JP7768751B2 - Heat storage device and heat exchange method - Google Patents

Description

This disclosure relates to a heat storage device and a heat exchange method.

Heat storage devices that use latent heat storage materials are known.

For example, Patent Document 1 describes a heat storage device in which a number of containers filled with latent heat storage material are arranged inside a heat storage tank. This heat storage device exchanges heat between the fluid flowing inside the heat storage tank and the latent heat storage material. Latent heat storage materials with different melting points are enclosed inside the containers. These containers are arranged in the direction of fluid flow inside the heat storage tank based on the melting points of the latent heat storage materials.

Japanese Unexamined Patent Publication No. 58-33097

The present disclosure provides a heat storage device that is advantageous in that it completes the solidification or melting of the cold storage material within a specified time.

The heat storage device in the present disclosure includes:
a heat storage tank for storing a heat transfer liquid;
a supply port disposed inside the heat storage tank and configured to introduce the heat transfer liquid into the heat storage tank;
a recovery port disposed inside the heat storage tank and directing the heat transfer liquid toward the outside of the heat storage tank;
a plurality of cold storage units including a first cold storage unit and a second cold storage unit, the cold storage unit being disposed between the supply port and the recovery port inside the heat storage tank;
the plurality of cold storage units pass the heat transfer liquid horizontally from the supply port toward the recovery port;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
a value obtained by dividing the sum of the volumes occupied by the plurality of second containers in the second cold storage unit by the sum of the surface areas of the plurality of second containers is smaller than a value obtained by dividing the sum of the volumes occupied by the plurality of first containers in the first cold storage unit by the sum of the surface areas of the plurality of first containers;
The second cold storage unit is arranged in the downstream area of the flow of the heat transfer liquid in the multiple cold storage units, at the upper ends of the multiple cold storage units in the vertical direction, at the lower ends of the multiple cold storage units in the vertical direction, or at both the upper ends and the lower ends.

In the heat storage device disclosed herein, even if the temperature of the heat transfer liquid introduced to the upper end of the downstream area is high when storing cold energy in multiple cold storage units, the amount of heat exchanged between the second cold storage material and the heat transfer liquid within a specified time period is likely to be large. In addition, even if the temperature of the heat transfer liquid introduced to the lower end of the downstream area is low when releasing cold energy from multiple cold storage units, the amount of heat exchanged between the second cold storage material and the heat transfer liquid within a specified time period is likely to be large. Therefore, the heat storage device disclosed herein is advantageous from the perspective of completing the solidification or melting of the cold storage material within a specified time period.

1 is a diagram showing the configuration of a heat storage device according to a first embodiment of the present invention; FIG. 2 is a perspective view showing an internal structure of a first cold storage unit in the heat storage device shown in FIG. 1 ; FIG. 2 is a perspective view showing a first container in the heat storage device shown in FIG. 1 ; FIG. 2 is a perspective view showing the internal structure of a second cold storage unit in the heat storage device shown in FIG. 1 ; FIG. 2 is a perspective view showing a second container in the heat storage device shown in FIG. 1 . Configuration diagram of a heat storage device in embodiment 2 FIG. 5 is a perspective view showing the internal structure of a second cold storage unit in the heat storage device shown in FIG. FIG. 5 is a perspective view showing a second container in the heat storage device shown in FIG. Graph showing the relationship between the temperature of the heat transfer liquid in the heat storage device and the melting point of the cold storage material in the second embodiment. Configuration diagram of a heat storage device in embodiment 3 FIG. 8 is a perspective view showing the internal structure of a second cold storage unit in the heat storage device shown in FIG. FIG. 8 is a perspective view showing a second container in the heat storage device shown in FIG. Graph showing the relationship between the temperature of the heat transfer liquid in the heat storage device and the melting point of the cold storage material in the third embodiment. Configuration diagram of a heat storage device in embodiment 4 FIG. 11 is a perspective view showing the internal structure of a first cold storage unit in the heat storage device shown in FIG. 10 . FIG. 11 is a perspective view showing a first container in the heat storage device shown in FIG. 10 . FIG. 11 is a perspective view showing the internal structure of a second cold storage unit in the heat storage device shown in FIG. 10 . FIG. 11 is a perspective view showing a second container in the heat storage device shown in FIG. 10 .

