JP6643753B2 - Heat transport system and heat transport method - Google Patents

Description

  The present invention relates to a heat transport system and a heat transport method, and more particularly, when performing an intermittent operation of repeating the operation and stop of the heat transport system by a loop-type thermosiphon system, while improving the startup characteristics immediately after the start of operation, The present invention relates to a heat transport system and a heat transport method capable of achieving high efficiency of a loop-type thermosiphon system.

Conventionally, a heat transport system that circulates a heat medium by a loop-type thermosiphon system between an evaporator that evaporates a heat medium liquid and a condenser that is installed at a level higher than the evaporator and condenses a heat medium gas. Has been adopted.
Examples of such a heat transport system include a heating medium gas pipe for sending a heating medium gas from an evaporator to a condenser, and a heating medium liquid pipe for sending a heating medium liquid from a condenser to an evaporator. The liquid pipe is provided with a heat medium receiver.
According to the heat transport system having the above configuration, during normal operation, the heat medium liquid is evaporated in the evaporator, the heat medium gas is sent to the condenser by the heat medium gas pipe, and the heat medium gas is condensed in the condenser. Then, for example, hot water is taken out by heat exchange with a heat medium gas, the heat medium liquid is sent to the evaporator through the heat medium liquid receiver by the heat medium liquid pipe, and, as described above, the heat medium is installed at a level higher than the evaporator By circulating the heat medium between the condenser and the condenser by a loop-type thermosiphon method, heat can be transported.

  On the other hand, a cooling system in which a load cooling device, a compressor, a heat storage device, a condenser, a liquid receiver, and an expansion valve are sequentially connected in this order by a refrigerant pipe, and a cooling circuit through which a cooling refrigerant flows, cools the load cooling device. In order to perform defrosting (defrosting) of the cooled load cooler, from the viewpoint of energy saving, a loop-type thermosiphon is used as a refrigerating device or an air conditioner that performs defrosting by using exhaust heat during cooling operation. For example, Patent Document 1 discloses a technique for performing defrost by natural circulation according to the present invention.

In this refrigerating apparatus, a load cooler, a compressor, a regenerator, a condenser, a liquid receiver, and an expansion valve are sequentially connected in this order by a refrigerant pipe, and a refrigerating apparatus that forms a cooling circuit in which a cooling refrigerant flows therein, Further, a defrost circuit that circulates between the load cooler and the heat storage device is provided.The defrost circuit has a heat absorbing portion that receives a heat medium for defrost flowing therein and absorbs heat from the heat storage agent in the heat storage device, and a load cooler. In the heat storage, the cooling circuit has a heat radiating part that radiates heat to the heat storage agent, and a cooling part that cools the load fluid in the load cooler. Is installed at a level lower than the load cooler, from the regenerator to the load cooler, the defrost heat medium heated by the heat absorbing portion flows through the defrost forward path, and from the load cooler to the regenerator. , Are provided with the backward defrosting flows defrosting heat medium cooled by the defrost unit.

According to the refrigerating apparatus having such a configuration, during the cooling operation, the refrigerant gas evaporated by cooling the load cooler is compressed by the compressor and radiates heat in the heat accumulator. Alternatively, the refrigerant liquid is condensed or supercooled by the condenser, the refrigerant liquid is received by the receiver, and the cooling liquid is cooled by forming 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 regenerator during the cooling operation of the load cooler, the heat medium gas for defrost is sent from the regenerator to the load cooler, while the load cooling is performed. By returning the defrosting heat transfer fluid resulting from the defrosting of the load cooler from the heat sink to the heat accumulator, a natural heat is generated between the hot heat accumulator located below and the cold load cooler located above. By configuring a loop-type thermosiphon by circulation, defrosting can be performed while the compressor is stopped, so that defrosting can be performed while achieving energy saving.

However, in such a refrigeration system, the following technical problems are caused due to the occurrence of a single-tube thermosiphon phenomenon during operation.
Here, the single-tube thermosiphon phenomenon is a phenomenon in which natural circulation is caused by a heat transport method by a phase change between a high-temperature portion located below and a low-temperature portion located above.

In this case, it is possible to switch between the refrigeration operation and the defrost operation by a single switching valve installed in the defrost forward pipe that sends the defrost heat medium gas from the regenerator to the load cooler, but it is possible to switch the defrost return path. When a check valve that allows only the flow from the load cooler to the regenerator is provided at a level lower than the liquid level of the defrosting heat medium in the defrosting return path when the refrigerating device is stopped, a single-tube thermosiphon A phenomenon may occur.
More specifically, on the return path for defrost in which the defrost heat medium cooled by the defrost section flows from the load cooler toward the regenerator, a check valve for preventing the flow of refrigerant from the regenerator to the load cooler is provided. It is provided outside the freezer, but it is unknown at what level the check valve is installed with respect to the liquid level of the defrost heat medium in the defrost return path when the refrigerating device is stopped, If the check valve is installed at a level lower than the liquid level of the defrosting heat medium in the defrosting return path when the refrigeration system is stopped, outside the freezer, more precisely, the freezing chamber wall of the defrosting return path and the liquid In the portion between the surface and the surface, the defrost heat medium evaporates by being heated, evaporates, is cooled and condensed in the freezer, and a useless heat load is input to the load cooler side, and the load cooler is cooled. Increased heat load caused , Reduced efficiency of the freezing operation occurs.
If such a check valve is not installed, the heat medium gas flows back from the regenerator to the load cooler, so that a useless heat load is input to the load cooler side and the heat medium liquid flows from the load cooler. Returning to the heat accumulator causes a temperature drop on the heat accumulator side, which increases the heat load on the load cooler and prolongs the defrost time.

