JP2008116099A - Goods storage device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To utilize a low temperature according to necessity in an article storage device such as a refrigerator comprising: an evaporator for freezing to achieve a normal freezing temperature by using a zeotropic refrigerant mixture; and an evaporator for low temperature to achieve low temperature independently from the evaporator for freezing, and loading a cascade cycle utilizing at least two temperatures. <P>SOLUTION: This article storage device comprises a low-temperature compartment to achieve the low temperature independently from a freezing compartment; and further comprises the evaporator 5 for freezing to cool the freezing compartment, the evaporator 11 for low temperature to cool the low-temperature compartment, and a circulation air trunk for circulating the cold air of the evaporator 5 for freezing to the low-temperature compartment. The low-temperature compartment is cooled by using the evaporator 11 for low temperature to achieve the low temperature. The evaporator 11 for low temperature is stopped, and the low-temperature compartment is cooled by using the circulation air trunk to achieve normal freezing temperature. Here, a refrigerant of low boiling point is stored in a cascade heat exchanger 7, in stopping the evaporator 11 for low temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a low-temperature evaporator that achieves a lower temperature (for example, −30 to −80 ° C.) independently of a freezing evaporator that achieves a normal freezing temperature (for example, −18 to −25 ° C.). The present invention relates to an article storage device such as a refrigerator provided.

  Conventionally, refrigerators that realize a low temperature of −30 to −80 ° C. lower than the normal freezing temperature have been proposed for the purpose of rapid freezing of food, quick ice making, or long-term storage of foods at low temperatures.

  However, when such a low temperature is realized, the refrigeration efficiency of the refrigeration cycle is significantly reduced, and there is a concern about an increase in power consumption.

  Accordingly, a refrigerator including a freezing evaporator that achieves a normal freezing temperature with relatively high refrigerating efficiency, and a low-temperature evaporator that realizes a lower temperature than the freezing temperature, independent of the freezing evaporator. Has been proposed (see, for example, Patent Document 1).

  This limits the refrigeration capacity of the low-temperature evaporator that achieves a lower temperature, but can suppress a significant increase in power consumption, so that a refrigerator that particularly requires energy-saving performance, such as a household refrigerator. Is a desirable configuration.

  Hereinafter, a conventional refrigerator will be described with reference to the drawings. FIG. 4 is a refrigeration cycle configuration diagram of a refrigerator showing a conventional example.

  As shown in FIG. 4, a conventional refrigerator uses a non-azeotropic refrigerant mixture as a refrigerant, and includes a compressor 1, a condenser 2, a gas-liquid separator 3, a freezing expansion mechanism 4, a freezing evaporator 5, and refrigeration. The evaporator 6 and the cascade heat exchanger 7 are provided.

  The cascade heat exchanger 7 includes a condensation pipe 8 connected to the gas phase side outlet of the gas-liquid separator 3 and an evaporation pipe 9 connected to the subsequent stage of the refrigeration evaporator 6.

  The refrigerator includes a low-temperature expansion mechanism 10, a low-temperature evaporator 11, and an internal heat exchanger 12. The internal heat exchanger 12 includes a supercooling pipe 13 connected to the condensation pipe 8, and a low-temperature evaporator. 11 is provided with a return pipe 14 connected to a subsequent stage.

  Here, the freezing evaporator 5 cools a freezing room (not shown) that realizes a normal freezing temperature, and the refrigerating evaporator 6 is a refrigerating room that realizes a refrigerating temperature higher than the normal freezing temperature ( The low temperature evaporator 11 cools a low temperature chamber (not shown) that realizes a low temperature lower than the normal refrigeration temperature.

  About the conventional refrigerator comprised as mentioned above, the operation | movement is demonstrated.

  The refrigerant discharged from the compressor 1 is cooled by the condenser 2 and partially condensed, and then separated into a liquid phase and a gas phase by the gas-liquid separator 3.