(Findings that form the basis of this disclosure)
At the time when the present inventors conceived the present disclosure, there was a technology in which a number of containers filled with latent heat storage materials were arranged in the direction of fluid flow inside a heat storage tank based on the melting points of the latent heat storage materials, as described in Patent Document 1. This technology makes it possible to obtain heat from the heat storage material or store heat in the heat storage material in a short period of time.

However, a new problem has been discovered: when multiple cold storage units are installed vertically and heat transfer liquid passes horizontally through the multiple cold storage units, the time required for complete solidification or melting of the cold storage material tends to be long. When solidifying the cold storage material, the heat transfer liquid, whose temperature has increased due to heat exchange with the cold storage material in the upstream and midstream regions of the heat storage liquid flow in the multiple cold storage units, tends to be directed to the upper vertical end in the downstream region. This tends to result in a long time required for complete solidification of the cold storage material at this upper end. When melting the cold storage material, the heat transfer liquid, whose temperature has decreased due to heat exchange with the cold storage material in the upstream and midstream regions of the heat storage liquid flow in the multiple cold storage units, tends to be directed to the lower vertical end in the downstream region. This tends to result in a long time required for complete melting of the cold storage material at this lower end. The inventors have newly discovered this problem and have come to form the subject of the present disclosure in order to solve it.

The present disclosure therefore provides a heat storage device that is advantageous from the perspective of completing the solidification or melting of the cold storage material within a specified time.

Embodiments will be described in detail below with reference to the drawings. However, more detailed explanations than necessary may be omitted. For example, detailed explanations of well-known matters or duplicate explanations of substantially identical configurations may be omitted. This is to avoid making the following explanation unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the accompanying drawings and the following explanation are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS. 1, 2A, 2B, 3A, and 3B.

[1-1. Configuration]
As shown in FIG. 1 , the heat storage device 1a includes a heat storage tank 10, a supply port 21, a recovery port 22, and a plurality of cold storage units 30. The heat storage tank 10 stores a heat transfer liquid 5. The supply port 21 is disposed inside the heat storage tank 10. The heat transfer liquid 5 is introduced into the heat storage tank 10 through the supply port 21. The recovery port 22 is disposed inside the heat storage tank 10. The heat transfer liquid 5 is introduced toward the outside of the heat storage tank 10 through the recovery port 22. The plurality of cold storage units 30 are disposed between the supply port 21 and the recovery port 22 inside the heat storage tank 10. The plurality of cold storage units 30 form a unit group 35. As shown in FIG. 1 , the plurality of cold storage units 30 include a first cold storage unit 30a and a second cold storage unit 30b. The plurality of cold storage units 30 pass the heat transfer liquid 5 horizontally from the supply port 21 toward the recovery port 22. In the heat storage tank 10, the plurality of cold storage units 30 are immersed in a heat transfer liquid 5 stored in the heat storage tank 10. The heat transfer liquid 5 is not limited to a specific liquid. For example, the heat transfer liquid 5 is water. The melting point of the heat transfer liquid 5 is not limited to a specific value. For example, the melting point of the heat transfer liquid 5 is 0°C.

As shown in FIG. 1, the heat storage device 1a includes, for example, a cooling device 50, a pump 61, an intake port 71, an exhaust port 72, a pump 81, and an object to be cooled 90.

As shown in FIG. 2A, the first cold storage unit 30a includes a plurality of first containers 31a. The first containers 31a contain a first cold storage material that changes phase between liquid and solid to store and release cold energy. In the first cold storage unit 30a, the plurality of first containers 31a are arranged parallel to one another. The plurality of first containers 31a are arranged, for example, along a direction intersecting the horizontal direction.

