side D through the pressure reducing valve (capillary tube) 26. The refrigerant on the secondary side D that has passed through 7 to 7'in the figure passes through the expansion valve 23, passes through the evaporator 25, and returns to the compressor 20. (State 1 in the figure)

  In this two-stage heat exchanger 24, the same heat dissipation and heat absorption as in the above-described one-stage heat exchanger 22 are performed. With only the first-stage heat exchanger 22, the evaporation ratio enthalpy becomes 0 when passing through the expansion valve 10, but by interposing the second-stage heat exchanger 24 before that, the final cooling capacity is maintained. The working pressure can be maintained at 3.0 MPa or less. Therefore, by implementing the present invention, it is possible to use the conventional general-purpose equipment within the standard, and obtain the refrigerating capacity close to that when using the conventional CFC. That is, the first stage heat exchanger 22 suppresses the high pressure, and the second stage heat exchanger 24 prevents the final cooling capacity from being attenuated. By combining these functions, the object of the present invention can be achieved as a whole.

  In the present embodiment, the heat exchanger has a two-stage configuration (two series), but of course, if necessary, it is possible to configure a configuration in which a large number of three or more heat exchangers are connected in series. Is.

20 compressor 21 condenser 22 first stage heat exchanger 23 expansion valve 24 second stage heat exchanger 25 evaporator 26 pressure reducing valve (capillary tube)
A, C Primary side B, D Secondary side

Claims (5)

  A refrigeration apparatus using a non-azeotropic mixed refrigerant in which carbon dioxide and HFO gas having a low GWP value are mixed as a refrigerant, and in order to reduce the high pressure of the refrigeration circuit to 3.0 MPa or less by cooling, a condenser of the refrigeration circuit, Between the expansion valve on the primary side of the evaporator, one heat transfer plate is provided inside the casing, and the heat transfer plate forms a primary side and a secondary side through which the refrigerant flows and having the same capacity. The heat transfer area of the heat transfer plate is the same on the primary side and the secondary side, and a plurality of heat exchangers are connected in series, and a pressure reducing valve is provided in front of the secondary inlet of each heat exchanger. A refrigeration system characterized by being arranged.   The refrigerating apparatus according to claim 1, wherein two heat exchangers are connected to each other to form a two-stage evaporation pressure reducing mechanism.   The refrigerating apparatus according to claim 1 or 2, wherein the refrigerant is a mixed gas of carbon dioxide having a GWP value of 1 and R1224yd (HFO-1224yd) having a GWP value of more than 0.8.   The refrigerating apparatus according to claim 1, wherein the pressure reducing valve is a capillary tube for adjusting the degree of pressure reduction.   The refrigerating apparatus according to claim 1, wherein the heat exchanger is configured to self-evaporate and condense.

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