  The liquid phase of the gas-liquid separator 3 containing a high-boiling refrigerant as a main component is decompressed by the freezing expansion mechanism 4 and is evaporated by the freezing evaporator 5 and the refrigerating evaporator 6 while gradually raising the evaporation temperature. Then, it evaporates while passing through the evaporation pipe 9 and returns to the compressor 1.

  On the other hand, the gas phase of the gas-liquid separator 3 mainly composed of a low-boiling-point refrigerant is liquefied while passing through the condensation pipe 8 and the supercooling pipe 13 and then decompressed by the low-temperature expansion mechanism 10 to evaporate at low temperature. Evaporate in vessel 11. Then, it vaporizes while passing through the return pipe 14 and returns to the compressor 1.

  At this time, the cascade heat exchanger 7 uses the latent heat of evaporation and sensible heat of the high-boiling refrigerant evaporated in the evaporating pipe 9 to condense the low-boiling refrigerant in the condensing pipe 8, thereby freezing in the low-temperature evaporator 11. Secure capacity. Further, in the internal heat exchanger 12, heat recovery is performed by supercooling the liquid refrigerant in the supercooling pipe 13 using latent heat of evaporation and sensible heat of the refluxing refrigerant in the return pipe 14.

  As a result, the refrigeration evaporator 5, the refrigeration evaporator 6, and the low temperature evaporator 11 have substantially the same low pressure, but due to the difference in refrigerant composition, the evaporation temperature of the refrigeration evaporator 5 is used as a reference. The refrigeration evaporator 6 can realize a higher evaporation temperature, and the low temperature evaporator 11 can realize a lower evaporation temperature.

  In this way, a non-azeotropic refrigerant mixture is used as the refrigerant, and the evaporation temperature lower than the evaporation temperature of the normal refrigeration evaporator 5 is reduced by using the gas-liquid separator 3 and the cascade heat exchanger 7. The refrigeration cycle realized by No. 11 is generally called a cascade cycle. By this cascade cycle, the refrigeration capacity of the low-temperature evaporator 11 that realizes a lower temperature is limited to a part of the refrigeration capacity produced by the compressor 1, but the refrigeration evaporator 5 and the refrigeration evaporator 6 are simultaneously realized. By doing so, a significant increase in power consumption can be suppressed.

Moreover, as a non-azeotropic refrigerant mixture used in such an autocascade cycle, a combination of a high-boiling refrigerant and a low-boiling refrigerant whose boiling point difference is approximately the same as the evaporation temperature difference is desirable (for example, Patent Document 2). reference).
JP-A-55-23861 JP 2003-287293 A

  However, with the above conventional configuration, even if there is no requirement for long-term storage of foods such as quick freezing, quick ice making, or food at low temperatures, the use of low temperatures cannot be stopped, resulting in meaningless power consumption There is a concern that it will increase.

  The present invention solves the conventional problems. A non-azeotropic refrigerant mixture is used, for example, along with a refrigerating evaporator that achieves a normal refrigerating temperature. An article storage device such as a refrigerator equipped with a cascade cycle that uses at least two temperatures provided with a low-temperature evaporator that realizes a lower temperature than the temperature, and the use of the low temperature can be stopped as necessary. The object is to provide a storage device.

  In order to solve the above-described conventional problems, the article storage device of the present invention includes a low-temperature chamber that is maintained at a temperature lower than the normal freezing temperature independently of the freezing chamber that is maintained at the normal freezing temperature. A freezing evaporator that cools the freezing chamber, a low temperature evaporator that cools the low temperature chamber, and a circulation air passage that circulates the cold air of the freezing evaporator to the low temperature chamber. In order to achieve a lower temperature than the normal refrigeration temperature, the low-temperature evaporator is cooled using the low-temperature evaporator, and when the normal refrigeration temperature is realized, the low-temperature evaporator is stopped and circulated. An air path is used to cool the cold room.

  In the article storage apparatus of the present invention, the low-boiling point refrigerant is stored in the cascade heat exchanger when the low-temperature evaporator is stopped.

