JP5842310B2 - Refrigeration apparatus and defrost method for load cooler - Google Patents

Description

  The present invention relates to a refrigeration apparatus and a defrosting method for a load cooler. More specifically, the present invention relates to a refrigeration apparatus capable of cooling a load cooler and defrosting while achieving energy saving, and a large heat transport limit. It is related with the defrost method of the load cooler which can shorten defrost time by doing.

  Conventionally, in order to perform defrosting (defrosting) of a cooled load cooler, from the viewpoint of energy saving, a refrigeration apparatus or an air conditioner that performs defrosting using exhaust heat during cooling operation is disclosed in, for example, Patent Literature 1 and Patent Document 2.

The refrigeration apparatus of Patent Document 1 is a carbon dioxide circulation / cooling system in which heat exchange between a carbon dioxide refrigerant and an ammonia refrigerant is performed by a cascade condenser, the carbon dioxide refrigerant is changed into a refrigerant liquid, and the ammonia refrigerant is vaporized. A hot gas heat exchanger that vaporizes the carbon dioxide refrigerant by heat generated in the ammonia refrigerant in the ammonia refrigerant circuit discharged from the condenser to convert it into hot gas, and sends the carbon dioxide refrigerant into the hot gas heat exchanger, and A defrost circuit is provided for supplying and defrosting hot gas generated in the gas heat exchanger into the load-side cooler.
According to such a defrost circuit, when defrosting (defrost) frost adhering to the load side cooler of the carbon dioxide refrigerant circuit during operation of the cooling system, heat generated in the ammonia refrigerant of the ammonia refrigerant circuit (exhaust heat) Is transferred to the carbon dioxide refrigerant side of the carbon dioxide refrigerant circuit in the hot gas heat exchanger and recovered, the carbon dioxide refrigerant is vaporized by the recovered exhaust heat into hot gas, and the hot gas is supplied to the load side cooler. Thus, it is possible to remove frost adhering to the load side cooler.

In the air conditioner of Patent Document 2, a chemical heat storage device is provided between the compressor and the first four-way switching valve via a second four-way switching valve, and the discharge of the compressor is performed using the chemical heat storage device during heating operation. It absorbs heat from the gas refrigerant, stores heat, and heats the refrigerant on the inlet side of the indoor heat exchanger with the stored heat during the defrost operation.
According to such an air conditioner, the low-temperature and low-pressure liquid refrigerant is heated by the heat stored in the chemical heat storage device on the inlet side of the indoor heat exchanger during the defrost operation and becomes a high-temperature and low-pressure gas refrigerant. Heat is exchanged with the indoor air that is guided to the exchanger and blown by the indoor fan, and warm air is blown into the indoor side, while the high-temperature and low-pressure gas refrigerant becomes low temperature due to heat radiation in the indoor heat exchanger and returns to the compressor.
Therefore, according to such a defrost technique, it is possible to store once the exhaust heat during the cooling operation, and to defrost using the heat.

However, such conventional defrost techniques have the following technical problems.
First, energy saving is insufficient. More specifically, it is possible to save energy to some extent in that defrosting is performed using exhaust heat during the cooling operation, but defrosting is performed while the compressor is operating even during the defrosting operation.
In this regard, in Patent Document 2, although exhaust heat from the cooling operation is stored in the heat storage tank, similarly to Patent Document 1, defrosting is performed while the compressor is operating.

Secondly, in order to use the exhaust heat of the cooling operation, heat transport is necessary. In the so-called wick type, there is a heat transport limit due to the capillary phenomenon, while in the so-called simple thermosiphon type, flooding is performed. There is a heat transport limit due to this, and in both cases, it takes defrost time.
More specifically, in the wick type, since it is a heat transport type between the high temperature part located above and the low temperature part located below, since it is transport using capillary phenomenon, the heat transport limit is naturally. Exists.
On the other hand, the thermosiphon type is a heat transport type between the high-temperature part located below and the low-temperature part located above, and since natural circulation occurs, there is no heat transport limit like the wick type. However, since a flooding occurs between the cold flow going downward and the hot flow going upward, a heat transport limit occurs from this point of view.

As described above, if the exhaust heat during the cooling operation is used by the conventional heat transport mode, the heat transport limit is small, which causes a long defrost time.
JP 2010-181093 A Japanese Patent Laid-Open No. 05-79731

  In view of the above technical problems, the object of the present invention is to reduce the defrost time by cooling the load cooler and defrosting while achieving energy saving, and by increasing the heat transport limit. It is an object of the present invention to provide a defrost method for a load cooler that can shorten the time.