Regarding the prolongation of the defrost time, the saturation temperature of the heat medium for defrost has been reduced before the start of the defrost operation due to the temperature drop on the regenerator side. Transformation occurs.

Regarding the above technical problems, there is a difference between such a refrigeration apparatus and the heat transport system that the former constitutes a loop-type thermosiphon in defrost operation and the latter constitutes a loop-type thermosiphon in normal operation. The high-temperature side evaporator is installed at a low level, and the low-temperature side condenser is installed at a high level. Both of them constitute a circulation circuit with a heating medium liquid pipe and a heating medium gas pipe, and a loop is formed by circulation of the heating medium. Since they are common in terms of configuring a thermosyphon, this is a common problem similarly caused in the heat transport system.
JP 2014-231921 A

  In view of the above technical problems, an object of the present invention is to improve the start-up characteristics immediately after the start of operation and improve the loop thermosyphon when performing intermittent operation in which the operation and stop of the heat transport system by the loop thermosiphon system are repeated. An object of the present invention is to provide a heat transport system and a heat transport method capable of achieving high efficiency of a siphon system.

In order to achieve the above object, a heat transport system of the present invention includes:
In a heat transport system that circulates a heat medium by a loop-type thermosiphon method, between an evaporator that evaporates a heat medium liquid and a condenser that is installed at a level higher than the evaporator and condenses a heat medium gas,
A heat medium gas pipe that sends a heat medium gas from the evaporator to the condenser, and a heat medium liquid pipe that sends a heat medium liquid from the condenser to the evaporator,
The heat medium liquid pipe is provided with a heat medium liquid receiver,
A first on-off valve is provided between the condenser and the heat medium receiver in the heat medium liquid pipe,
Further, a bypass pipe communicating between the evaporator and the condenser of the heat medium gas pipe and between the first opening / closing valve of the heat medium liquid pipe and the heat medium receiver is provided. ,
A second on-off valve and a third on-off valve are provided on the inlet side of the condenser of the heat medium gas pipe and the bypass pipe, respectively.
When operating the system, the first on-off valve and the second on-off valve are opened and the third on-off valve is closed, and when the system is stopped, the first on-off valve and the second on-off valve are closed, The third on-off valve is opened.

According to the heat transport system having the above configuration, during the normal operation of the system, the first on-off valve provided between the condenser of the heat medium liquid pipe and the heat medium receiver, and the heat medium gas pipe A second opening / closing valve provided on the inlet side of the condenser is opened, and a third opening / closing valve provided on a bypass pipe communicating between the evaporator and the condenser and between the condenser and the heat medium receiver. By closing the valve, the heat medium liquid is evaporated in the evaporator, the heat medium gas is sent to the condenser by the heat medium gas pipe, and the heat medium gas is condensed in the condenser, for example, by heat exchange with the heat medium gas. Take out the hot water, send the heat transfer fluid to the evaporator via the heat transfer fluid receiver by the heat transfer fluid pipe, and the loop thermosiphon between the condenser and the condenser installed above the evaporator. By circulating the heat medium according to the method, heat can be transported.
On the other hand, when the system is stopped, the temperature of the heat medium receiver is higher in the heat medium liquid pipe than the temperature of the heat medium receiver in the refrigerator where the condenser is installed. The single-tube thermosiphon phenomenon in which the heat medium in the medium receiver evaporates and turns into gas, flows through the heat medium liquid pipe toward the condenser, is cooled in the refrigerator, becomes a heat medium liquid, and returns to the liquid receiver. In the heat medium gas pipe, the heat medium liquid cooled in the condenser flows through the heat medium gas pipe toward the evaporator, evaporates in the evaporator to become a gas, and the heat medium gas pipe flows toward the condenser. When the single pipe thermosiphon phenomenon occurs, the first open / close valve and the second open / close valve are closed, and the third open / close valve is opened. When the liquid flows back to the condenser or the heating medium gas flows back to the evaporator, The heat medium gas from the evaporator flows into the heat medium receiver by bypassing the condenser without passing through the bypass pipe without causing a single-tube thermosiphon phenomenon. When the intermittent operation of repeating the operation and stop of the heat transport system by the loop thermosiphon method is started because the heat medium liquid is heated and the decrease in the saturation temperature of the heat medium in the evaporator is suppressed, the operation starts. Immediate rise characteristics can be improved, and high efficiency of the loop thermosiphon system can be achieved.

Further, in the evaporator, it is preferable that the heat medium liquid absorbs heat and evaporates.
Further, in the condenser, the heat medium gas may radiate heat and condense.
Still further, in the evaporator, the heat transfer medium gas may absorb heat and evaporate, while the heat transfer medium gas releases heat and condenses in the condenser.
In addition, in the evaporator, it is preferable that the heat medium liquid is evaporated by collecting external exhaust heat.
Further, in the condenser, it is preferable to supply hot water to the outside by condensing the heating medium gas.
Furthermore, it is preferable that hot water is supplied to the outside by condensing the heat medium gas in the condenser while evaporating the heat medium liquid by recovering the exhaust heat from the outside in the evaporator.
Additionally, the one-way valve may be a check valve.

