JP2019113207A - Cooler using air refrigerant cycle - Google Patents

Abstract

To provide a cooler using an air refrigerant cycle, capable of prolonging a cooling operation time.SOLUTION: A cooler 1 using an air refrigerant cycle comprises: a compressor C configured to compress air recovered from a chamber to be cooled 2; heat exchangers 3, 4 configured to cool air compressed by the compressor C; an expander E configured to expand air cooled by the heat exchangers 3, 4; and a defroster 6 configured to collect moisture contained in air flowing from the expander E to the chamber to be cooled 2, as frost. Between the heat exchangers 3, 4 and the expander E, dehumidification means 5 of removing moisture contained in air flowing from the heat exchangers 3, 4 to the expander E is provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling device using an air refrigerant cycle.

  DESCRIPTION OF RELATED ART The cooling device applied to to-be-cooled rooms, such as a warehouse, in order to preserve | save various raw materials, processed products, fresh food etc. is known widely. In such a cooling device, a refrigerant such as fluorocarbon was conventionally used, but in recent years, a cooling device using an air refrigerant is required from the viewpoint of environmental protection.

  As a cooling device using an air refrigerant, for example, as disclosed in Patent Document 1, a compressor that compresses air taken into a pipe path from a chamber to be cooled, and high-pressure high-temperature air compressed by the compressor are cooled Heat exchanger, and an expander for expanding high-pressure low-temperature air cooled by the heat exchanger to a low pressure (approximately 1 atmosphere), and the cryogenic air expanded by the There is a cooling system using an open air refrigerant cycle that supplies

  In a cooling device using such an open air refrigerant cycle, the outside air (atmosphere) flowing in from the inlet / outlet of the chamber to be cooled and the breath of the worker working in the chamber may be mixed. Since the amount of water contained in the air in the cooling device changes due to the outside air or exhalation, the water in the air coagulates in the piping path of the cooling device, particularly on the downstream side of the expander having a low temperature, and frost is formed. In some cases, extremely low temperature air containing a large amount of frost is blown into the chamber to be cooled. Then, the cooling device of patent document 1 has provided the defroster which collects the water | moisture content contained in air of ultra-low temperature between an expander and a to-be-cooled room.

WO 2006/011297 (Page 7, FIG. 1)

  In the cooling device of Patent Document 1, since the defroster is provided on the downstream side of the expander, which is likely to generate frost, the moisture in the air at extremely low temperature can be efficiently collected, and the cooling chamber can be cooled. Although it is possible to suppress the blowing out of the frost, it is easy for the defroster to be clogged because the amount of the frost collected in the defroster is large, and the frost attached to the defroster There was a need to perform defrost operation frequently to eliminate it. Since the cooling operation is stopped when performing the defrosting operation, there is a possibility that the room to be cooled can not be stably cooled to the desired temperature, and the room temperature may rise.

  The present invention has been made in view of such problems, and it is an object of the present invention to provide a cooling device using an air refrigerant cycle that can extend the cooling operation time.

In order to solve the above-mentioned subject, a cooling device using an air refrigerant cycle of the present invention is:
From the compressor for compressing the air recovered from the cooled chamber, the heat exchanger for cooling the air compressed by the compressor, the expander for expanding the air cooled by the heat exchanger, and the expander A cooling device using an air refrigerant cycle, comprising: a defroster for collecting as a frost the water contained in the air flowing into the room to be cooled;
A dehumidifying unit is provided between the heat exchanger and the expander for removing moisture contained in the air flowing from the heat exchanger to the expander.
According to this feature, the moisture contained in the air flowing from the heat exchanger to the expander is removed by the dehumidifying means, whereby the amount of moisture contained in the air flowing from the expander to the cooled chamber can be reduced. Can extend the time until clogging occurs, so the cooling operation time of the cooling device can be extended.

The dehumidifying means is characterized in that the air flowing from the heat exchanger to the expander is cooled to cause dew condensation.
According to this feature, it is possible to remove moisture contained in the air flowing from the heat exchanger to the expander by cooling and condensing the air flowing from the heat exchanger to the expander.

The dehumidifying unit is characterized in that a part of a flow passage communicating the expander with the cooled chamber extends to the vicinity of a flow passage communicating the heat exchanger with the expander. And
According to this feature, it is possible to cool the air flowing through the flow passage connecting the heat exchanger and the expander using the air flowing through the flow passage connecting the expander and the cooled chamber. It is not necessary to provide a dehumidifying means in order to simplify the cooling device.