In order to achieve the above object, the refrigeration apparatus of the present invention comprises:
In a refrigeration system that constitutes a cooling circuit by sequentially connecting a load cooler, a compressor, a heat accumulator, a condenser, a liquid receiver, and an expansion valve in this order by refrigerant piping,
The regenerator is installed at a lower level than the load cooler;
The refrigerant pipe that constitutes the inflow part to the load cooler or the refrigerant pipe that constitutes the outflow part from the load cooler and the inflow part to the heat accumulator A first bypass pipe connecting the refrigerant pipe or the refrigerant pipe of any one of the refrigerant pipes constituting the outflow portion from the regenerator;
The refrigerant pipe constituting the inflow part to the load cooler, or the other refrigerant pipe with respect to the one of the refrigerant pipes of the refrigerant pipe constituting the outflow part from the load cooler, and the heat accumulator A second bypass pipe connecting the other refrigerant pipe to the refrigerant pipe of any one of the refrigerant pipe constituting the inflow part to the refrigerant or the refrigerant pipe constituting the outflow part from the regenerator, Have
Thereby, while using the heat stored during the cooling operation of the load cooler in the heat accumulator, the refrigerant gas is sent from the heat accumulator to the load cooler via the first bypass pipe, A loop type thermosiphon is configured to return the refrigerant liquid generated as a result of defrosting the load cooler from the load cooler to the heat accumulator via the second bypass pipe.

According to the refrigeration apparatus having the above configuration, the refrigerant gas evaporated by cooling the load cooler during the cooling operation is compressed by the compressor and dissipated in the heat accumulator, and as a result, the heat is stored, and the refrigerant gas or The refrigerant liquid is condensed or supercooled by the condenser, and the refrigerant liquid is received by the liquid receiver, and the load cooler is cooled by configuring a cooling circuit that cools the load cooler again through the expansion valve.
On the other hand, during the defrost operation of the load cooler, by using the heat stored in the heat accumulator during the cooling operation of the load cooler, the refrigerant gas is supplied from the heat accumulator to the load cooler via the first bypass pipe. On the other hand, by returning the refrigerant liquid generated as a result of defrosting the load cooler from the load cooler to the heat accumulator through the second bypass pipe, the hot side heat accumulator located below and the cold side located above By constructing a loop-type thermosyphon with natural circulation with the load cooler, it is possible to defrost with the compressor stopped, and with a small heat transport limit by the conventional wick type or thermosyphon type It is possible to defrost while achieving energy saving without causing problems.

Further, the first bypass pipe connects a first refrigerant pipe connecting the load cooler and the compressor, and a fourth refrigerant pipe connecting the heat accumulator and the condenser,
The second bypass pipe connects a third refrigerant pipe connecting the expansion valve and the load cooler and a second refrigerant pipe connecting the compressor and the heat accumulator,
The connection position of the first refrigerant pipe to the load cooler may be at a lower level than the connection position of the third refrigerant pipe to the load cooler.
Furthermore, a first switching valve is provided on the compressor side from the connection position of the first bypass pipe to the fourth refrigerant pipe,
From the connection position of the second bypass pipe to the second refrigerant pipe, a second switching valve is provided on the condenser side,
From the connection position of the first bypass pipe to the first refrigerant pipe, a third switching valve is provided on the compressor side,
A fourth switching valve may be provided in the middle of the first bypass pipe.

Furthermore, the first bypass pipe connects a first refrigerant pipe connecting the load cooler and the compressor and a second refrigerant pipe connecting the compressor and the heat accumulator,
The second bypass pipe connects a third refrigerant pipe connecting the expansion valve and the load cooler and a fourth refrigerant pipe connecting the heat accumulator and the condenser,
The connection position of the first refrigerant pipe to the load cooler may be a level above the connection position of the third refrigerant pipe to the load cooler.
In addition, a first switching valve is provided on the compressor side from the connection position of the first bypass pipe to the second refrigerant pipe,
From the connection position of the second bypass pipe to the fourth refrigerant pipe, a second switching valve is provided on the condenser side,
From the connection position of the first bypass pipe to the first refrigerant pipe, a third switching valve is provided on the compressor side,
A fourth switching valve may be provided in the middle of the first bypass pipe.