In order to achieve the above object, the heat transport method of the present invention,
In a heat transport method for circulating a heat medium by a loop-type thermosiphon method, between an evaporator for evaporating a heat medium liquid and a condenser installed at a level higher than the evaporator and condensing a heat medium gas,
During normal operation, the heat medium is evaporated in the evaporator, the heat medium gas is sent to the condenser, the heat medium gas is condensed in the condenser, and the heat medium liquid is evaporated through the heat medium receiver. To transfer heat between the evaporator and the condenser installed at a level higher than the evaporator by circulating a heat medium by a loop-type thermosiphon method,
When the operation is stopped, the heat medium gas from the evaporator is bypassed to the condenser while suppressing the back flow of the heat medium from the condenser to the evaporator and / or the back flow of the heat medium from the evaporator to the condenser. Flow to the heat medium receiver.
When the system is stopped, a loop-type thermosiphon may be constituted by the heat medium gas pipe, the bypass pipe, and the heat medium liquid pipe.

In order to achieve the above object, a heat transport system of the present invention includes:
In the heat transport system that sequentially connects the load cooler, the compressor, the heat storage device, the condenser, the heat medium receiver, and the expansion valve by the refrigerant pipe in this order, and forms a cooling circuit,
The regenerator is installed below the load cooler,
Any one of the refrigerant pipes constituting the inflow section to the load cooler or the refrigerant pipe constituting the outflow section from the load cooler and an inflow section to the regenerator. A first bypass pipe connecting the refrigerant pipe, or one of the refrigerant pipes forming the outflow portion from the regenerator, to the refrigerant pipe,
The refrigerant pipe constituting the inflow portion to the load cooler, or the other refrigerant pipe with respect to the one of the refrigerant pipes constituting the outflow portion from the load cooler, and the regenerator A second bypass pipe connecting the other refrigerant pipe to the one of the refrigerant pipes of the refrigerant pipe constituting the inflow section to the refrigerant pipe or the refrigerant pipe constituting the outflow section from the regenerator, Has,
Thereby, by utilizing the heat stored during the cooling operation of the load cooler in the regenerator, the refrigerant gas is sent from the regenerator to the load cooler via the first bypass pipe, while the refrigerant gas is sent. A loop-type thermosiphon configured to return a refrigerant liquid resulting from defrosting the load cooler from the load cooler to the regenerator through the second bypass pipe;
The second bypass pipe is provided with a heat medium receiver.
A first on-off valve is provided between the load cooler of the second bypass pipe and the heat medium receiver,
Furthermore, a third bypass pipe communicating between the heat storage unit and the load cooler of the first bypass pipe and between the first on-off valve and the heat medium receiver of the second bypass pipe. Is provided,
A second on-off valve and a third on-off valve are provided on an entrance side of the load cooler of the first bypass pipe and on the third bypass pipe, respectively.
During the defrost operation, the first on-off valve and the second on-off valve are opened and the third on-off valve is closed. When the defrost operation is stopped, the first on-off valve and the second on-off valve are closed, The third on-off valve is opened.

A first embodiment of a heat transport system according to the present invention will be described below in detail with reference to the drawings.
As shown in FIG. 1, a refrigeration apparatus 10 serving as a heat transport system connects a load cooler 12, a compressor 14, a heat storage unit 16, a condenser 18, a liquid receiver 20, and an expansion valve 22 in this order by refrigerant piping. To form a cooling circuit. The regenerator 16 is installed at a lower level (level difference H) than the load cooler 12, and connects the third refrigerant pipe 28 connecting the expansion valve 22 and the load cooler 12 to the compressor 14 and the regenerator 16. A first bypass pipe 27 connecting the second refrigerant pipe 26; a first refrigerant pipe 24 connecting the load cooler 12 and the compressor 14; a fourth refrigerant pipe 30 connecting the regenerator 16 and the condenser 18; And a 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 receiver 20 are connected by a sixth refrigerant pipe 50.
Thus, by utilizing the heat stored in the regenerator 16 during the cooling operation of the load cooler 12, the refrigerant gas is sent from the regenerator 16 to the load cooler 12 via the first bypass pipe 27, while the load is A loop-type thermosiphon is configured to return the refrigerant liquid generated as a result of defrosting the load cooler 12 from the cooler 12 to the regenerator 16 via the second bypass pipe 31.

The relative installation level difference H of the regenerator 16 to the load cooler 12 and the relative position of the connection position of the first refrigerant pipe 24 to the load cooler 12 relative to the connection position of the third refrigerant pipe 28 to the load cooler 12. The installation level difference h may be determined as appropriate from the viewpoint of configuring a loop-type thermosiphon.
Further, a fifth refrigerant pipe 40 connecting the liquid receiver 20 and the expansion valve 22 and a third bypass pipe 42 connecting the fourth refrigerant pipe 30 to the regenerator 16 side of the second switching valve 34 are provided. A fifth switching valve 44 is provided in the middle of the third bypass pipe 42, and the refrigerant is transferred 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 to the refrigerant. The liquid is sent to the regenerator 16.
Further, 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.

A heat medium receiver 90 is provided in the second bypass pipe 31, and a first open / close valve 64 is provided between the load cooler 12 and the heat medium receiver 90 of the second bypass pipe 31. Further, a bypass pipe communicating between the heat storage unit 16 and the load cooler 12 of the first bypass pipe 27 and between the first opening / closing valve 64 of the second bypass pipe 31 and the heat medium receiver 90. 92 are provided.
A second on-off valve 38 and a third on-off valve 94 are provided on the inlet side of the load cooler 12 of the first bypass pipe 27 and on the bypass pipe 92, respectively.
As will be described later, at the time of the defrost operation, the first on-off valve 64 and the second on-off valve 38 are opened, the third on-off valve 94 is closed, and the first bypass pipe 27 and the second bypass pipe 31 are used to control the loop thermostat. When the defrost operation is stopped, the first on-off valve 64 and the second on-off valve 38 are closed, the third on-off valve 94 is opened, and a part of the first bypass pipe 27, the bypass pipe 92 and the second Similarly, a loop type thermosiphon is constituted by a part of the bypass pipe 31.

