JP2008298322A - Air refrigerant type refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air refrigerant type heat exchanger capable of melting ice attached to a cold recovering heat exchanger and discharging the same without jumboizing a device. <P>SOLUTION: In this air refrigerant type refrigerating device constituting a refrigerating cycle system comprising a compressor for compressing the air recovered from a cooled compartment, a cooler for cooling the compressed air, and an expander for expanding the cooled compressed air, and supplying the air of low-temperature obtained by compression, cooling and expanding the air recovered from the cooled compartment to the cooled compartment, the heat exchanger for recovering cold is disposed to exchange heat between the air recovered from the cooled compartment and introduced to the compressor and the air introduced to the expander by opposed flow, and the heat exchanger for recovering cold is disposed in a state that the compressed air flows upward from a lower part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air refrigerant refrigeration apparatus that forms a refrigeration cycle using air as a refrigerant, and more specifically, melts and discharges snow and ice adhering to the inside of a heat exchanger for recovering cold heat provided in the refrigeration cycle. The present invention relates to a possible air refrigerant refrigeration apparatus.

From the viewpoint of protecting the global environment, refrigeration systems that use chlorofluorocarbon refrigerants are being reviewed. Also, from the viewpoint of safety, there are still problems in the refrigeration apparatus using an ammonia-based refrigerant. Therefore, an air refrigerant refrigeration apparatus using air as a refrigerant without using any chlorofluorocarbon refrigerant or ammonia refrigerant is used.
The air-refrigeration refrigeration system converts air into high-temperature and high-pressure air using a compressor, cools it using a cooler, and then introduces it into a cooled room as low-temperature and low-pressure air using an expander. The cooling object is cooled, and the air after cooling the object to be cooled is again introduced into the compressor to form a refrigeration cycle. Further, in such an air refrigerant refrigeration apparatus, generally, heat recovery for cold recovery, in which the air recovered from the chamber to be cooled and introduced into the compressor is heat-exchanged with the air introduced into the expander to recover the cold energy. A vessel is provided.

  However, in the air refrigerant type refrigeration apparatus as described above, moisture in the form of snow or mist is sucked from the room to be cooled, and the heat exchanger for cold heat recovery is inhaled by inhaling the snow or mist of water. It adheres as ice inside the low-temperature channel. Further, when the water in the form of snow or mist passes through the heat recovery heat exchanger, the air containing the water is compressed by the compressor and then cooled by the cooler and the heat recovery heat exchanger. When this occurs, it becomes ice and adheres to the inside of the high-temperature side flow path of the heat exchanger for cold energy recovery. If moisture freezes inside the cold heat recovery heat exchanger, the heat transfer area is reduced and the performance is deteriorated in the cold heat recovery heat exchanger. Further, in the air refrigerant refrigerator, an expander-integrated compressor in which a compressor and an expander are integrated is generally used. In an air refrigerant refrigerator using such an expander-integrated compressor, The icing of water inside the heat recovery heat exchanger changes the pressure balance between the compressor and the expander, which causes the balance of the rotating machine as a power source to be lost and affects the durability of the equipment.

  Therefore, an ice collector is attached to the outlet side of the expander, and a so-called defrost operation is performed in which the heated air flows to drain as drainage in order to remove ice or frost collected by the ice collector. For example, Patent Literature 1 discloses an air refrigerant refrigeration apparatus that can perform a cooling operation after a pre-cooling operation after a defrost operation by providing a bypass.

JP 2006-118772 A

  However, since the air refrigerant refrigeration apparatus disclosed in Patent Document 1 requires an ice collector, the apparatus becomes large, and in addition, drain is accumulated in the heat exchanger for cold heat recovery by defrost operation. The drain cannot be removed, and when the cooling operation is performed again, the drain is frozen again in the cold heat recovery heat exchanger. Therefore, a reheat heater for heating the drain that has been frozen again at the time of pre-cooling is required, and the apparatus becomes large.

  Accordingly, the present invention provides an air-refrigerant heat exchanger capable of melting and discharging ice adhering to the cold recovery heat exchanger without increasing the size of the apparatus in view of the problems of the prior art. For the purpose.