A third bypass pipe for connecting the fifth refrigerant pipe connecting the liquid receiver and the expansion valve and the heat storage side of the second switching valve of the fourth refrigerant pipe;
A fifth switching valve is provided in the middle of the third bypass pipe;
The refrigerant liquid may be sent from the liquid receiver to the heat accumulator through a part of the fifth refrigerant pipe, the third bypass pipe, and a part of the fourth refrigerant pipe.
Furthermore, a regenerator that connects a portion of the second refrigerant pipe between the first switching valve and the compressor and a portion of the fourth refrigerant pipe between the second switching valve and the condenser. A bypass pipe is further provided,
A sixth switching valve may be provided in the middle of the heat accumulator bypass pipe.
In addition, the heat storage material of the heat storage device is preferably a latent heat storage material.

Moreover, it is good to naturally supply the refrigerant | coolant amount required for the defrost of the said load cooler from the said receiver via a said 3rd bypass pipe before defrost.
Furthermore, a pump is provided between the liquid receiver of the fifth refrigerant pipe and the branch portion with the third bypass pipe, or in the middle of the third bypass pipe, so that before defrosting, from the liquid receiver The amount of refrigerant necessary for defrosting the load cooler may be forcibly supplied via the third bypass pipe.

In order to achieve the above object, a defrost method for a load cooler according to the present invention comprises:
A defrosting method for a load cooler located at the uppermost level, which is cooled by a cooling circuit having a compressor for compressing refrigerant gas,
Storing the sensible heat or latent heat of condensation of the refrigerant gas discharged from the compressor during the cooling operation of the load cooler;
Defrosting the load cooler by a thermosiphon method using the stored heat,
Have a configuration.

Furthermore, the heat storage stage is performed by a heat storage unit installed at a lower level than the load cooler,
In the thermosiphon system, a loop defrost circuit is preferably formed between the load cooler and the heat accumulator.
Further, the cooling operation may include a step of bypassing the heat storage device after the heat storage step.

Embodiments of a refrigeration apparatus according to the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 1, the refrigeration apparatus 10 includes a load cooler 12, a compressor 14, a heat accumulator 16, a condenser 18, a liquid receiver 20, and an expansion valve 22 sequentially connected in this order by refrigerant piping, Configure. The heat accumulator 16 is installed at a lower level (level difference H) than the load cooler 12 and connects the third refrigerant pipe 28 that connects the expansion valve 22 and the load cooler 12, the compressor 14, and the heat accumulator 16. A first bypass pipe 27 that connects the second refrigerant pipe 26, a first refrigerant pipe 24 that connects the load cooler 12 and the compressor 14, and a fourth refrigerant pipe 30 that connects the regenerator 16 and the condenser 18. And the connection position of the first refrigerant pipe 24 to the load cooler 12 is lower than the connection position of the third refrigerant pipe 28 to the load cooler 12 (level difference). h). The condenser 18 and the liquid receiver 20 are connected by a sixth refrigerant pipe 50.
Thereby, the refrigerant gas is sent from the heat accumulator 16 to the load cooler 12 via the first bypass pipe 27 by using the heat accumulated in the cooling operation of the load cooler 12 in the heat accumulator 16, while the load A loop-type thermosyphon is configured to return the refrigerant liquid generated as a result of defrosting the load cooler 12 from the cooler 12 to the heat accumulator 16 via the second bypass pipe 31.
The relative installation level difference H of the heat accumulator 16 with respect to the load cooler 12 and the relative position of the connection position of the first refrigerant pipe 24 to the load cooler 12 with respect to the connection position of the third refrigerant pipe 28 to the load cooler 12. An appropriate installation level difference h may be determined as appropriate from the viewpoint of configuring a loop thermosyphon.
Furthermore, a third bypass pipe 42 that connects the fifth refrigerant pipe 40 that connects the liquid receiver 20 and the expansion valve 22 and the heat storage 16 side of the second switching valve 34 of the fourth refrigerant pipe 30 is provided, A fifth switching valve 44 is provided in the middle of the third bypass pipe 42, and the refrigerant is supplied from the receiver 20 through a part of the fifth refrigerant pipe 40, the third bypass pipe 42, and a part of the fourth refrigerant pipe 30. The liquid is sent to the heat accumulator 16.
Furthermore, a regenerator bypass pipe 46 that connects the second refrigerant pipe 26 and the fourth refrigerant pipe 30 is provided, and a sixth switching valve 48 is provided in the middle of the regenerator bypass pipe 46.