As described below, a switching valve is provided in each of the refrigerant pipes (the first refrigerant pipe 24, the second refrigerant pipe 26, and the fourth refrigerant pipe 30) from the viewpoint of switching between the normal operation mode and the defrost operation mode. Have been.
More specifically, a first switching valve 32 is provided on the compressor 14 side from a connection position of the first bypass pipe 27 to the second refrigerant pipe 26, and a connection of the second bypass pipe 31 to the fourth refrigerant pipe 30. A second switching valve 34 is provided on the condenser 18 side from the position, and a third switching valve 36 is provided on the compressor 14 side from a connection position of the second bypass pipe 31 to the first refrigerant pipe 24, and a first bypass is provided. A second on-off valve 38 is provided in the middle of the pipe 27.
The second refrigerant pipe 26 has a check valve 62 for preventing the flow of the refrigerant from the heat accumulator 16 to the compressor 14, and the second bypass pipe 31 has a check valve 62 for cooling the refrigerant from the heat accumulator 16 to the load cooler 12. The first on-off valve 64 for preventing the flow and the third bypass pipe 42 are provided with check valves 66 for preventing the flow of the refrigerant from the heat storage device 16 to the liquid receiver 20, respectively.
The load cooler 12 is installed in a refrigerator, for example, for cooling a refrigerator, a refrigerated warehouse, a shipping room, or the like.
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, a latent heat storage material includes paraffin, and a sensible heat storage material includes water.

As described later, in the initial stage of the defrost operation mode, the amount of refrigerant required for defrosting the load cooler 12 from the liquid receiver 20 is naturally supplied 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 receiver 20 and the expansion valve 22 is located downstream of the compressor 14 and has a relatively high pressure. In the loop-type thermosiphon configured by connecting the load cooler 12 and the regenerator 16 by the first bypass pipe 27 and the second bypass pipe 31, the high-pressure side regenerator 16 and the low-pressure side load cooling Since the communication with the vessel 12 results in a relatively intermediate pressure, the refrigerant can be naturally supplied from the receiver 20 to the load cooler 12 by this differential pressure.
As a modified example, a pump (not shown) is provided between the receiver 20 of the fifth refrigerant pipe 40 and the branch portion with the third bypass pipe 42 or in the middle of the third bypass pipe 42, whereby a defrost is provided. Prior to this, the amount of refrigerant required 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-described configuration will be described below with reference to FIGS.
Regarding the operation method of the refrigeration apparatus 10, as the operation modes, the normal operation mode 1 (heat storage stage) (FIG. 2), the normal operation mode 2 (after the end of heat storage) (FIG. 3), the defrost operation mode (initial stage) (FIG. 4) , And a 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 is opened. The compressor 14 is operated with the fifth switching valve 44 closed.
The second on-off valve 38 of the first bypass pipe 27 is closed, and the refrigerant is not bypassed by the first on-off valve 64 of the second bypass pipe 31 via the first bypass pipe 27 and the second bypass pipe 31. Like that.
The refrigerant flows from the load cooler 12 to the compressor 14 via the first refrigerant pipe 24, is compressed therein, and further flows from the compressor 14 to the regenerator 16 via the second refrigerant pipe 26, where The refrigerant dissipates heat, is stored in the heat storage unit 16, further flows from the heat storage unit 16 through the fourth refrigerant pipe 30 into the condenser 18, where it is condensed or supercooled, and further from the condenser 18 through the sixth refrigerant pipe 50. And a certain amount of refrigerant liquid is received therein. Further, the liquid refrigerant flows from the liquid receiver 20 to the expansion valve 22 through the fifth refrigerant pipe 40, where the expansion valve The degree of superheat of the refrigerant is adjusted by adjusting the opening degree of the refrigerant 22, and the refrigerant is returned from the expansion valve 22 to the load cooler 12 via the third refrigerant pipe 28 to form a cooling circuit.
As described above, the refrigerant flows as indicated by the arrow in FIG. 2 and is in a gas state between the load cooler 12 and the regenerator 16 via the compressor 14, and in particular, the load cooler 12 and the compressor 14 Is a low-pressure gas state, while a high-pressure gas state is between the compressor 14 and the regenerator 16, while a liquid or wet vapor state is between the regenerator 16 and the load cooler 12 through the expansion valve 22. It is.

Next, as shown in FIG. 3, in the normal operation mode 2 (after the end of the heat storage), the first switching valve 32, the second switching valve 34, and the third switching valve 36, as in the normal operation mode 1 (FIG. 2). Then, the compressor 14 is operated with the second on-off valve 38 and the fifth switching valve 44 closed while the expansion valve is opened.
Note that, similarly to the normal operation mode 1 (FIG. 2), the second on-off valve 38 of the first bypass pipe 27 is closed, and the first on-off valve 64 of the second bypass pipe 31 causes the first bypass pipe 27 and the second The refrigerant is prevented from bypassing through the two bypass pipes 31.
This operation mode is a normal operation mode similarly to the operation mode of FIG. 2. In FIG. 2, the heat storage is being performed. However, in the normal operation mode 2 of FIG.