The dehumidifying means is characterized in that a flow passage communicating the defroster with the cooled chamber extends to the vicinity of a flow passage communicating the heat exchanger with the expander. .
According to this feature, after the frost is collected by the defroster, the air passing through the flow passage connecting the defroster and the cooled chamber is used to connect the heat exchanger and the expander. As the air flowing through the passage can be cooled, it does not affect the ability of the defroster to collect frost.

The cooling device includes a heater provided in the vicinity of the defroster, a bypass passage connecting the flow passage communicating the defroster and the cooled chamber, and the compressor; the defroster; And a switching unit that causes a flow passage communicating with the cooling chamber to be communicated with either the cooling chamber or the bypass passage.
According to this feature, the defrosting operation can be performed by causing the flow path communicating the defroster and the cooling chamber to communicate with the bypass passage by the switching means, and when performing the defrosting operation, the air warmed by the heater Since the heat is exchanged with the air flowing in the flow passage connecting the heat exchanger and the expander via the flow passage connecting the defroster and the cooled chamber, it flows downstream of the heat exchanger You can warm the air quickly.

It is a figure which shows the cooling state of the cooling device using the air refrigerant | coolant cycle in the Example of this invention. (A) is a perspective view which shows a 3rd heat exchanger, (b) is the elements on larger scale of a 3rd heat exchanger. (A) is a plane view cross section schematic diagram showing a defroster, and (b) is a side view section schematic diagram showing a defroster. It is a figure which shows the defrost state of the cooling device using an air refrigerant | coolant cycle. It is a figure which shows another form of the cooling device which used the air refrigerant cycle. It is a figure which shows another form of the cooling device which used the air refrigerant cycle.

  EMBODIMENT OF THE INVENTION The form for implementing the cooling device using the air refrigerant | coolant cycle which concerns on this invention is demonstrated below based on an Example.

  A cooling device using an air refrigerant cycle according to an embodiment will be described with reference to FIGS. 1 to 6.

  As shown in FIG. 1, the cooling device 1 in the present embodiment is a piping system connected to a room to be cooled 2 which is a space for storing objects to be cooled such as various materials, processed products, and fresh food products. is there. The cooling device 1 is a cooling device using an air refrigerant cycle that sucks in air from the cooled chamber 2 and cools the air in the cooling device 1 and then reduces the air into the cooled chamber 2.

  More specifically, since the cooling chamber 2 has an inlet / outlet through which an operator can enter and exit from the outside, the inside of the cooling chamber 2 operates in the outside air (atmosphere) flowing in from the inlet / outlet and the cooling chamber. Worker's breath is inevitably mixed. That is, it is a cooling device using a so-called open type air refrigerant cycle in which the amount of water contained in the air taken into the cooling device 1 changes. The cooling device 1 can be applied to refrigeration, refrigeration, air conditioning and cooling, etc., depending on the difference in temperature and pressure of the system, and is more preferably applied to a refrigeration system in an ultra-low temperature range of -55.degree.

  Next, the structure of the cooling device 1 will be described. The cooling device 1 includes a compressor C (compressor), a first heat exchanger 3, a second heat exchanger 4, a third heat exchanger 5 (dehumidifying heat exchanger), an expansion turbine E (expander), and a defrost The apparatus 6 is mainly provided, and these devices are connected in a communicable state through pipes and valves as described later.

  Specifically, the high temperature side pipe 3 a of the first heat exchanger 3 is connected to the downstream side of the compressor C via the pipe 7 a. The high temperature side piping 4 a of the second heat exchanger 4 is connected to the downstream side of the high temperature side piping 3 a of the first heat exchanger 3 via the piping 7 b, and the high temperature side piping 4 a of the second heat exchanger 4 is The high temperature side flow passage 5a of the third heat exchanger 5 is connected to the downstream side of the third heat exchanger 5 via a pipe 7c. An expansion turbine E is connected to the downstream side of the high temperature side flow passage 5a of the third heat exchanger 5 via a pipe 7d, and a defroster 6 is connected to the downstream side of the expansion turbine E via a pipe 7e. Is connected. The low temperature side flow passage 5b of the third heat exchanger 5 is connected to the downstream side of the defroster 6 via the pipe 7f, and the downstream side of the low temperature side flow passage 5b of the third heat exchanger 5 The inlet valve 8 (switching means) is connected via the pipe 7g, and the downstream side of the inlet valve 8 is connected to one vent (not shown) in the cooled chamber 2 via the pipe 7h. An outlet valve 9 (switching means), which is a three-way switching valve, is connected to the other vent (not shown) in the chamber 2 to be cooled via a piping 7j. The low temperature side pipe 4b of the second heat exchanger 4 is connected to the compressor C at a downstream side of the low temperature side pipe 4b of the second heat exchanger 4 via a pipe 7m. Further, the pipe 7 g has a branched bypass pipe 7 n, and the bypass pipe 7 n is connected to the outlet valve 9.