As described below, each refrigerant pipe (the first refrigerant pipe 24, the second refrigerant pipe 26, and the fourth refrigerant pipe 30) is provided with a switching valve from the viewpoint of switching between the normal operation mode and the defrost operation mode. It has been.
More specifically, the first switching valve 32 is provided on the compressor 14 side from the connection position of the first bypass pipe 27 to the second refrigerant pipe 26, and the second bypass pipe 31 is connected to the fourth refrigerant pipe 30. The second switching valve 34 is provided on the condenser 18 side from the position, and the third switching valve 36 is provided on the compressor 14 side from the connection position of the second bypass pipe 31 to the first refrigerant pipe 24, and the first bypass A fourth switching valve 38 is provided in the middle of the pipe 27.
The second refrigerant pipe 26 has a check valve 62 that blocks the flow of refrigerant from the regenerator 16 to the compressor 14, and the second bypass pipe 31 has a refrigerant flow from the heat accumulator 16 to the load cooler 12. The check valve 64 that blocks the flow and the check valve 66 that blocks the flow of the refrigerant from the heat accumulator 16 to the liquid receiver 20 are respectively provided in the third bypass pipe 42.

The load cooler 12 is installed in, for example, a refrigerator such as a freezer, a refrigerated warehouse, and a shipping room.
The heat storage material of the heat storage device 16 may be a latent heat storage material or a sensible heat storage material. For example, the latent heat storage material is paraffinic, and the sensible heat storage material is water.

As will be described later, in the initial stage of the defrost operation mode, the refrigerant amount necessary for defrosting the load cooler 12 is naturally supplied from the liquid receiver 20 via the third bypass pipe 42 before defrosting.
More specifically, when the compressor 14 is stopped, the refrigerant in the fifth refrigerant pipe 40 between the liquid receiver 20 and the expansion valve 22 is downstream from the compressor 14 and has a relatively high pressure. In the loop type thermosiphon configured by connecting the load cooler 12 and the heat accumulator 16 by the first bypass pipe 27 and the second bypass pipe 31, the high-pressure side heat accumulator 16 and the low-pressure side load cooling are connected. By communicating with the vessel 12, a relatively medium pressure is obtained, so that the refrigerant can be naturally supplied from the liquid receiver 20 to the load cooler 12 by this differential pressure.
As a modification, a pump (not shown) is provided between the receiver 20 of the fifth refrigerant pipe 40 and the branching section with the third bypass pipe 42 or in the middle of the third bypass pipe 42, thereby defrosting. Before, the amount of refrigerant necessary for defrosting the load cooler 12 may be forcibly supplied from the liquid receiver 20 via the third bypass pipe 42.

The operation of the refrigeration apparatus 10 having the above configuration will be described below with reference to FIGS. 2 to 5 through the description of the operation method of the refrigeration apparatus 10.
Regarding the operation method of the refrigeration apparatus 10, as operation modes, normal operation mode 1 (heat storage stage) (FIG. 2), normal operation mode 2 (after the end of heat storage) (FIG. 3), defrost operation mode (initial stage) (FIG. 4) And defrost operation mode (normal stage) (FIG. 5).

First, as shown in FIG. 2, in the normal operation mode 1 (heat storage stage), the first switching valve 32, the second switching valve 34, the third switching valve 36 and the expansion valve 22 are opened, while the fourth switching valve 38. The compressor 14 is operated with the fifth switching valve 44 closed.
The fourth switching valve 38 of the first bypass pipe 27 is closed so that the refrigerant is not bypassed by the check valve 64 of the second bypass pipe 31 via the first bypass pipe 27 and the second bypass pipe 31. I have to.
The refrigerant flows into the compressor 14 from the load cooler 12 through the first refrigerant pipe 24, is compressed here, and further flows into the heat accumulator 16 from the compressor 14 through the second refrigerant pipe 26, where The refrigerant dissipates heat, is stored in the heat accumulator 16, further flows from the heat accumulator 16 into the condenser 18 through the fourth refrigerant pipe 30, where it is condensed or supercooled, and further from the condenser 18 through the sixth refrigerant pipe 50. Then, a certain amount of refrigerant liquid is received, and the liquid refrigerant flows from the liquid receiver 20 into the expansion valve 22 via the fifth refrigerant pipe 40, where the expansion valve The degree of superheat of the refrigerant is adjusted by adjusting the opening degree of 22, and the refrigerant is further returned from the expansion valve 22 to the load cooler 12 via the third refrigerant pipe 28 to constitute a cooling circuit.
As described above, the refrigerant flows as shown by the arrows in FIG. 2, and is in a gas state between the load cooler 12 and the heat accumulator 16 through the compressor 14, particularly the load cooler 12 and the compressor 14. Between the compressor 14 and the heat accumulator 16, and between the compressor 14 and the regenerator 16, while between the regenerator 16 and the load cooler 12 via the expansion valve 22, a liquid or wet steam state It is.