More specifically, the flow path of the refrigerant gas discharged from the compressor 14 may be the same as during the heat storage in FIG.
That is, the refrigerant flows from the load cooler 12 into the compressor 14 via the first refrigerant pipe 24, is compressed therein, and further flows from the compressor 14 into the regenerator 16 via the second refrigerant pipe 26, Here, the refrigerant radiates heat, is stored in the heat storage device 16, further flows from the heat storage device 16 through the fourth refrigerant pipe 30 into the condenser 18, where it is condensed or supercooled, and further from the condenser 18 to the sixth refrigerant pipe 50. , And a certain amount of refrigerant liquid is received therein. Further, the liquid refrigerant flows from the liquid receiver 20 to the expansion valve 22 through the fifth refrigerant pipe 40, By adjusting the degree of opening of the expansion valve 22, the degree of superheat of the refrigerant is adjusted, and the refrigerant returns from the expansion valve 22 to the load cooler 12 via the third refrigerant pipe 28 to form a cooling circuit.
However, since the refrigerant gas discharged from the compressor 14 flows to the condenser 18 via the regenerator 16, a pressure loss in the regenerator 16 is inevitably generated. By opening the sixth switching valve 48 instead of closing the first switching valve 32, the refrigerant gas discharged from the compressor 14 bypasses the regenerator 16 via the regenerator bypass pipe 46.

Next, as shown in FIG. 4, in the defrost operation mode (initial stage), the compressor 14 is stopped and the second on-off valve 38 and the fifth switching valve 44 are opened, while the first switching valve 32 and the second switching valve 44 are opened. The switching valve 34, the third switching valve 36, and the expansion valve 22 are closed.
In other words, 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, the refrigerant liquid flows from the receiver 20 to the first bypass pipe 27, the second bypass pipe 31, and the third bypass pipe 42. While flowing to the regenerator 16 via the three bypass pipes 42, a loop-type thermosiphon by natural circulation is configured between the regenerator 16 and the load cooler 12.

In this case, especially in the defrost operation mode (initial stage) immediately after the freezing operation, the refrigerant in the fifth refrigerant pipe 40 between the receiver 20 and the expansion valve 22 is located downstream of the compressor 14 and is relatively low. On the other hand, in a loop-type thermosiphon configured by connecting the load cooler 12 and the regenerator 16 with the first bypass pipe 27 and the second bypass pipe 31, the high-pressure side regenerator 16 Since the communication with the load cooler 12 on the low pressure side results in a relatively intermediate pressure, the refrigerant can be naturally supplied from the receiver 20 to the load cooler 12 by this differential pressure.
At this time, in the loop-type thermosiphon, the required amount of refrigerant is an amount sufficient for the thermosiphon to circulate smoothly and to obtain a predetermined heat transport required for defrosting the load cooler 12. It depends on the capacity of the vessel 12 and the length of each of the first bypass pipe 27 and the second bypass pipe 31 which are part of the loop type thermosiphon.
At the time when the compressor 14 is stopped, if the amount of the retained refrigerant is sufficient, it is not necessary to send the liquid from the liquid receiver 20 to the heat accumulator 16 via the third bypass pipe 42, and the fifth switching valve 44 , The defrost operation only by the loop-type thermosiphon may be performed.
As described above, the refrigerant flows as indicated by the arrow in FIG. 4, and is liquid from the liquid receiver 20 to the regenerator 16 via the fifth refrigerant pipe 40 and the third bypass pipe, and from the regenerator 16 to the second refrigerant. The gas to the load cooler 12 via the pipe 26 and the first bypass pipe 27 is in a gas state, and the liquid from the load cooler 12 to the regenerator 16 via the second bypass pipe 31 is in a liquid state.

Next, as shown in FIG. 5, in the defrost operation mode (normal stage), the compressor 14 is stopped and the second on-off valve 38 is opened, while the first switching valve 32 and the second 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 absorbed) by the heat storage of the heat storage unit 16 flows from the second refrigerant pipe 26 to the load cooler 12 via the first bypass pipe 27, where the refrigerant gas is condensed (radiated). As a result, the load cooler 12 is defrosted, the defrost attached to the load cooler 12 is performed, and the refrigerant liquid returns from the second bypass pipe 31 to the regenerator 16 via the fourth refrigerant pipe 30, and this natural By repeating the circulation, a loop type thermosiphon is constructed.
Note that the oil of the compressor 14 flowing into the load cooler 12 flows out to the first refrigerant pipe 24 at a lower level than the third refrigerant pipe 28 and is sent to the bend unit 80.
When the defrosting of the load cooler 12 is completed by the defrost operation, the operation returns to the normal operation mode 1 and the heat storage may be restarted in preparation for the next defrost operation.

For example, when the intermittent operation of the defrost operation, that is, the defrost operation and the stop of the defrost operation are repeated, the operation is performed as follows.
When the defrost operation is stopped, the temperature of the heat medium receiver is higher in the second bypass pipe 31 than the temperature of the heat medium receiver and the temperature in the refrigerator where the load cooler 12 is installed. The heat medium in the heat medium receiver 90 evaporates and turns into gas, flows through the second bypass pipe 31 toward the load cooler 12, and is cooled in the refrigerator to become a heat medium liquid. In the first bypass pipe 27, the heat transfer medium cooled in the load cooler 12 flows toward the regenerator 16 in the first bypass pipe 27, and the regenerator 16 in the first bypass pipe 27 returns. When the single pipe thermosiphon phenomenon occurs which evaporates into gas and flows through the first bypass pipe 27 toward the load cooler 12, the first on-off valve 64 and the second on-off valve 38 are closed, and the third on-off valve is closed. By opening 94, the second In the heat pipe 31 and the first bypass pipe 27, the heat medium flows back to the load cooler 12 and the heat medium gas flows back to the heat accumulator 16 so that the so-called single pipe thermosiphon phenomenon does not occur. The heat medium gas from the heat accumulator 16 flows to the heat medium receiver 90 by bypassing the load cooler 12 through the heat storage medium, whereby the heat medium liquid received by the heat medium receiver 90 is heated. In addition, since the decrease in the saturation temperature of the heat medium in the heat storage unit 16 is suppressed, when performing the intermittent operation in which the operation and the stop of the heat transport system by the loop-type thermosiphon system are repeated, the rising characteristics immediately after the operation is started are improved. At the same time, it is possible to achieve high efficiency of the loop thermosiphon system.