In order to solve the above problems, in the present invention,
A compressor that compresses air collected from the cooled chamber; a cooler that cools compressed air; and an expander that expands the cooled compressed air; compresses, cools, and expands the air collected from the cooled chamber In the air refrigerant refrigeration apparatus constituting the refrigeration cycle system for supplying the low temperature air obtained by the operation to the cooled chamber, the air recovered from the cooled chamber and introduced into the compressor is introduced into the expander A heat recovery heat exchanger that exchanges heat with air in a counter flow is installed, and the heat recovery heat exchanger is arranged so that the compressed air flow direction is from the lower side to the upper side.

  The cold heat recovery heat exchanger to which ice or snow adheres is used as a counter flow, and the compressed air flow direction is set from the lower side to the upper side. When the temperature of the cold heat recovery heat exchanger becomes 0 ° C or higher when the device is stopped, moisture falls by its own weight. To do. Further, by setting the flow of the compressed air, that is, the flow of the high temperature side air from the lower side to the upper side, the temperature in the cold heat recovery heat exchanger gradually increases from the upper side to the lower side. Therefore, even when drain is accumulated in the heat exchanger for collecting cold energy, no reheat heater is required.

  The cold heat recovery heat exchanger may be arranged such that the flow path of the counterflow is in a vertical direction. As a result, the effect of the moisture in the cold heat recovery heat exchanger falling by its own weight is further enhanced as described above.

  Also, a first bypass passage for flowing the air that has passed through the compressor and the heat recovery heat exchanger to the recovered air side from the cooling chamber of the heat recovery heat exchanger bypassing the expander and the cooling target chamber And a second bypass passage that causes the air that has passed through the expander to flow around the cooled chamber and flow to the side of the recovered air from the cooled chamber of the heat recovery heat exchanger, Defrosting operation in which the air in the apparatus is circulated through the first bypass path after closing, and a pre-cooling operation in which the air in the apparatus is circulated through the second bypass path after closing the first bypass path, In addition, the first and second bypass passages are closed to enable a cooling operation for circulating the air in the apparatus.

  When the heated air remaining in the apparatus during the defrost operation without being precooled is supplied to the cooled chamber, the temperature of the cooled chamber rises and condensed water is generated in the cooled chamber. However, after the defrosting operation, the precooling operation that bypasses the cooled chamber is performed to cool the air without supplying the heated air remaining in the apparatus during the defrosting operation to the cooled chamber. And the generation of condensed water can be prevented.

  For switching between cooling operation and defrost operation, for example, a differential pressure gauge that measures the differential pressure between the outlet and the inlet is provided on each of the high temperature side and the low temperature side of the heat recovery heat exchanger, and an increase in the pressure loss of the heat exchanger is detected. In this case, it is preferable that the defrosting operation is automatically started.

In addition, a heating device that heats the air that has passed through the compressor is provided, and the air that has passed through the compressor is heated by the heating device during the defrost operation and then introduced into the heat exchanger. To do.
As a result, the heating time in the apparatus during the defrosting operation can be shortened.

  As described above, according to the present invention, it is possible to provide an air refrigerant heat exchanger capable of melting and discharging ice adhering to the cold heat recovery heat exchanger without increasing the size of the apparatus. .

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

FIG. 1 is a flowchart of an example of the air refrigerant refrigeration apparatus of the present invention.
In the air refrigerant refrigeration apparatus according to the first embodiment, the compressor 1, the cooler 2, the heat recovery heat exchanger 5 and the expander 8 are arranged in the order of the air flow, and the air that has passed through these is supplied to the room 9 to be cooled. It is configured to be introduced. The return air from the room 9 to be cooled is heat-exchanged with the air passing through the cooler 2 in the heat recovery heat exchanger 5 and circulated to the compressor 1 to form a refrigeration cycle.

The rotating shafts of the compressor 1 and the expander 8 are coaxially connected to the drive shaft of the motor 19 for driving, and the rotational power of the expander 8 is transmitted to the rotating shaft of the compressor 1. Power recovery is done.
The cooler 2 is a finned tube heat exchanger, and the cooling water 3 is passed through the plate. A heater 4 for heating the air passing through the cooler 2 is also provided. In the first embodiment, a fin tube type heat exchanger is used as the cooler 2, but other types of coolers may be used as long as the air that has passed through the compressor 1 can be cooled.

  Also, a first bypass path 21 that bypasses the expander 8 and the cooled chamber 9 and a second bypass path 22 that bypasses the cooled chamber 9 are provided, and valves 11 and 12 are provided in the respective bypass paths. . Further, in the air flow path from the expander 8 to the cooled chamber 9, a valve 14 is provided on the downstream side of the air flow from the second bypass path 22, and a heat exchanger for recovering cold from the cooled chamber 9 is provided. The valve 13 is provided on the upstream side of the air flow from the second bypass path 22.