Next, as shown in FIG. 3, in the normal operation mode 2 (after the end of heat storage), as in the normal operation mode 1 (FIG. 2), the first switching valve 32, the second switching valve 34, and the third switching valve 36. The compressor 14 is operated with the expansion valve open and the fourth switching valve 38 and the fifth switching valve 44 closed.
As in the normal operation mode 1 (FIG. 2), the fourth switching valve 38 of the first bypass pipe 27 is closed, and the first bypass pipe 27 and the second bypass valve 64 of the second bypass pipe 31 are closed by the check valve 64. The refrigerant is prevented from bypassing through the bypass pipe 31.
The normal operation mode is the normal operation mode as in the operation mode of FIG. 2, but the heat is being stored in FIG. 2, but the normal operation mode 2 of FIG. 3 is a mode after the end of the heat storage.

More specifically, the flow path of the refrigerant gas discharged from the compressor 14 may be the same as that during heat storage in FIG.
That is, the refrigerant flows into the compressor 14 from the load cooler 12 through the first refrigerant pipe 24, is compressed here, and further flows into the heat accumulator 16 from the compressor 14 through the second refrigerant pipe 26, Here, the refrigerant dissipates heat, is stored in the heat accumulator 16, and further flows from the heat accumulator 16 into the condenser 18 via the fourth refrigerant pipe 30, where it is condensed or supercooled, and further from the condenser 18 to the sixth refrigerant pipe 50. Into the receiver 20 where a certain amount of refrigerant liquid is received, and the liquid refrigerant flows into the expansion valve 22 from the receiver 20 via the fifth refrigerant pipe 40, where By adjusting the opening degree of the expansion valve 22, the degree of superheat of the refrigerant is adjusted, and the refrigerant is returned from the expansion valve 22 to the load cooler 12 through the third refrigerant pipe 28 to constitute a cooling circuit.
However, since the discharge refrigerant gas from the compressor 14 flows to the condenser 18 through the heat accumulator 16, a pressure loss in the heat accumulator 16 is inevitably generated. In order to eliminate such pressure loss, Instead of closing the first switching valve 32, the refrigerant gas discharged from the compressor 14 bypasses the heat accumulator 16 via the heat accumulator bypass pipe 46 by opening the sixth switching valve 48.

Next, as shown in FIG. 4, in the defrosting operation mode (initial stage), the compressor 14 is stopped and the fourth switching valve 38 and the fifth switching valve 44 are opened, while the first switching valve 32 and the second switching valve 32 are opened. The switching valve 34, the third switching valve 36, and the expansion valve 22 are closed.
That is, the refrigerant liquid is allowed to flow from the receiver 20 by allowing the refrigerant to flow through the first bypass pipe 27, the second bypass pipe 31, and the third bypass pipe 42 while stopping the cooling circuit in the normal operation mode. While flowing to the heat accumulator 16 via the 3 bypass pipe 42, a loop-type thermosiphon by natural circulation is configured between the heat accumulator 16 and the load cooler 12.

In this case, in particular, the defrosting operation mode (initial stage) immediately after the freezing operation, the refrigerant in the fifth refrigerant pipe 40 between the liquid receiver 20 and the expansion valve 22 is downstream from the compressor 14 and relatively On the other hand, in the loop type thermosyphon configured by connecting the load cooler 12 and the heat accumulator 16 by the first bypass pipe 27 and the second bypass pipe 31, The communication with the load cooler 12 on the low-pressure side results in a relatively medium pressure, so that the refrigerant can be naturally supplied from the liquid receiver 20 to the load cooler 12 by this differential pressure.
At this time, the necessary amount of refrigerant is an amount sufficient for the thermosyphon to circulate smoothly and to obtain the predetermined heat transport necessary for defrosting the load cooler 12 in the loop thermosyphon. It changes according to the capacity | capacitance of the container 12, and the piping length of each of the 1st bypass pipe 27 and the 2nd bypass pipe 31 which are some loop-type thermosiphons.
If the amount of refrigerant retained is sufficient when the compressor 14 is stopped, it is not necessary to feed the receiver 14 from the receiver 20 via the third bypass pipe 42 and the fifth switching valve 44. It is only necessary to perform the defrost operation with the loop type thermosiphon in a state where is closed.
As described above, the refrigerant flows as shown by the arrows in FIG. 4, and the liquid is from the liquid receiver 20 to the heat accumulator 16 through the fifth refrigerant pipe 40 and the third bypass pipe, and from the heat accumulator 16 to the second refrigerant. A gas state is obtained from the pipe 26 and the first bypass pipe 27 to the load cooler 12, and a liquid state is obtained from the load cooler 12 to the heat accumulator 16 through the second bypass pipe 31.