  The compressor C and the expansion turbine E are driven by a motor 10. The motor 10 includes a pair of coaxially extending drive shafts 10a and 10b, to each of which a compressor C and an expansion turbine E are connected, and the expansion turbine E generated by high pressure air on the upstream side of the expansion turbine E The rotational power is transmitted to the drive shaft 10a of the compressor C via the drive shaft 10b, whereby power recovery is performed.

  Further, the motor 10 is connected to an air-cooling circulation channel 12 in which air is circulated by an air-cooling fan F, and is cooled by the fan F and the air-cooling circulation channel 12. Further, a radiator 13 that exchanges heat with air in the air cooling circulation channel 12 is connected to the air cooling circulation channel 12.

  In the present embodiment, the first heat exchanger 3 is a water-cooled heat exchanger, and the high temperature side piping 3a through which air flows from the compressor C to the second heat exchanger 4 and the high temperature side piping 3a are separate systems. A low temperature side pipe 3b through which cooling water circulates is provided, and by exchanging heat between the high temperature side pipe 3a and the low temperature side pipe 3b, air flowing in the high temperature side pipe 3a can be cooled. ing. The high-temperature side pipe 3a and the low-temperature side pipe 3b referred to here are the high-temperature side and the low-temperature side when the air flowing inside the two pipes performing heat exchange in the first heat exchanger 3 is compared.

  The second heat exchanger 4 includes a high temperature side pipe 4 a through which the air cooled by the first heat exchanger 3 flows, and a low temperature side pipe 4 b through which the air flows from the cooled chamber 2 to the compressor C By exchanging heat between the side piping 4a and the low temperature side piping 4b, the air flowing through the high temperature side piping 4a can be cooled. The high-temperature side pipe 4 a and the low-temperature side pipe 4 b referred to here are the high-temperature side and the low-temperature side when the air flowing inside the two pipes performing heat exchange in the second heat exchanger 4 is compared.

  The third heat exchanger 5 includes a high temperature side flow passage 5a through which the air cooled by the second heat exchanger 4 flows, and a low temperature side flow passage 5b flowing from the defroster 6 to the cooled chamber 2 By exchanging heat between the side flow passage 5a and the low temperature side flow passage 5b, the air flowing through the high temperature side flow passage 5a can be cooled. The high-temperature side flow passage 5a and the low-temperature side flow passage 5b referred to here are the high-temperature side and the low-temperature side when comparing the air flowing inside the two pipes performing heat exchange in the third heat exchanger 5. .

  Here, the structure of the 3rd heat exchanger 5 is demonstrated using Fig.2 (a), (b). The third heat exchanger 5 is composed of a box-like case 5c and a plurality of panel bodies 5d disposed substantially in parallel in the case 5c and spaced apart by a predetermined distance. The case 5c has a pair of pipes 5c connected to one side and a pipe 7d connected to the other side, and has a pair of openings 5e facing each other. In the case 5c, one of the pipes 7f is connected to one side and the other pipe 7g is connected to the other, and the case 5c has a pair of openings 5f facing each other. An air gap is formed between the adjacent panel bodies 5d, and the air gap is configured as a high temperature side flow passage 5a communicating with the pipe 7c and the pipe 7d through the opening 5e. Further, the panel body 5d is formed of a metal (for example, aluminum) having high thermal conductivity, is formed in a cylindrical shape in which both ends are open and the inside is in communication, and the inside of the panel body 5d is the opening 5f. It is configured as a low temperature side flow passage 5b communicating with the pipe 7f and the pipe 7g. As a result, the air passing through the high temperature side flow passage 5a and the air passing through the low temperature side flow passage 5b are prevented from being mixed with each other, and heat exchange is performed between them via the panel body 5d.