  The article storage device of the present invention, when realizing a normal refrigeration temperature in a low temperature chamber, stops the low temperature evaporator, and additionally cools the low temperature chamber using a circulation air passage, The temperature of the low greenhouse can be raised to the normal refrigeration temperature, the refrigeration load can be reduced, and the increase in power consumption can be suppressed. Further, by storing the low boiling point refrigerant in the cascade heat exchanger, the high pressure can be lowered when the low temperature evaporator is stopped, and the refrigeration efficiency can be improved.

  The invention according to claim 1 is equipped with a cascade cycle that uses a non-azeotropic refrigerant mixture to form a first temperature at least in a freezing temperature range and a second temperature lower than the first freezing temperature. The article storage device includes a freezing room maintained at a first temperature and a cold room maintained at the second temperature, and the temperature of the cold room can be switched to the first temperature. is there.

  By adopting such a configuration, the temperature of the low temperature chamber can be raised to the temperature of the freezer compartment or a freezing temperature close thereto as necessary to reduce the refrigeration load and suppress an increase in power consumption.

  The invention according to claim 2 is a refrigerating evaporator for cooling the freezing chamber, a low temperature evaporator for cooling the low temperature chamber, and a circulation air passage for circulating cold air of the freezing evaporator to the low temperature chamber. The low temperature evaporator is used to maintain the second temperature in the low temperature chamber, the low temperature evaporator is stopped to maintain the first temperature, and the circulation air passage is used for the freezing. The low temperature chamber is cooled by an evaporator.

  With such a configuration, the refrigeration evaporator is used when raising the temperature of the cold room to the temperature of the freezer or a refrigeration temperature close to the temperature of the freezer. Cooling is performed using the high evaporation temperature of the evaporator, and as a result, the power consumption can be further suppressed.

  The invention according to claim 3 includes a cascade heat exchanger that condenses the low-boiling point refrigerant using the latent heat of vaporization of the high-boiling point refrigerant, and the cascade temperature is changed when the temperature of the low temperature chamber is switched to the first temperature. A low boiling point refrigerant is stored in the heat exchanger.

  With such a configuration, when the low-temperature evaporator is stopped, the high pressure can be reduced, and the refrigeration efficiency can be improved.

  The invention according to claim 4 includes a gas-liquid separator that separates a liquid-phase high-boiling-point refrigerant and a gas-phase low-boiling-point refrigerant, the cascade heat exchanger is provided below the gas-liquid separator, The gas-liquid separator and the cascade heat exchanger are connected by a check valve.

  With such a configuration, when the low-boiling point refrigerant is stored in the cascade heat exchanger, even if the pressure of the low-boiling point refrigerant abnormally increases with the increase in the ambient temperature of the cascade heat exchanger, By opening the refrigerant to the gas-liquid separator, an increase in pressure can be suppressed, and safety can be improved.

  According to the fifth aspect of the present invention, when the low-boiling point refrigerant is stored in the cascade heat exchanger, the refrigeration blower fan that blows the cold air of the refrigeration evaporator is stopped and the compressor is operated with low capacity. It is what you do.

  By adopting such a configuration, the cooling of the freezer compartment can be stopped and the low-boiling point refrigerant can be quickly stored (completed), and the rapid decrease in the evaporation pressure during storage of the low-boiling point refrigerant can be suppressed. Can do.

  According to a sixth aspect of the present invention, the cascade heat exchanger is embedded in a urethane foam heat insulating material provided on a back surface of an article storage device forming the freezing chamber and the low temperature chamber, and a vacuum heat insulating material is provided on an outer side thereof. Is installed.

  By adopting such a heat insulation configuration, when the low boiling point refrigerant is stored in the cascade heat exchanger, the pressure of the low boiling point refrigerant in the cascade heat exchanger is prevented from abnormally increasing due to the influence of the outside air temperature. be able to.