The shape of the first container 31a is not limited to a specific shape. As shown in FIG. 2B, the first container 31a is, for example, flat. The first container 31a may have an uneven surface, for example. In this case, the main surfaces of the multiple first containers 31a face in a direction intersecting the horizontal direction related to the passage of the heat transfer liquid 5. The main surfaces of the first containers 31a may extend along the vertical direction or the horizontal direction.

As shown in FIG. 2A, the first cold storage unit 30a includes, for example, a box 31b and a pair of lids 31c. The box 31b is cylindrical and open at both vertical ends. The openings at both vertical ends of the box 31b are covered by a pair of lids 31c. Multiple first containers 31a are arranged at predetermined intervals inside the box 31b. This forms a flow path for the heat transfer liquid 5 inside the box 31b. In addition, the box 31b has openings formed on a pair of side surfaces arranged in the horizontal direction. Therefore, the heat transfer liquid 5 can pass through the first cold storage unit 30a along the horizontal direction, and heat exchange occurs between the heat transfer liquid 5 and the first cold storage material. Openings may be formed on other side surfaces of the box 31b, or on at least one of the pair of lids 31c.

As shown in FIG. 3A, the second cold storage unit 30b includes multiple second containers 32a. The second containers 32a contain a second cold storage material that changes phase between liquid and solid to store and release cold energy. In the second cold storage unit 30b, the multiple second containers 32a are arranged parallel to one another. The multiple second containers 32a are arranged, for example, along a direction intersecting the horizontal direction.

The shape of the second container 32a is not limited to a specific shape. As shown in FIG. 3B, the second container 32a is, for example, flat. The second container 32a may have an uneven surface, for example.

The second cold storage unit 30b includes, for example, a box 31b and a pair of lids 31c. The box 31b and the pair of lids 31c of the second cold storage unit 30b are configured, for example, in the same manner as the box 31b and the pair of lids 31c of the first cold storage unit 30a. Multiple second containers 32a are arranged at predetermined intervals inside the box 31b. This forms a flow path for the heat transfer liquid 5 inside the box 31b. The heat transfer liquid 5 can pass through the second cold storage unit 30b in the horizontal direction, and heat exchange occurs between the heat transfer liquid 5 and the second cold storage material.

In the heat storage device 1a, the value V2 in the second cold storage unit 30b is smaller than the value V1 in the first cold storage unit 30a. The value V2 is the sum C2 of the volumes occupied by the multiple second containers 32a in the second cold storage unit 30b divided by the sum of the surface areas of the multiple second containers 32a. The value V1 is the sum C1 of the volumes occupied by the multiple first containers 31a in the first cold storage unit 30a divided by the sum of the surface areas of the multiple first containers 31a.

The ratio V2/V1 of value V2 to value V1 is not limited to a specific value. V2/V1 is, for example, 0.5 or greater and 0.8 or less. This value can be adjusted appropriately depending on the number of cold storage units 30, the temperature of the heat transfer liquid 5 discharged from the supply port 21 during cold storage operation or cold release operation, the time allowed for cold storage operation or cold release operation, the shape of the container, etc.

In the heat storage device 1a, the average thickness of the second container 32a is, for example, smaller than the average thickness of the first container 31a. The average thickness of the first container 31a and the second container 32a can be determined, for example, by dividing the volume of the first container 31a or the second container 32a by the area of the first container 31a or the second container 32a when viewed in plan along the thickness direction.

In the heat storage device 1a, the ratio C2/C1 of the sum C2 to the sum C1 is not limited to a specific value. C2/C1 is, for example, 0.5 or greater, and may be 0.6 or greater, 0.7 or greater, 0.8 or greater, 0.9 or greater, or 1. C2/C1 is, for example, 2 or less, 1.8 or less, 1.5 or less, or 1.2 or less.