  As shown in FIGS. 3 (a) and 3 (b), the defroster 6 has a box-like case 6a connecting the pipe 7e and the pipe 7f, the case 6a in the space on the pipe 7e side and the pipe 7f side. It is comprised from the mesh member 6b divided into space. As will be described later, when the air flowing from the expansion turbine E to the pipe 7f and the low temperature side flow passage 5b of the third heat exchanger 5 passes through the pipe 7e, the moisture contained in the air passes through the mesh member 6b. It attracts to the mesh member 6b as frost.

  Further, around the defroster 6, detection means 14 for detecting clogging of the defroster 6 is provided. The detection means 14 includes a pressure gauge 14a connected upstream of the mesh member 6b of the defroster 6, a pressure gauge 14b connected downstream of the mesh member 6b, and pressure gauges 14a and 14b. The differential pressure gauge 14c measures differential pressure, and when the differential pressure measured by the differential pressure gauge 14c becomes equal to or higher than a predetermined threshold, the defroster 6 detects as clogging. . The cooling device 1 is configured to switch to a defrost operation in which defrosting in the defroster 6 and each of the pipes and devices is performed when the detection means 14 detects clogging of the defroster 6. The defrosting operation will be described in detail later.

  In addition, the cooling device 1 has a control unit (not shown) electrically connected to the motor 10, the inlet valve 8, the outlet valve 9, the detection unit 14 and the like described above, and the control unit Based on the received information of the differential pressure of the defroster 6, the drive operation of the motor 10 and the opening / closing operation of the valve are performed, and switching control of the cooling operation or the defrost operation is possible.

  Next, the operation when the cooling device 1 is in the cooling operation will be described. In the following description, based on the internal air A1 (about 1 atm, about -55 ° C.) in the cooled chamber 2, high pressure means that the pressure is higher than that of the internal air A1. Pressure refers to approximately the same pressure as in-chamber air A1, and the same temperature refers to a temperature within 10 ° C. of error compared to in-chamber air A1, and high temperature and low temperature are the same temperature. It indicates that the temperature is higher or lower than the temperature.

  During the cooling operation, the inlet valve 8 is opened, the low temperature side flow passage 5b of the third heat exchanger 5 and the cooled chamber 2 are communicated, and the bypass pipe 7n side of the outlet valve 9 is closed. And a circulation path for cooling operation which is opened so that the low temperature side pipe 4b of the second heat exchanger 4 communicates with each other.

  When the compressor C and the expansion turbine E are driven, the compressor C sucks and compresses the normal-pressure high-temperature air A1 '(about 1 atm, about 40 ° C) in the pipe 7m. The high-pressure high-temperature air A2 compressed by the compressor C has a pressure of about 2 atm and about 120 ° C., and is discharged to the high temperature side pipe 3a of the first heat exchanger 3 through the pipe 7a.

  Since the cooling water is circulating in the low temperature side piping 3b of the first heat exchanger 3 during the cooling operation, the high pressure high temperature air A2 discharged to the high temperature side piping 3a of the first heat exchanger 3 is the first thermal The heat is exchanged with the cooling water of the low temperature side piping 3 b of the exchanger 3 to become high pressure high temperature air A 3 of about 2 atmospheres and about 45 ° C., and is discharged to the high temperature side piping 4 a of the second heat exchanger 4.

  The high-pressure high-temperature air A3 discharged to the high-temperature side pipe 4a of the second heat exchanger 4 is sucked into the compressor C via the low-temperature side pipe 4b of the second heat exchanger 4 from the cooled chamber 2 The heat is exchanged with about 1 atm, about -55 ° C, and becomes about 2 atm, about -50 ° C high-pressure isothermal air A4, and is discharged to the high temperature side flow passage 5a of the third heat exchanger 5. At this time, part of the water contained in the high-pressure high-temperature air A3 is transferred to the inner peripheral surface of the high-temperature side pipe 4a of the second heat exchanger 4 by heat exchange with the high-temperature high-temperature air A3. Since it adheres as frost, the amount of water contained in the high-pressure same-temperature air A4 discharged to the high-temperature side flow passage 5a of the third heat exchanger 5 decreases. On the other hand, the internal air A1 at about -55 ° C exchanges heat with the high-pressure high-temperature air A3 to become normal-pressure high-temperature air A1 'at about 40 ° C and flows into the pipe 7m.