Next, an example of the operation during the cooling operation of the air refrigerant heat exchanger according to the first embodiment will be described with reference to FIG. In the cooling operation, the four valves 11, 12, 13, and 14 provided in FIG. 1 are operated with the valves 11 and 12 closed and the valves 13 and 14 opened.
A normal pressure air of about −60 ° C. in the cooled device 9 is sucked and introduced from above into the low temperature side flow path 7 of the heat recovery heat exchanger 5. The air introduced into the low temperature side flow path 7 is converted into the air introduced into the high temperature side flow path 6 of the cold heat recovery heat exchanger 5 via the compressor 1 and the cooler 2 described later in the cold heat recovery heat exchanger 5. It becomes atmospheric pressure of about 35 ° C by applying the cold heat.

  The normal pressure air that has become about 35 ° C. through the cold heat recovery heat exchanger 5 is compressed to the required pressure by the compressor 1, and the temperature rises to about 93 ° C. at that time, so the air is cooled to about 40 ° C. by the cooler 2. And it introduce | transduces into the high temperature side flow path 6 of the heat exchanger 5 for cold-heat recovery from the downward direction. Here, heat is exchanged with about −60 ° C. air in the low temperature side flow path 7 of the cold heat recovery heat exchanger 5 to cool to about −55 ° C.

The air cooled to about −55 ° C. through the cold recovery heat exchanger 5 is introduced into the expander 8 and expanded to near atmospheric pressure to reach about −80 ° C. A refrigeration cycle system that cools the inside of the room 9 to be cooled is configured by supplying air to the room 9 to be cooled in this way.
That is, during the cooling operation, the compressor 1 → the cooler 2 → the high temperature side passage 6 of the cold heat recovery heat exchanger 5 → the expander 8 → the cooled room 9 → the low temperature side passage 7 of the cold heat recovery heat exchanger 5 → A refrigeration cycle system that circulates air in the order of the compressor 1 is configured.

  However, in such an air refrigerant type refrigeration apparatus, the water in the form of snow or mist is sucked from the chamber 9 to be cooled, and the heat exchanger 5 for recovering cold heat is inhaled by the inhalation of the snow or mist of water. It adheres as ice inside the low temperature side flow path 7. Further, when the snow or mist of moisture passes through the cold heat recovery heat exchanger 5, the air containing the moisture is compressed by the compressor 1, and then the cooler 2 and the cold heat recovery heat exchange. When cooled in the vessel 5, it becomes ice and adheres to the inside of the high temperature side flow path 6 of the heat exchanger 5 for collecting cold heat. When moisture freezes inside the cold heat recovery heat exchanger 5, the heat transfer area in the cold heat recovery heat exchanger 5 decreases, and the refrigerator performance decreases. In addition, when the compressor 1 and the expander 8 are integrated as in the first embodiment, the pressure balance between the compressor 1 and the expander 8 changes due to moisture icing inside the cold heat recovery heat exchanger 5. As a result, the balance of the motor 19 as a power source is lost, and the durability of the device is affected.

  Therefore, when moisture freezes inside the cold heat recovery heat exchanger 5, a defrost operation is performed to remove the frozen moisture. For switching from the cooling operation to the defrost operation, for example, a differential pressure gauge for measuring the differential pressure between the outlet and the inlet is provided in each of the low-temperature side channel 5 and the high-temperature side channel 6 of the heat exchanger 5 for recovering cold heat to exchange heat. When an increase in the pressure loss of the vessel is detected, the defrosting operation may be automatically started.

  An example of the operation at the time of defrost operation of the air refrigerant heat exchanger in the first embodiment will be described with reference to FIG. The four valves 11, 12, 13 and 14 provided in FIG. 1 are operated with the valve 11 opened and the valves 12, 13 and 14 closed during the defrost operation.

The air introduced into the compressor 1 is compressed to the required pressure by the compressor 1 and at the same time the temperature rises and is introduced into the cooler 2. In the cooler 2, the flow of the cooling water 3 is stopped, and the heater 4 is operated to further raise the temperature of the air and introduce the air into the high-temperature side flow path 6 of the heat exchanger 5 for recovering cold heat from below.
The air introduced from below into the high temperature side flow path 6 of the heat exchanger 5 for cold heat recovery flows through the high temperature side flow path 6 and then flows into the first bypass path 21. At this time, the valve 11 provided in the first bypass 21 is opened as described above. If the valve 11 is kept open, the air flow rate to the expander 8 is less than that when the valve 11 is closed due to air resistance, and the air flows to the first bypass path 21 side without the air flow. . Therefore, the air flow between the first bypass path 21 side and the expander 8 side can be switched by opening and closing the valve 11.