Next, as shown in FIG. 5, in the defrost operation mode (normal stage), the compressor 14 is stopped and the fourth switching valve 38 is opened, while the first switching valve 32 and the second switching valve 38 are opened as in FIG. The switching valve 34, the third switching valve 36, the fifth switching valve 44 and the expansion valve 22 are closed.
More specifically, the refrigerant gas evaporated (heat absorption) by the heat storage of the heat accumulator 16 flows from the second refrigerant pipe 26 through the first bypass pipe 27 to the load cooler 12, where the refrigerant gas is condensed (heat radiation). As a result, the defrosting of the load cooler 12 is performed, the defrosting attached to the load cooler 12 is performed, and the refrigerant liquid returns from the second bypass pipe 31 to the heat accumulator 16 through the fourth refrigerant pipe 30, and this natural By repeating the circulation, a loop thermosyphon is formed.
Note that the oil of the compressor 14 flowing into the load cooler 12 flows out from the third refrigerant pipe 28 to the first refrigerant pipe 24 at a lower level and is sent to the bend unit 80.
When the defrosting of the load cooler 12 is completed by this defrosting operation, it is sufficient to return to the normal operation mode 1 and resume heat storage in preparation for the next defrosting operation.

The switching timing between the normal operation mode (FIGS. 2 and 3) and the defrost operation mode (FIGS. 4 and 5) may be manually switched as appropriate according to the state of frost generation in the load cooler 12. Alternatively, when the load in the load cooler 12 is relatively constant and the progress of frost is relatively regular, a timer may be set in advance to automatically switch.
Timing of switching from normal operation mode 1 (FIG. 2) to normal operation mode 2 (FIG. 3), and timing of switching from defrost operation mode (initial) (FIG. 2) to defrost operation mode (normal) (FIG. 3) For example, the temperature may be automatically set by a timer, or the temperature of a heat transfer tube (not shown) of the load cooler 12 may be detected and set based on the detected temperature.

According to the refrigeration apparatus 10 having the above configuration, the refrigerant gas evaporated by cooling the load cooler 12 during the cooling operation is compressed by the compressor 14 and dissipated in the heat accumulator 16, and as a result, heat is stored. The refrigerant gas or the refrigerant liquid is condensed or supercooled by the condenser 18, and the refrigerant liquid is received by the liquid receiver 20, and the cooling circuit is configured to cool the load cooler 12 again through the expansion valve 22. The load cooler 12 is cooled.

On the other hand, during the defrost operation of the load cooler 12, the first bypass pipe 27 is connected from the heat accumulator 16 to the load cooler 12 by using the heat stored in the heat accumulator 16 during the cooling operation of the load cooler 12. The refrigerant gas is sent to the heat accumulator 16 from the load cooler 12 via the second bypass pipe 31 and the refrigerant liquid generated as a result of defrosting the load cooler 12 is returned to the hot side located below. By constructing a loop-type thermosiphon by natural circulation between the heat accumulator 16 and the cold-side load cooler 12 positioned above, it is possible to perform defrost in a state where the compressor 14 is stopped. It is possible to perform defrosting while achieving energy saving without causing the problem of a small heat transport limit due to the wick type or thermosiphon type.