The timing of switching 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, if the load on the load cooler 12 is relatively constant and the progress of frost is relatively regular, a timer may be set in advance and the switching may be performed automatically.
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 may be set by detecting the temperature of a heat transfer tube (not shown) of the load cooler 12 and detecting the detected temperature.
When the defrost operation is performed intermittently, during the stop of the defrost operation, the normal cooling operation may be restarted or may be stopped, and from the viewpoint of the heat storage amount in the heat storage unit 16 required for the defrost operation. When the heat storage amount is insufficient, the heat may be stored by restarting the normal cooling operation while the defrost operation is stopped.

According to the refrigeration apparatus 10 having the above-described configuration, during the cooling operation, the refrigerant gas evaporated by cooling the load cooler 12 is compressed by the compressor 14 and radiates heat in the heat accumulator 16, thereby storing heat. The refrigerant gas or the refrigerant liquid is condensed or supercooled by the condenser 18, the refrigerant liquid is received by the receiver 20, and the cooling circuit is configured to cool the load cooler 12 again through the expansion valve 22. Then, 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 utilizing the heat stored in the heat accumulator 16 during the cooling operation of the load cooler 12. While the refrigerant gas is sent from the load cooler 12 to the regenerator 16 via the second bypass pipe 31 to return the refrigerant liquid resulting from the defrost of the load cooler 12, so that the lower hot side By forming a loop-type thermosiphon by natural circulation between the regenerator 16 and the load cooler 12 on the cold side located above, defrosting with the compressor 14 stopped can be performed. Defrosting can be achieved while achieving energy saving without causing a problem of a small heat transfer limit due to the wick type or the thermosiphon type.

According to the defrosting (defrosting) method of the load cooler 12 having the above-described configuration, the load cooler 12 located at the uppermost level is cooled by the cooling circuit having the compressor 14 that compresses the refrigerant gas. In addition, during the cooling operation of the load cooler 12, the stage of storing the sensible heat or the latent heat of condensation of the refrigerant gas discharged from the compressor 14 and utilizing the stored heat to load cooler 12 by a thermosiphon method. A defrosting step, wherein the heat storage step is performed by a heat storage unit 16 installed at a level lower than the load cooler 12. In the thermosiphon system, a loop type defrosting operation is performed between the load cooler 12 and the heat storage unit 16. A circuit may be configured to include a step of bypassing the heat storage unit 16 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 FIGS. In the following description, the same components as those of the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted. The features of the present embodiment will be described in detail.
The feature of this embodiment lies in the operation for preventing the occurrence of the single-tube thermosiphon phenomenon. More specifically, as in the first embodiment, a heat transport system that circulates a heat medium by a loop-type thermosiphon system. In the first embodiment, the defrost operation is performed by the loop-type thermosiphon system to prevent the so-called single-tube thermosiphon phenomenon during the intermittent operation of the defrost operation. In the present embodiment, the operation by the loop-type thermosiphon system is the heat supply operation, which is different in that the so-called single tube thermosiphon phenomenon is prevented from occurring during the intermittent operation of the heat supply operation.
For this reason, in the first embodiment, a regenerator is used to heat the refrigeration operation refrigerant to a high temperature, and a load cooler is used to heat the refrigerant gas to a low temperature by being used for defrost. In contrast, in the present embodiment, the evaporator 16 is used for recovering external exhaust heat, and the heat medium is set to a high temperature. The condenser 12 is used to heat the external medium and supply it with hot water, so that the temperature of the heat medium is low, and a high-temperature part is formed at a low level and a low-temperature part is formed at a high level.

More specifically, as shown in FIG. 6, a loop-type thermostat is provided between an evaporator 16 for evaporating the heat medium liquid and a condenser 12 installed above the evaporator 16 and condensing the heat medium gas. In a heat transport system that circulates a heat medium by a siphon method, a heat medium gas pipe 27 that sends a heat medium gas from the evaporator 16 to the condenser 12 and a heat medium liquid pipe that sends a heat medium liquid from the condenser 12 to the evaporator 16 31.
In the evaporator 16, the heat medium liquid is evaporated by recovering the external exhaust heat, and in the condenser 12, the heat medium gas is condensed to supply hot water to the outside. I use it as.
The heat medium liquid pipe 31 is provided with a heat medium liquid receiver 90, and a first open / close valve 64 is provided between the condenser 12 and the heat medium liquid receiver 90 of the heat medium liquid pipe 31. Further, a bypass pipe 92 is provided for communicating between the evaporator 16 and the condenser 12 of the heat medium gas pipe 27 and between the first opening / closing valve 64 of the heat medium liquid pipe 31 and the heat medium receiver. A second on-off valve 38 and a third on-off valve 94 are provided on the inlet side of the condenser 12 of the heat medium gas pipe 27 and on the bypass pipe 92, respectively.
The first opening / closing valve 64 may be a check valve that allows a one-way flow from the condenser 12 to the heat medium receiver, or may be a normal electric opening / closing valve as in the first embodiment.
As shown in FIG. 7, at the time of the heat supply operation, the first opening / closing valve 64 and the second opening / closing valve 38 are opened, the third opening / closing valve 94 is closed, and the heat medium gas pipe 27 and the heat medium liquid pipe 31 form a loop. As shown in FIG. 8, when the heat supply operation is stopped, the first on-off valve 64 and the second on-off valve 38 are closed, the third on-off valve 94 is opened, and the heating medium gas pipe 27 is closed. , A bypass pipe 92 and a part of the heat medium liquid pipe 31 similarly constitute a loop-type thermosiphon.
In the evaporator 16, hot water may be supplied to the outside by condensing the heat medium gas in the condenser 12 while evaporating the heat medium liquid by collecting external exhaust heat.
As a modified example, as in the first embodiment, when the evaporator 16 is a heat storage device, the heat medium gas is condensed in the condenser 12 to supply hot water to the outside. On the other hand, when the external supply of hot water is stopped, the heat may be stored by recovering the external exhaust heat using a heat storage device.