The air that has passed through the first bypass path 21 is introduced from above into the low temperature side flow path 7 of the heat exchanger 5 for recovering cold heat. At this time, since the valve 12 and the valve 13 are closed as described above, the air that has passed through the first bypass passage 21 does not flow to the second bypass passage 22 side and the cooled chamber 9 side.
The air introduced from above into the low temperature side flow path 7 of the heat recovery heat exchanger 5 is introduced into the compressor 1 after passing through the low temperature side flow path 7.

  That is, during the defrosting operation, the compressor 1 → the cooler 2 (used as a heater by the operation of the heater 4) → the high temperature side flow path 6 of the cold heat recovery heat exchanger 5 → the first bypass path 21 → for cold heat recovery. High temperature air is circulated in the order of the low temperature side passage 7 of the heat exchanger 5 → the compressor 1. By circulating the high-temperature air in this way, it is possible to melt and remove the ice frozen in the cold heat recovery heat exchanger 5.

  FIG. 2 is a schematic configuration diagram around the heat exchanger 5 for cold energy recovery, and FIG. 3 is a partial perspective view of the inside of the heat exchanger 5 for cold energy recovery. Based on FIG.2 and FIG.3, the periphery operation | movement is demonstrated to the heat exchanger 5 for cold recovery at the time of a defrost driving | operation.

  The high-temperature air that has passed through the cooler 2 used as a heater by the operation of the compressor 1 and the heater 4 is introduced into the cold heat recovery heat exchanger 5 from the introduction passage 63 provided at the lower part of the cold heat recovery heat exchanger 5. The inside of the heat exchanger 5 for recovering cold heat is discharged from the discharge passage 64 in a flow as indicated by 60, for example, from below to above. The air discharged from the discharge passage 64 is introduced into the cold heat recovery heat exchanger 5 through the first bypass passage 21 and introduced into the cold heat recovery heat exchanger 5 through the introduction passage 73 provided on the cold heat recovery heat exchanger 5. The inside of the exchanger 5 is discharged from the discharge passage 74 in a flow as indicated by 70, for example, from above to below and introduced into the compressor 1. In addition, as shown in FIG. 3, the cold recovery heat exchanger 5 is a plate fin type heat exchanger, and is configured to be able to perform heat exchange with a counterflow in the vertical direction.

  In this way, during the defrost operation, high temperature air is passed through the cold heat recovery heat exchanger 5 to melt and remove the ice frozen in the cold heat recovery heat exchanger 5. Moreover, since the air flow in the heat exchanger is set in the vertical direction, the water generated by melting ice by the defrost operation falls by its own weight. Water (drain) that has fallen due to its own weight accumulates in drain traps 61 and 71 provided below the respective flow paths. If necessary, the accumulated drain is stopped after the compressor 1 is stopped and the valve 11 is closed, and then the valves 62 and 72 provided below the drain traps 61 and 71 are opened to discharge the accumulated drain to the outside.

  Here, when switching to the normal cooling operation after the defrost operation, the heated air remaining in the apparatus by the defrost operation is supplied to the cooled chamber 9, the temperature of the cooled chamber 9 rises, Since condensed water is generated in the cooling chamber 9, after the defrost operation, a precooling operation bypassing the cooled chamber 9 is performed, so that the heated air remaining in the apparatus during the defrosting operation is transferred to the cooled chamber. Without supplying, air can be cooled and generation of condensed water can be prevented.

  An example of the operation during the precooling operation of the air refrigerant heat exchanger according to the first embodiment will be described with reference to FIG. The four valves 11, 12, 13, and 14 provided in FIG. 1 are operated with the valve 12 opened and the valves 11, 13, and 14 closed during the pre-cooling operation.

  By opening the valve 12 and closing the valves 11, 13, and 14, only the chamber 9 to be cooled in the above-described cooling operation is bypassed, and the compressor 1 → the cooler 2 → the high temperature side of the heat exchanger 5 for collecting cold The air is circulated in the order of the flow path 6 → the expander 8 → the low temperature side passage 7 of the heat recovery heat exchanger 5 → the compressor 1. The pre-cooling operation is performed in this way, and the heated air in the apparatus is cooled by the expander 8 and circulates bypassing the cooled chamber 9. By performing the pre-cooling operation and sufficiently cooling the air in the apparatus and then starting the cooling operation, it is possible to switch from the defrost operation to the cooling operation without supplying the heated air to the chamber 9 to be cooled.