  Hereinafter, embodiments of a refrigeration system according to the present invention will be described with reference to the drawings. In addition, about the same component as the conventional component shown in FIG. 4, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

(Embodiment 1)
FIG. 1 is a refrigerant circuit diagram when the article storage device according to Embodiment 1 of the present invention is a refrigerator, FIG. 2 is a schematic diagram of an internal air passage of the refrigerator according to Embodiment 1, and FIG. It is a schematic diagram around the cascade heat exchanger of the refrigerator in the form 1.

  As shown in FIG. 1, the refrigerator uses a non-azeotropic refrigerant as a refrigerant, and includes a compressor 1, a condenser 2, a gas-liquid separator 3, a freezing expansion mechanism 4, a freezing evaporator 5, and cascade heat exchange. A vessel 7 is provided.

  The cascade heat exchanger 7 includes a condensing pipe 8 connected to a gas phase side outlet of the gas-liquid separator 3 through an on-off valve 20 and an evaporating pipe 9 connected to a subsequent stage of the refrigeration evaporator 5. Yes.

  The refrigerant circuit includes a low-temperature expansion valve 21 and a check valve 24. The low-temperature expansion valve 21 adjusts the refrigerant flow rate and has a fully closed function. Further, the check valve 24 connects the liquid phase side outlet of the gas-liquid separator 3 to the condensation pipe 8 disposed at a position lower than the liquid phase side. The outlet pipe of the low-temperature evaporator 11 merges with the outlet pipe of the refrigeration evaporator 5 and is connected to the evaporation pipe 9.

  The refrigeration evaporator 5 and the low-temperature evaporator 11 are provided with a low-temperature blower fan 22 and a refrigeration blower fan 23 for promoting heat exchange and supplying cold air to the respective locations.

  The freezing evaporator 5 cools the freezing room 30 that realizes a normal freezing temperature, the freezing room 31 that realizes a higher refrigerating temperature, and the vegetable room 32, and the low-temperature evaporator 11 includes the freezing evaporator 5 and It independently cools the low temperature chamber 33 that realizes a lower temperature than the freezing temperature.

  Here, the above-mentioned normal freezing temperature defines, for example, a temperature range of −18 ° C. to −25 ° C. used in a domestic refrigerator-freezer and the like, and is the first temperature in the freezing temperature range of the present invention. The low temperature by the low temperature evaporator 11 defines a temperature range lower than the first temperature, for example, −30 ° C. to −80 ° C., and corresponds to the second temperature of the present invention. To do. In the following description, the second temperature will be referred to as a refrigeration low temperature for convenience of description.

  As shown in FIG. 2, the refrigeration blower fan 23 circulates the cold air of the refrigeration evaporator 5 to the freezer compartment 30 through the refrigeration duct 40 and also refrigeration through the branch duct 41 and the refrigeration damper 42. The cool air of the evaporator 5 is circulated to the refrigerator compartment 31.

  Further, the low temperature blower fan 22 circulates the cold air of the low temperature evaporator 11 to the low temperature chamber 33 through the low temperature duct 43. Further, the refrigeration duct 40 is connected to the low temperature chamber 33 via a circulation air passage A44, a circulation air passage B45, and a low temperature damper 46. Note that the vegetable compartment 32 is positioned so as to be sandwiched between the freezer compartment 30 and the low temperature compartment 33, and is configured to be cooled by heat conduction from the freezer compartment 30 and the low temperature compartment 33.

  As shown in FIG. 3, the cascade heat exchanger 7 has a double pipe configuration in which the condensation pipe 8 is an inner pipe and the evaporation pipe 9 is an outer pipe, and in the urethane foam heat insulating material 50 that insulates the outer wall of the refrigerator compartment 31. Buried. Further, a vacuum heat insulating panel 51 having a heat insulating performance higher than that of the urethane foam heat insulating material 50 is embedded on the outer side. The vacuum heat insulation panel 51 has a heat insulation performance about 10 times that of the urethane foam heat insulating material 50.

  The urethane foam heat insulating material 50 and the vacuum heat insulating panel 51 are filled between an inner box 52 that forms the refrigerator compartment 31 and the freezer compartment 30 and an outer box 53 that forms the outer shell of the refrigerator.