  The high-pressure same-temperature air A4 discharged to the high-temperature side flow passage 5a of the third heat exchanger 5 flows in the low-temperature side flow passage 5b of the third heat exchanger 5 to be described later. C., and becomes high pressure same-temperature air A5 of about -2 atm and about -60.degree. At this time, the high-pressure same-temperature air A4 exchanges heat with the normal-pressure low-temperature air A7, whereby one of the moisture contained in the high-pressure same-temperature air A4 on the outer peripheral surface of the panel body 5d constituting the high temperature side flow passage 5a. Since the portion adheres as frost, the amount of water contained in the high-pressure same-temperature air A5 discharged to the expansion turbine E decreases.

  The high pressure same-temperature air A5 discharged to the expansion turbine E is expanded by the expansion turbine E to become normal pressure low-temperature air A6 of about 1 atm and about -90 ° C, and the moisture contained in the normal pressure low-temperature air A6 A part becomes frost and mixes with cold air and is discharged to the defroster 6.

  When normal pressure low-temperature air A6 discharged into the defroster 6 passes through the mesh member 6b of the defroster 6, the frost contained in the normal pressure low-temperature air A6 adheres to the mesh member 6b, whereby It becomes normal pressure low temperature air A7 (about 1 atmosphere, about -90 ° C.) having a smaller amount of water than normal pressure low temperature air A6. The normal pressure low temperature air A <b> 7 is discharged to the low temperature side flow passage 5 b of the third heat exchanger 5. As described above, since the moisture is removed by the defroster 6 from the normal pressure low temperature air A6 expanded by the expansion turbine E, it is possible to suppress the frost from blowing out into the chamber 2 to be cooled.

  The normal pressure low temperature air A7 discharged to the low temperature side flow passage 5b of the third heat exchanger 5 is heat-exchanged with the high pressure same temperature air A4 discharged to the high temperature side flow passage 5a of the third heat exchanger 5 Then, it becomes normal pressure low-temperature air A 8 of about 1 atm and about -80 ° C., and is discharged to the cooled chamber 2 through the inlet valve 8. The normal pressure low-temperature air A8 discharged into the to-be-cooled chamber 2 is mixed with air or the like flowing from the outside of the to-be-cooled chamber 2 to become the in-chamber air A1 of about -55 ° C.

  Next, the defrosting operation of the cooling device 1 will be described based on FIG. As described above, when it is detected that the differential pressure between the upstream side and the downstream side of the defroster 6 has become equal to or more than the predetermined threshold value by the differential pressure gauge 14c during the cooling operation of the cooling device 1, the cooling device 1 Control unit (not shown) switches to the defrost operation.

  As shown in FIG. 4, in the defrosting operation, the inlet valve 8 is closed so that the pipe 7 g is disconnected from the cooled chamber 2, and the bypass pipe 7 n side of the outlet valve 9 is opened. And the pipe 7k communicate with each other, and by closing the space between the pipe 7j and the pipe 7k of the outlet valve 9, the low temperature side pipe 4b of the cooled chamber 2 and the second heat exchanger 4 is disconnected. A circulation channel is formed.

  The compressor C and the expansion turbine E in the defrosting operation are driven by the motor 10 having a rotational speed (for example, about one third) lower than the rotational speed in the cooling operation. The compressor C sucks and compresses the air A11 'in the pipe 7m. The air A21 compressed by the compressor C has a lower pressure and a lower temperature than the low temperature side pipe 4b of the second heat exchanger 4 in the cooling operation, and the high temperature of the first heat exchanger 3 passes through the pipe 7a. It is discharged to the side piping 3a. During the defrosting operation, the fan F for air cooling of the motor 10 stops the operation.

  During the defrosting operation, since the first heat exchanger 3 is stopped, the air A21 becomes air A31 which has not been heat-exchanged and the high temperature is maintained, and is discharged to the high temperature side pipe 4a of the second heat exchanger 4. The air A31 discharged to the high temperature side pipe 4a of the second heat exchanger 4 is heat-exchanged with the low temperature side pipe 4b of the second heat exchanger 4 to become air A41, and the high temperature side flow path of the third heat exchanger 5 It is discharged to 5a. The air A41 discharged to the high temperature side flow passage 5a of the third heat exchanger 5 exchanges heat with the air A71 flowing in the low temperature side flow passage 5b of the third heat exchanger 5 to become air A51, and the expansion turbine E It is discharged.