        According to the defrosting (defrosting) method of the load cooler 12 having the above configuration, the load cooler 12 is defrosted by the cooling circuit having the compressor 14 for compressing the refrigerant gas and is positioned at the uppermost level. Then, during the cooling operation of the load cooler 12, the stage of storing the sensible heat or latent heat of condensation of the refrigerant gas discharged from the compressor 14 and the thermosyphon method are used to store the load cooler 12 using the stored heat. A defrosting stage, and the heat storage stage is performed by a heat storage unit 16 installed at a lower level than the load cooler 12, and the thermosiphon system is a loop type defrost between the load cooler 12 and the heat storage unit 16. A circuit may be configured, and a step of bypassing the heat accumulator 16 may be provided after the heat storage step is completed during the cooling operation.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In the following description, the same constituent elements as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The characteristic portions of the present embodiment will be described in detail.
The characteristic part of the present embodiment is in the loop type defrost circuit, and more specifically, in the connection positions of the first bypass pipe 27 and the second bypass pipe 31 to the load cooler 12.
More specifically, as in the first embodiment, the connection position of the first bypass pipe 27 that sends the refrigerant gas to the load cooler 12 to the load cooler 12 is the second position where the refrigerant liquid is sent from the load cooler 12. Although it is common that the level is higher than the connection position of the bypass pipe 31 to the load cooler 12 (level difference h), unlike the first embodiment, the load cooler of the first bypass pipe 27 is different from the first embodiment. The connection position to 12 is the downstream side of the load cooler 12, that is, the first refrigerant pipe 24. On the other hand, the connection position of the second bypass pipe 31 to the load cooler 12 is upstream of the load cooler 12. Side, that is, the third refrigerant pipe 28.
In the first embodiment, when the oil of the compressor 14 flows into the load cooler 12 through the circulation of the refrigerant, this oil is provided in the first refrigerant pipe 24 on the downstream side of the load cooler 12. In order to send it to the bend section 80, the connection relationship along the flow direction of the refrigerant is used. When installing the oil separation function, such a connection relationship is not necessarily required, and a connection relationship as in the present embodiment is also possible.
The specific defrosting method is the same as that of the first embodiment except that the flow path of the defrosting fluid is different between the heat accumulator and the load cooler in the loop type defrost circuit. Therefore, the description is omitted.

The embodiments of the present invention have been described in detail above, but various modifications or changes can be made by those skilled in the art without departing from the scope of the present invention.
For example, in the first embodiment and the second embodiment, as the connection of the first bypass pipe 27 to the regenerator 16 side, as the connection of the second refrigerant pipe 26 side, one second bypass pipe 31 to the regenerator 16 side, Although described as the 4th refrigerant | coolant piping 30 side, it is not limited to it, As the connection to the heat accumulator 16 side of the 1st bypass pipe 27, the heat accumulator 16 of the 4th refrigerant | coolant piping 30 side, one side 2nd bypass pipe 31 is used. The side connection may be on the second refrigerant pipe 26 side.
For example, in this embodiment, although demonstrated as the heat storage device 16, it is not limited to it, A heat storage tank may be sufficient as long as the heat storage from a refrigerant | coolant is possible.
For example, in this embodiment, at the end stage of heat storage in normal operation (FIG. 3), the sixth switching valve 48 is opened instead of closing the first switching valve 32 in order to eliminate pressure loss in the heat storage tank. However, the present invention is not limited thereto, and the heat accumulator bypass pipe 46 may be omitted if the pressure loss in the heat accumulator 16 is not high.

For example, in the present embodiment, in the initial stage of the defrost operation (FIG. 4), it has been described that the refrigerant amount required for the loop thermosyphon is fed. However, the present invention is not limited thereto, and at the time when the compressor 14 is stopped. If the amount of refrigerant retained is sufficient, such an operation is not necessary, and the third bypass pipe 42 itself may be omitted depending on circumstances.

1 is a configuration diagram of a refrigeration apparatus 10 according to a first embodiment of the present invention. In the refrigeration apparatus 10 according to the first embodiment of the present invention, FIG. In the refrigeration apparatus 10 which concerns on 1st Embodiment of this invention, it is a figure similar to FIG. 1 which shows the normal cooling driving | operation after completion | finish of heat storage. In the refrigeration apparatus 10 according to the first embodiment of the present invention, it is the same diagram as FIG. 1 showing the initial defrost operation. In refrigeration apparatus 10 concerning a 1st embodiment of the present invention, it is the same figure as Drawing 1 showing usual defrost operation. It is a figure similar to FIG. 1 of the freezing apparatus 10 which concerns on 2nd Embodiment of this invention.

h level difference H level difference 10 refrigeration apparatus 12 load cooler 14 compressor 16 heat accumulator 18 condenser 20 receiver 22 expansion valve 24 first refrigerant pipe 26 second refrigerant pipe 28 third refrigerant pipe 30 fourth refrigerant pipe 27 first 1 bypass pipe 31 2nd bypass pipe 32 1st switching valve 34 2nd switching valve 36 3rd switching valve 38 4th switching valve 40 5th refrigerant | coolant piping 42 3rd bypass pipe 44 5th switching valve 46 Regenerator bypass pipe 48 1st 6 switching valve 50 6th refrigerant piping 62 check valve 64 check valve 66 check valve 80 bend part

Claims (10)