As shown in FIG. 1, the second cold storage units 30b are arranged, for example, in the downstream region 35d of the flow of the heat transfer liquid 5 in the cold storage units 30, at the upper end 35p and lower end 35q of the multiple cold storage units 30 in the vertical direction.

For example, a first cold storage unit 30a is arranged in a location other than the upper end 35p and lower end 35q of the multiple cold storage units 30.

As shown in FIG. 1, the upper end 35p and the lower end 35q are spaced apart in the vertical direction. The first cold storage unit 30a is disposed, for example, in the downstream region 35d, between the upper end 35p and the lower end 35q in the vertical direction.

The first and second cold accumulator materials are not limited to specific cold accumulator materials. Each of the first and second cold accumulator materials includes, for example, a substance capable of forming a clathrate hydrate. The compositions of the first and second cold accumulator materials may be the same or different. The melting points of the first and second cold accumulator materials are not limited to specific values. The melting points of the first and second cold accumulator materials are, for example, 7°C.

The material of the first container 31a and the second container 32a is not limited to a specific material. The material of the first container 31a and the second container 32a is, for example, a resin material such as polyethylene or polypropylene.

As shown in FIG. 1, the heat storage device 1a has a first circulation path 25 that circulates the heat transfer liquid 5 between the heat storage tank 10 and the cooling device 50. A pump 61 is disposed in the first circulation path 25. When the pump 61 is operated, the heat transfer liquid 5 stored in the heat storage tank 10 is taken in through the recovery port 22 and guided to the cooling device 50 through the inlet 52 of the cooling device 50. The heat transfer liquid 5 then passes through the outlet 53 and supply port 21 of the cooling device 50 and is supplied to the inside of the heat storage tank 10.

The heat storage device 1a is equipped with a second circulation path 75 that circulates the heat transfer liquid 5 between the heat storage tank 10 and the object to be cooled 90. A pump 81 is disposed in the second circulation path 75. The suction port 71 and discharge port 72 are disposed inside the heat storage tank 10. The suction port 71 is disposed at a lower position than the discharge port 72. When the pump 81 is operated, the heat transfer liquid 5 stored in the heat storage tank 10 is taken in through the suction port 71 and directed to the object to be cooled 90. The heat transfer liquid 5 then passes through the object to be cooled 90 and is returned to the inside of the heat storage tank 10 through the discharge port 72.

The temperature of the object to be cooled 90 is adjusted to approach a predetermined target temperature. The target temperature is not limited to a specific value. The target temperature is, for example, higher than the melting points of the first and second regenerator materials. The target temperature is, for example, 12°C. The object to be cooled 90 may be, for example, a device that needs to be adjusted to a target temperature in a predetermined manufacturing process.

[1-2. Operation]
An example of the operation of the heat storage device 1a configured as described above will be described below. First, the operation of the heat storage device 1a when a cold storage operation for storing cold energy in the plurality of cold storage units 30 and a cooling operation for the object to be cooled 90 are simultaneously performed will be described.