  The air A <b> 51 discharged to the expansion turbine E is expanded by the expansion turbine E to become air A <b> 61, and is discharged to the defroster 6. Since the rotational transfer speed of the expansion turbine E is lower than the rotational speed during the cooling operation, the temperature of the air A61 expanded by the expansion turbine E decreases by a smaller temperature than that during the cooling operation.

  At the time of defrosting operation, the heater 15 to which the electric heating unit is connected in the defroster 6 is operated, whereby the frost accumulated in the defroster 6 can be melted. The air A61 discharged to the defroster 6 mixes with the air in the defroster 6 warmed by the heat generated from the heater 15 to become air A71 and discharged to the low temperature side flow passage 5b of the third heat exchanger 5 Be done.

  As shown in FIGS. 3 (a) and 3 (b), the bottom surface 6c of the defroster 6 is formed in a mortar shape, and the lowermost portion of the bottom surface of the defroster 6 communicates with the outside. An open / close drain valve 6d is provided. According to this, it is possible to discharge the water generated by the defrosting of the defroster 6 being melted by the heater 15 to the outside through the drain valve 6d.

  The air A71 discharged to the low temperature side flow passage 5b of the third heat exchanger 5 exchanges heat with the air A41 discharged to the high temperature side flow passage 5a of the third heat exchanger 5 to become air A81, and the second heat It is discharged into the low temperature side pipe 4 b of the exchanger 4. The air A 71 is warmed by the heat of the heater 15 and exchanges heat with the high temperature side flow passage 5 a of the third heat exchanger 5, so a predetermined section downstream of the second heat exchanger 4 (pipe 7 c, The temperature of the air flowing in the section of the high temperature side flow passage 5a, the piping 7d, the expansion turbine E, the piping 7e, the defroster 6 and the low temperature side flow passage 5b rises as it circulates in the above path.

  Since the inside of the 3rd heat exchanger 5 is heated by this, the frost adhering to the outer surface of panel object 5d of the 3rd heat exchanger 5 can be melted now. Although not shown, the lower portion of the third heat exchanger 5 is formed in a mortar shape, and at the lowermost portion thereof, an open / close drain valve communicating with the outside is provided. According to this, it is possible to discharge the water generated by melting the frost to the outside through the drain valve.

  As described above, during the defrosting operation, the rotational transfer speed of the expansion turbine E is low, the air A21 is not cooled in the first heat exchanger 3, and the cold air (air in the storage A1) from the cooled room 2 The temperature of the air in the cooling device 1 becomes higher than that in the cooling operation due to the reason that it does not enter, the heater 15 operates, and the like, and the frost in the cooling device 1 can be melted. Further, in a predetermined section downstream of the second heat exchanger 4 in which frost is likely to be generated compared to other portions, the heat of the heater 15 is heat exchanged by the third heat exchanger 5 to circulate air. Since it is possible, the frost in the predetermined section can be melted efficiently.

  As described above, as the dehumidifying means for removing the water contained in the high-pressure same-temperature air A4 flowing from the second heat exchanger 4 to the expansion turbine E between the second heat exchanger 4 and the expansion turbine E Since the third heat exchanger 5 is provided, the amount of water contained in the normal pressure low temperature air A6 flowing from the expansion turbine E to the defroster 6 can be reduced during the cooling operation, and the defroster 6 is clogged. Since the time until it can be extended, the cooling operation time of the cooling device 1 can be lengthened.

  Specifically, when the cooling device 1 detects that the differential pressure between the upstream side and the downstream side of the defroster 6 has become equal to or higher than a predetermined threshold value by the differential pressure gauge 14c during the cooling operation, the cooling device 1 performs the defrosting operation. Since the configuration is switched, the amount of water contained in the normal pressure low-temperature air A6 is reduced by the third heat exchanger 5 and the time until the defroster 6 becomes clogged (time to start the defrost operation) Can extend the cooling operation time of the cooling device 1. That is, since the moisture of the air flowing in the cooling device 1 can be dispersed and removed by the third heat exchanger 5 and the defroster 6, the cooling operation time of the cooling device 1 can be extended.