In a refrigeration system that constitutes a cooling circuit by sequentially connecting a load cooler, a compressor, a heat accumulator, a condenser, a liquid receiver, and an expansion valve in this order by refrigerant piping,
The regenerator is installed at a lower level than the load cooler;
The refrigerant pipe that is one of the refrigerant pipe that forms the inflow portion to the load cooler during normal cooling operation or the refrigerant pipe that forms the outflow portion from the load cooler during normal cooling operation And the refrigerant pipe that constitutes the inflow part to the regenerator during the normal cooling operation, or the refrigerant pipe that constitutes the outflow part from the heat accumulator during the normal cooling operation. A first bypass pipe connecting the
The refrigerant pipe constituting the inflow part to the load cooler during normal cooling operation or the refrigerant pipe of the refrigerant pipe constituting the outflow part from the load cooler during normal cooling operation The other refrigerant pipe with respect to the pipe, the refrigerant pipe constituting the inflow part to the regenerator during the normal cooling operation, or the refrigerant pipe constituting the outflow part from the regenerator during the normal cooling operation. A second bypass pipe connecting the other refrigerant pipe to the one of the refrigerant pipes,
Thereby, while using the heat stored during the cooling operation of the load cooler in the heat accumulator, the refrigerant gas is sent from the heat accumulator to the load cooler via the first bypass pipe, A refrigeration apparatus comprising a loop thermosyphon that returns a refrigerant liquid generated as a result of defrosting the load cooler from the load cooler to the heat accumulator via the second bypass pipe. The first bypass pipe connects a first refrigerant pipe connecting the load cooler and the compressor, and a fourth refrigerant pipe connecting the heat accumulator and the condenser,
The second bypass pipe connects a third refrigerant pipe connecting the expansion valve and the load cooler and a second refrigerant pipe connecting the compressor and the heat accumulator,
2. The refrigeration apparatus according to claim 1, wherein a connection position of the first refrigerant pipe to the load cooler is lower than a connection position of the third refrigerant pipe to the load cooler. From the connection position of the first bypass pipe to the fourth refrigerant pipe, a first switching valve is provided on the compressor side,
From the connection position of the second bypass pipe to the second refrigerant pipe, a second switching valve is provided on the condenser side,
From the connection position of the first bypass pipe to the first refrigerant pipe, a third switching valve is provided on the compressor side,
The refrigeration apparatus according to claim 2, wherein a fourth switching valve is provided in the middle of the first bypass pipe. The first bypass pipe connects a first refrigerant pipe connecting the load cooler and the compressor, and a second refrigerant pipe connecting the compressor and the heat accumulator,
The second bypass pipe connects a third refrigerant pipe connecting the expansion valve and the load cooler and a fourth refrigerant pipe connecting the heat accumulator and the condenser,
2. The refrigeration apparatus according to claim 1, wherein a connection position of the first refrigerant pipe to the load cooler is an upper level than a connection position of the third refrigerant pipe to the load cooler. From the connection position of the first bypass pipe to the second refrigerant pipe, a first switching valve is provided on the compressor side,
From the connection position of the second bypass pipe to the fourth refrigerant pipe, a second switching valve is provided on the condenser side,
From the connection position of the first bypass pipe to the first refrigerant pipe, a third switching valve is provided on the compressor side,
The refrigeration apparatus according to claim 4, wherein a fourth switching valve is provided in the middle of the first bypass pipe. Furthermore, a third bypass pipe is provided for connecting the fifth refrigerant pipe connecting the liquid receiver and the expansion valve and the heat storage side of the second switching valve of the fourth refrigerant pipe,
A fifth switching valve is provided in the middle of the third bypass pipe;
The refrigerant liquid is sent from the liquid receiver to the heat accumulator through a part of the fifth refrigerant pipe, the third bypass pipe, and a part of the fourth refrigerant pipe. The refrigeration apparatus according to claim 1. Furthermore, a regenerator bypass that connects a portion of the second refrigerant pipe between the first switching valve and the compressor and a portion of the fourth refrigerant pipe between the second switching valve and the condenser. A tube is provided,
The refrigeration apparatus according to any one of claims 1 to 6, wherein a sixth switching valve is provided in the middle of the regenerator bypass pipe. The refrigeration apparatus according to claim 1, wherein the heat storage material of the heat storage device is a latent heat storage material. Prior to defrosting, the amount of refrigerant necessary for defrosting the load cooler from the receiver is set to the third amount.
The refrigeration apparatus according to claim 6, which is naturally supplied via a bypass pipe. Between the liquid receiver of the fifth refrigerant pipe and a branch portion with the third bypass pipe, or a third
The pump is provided in the middle of the bypass pipe, thereby forcibly supplying the refrigerant amount necessary for defrosting the load cooler from the receiver via the third bypass pipe before defrosting. Refrigeration equipment.

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