According to the heat transport system having the above configuration, during normal operation of the system, the first on-off valve 64 provided between the condenser 12 of the heat medium liquid pipe 31 and the heat medium receiver 90, and The second opening / closing valve 38 provided on the inlet side of the condenser 12 of the heat medium gas pipe 27 is opened, and between the evaporator 16 and the condenser 12 and between the condenser 12 and the heat medium receiver 90. By closing the third opening / closing valve 94 provided in the bypass pipe 92 which connects the heating medium, the heat medium liquid is evaporated in the evaporator 16, the heat medium gas is sent to the condenser 12 by the heat medium gas pipe 27, and the heat medium gas is sent to the condenser 12. The heat medium gas is condensed, for example, hot water is taken out by heat exchange with the heat medium gas, and the heat medium liquid is sent to the evaporator 12 through the heat medium liquid pipe 90 through the heat medium liquid pipe 31. Between the condenser 12 installed above the evaporator 16 and the condenser 12 By circulating a heating medium through flop type thermosiphon system, it is possible to heat transport.

On the other hand, when the system is stopped, in the heat medium liquid pipe 31, the heat medium liquid receiver temperature is higher than the heat medium liquid receiver temperature and the temperature at which the condenser 12 is installed. A single pipe in which the heat medium in the medium receiver 90 evaporates and turns into gas, flows through the heat medium liquid pipe 31 toward the condenser 12, is cooled in the refrigerator, becomes a heat medium liquid, and returns to the liquid receiver 90. A thermosiphon phenomenon occurs, or in the heat medium gas pipe 27, the heat medium liquid cooled in the condenser 12 flows through the heat medium gas pipe 27 toward the evaporator 16, and evaporates into a gas in the evaporator 16. When a single pipe thermosiphon phenomenon flowing through the heat medium gas pipe 27 toward the condenser 12 occurs, the first on-off valve 64 and the second on-off valve 38 are closed, and the third on-off valve 94 is opened. The heat medium liquid pipe 31 and the heat medium gas pipe 27 When the liquid flows back to the condenser 12 or the heat medium gas flows back to the evaporator 16, the heat medium gas from the evaporator 16 is condensed via the bypass pipe 92 without causing a so-called single tube thermosiphon phenomenon. The heat medium received by the heat medium receiver 90 is heated by flowing to the heat medium receiver 90 by bypassing the heater 12, and the decrease in the saturation temperature of the heat medium in the evaporator 16 is suppressed. Therefore, in the case of intermittent operation in which the operation and stop of the heat transfer system by the loop thermosiphon system are repeated, the startup characteristics immediately after the start of operation can be improved and the efficiency of the loop thermosiphon system can be improved. is there.

As a heat transport method using the heat transport system having the above configuration, an evaporator 16 that evaporates a heat medium liquid and a condenser 12 that is installed at a level higher than the evaporator 16 and condenses a heat medium gas are used. In a heat transport method in which a heat medium is circulated by a loop-type thermosiphon method, during a normal operation, a heat medium liquid is evaporated in an evaporator 16, a heat medium gas is sent to a condenser 12, and the heat medium is By condensing the gas and sending the heat transfer fluid to the evaporator 16 via the heat transfer medium receiver 90, a loop is formed between the evaporator 16 and the condenser 12 installed above the evaporator 16. By circulating the heat medium by a thermosyphon system, heat is transported, and when the operation is stopped, the heat medium flows back from the condenser 12 to the evaporator 16 and / or the heat medium evaporator 16 changes from the condenser 12 The backflow to One, is intended to flow the heating medium gas from the evaporator 16 to the condenser 12 by bypassing the heat medium for the liquid receiver 90.

Although the embodiments of the present invention have been described in detail above, 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, the connection of the first bypass pipe 27 to the regenerator 16 is performed on the second refrigerant pipe 26 side, while the connection of the second bypass pipe 31 on the regenerator 16 side is performed on the fourth refrigerant pipe 30. Although described as the side, the connection is not limited thereto, as the connection of the first bypass pipe 27 to the regenerator 16 side, the connection of the fourth refrigerant pipe 30 to the side, while the connection of the second bypass pipe 31 to the regenerator 16 side, The second refrigerant pipe 26 may be provided.
For example, in the present embodiment, the heat storage device 16 has been described. However, the heat storage device is not limited thereto, and may be a heat storage tank as long as heat can be stored from a refrigerant.
For example, in the present embodiment, in order to eliminate the pressure loss in the heat storage tank, the sixth switching valve 48 is opened instead of closing the first switching valve 32 at the end stage of the heat storage in the normal operation (FIG. 3). However, the present invention is not limited to this, and the heat storage device bypass pipe 46 may be omitted if the pressure loss in the heat storage device 16 is not high.