  Further, the high-pressure high-temperature air A3 passing through the high-temperature side pipe 4a of the second heat exchanger 4 and the inside air A1 passing through the low-temperature side pipe 4b of the second heat exchanger 4 from the cooled chamber 2 are heat exchanged. When the air is contained, a part of the water contained in the high pressure high temperature air A3 adheres to the inner peripheral surface of the high temperature side pipe 4a of the second heat exchanger 4 as a frost, so the water contained in the high pressure same temperature air A4 Although the amount is reduced, the high-pressure same-temperature air A4 (about -50.degree. C.) is higher in temperature than the normal-pressure low-temperature air A6 (about -90.degree. C.) expanded by the expansion turbine E, and Since high-pressure high-temperature air A3 of about 45 ° C. flows into the high-temperature side pipe 4a, the amount of frost adhering to the inner circumferential surface of the high-temperature side pipe 4a of the second heat exchanger 4 adheres to the defroster 6 Less than the amount of frost.

  On the other hand, in the third heat exchanger 5, heat exchange is performed between the high pressure isothermal air A4 (about -50.degree. C.) and normal pressure low temperature air A7 (about -90.degree. C.) after passing through the defroster 6. It is supposed to be According to this, since the temperature of the high-pressure same-temperature air A4 is cooled by the normal-pressure low-temperature air A7, the amount of saturated water vapor of the high-pressure same-temperature air A4 decreases and dew condensation occurs. Since it adheres to the inner peripheral surface of the high temperature side flow path 5a of the heat exchanger 5 and becomes frost, it is possible to remove the water contained in the high-pressure same-temperature air A5. That is, in the third heat exchanger 5, the high-pressure same-temperature air A4 further cooled by the second heat exchanger 4 is further included in the high-pressure same-temperature air A5 by further cooling the low-temperature normal-pressure low-temperature air A7. Moisture can be positively attached to the inner peripheral surface of the high temperature side flow passage 5a of the third heat exchanger 5, and the moisture contained in the high-pressure same-temperature air A5 can be removed.

  Further, in the third heat exchanger 5, heat exchange is performed between the high-pressure same-temperature air A4 and the normal-pressure low-temperature air A7 after passing through the defroster 6, so that a new defroster or There is no need to prepare dehumidifying means such as a cooler for cooling the high temperature side flow passage 5a, and the structure of the cooling device 1 can be simplified. In addition, since normal pressure low temperature air A7 after passing through defroster 6 exchanges heat with high pressure same temperature air A4, it can be introduced into defroster 6 without raising the temperature of normal pressure low temperature air A6. Therefore, the ability to collect frost in the defroster 6 is not affected.

  Further, during the defrosting operation, the inlet valve 8 is closed so that the pipe 7g is disconnected from the cooled chamber 2, and the bypass pipe 7n side of the outlet valve 9 is opened so that the bypass pipe 7n communicates with the pipe 7k. As a result, by closing the space between the pipe 7 j and the pipe 7 k of the outlet valve 9, a defrost operation circulation flow path is formed in which the low temperature side pipe 4 b of the cooled chamber 2 and the second heat exchanger 4 are disconnected. Be done. That is, during the defrosting operation, the air A 71 warmed by the heat of the heater 15 for warming the interior of the defroster 6 is discharged to the low temperature side flow passage 5 b of the third heat exchanger 5, and the high temperature side stream of the third heat exchanger 5 Because it exchanges heat with the passage 5a, a predetermined section (pipe 7c, high temperature side flow passage 5a, piping 7d, expansion turbine E, downstream of the second heat exchanger 4 is more likely to generate frost than other parts. Air flowing in the section of the pipe 7 e, the defroster 6 and the low temperature side flow passage 5 b can be warmed up quickly. In addition, since the temperature in the piping system is rising by the above-described defrost operation, after completion of the defrost operation, the pipe 7g, the bypass pipe 7n and the pipe 7k are opened and the cooled chamber 2 side is blocked. As it is, it is preferable to perform a cooling operation for a fixed time until the temperature in the piping system is lowered, and open the cooled chamber 2 side after the elapse of the fixed time. This can prevent the temperature rise in the chamber 2 to be cooled.