  About the refrigerator of Embodiment 1 comprised as mentioned above, the operation | movement is demonstrated.

  First, when the low temperature chamber 33 is maintained at a low temperature, the refrigeration blower fan 23, the low temperature blower fan 22 and the compressor 1 are driven, and the open / close valve 20 is opened and the low temperature damper 46 is opened in a series of this operation. The operation of closing and adjusting the low temperature expansion valve 21 to a predetermined opening is performed.

  The refrigerant discharged from the compressor 1 is cooled by the condenser 2 and partially condensed as indicated by solid arrows in FIG. 1, and then separated into a liquid phase and a gas phase by the gas-liquid separator 3.

  Here, the liquid phase (liquid component) in the gas-liquid separator 3 mainly composed of a high-boiling-point refrigerant is decompressed by the refrigeration expansion mechanism 4 as indicated by the solid line arrows, and is used for refrigeration while gradually raising the evaporation temperature. Evaporate in the evaporator 5. Then, if it is in the case of an optimal heat load balance while passing through the evaporation pipe 9, it is completely vaporized and returned to the compressor 1.

  On the other hand, the gas phase (gas component) in the gas-liquid separator 3 mainly composed of a low-boiling point refrigerant is complete as long as it is in an optimal heat load balance while passing through the condensation pipe 8 as indicated by the broken line arrow. After being liquefied, the pressure is reduced by the low temperature expansion valve 21 and evaporated by the low temperature evaporator 11. Then, if it is in the case of an optimal heat load balance while passing through the evaporation pipe 9, it is completely vaporized and returned to the compressor 1.

  As a result, the refrigeration evaporator 5 and the low temperature evaporator 11 have substantially the same low pressure, but if the evaporation temperature of the refrigeration evaporator 5 is based on the difference in refrigerant composition, the low temperature evaporator 11 is more A low evaporation temperature can be realized.

  Then, the cold air in the freezing evaporator 5 is circulated through the freezing room 30 and the refrigerating room 31 through the freezing duct 40 and the branch duct 41 by driving of the freezing blower fan 23 as indicated by solid arrows in FIG. And the inside of the freezer compartment 30 and the refrigerator compartment 31 is cooled. The temperature adjustment control of the refrigerator compartment 31 is performed by opening and closing the refrigerator damper 42 intermittently.

  Further, the cold air in the low temperature evaporator 11 is circulated through the low temperature chamber 33 via the low temperature duct 43 by driving the low temperature blower fan 22 as shown by the broken line arrows in FIG. Cool at temperature.

  On the other hand, in the case where the low temperature chamber 33 is kept in the freezing temperature range due to the purpose of changing the object to be frozen or changing the usage, the open / close valve 20 is opened, the low temperature expansion valve 21 is fully closed, and the freezing fan 23 is stopped. The compressor 1 is operated at a low speed for a predetermined time.

  As a result, the refrigerant discharged from the compressor 1 is cooled by the condenser 2 as shown by the solid line arrow in FIG. 1 and partially condensed, and then separated into a liquid phase and a gas phase by the gas-liquid separator 3. .

  The liquid phase of the gas-liquid separator 3 containing the high-boiling refrigerant as a main component is decompressed by the refrigerating expansion mechanism 4, passes through the refrigerating evaporator 5, and then gradually increases the evaporating temperature through the evaporating pipe 9. Evaporate. Then, when the heat load balance is optimal in the evaporation pipe 9, it is completely vaporized and returned to the compressor 1.

  On the other hand, the gas phase of the gas-liquid separator 3 mainly composed of a low boiling point refrigerant is liquefied while passing through the condensation pipe 8 and stays in the path of the condensation pipe 8.

  At this time, by stopping the refrigeration blower fan 23, the evaporation capacity is concentrated in the evaporation pipe 9, and the low-boiling point refrigerant is quickly stored in the condensation pipe 8 path, and the low-pressure pressure due to a rapid decrease in the refrigeration load. It is desirable to operate the compressor 1 at a low speed (low capacity operation) in order to suppress an abnormal drop of the engine.