Table 1 summarizes the operating state of the compressor 1 and the open / close states of the valves 11, 12, 13, 14, 62 and 72 during the above-described cooling operation, defrost operation, moisture discharge, and pre-cooling operation.
During the cooling operation, the valves 13 and 14 are opened, the valves 11 and 12 provided in the first and second bypass paths are closed, and the inside of the cooled chamber 9 is cooled.
For example, when a defrost operation is required, such as detecting an increase in pressure loss of the heat recovery heat exchanger 5, the valve 11 is opened and the valves 13 and 14 are closed to perform the defrost operation.
After defrosting for about 1 hour and removing ice in the heat exchanger for cold energy recovery, the compressor 1 is stopped to stop the circulation, the valve 11 is closed, and the drain traps 61 and 71 are provided below. The valves 62 and 72 are opened, and the drain accumulated in the drain trap is discharged out of the system.
When the moisture discharge is completed, the valves 62 and 72 are closed, the valve 12 is opened, the compressor 1 is operated, and the pre-cooling operation is performed.
When the pre-cooling operation is performed and the inside of the apparatus is sufficiently cooled and stabilized, the valve 13 is opened and the valve 12 is closed to switch to the cooling operation.

  In this way, the heat recovery heat exchanger 5 is configured so as to perform heat exchange with a counterflow in the vertical direction, and the high temperature side passage is arranged from the lower side to the upper side, and the cooling operation → defrost operation → water discharge → By performing the pre-cooling operation → the cooling operation, it is possible to melt and discharge the ice adhering to the cold heat recovery heat exchanger without increasing the size of the apparatus.

  The apparatus can be used as an air-refrigerant heat exchanger that can melt and discharge ice adhering to the cold-heat recovery heat exchanger without increasing the size of the apparatus.

It is a flowchart of an example of the air refrigerant type refrigeration apparatus of this invention. It is a schematic block diagram around the heat exchanger for cold energy recovery. It is a fragmentary perspective view inside the heat exchanger for cold heat recovery.

Explanation of symbols

1 Compressor 2 Cooler 3 Cooler 4 Heater (Heating device)
5 Heat exchanger for cold energy recovery 6 High temperature side flow path 7 Low temperature side flow path 8 Expander 9 Cooled room 21 First bypass path 22 Second bypass path 61, 71 Drain trap

Claims (4)

A compressor that compresses air collected from the cooled chamber; a cooler that cools compressed air; and an expander that expands the cooled compressed air; compresses, cools, and expands the air collected from the cooled chamber In an air refrigerant refrigeration apparatus constituting a refrigeration cycle system for supplying low temperature air obtained by
Installing a heat recovery heat exchanger for exchanging heat in a counter flow with air introduced into the expander and recovered from the cooled chamber and introduced into the compressor;
The air refrigerant refrigeration apparatus, wherein the cold heat recovery heat exchanger is arranged so that a flow direction of the compressed air is from the lower side to the upper side.   The air refrigerant refrigeration apparatus according to claim 1, wherein the cold heat recovery heat exchanger is disposed such that the flow path of the counterflow is in a vertical direction. A first bypass passage for flowing the air that has passed through the compressor and the heat recovery heat exchanger to the recovery air side from the cooling chamber of the heat recovery heat exchanger, bypassing the expander and the cooling chamber; A second bypass passage is provided for flowing the air that has passed through the expander, bypassing the cooled chamber, and flowing to the recovered air side from the cooled chamber of the heat recovery heat exchanger,
A defrost operation in which the air in the apparatus is circulated through the first bypass path after the second bypass path is closed, and the air in the apparatus is passed through the second bypass path after the first bypass path is closed. The air-cooling type according to claim 1 or 2, wherein a pre-cooling operation for circulating the air and a cooling operation for circulating the air in the apparatus by closing the first bypass path and the second bypass path are possible. Refrigeration equipment.   A heating device is provided for heating the air that has passed through the compressor, and the air that has passed through the compressor is heated by the heating device during the defrost operation and then introduced into the heat exchanger. Item 4. The air refrigerant refrigeration apparatus according to Item 3.

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