For example, in the present embodiment, the description has been given of the case where the required amount of refrigerant is supplied to the loop type thermosiphon in the initial stage of the defrost operation (FIG. 4). However, the present invention is not limited to this. Such operation is unnecessary when the amount of the retained refrigerant is sufficient, and the third bypass pipe 42 itself may be omitted in some cases.

FIG. 1 is a configuration diagram of a heat transport system 10 according to a first embodiment of the present invention. FIG. 2 is a view similar to FIG. 1 illustrating a normal cooling operation during heat storage in the heat transport system 10 according to the first embodiment of the present invention. FIG. 2 is a view similar to FIG. 1 showing a normal cooling operation after the end of heat storage in the heat transport system 10 according to the first embodiment of the present invention. FIG. 2 is a view similar to FIG. 1 showing an initial defrost operation in the heat transport system 10 according to the first embodiment of the present invention. FIG. 2 is a view similar to FIG. 1 illustrating a normal defrost operation in the heat transport system 10 according to the first embodiment of the present invention. It is a lineblock diagram of a heat transportation system concerning a 2nd embodiment of the present invention. It is a figure similar to FIG. 6 which shows the normal heat supply operation in the heat transport system which concerns on 2nd Embodiment of this invention. It is a figure like FIG. 6 which shows the stop state of the heat supply operation | movement in the heat transport system which concerns on 2nd Embodiment of this invention.

h Level difference H Level difference 10 Refrigeration system 12 Load cooler 14 Compressor 16 Heat storage device 18 Condenser 20 Liquid receiver 22 Expansion valve 24 First refrigerant pipe 26 Second refrigerant pipe 28 Third refrigerant pipe 30 Fourth refrigerant pipe 27 1 bypass pipe 31 2nd bypass pipe 32 1st switching valve 34 2nd switching valve 36 3rd switching valve 38 2nd on-off valve 40 5th refrigerant pipe 42 3rd bypass pipe 44 5th switching valve 46 regenerator bypass pipe 48th 6 switching valve 50 6th refrigerant pipe 62 Check valve 64 1st on-off valve 66 Check valve 80 Bend section 90 Heat medium receiver 92 Bypass pipe 94 3rd on-off valve

Claims (10)

Heat that circulates the heat medium by a loop-type thermosiphon system between an evaporator that evaporates the heat medium liquid by external heat recovery and a condenser that is installed above the evaporator and condenses the heat medium gas. In the transportation system,
A heat medium gas pipe that sends a heat medium gas from the evaporator to the condenser, and a heat medium liquid pipe that sends a heat medium liquid from the condenser to the evaporator,
The heat medium liquid pipe is provided with a heat medium receiver.
A first on-off valve is provided between the condenser and the heat medium receiver of the heat medium liquid pipe,
Further, a bypass pipe communicating between the evaporator and the condenser of the heat medium gas pipe and between the first opening / closing valve of the heat medium liquid pipe and the heat medium receiver is provided. ,
A second on-off valve and a third on-off valve are provided on the inlet side of the condenser of the heat medium gas pipe and on the bypass pipe, respectively.
When operating the system, the first on-off valve and the second on-off valve are opened and the third on-off valve is closed, and when the system is stopped, the first on-off valve and the second on-off valve are closed, The heat transport system, wherein the third on-off valve is opened. The heat transport system according to claim 1, wherein the heat medium liquid absorbs heat and evaporates in the evaporator. The heat transport system according to claim 1, wherein the heat medium gas releases heat and condenses in the condenser. The heat transport system according to claim 1, wherein, in the evaporator, the heat medium liquid absorbs heat and evaporates, while the heat medium gas radiates heat and condenses in the condenser. The heat transport system according to claim 2, wherein the heat medium liquid is evaporated by recovering external exhaust heat in the evaporator. The hot water is supplied to the outside by condensing a heat carrier gas in the condenser.
A heat transport system according to claim 1. The hot water is supplied to the outside by condensing a heat medium gas in the condenser while evaporating a heat medium liquid by recovering external exhaust heat in the evaporator. Heat transport system. The heat transport system according to claim 1, wherein the first on-off valve is a check valve that allows a one-way flow from the condenser to the heat medium receiver. The heat transport system according to claim 1, wherein when the system is stopped, a loop-type thermosiphon is configured by the heat medium gas pipe, the bypass pipe, and the heat medium liquid pipe. Heat that circulates the heat medium by a loop-type thermosiphon system between an evaporator that evaporates the heat medium liquid by external heat recovery and a condenser that is installed above the evaporator and condenses the heat medium gas. In the transportation method,
During normal operation, the heat medium is evaporated in the evaporator, the heat medium gas is sent to the condenser, the heat medium gas is condensed in the condenser, and the heat medium liquid is evaporated through the heat medium receiver. To transfer heat between the evaporator and the condenser installed at a level higher than the evaporator by circulating a heat medium by a loop-type thermosiphon method,
When the operation is stopped, the heat medium gas from the evaporator is bypassed to the condenser while suppressing the back flow of the heat medium from the condenser to the evaporator and / or the back flow of the heat medium from the evaporator to the condenser. Flow to the heat medium receiver,
A heat transport method characterized by the above-mentioned.

Images