  Then, after a predetermined time has elapsed, the on-off valve 20 is closed, the low-temperature damper 46 is opened, the low-temperature expansion valve 21 is fully closed, the refrigeration blower fan 23 and the compressor 1 are operated, and the low-temperature fan 22 Is stopped.

  Therefore, after the refrigerant discharged from the compressor 1 is cooled and condensed by the condenser 2, the refrigerant mainly composed of a high boiling point refrigerant is supplied from the gas-liquid separator 3 to the refrigeration expansion mechanism 4 and decompressed. The Then, it evaporates and gradually evaporates when passing through the refrigeration evaporator 5, evaporates while passing through the evaporating pipe 9, and returns to the compressor 1.

  As a result, the pressure of the refrigeration evaporator 5 becomes a low pressure substantially equal to that when the low temperature chamber 33 is maintained at a low temperature, and a refrigeration temperature can be realized and a refrigerant mainly composed of a low boiling point refrigerant is cascaded. By storing in the condensing pipe 8 of the heat exchanger 7, the high pressure can be reduced, the power of the compressor 1 can be reduced, and the power consumption can be reduced.

  And the cold air of the freezing evaporator 5 circulates through the freezing room 30 and the refrigerating room 31 through the freezing duct 40 and the branch duct 41, respectively, as shown by the solid line arrows in FIG. Further, the temperature of the refrigeration chamber 31 is adjusted by opening and closing the refrigeration damper 42.

  Further, the cold air of the refrigeration evaporator 5 circulates through the low temperature chamber 33 through the circulation air passage A44 and the circulation air passage B45 as shown by a dotted arrow in FIG.

  At this time, the low boiling point refrigerant staying in the condensing pipe 8 is constantly cooled and stably held during the cooling operation by the evaporating pipe 9 through which the low-temperature recirculating refrigerant passes, and by the vacuum heat insulating panel 51 arranged on the outer side. It is cut off from the outside air temperature and kept at a low temperature even while cooling is stopped. In addition, when the cooling operation is stopped for a long time and the temperature and pressure of the condensation pipe 8 are increased, the pressure of the condensation pipe 8 is higher than that of the gas-liquid separator 3, and the check valve 24 is opened and the condensation pipe 8 is opened. Since the low-boiling point refrigerant is opened to the gas-liquid separator 3, an abnormal increase in pressure can be avoided.

  As described above, in the first embodiment, the freezer compartment 30 is provided independently of the freezer compartment 30 and a low temperature compartment 33 that realizes a low temperature for freezing lower than the temperature of the freezer compartment 30 is provided, and the freezer compartment 30 is cooled. The low temperature evaporator 33 includes a freezing evaporator 5, a low temperature evaporator 11 that cools the low temperature chamber 33, and a circulation air path A 44 and a circulation air path B 45 that circulate the cold air of the freezing evaporator 5 to the low temperature chamber 11. In the case of realizing the above-described low temperature of the refrigeration, the low temperature evaporator 33 is used to cool the low temperature chamber 33, and in the case of realizing the normal refrigeration temperature used in the freezing chamber 30, the cascade heat exchanger 7 has a low boiling point. While storing the refrigerant and cooling the low temperature chamber 33 using the circulation air path A44 and the circulation air path B45, the storage temperature, which is the refrigeration load of the low temperature chamber 30, is increased to the normal refrigeration temperature, and the refrigeration load is reduced. To reduce Refrigeration capacity required can be reduced, as a result, it is possible to suppress an increase in power consumption.

  Further, by storing the low boiling point refrigerant in the cascade heat exchanger 7, the high pressure can be lowered when the low temperature evaporator 11 is stopped, and as a result, the refrigeration efficiency can be improved.