  In the above embodiment, in the cooling operation, heat exchange is performed between the low pressure air A7 after passing through the defroster 6 and the high pressure same-temperature air A4 after passing through the second heat exchanger 4. Although the form was illustrated, as FIG. 5 shows, piping 7e 'extended from the expansion turbine E is connected to the low temperature side flow path 5b of the 3rd heat exchanger 5, and piping 7f' extended from the low temperature side flow path 5b is In the third heat exchanger 5, the normal pressure low-temperature air A6 expanded by the expansion turbine E is connected to the defroster 6 and a pipe 7g ′ extending from the defroster 6 is connected to the cooled chamber 2 and the bypass pipe 7n. The low temperature side flow passage 5b may be discharged to exchange heat with the high pressure same temperature air A4 of the high temperature side flow passage 5a.

  Further, as shown in FIG. 6, an auxiliary defroster 16 may be provided between the high temperature side flow passage 5 a of the third heat exchanger 5 and the expansion turbine E. According to this, since the water contained in the high-pressure same-temperature air A5 flowing from the high temperature side flow passage 5a to the expansion turbine E can be collected as frost by the auxiliary defroster 16, the flow from the expansion turbine E to the defroster 6 The amount of water contained in the pressurized low-temperature air A6 can be further reduced. In addition, since the structure of the auxiliary defroster 16 is the same as that of the above-mentioned defroster 6, description is abbreviate | omitted. In addition, the high-pressure isothermal air A5 after the temperature is lowered by the third heat exchanger 5 by the third heat exchanger 5 by the third heat exchanger 5 is passed through the auxiliary defroster 16 to capture moisture as frost. Easy to collect. Note that only the auxiliary defroster 16 may be provided between the second heat exchanger 4 and the expansion turbine E as a dehumidifying unit, and the configuration of the third heat exchanger 5 may be omitted.

  Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and any changes or additions may be made without departing from the scope of the present invention. Be

  For example, in the embodiment, the third heat exchanger 5 is provided in the flow passage between the second heat exchanger 4 and the expansion turbine E, and a part of the flow passage on the downstream side of the expansion turbine E is used. Although the form which cools the air which flows through the flow path between the 2nd heat exchanger 4 and expansion turbine E was illustrated, it is not restricted to this, for example, it replaces with the 3rd heat exchanger 5 and another cooler makes the 3rd The air flowing in the flow path between the heat exchanger 4 and the expansion turbine E may be cooled.

DESCRIPTION OF SYMBOLS 1 Cooling device 2 to-be-cooled room 3 1st heat exchanger 4 2nd heat exchanger 5 3rd heat exchanger (dehumidification means)
5a High temperature side flow path (flow path)
5b Low temperature side flow path (flow path)
6 Defroster 7n Bypass pipe (bypass)
8 Inlet valve (switching means)
9 outlet valve (switching means)
15 heater C compressor (compressor)
E Expansion turbine (expansion machine)

Claims (5)

From the compressor for compressing the air recovered from the cooled chamber, the heat exchanger for cooling the air compressed by the compressor, the expander for expanding the air cooled by the heat exchanger, and the expander A cooling device using an air refrigerant cycle, comprising: a defroster for collecting as a frost the water contained in the air flowing into the room to be cooled;
A dehumidifying means is provided between the heat exchanger and the expander for removing water contained in the air flowing from the heat exchanger to the expander, and an air refrigerant cycle is used. Cooling system.   The cooling device using an air refrigerant cycle according to claim 1, wherein the dehumidifying means cools and condenses the air flowing from the heat exchanger to the expander.   The dehumidifying unit is characterized in that a part of a flow passage communicating the expander with the cooled chamber extends to the vicinity of a flow passage communicating the heat exchanger with the expander. A cooling device using the air refrigerant cycle according to claim 2.   The dehumidifying means is characterized in that a flow passage communicating the defroster with the cooled chamber extends to the vicinity of a flow passage communicating the heat exchanger with the expander. A cooling device using the air refrigerant cycle according to claim 3.   The cooling device includes a heater provided in the vicinity of the defroster, a bypass passage connecting the flow passage communicating the defroster and the cooled chamber, and the compressor; the defroster; 5. The air according to any one of claims 1 to 4, further comprising: switching means for causing a flow passage communicating with the cooling chamber to communicate with either the cooling chamber or the bypass passage. Cooling device using refrigerant cycle.

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