  In the first embodiment, the temperature of the low temperature chamber 30 is raised to the normal freezing temperature. However, the temperature of the low temperature chamber 30 is adjusted to be equal to or higher than the freezing temperature by controlling the opening and closing of the low temperature damper 46. Such control makes it possible to further reduce the refrigeration load, further reduce the required refrigeration capacity and further suppress the increase in power consumption.

  Further, when the temperature of the low temperature chamber 30 is adjusted to the refrigeration temperature or higher, the required refrigeration capacity (refrigeration load) is low and the high pressure is low, so that the compressor 1 is refrigerated to increase the efficiency of the refrigeration cycle. It is desirable to operate at a lower speed (lower capacity) in accordance with the load.

  In the first embodiment, the internal heat exchange for recovering the cold exhaust heat of the recirculated refrigerant returning to the compressor 1 with the condensate refrigerant is omitted. However, both the freezing evaporator 5 and the low-temperature evaporator 11 have internal heat. It is good also as composition which performs exchange.

  The article storage apparatus according to the present invention is a low-temperature evaporator in an article storage apparatus such as a refrigerator provided with a low-temperature evaporator that achieves a lower temperature independently of a freezing evaporator that achieves a normal freezing temperature. Therefore, the increase in power consumption can be suppressed, so that the present invention can also be applied to refrigeration equipment such as a showcase and a commercial refrigerator-freezer that require energy saving.

Refrigerant circuit diagram of refrigerator in Embodiment 1 of the present invention Schematic diagram of the air passage inside the refrigerator in the first embodiment Schematic diagram around the cascade heat exchanger of the refrigerator in the first embodiment Refrigerant circuit diagram of a refrigerator showing a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Gas-liquid separator 5 Evaporator for freezing 7 Cascade heat exchanger 11 Evaporator for low temperature 20 Open-close valve 21 Expansion valve for low temperature 23 Blower fan for freezing 24 Check valve 30 Freezing room 31 Refrigeration room 33 Low greenhouse 40 Freezing duct 43 Duct for low temperature 44 Circulation air passage A
45 Circulation air passage B
46 Low temperature damper 50 Urethane foam insulation 51 Vacuum insulation panel (vacuum insulation)

Claims (6)

  In an article storage device equipped with a cascade cycle that uses a non-azeotropic refrigerant mixture to form a first temperature at least in a freezing temperature range and a second temperature lower than the first freezing temperature, the first temperature An article storage device comprising: a freezing room maintained in step 1; and a cold room maintained at the second temperature, wherein the temperature of the cold room can be switched to the first temperature.   A freezing evaporator that cools the freezing chamber; a low-temperature evaporator that cools the low-temperature chamber; and a circulation air passage that circulates cold air from the freezing evaporator to the low-temperature chamber, The low-temperature evaporator is used for maintaining the second temperature, the low-temperature evaporator is stopped for maintaining the first temperature, and the low-temperature chamber is cooled by the freezing evaporator using the circulation air passage. The article storage device according to claim 1.   A cascade heat exchanger that condenses the low boiling point refrigerant using the latent heat of vaporization of the high boiling point refrigerant is provided, and the low boiling point refrigerant is stored in the cascade heat exchanger when the temperature of the low temperature chamber is switched to the first temperature. The article storage device according to claim 1 or 2, wherein the article storage device is configured as described above.   A gas-liquid separator that separates a liquid-phase high-boiling-point refrigerant and a gas-phase low-boiling-point refrigerant; the cascade heat exchanger is provided below the gas-liquid separator; and the gas-liquid separator and the cascade heat exchange The article storage device according to claim 3, wherein the containers are connected by a check valve.   5. The compressor according to claim 3, wherein when the low-boiling-point refrigerant is stored in the cascade heat exchanger, the refrigeration blower fan that blows the cold air of the refrigeration evaporator is stopped and the compressor is operated with low capacity. Article storage device.   The cascade heat exchanger is embedded in a urethane foam heat insulating material provided on a back surface of an article storage device that forms the freezing chamber and the low temperature chamber, and a vacuum heat insulating material is installed on the outer side thereof. The article storage device according to any one of the above.

Images