By operating the pump 61, the heat transfer liquid 5 stored in the heat storage tank 10 is taken in through the recovery port 22 and passes through the cooling device 50. As a result, in the cooling device 50, the heat transfer liquid 5 is cooled to a temperature higher than its melting point but lower than the melting point of the first cold storage material. The heat transfer liquid 5 is then discharged through the supply port 21 and supplied to the heat storage tank 10. The heat transfer liquid 5 supplied to the heat storage tank 10 passes horizontally through the multiple cold storage units 30 inside the heat storage tank 10 toward the recovery port 22. The heat transfer liquid 5 is first guided to the first cold storage unit 30a, which is closest to the supply port 21 in the horizontal direction among the multiple cold storage units 30. The heat transfer liquid 5 passes through an opening formed in one of the pair of side surfaces of the box 31b of this first cold storage unit 30a, enters the box 31b, and flows through the gaps between the multiple first containers 31a arranged inside the box 31b. The heat transfer liquid 5 then passes through an opening formed in the other of the pair of side surfaces of the box 31b and is guided to another first cold storage unit 30a located downstream. This causes heat exchange between the heat transfer liquid 5 and the first cold storage material. As a result, the temperature of the cold storage material in each cold storage unit 30, starting from the cold storage unit 30 located in the upstream region of the flow of the heat transfer liquid 5 in the multiple cold storage units 30, drops to a temperature below the melting point of the cold storage material. This causes the cold storage material in the multiple cold storage units 30 to change phase from liquid to solid, storing cold energy. The heat transfer liquid 5 exchanges heat with the cold storage material, such as the first cold storage material, in the upstream and midstream regions of the flow of the heat transfer liquid 5 in the multiple cold storage units 30. This causes the heat of solidification generated by the solidification of the cold storage material, and the temperature of the heat transfer liquid 5 rises. As a result, in the downstream region 35d, a predetermined temperature distribution occurs in the heat transfer liquid 5 in the vertical direction, and the temperature of the heat transfer liquid 5 introduced to the upper end 35p of the downstream region 35d tends to be higher than the temperature of the heat transfer liquid 5 introduced to other parts of the downstream region 35d.

By operating the pump 81, the heat transfer liquid 5 stored in the heat storage tank 10 is drawn in through the suction port 71 and supplied to the object to be cooled 90. As the heat transfer liquid 5 cools the object to be cooled 90, the temperature of the heat transfer liquid 5 increases. The heated heat transfer liquid 5 passes through the discharge port 72 and is returned to the heat storage tank 10. In the heat storage tank 10, the heat transfer liquid 5 that has passed through the multiple cold storage units 30 to store cold is mixed with the heat transfer liquid 5 whose temperature has increased by cooling the object to be cooled 90. As a result, the temperature of the heat transfer liquid 5 near the recovery port 22 becomes higher than the temperature of the heat transfer liquid 5 immediately after passing through the multiple cold storage units 30. Therefore, the heat transfer liquid 5 having a higher temperature than the temperature of the heat transfer liquid 5 immediately after passing through the multiple cold storage units 30 is sent to the cooling device 50. On the other hand, the temperature of the heat transfer liquid 5 sent to the object to be cooled 90 is lower than the temperature of the heat transfer liquid 5 whose temperature has increased by cooling the object to be cooled 90. Therefore, the heat transfer liquid 5 sent to the object to be cooled 90 has a high density and so descends inside the heat storage tank 10, reaching the vicinity of the suction port 71, which is located lower than the discharge port 72, where it is taken in again through the suction port 71 and sent to the object to be cooled 90.

Next, we will explain the operation of the heat storage device 1a when simultaneously performing a cold release operation in which cold energy is released from multiple cold storage units 30 and a cooling operation for the object to be cooled 90.

By operating the pump 61, the heat transfer liquid 5 stored in the heat storage tank 10 is taken in through the recovery port 22 and passes through the cooling device 50. During cold-discharge operation, the heat transfer liquid 5 is adjusted by the cooling device 50 to a temperature above the melting point of the first cold storage material. The refrigerant liquid 5 is then discharged through the supply port 21 and supplied to the heat storage tank 10. The heat transfer liquid 5 supplied to the heat storage tank 10 passes horizontally through multiple cold storage units 30 inside the heat storage tank 10 toward the recovery port 22. The heat transfer liquid 5 is first guided to the first cold storage unit 30a, which is closest to the supply port 21 in the horizontal direction among the multiple cold storage units 30. The heat transfer liquid 5 passes through an opening formed in one of the pair of side surfaces of the box 31b of this first cold storage unit 30a, enters the box 31b, and flows through the gaps between the multiple first containers 31a arranged inside the box 31b. The heat transfer liquid 5 then passes through an opening formed in the other of the pair of side surfaces of the box 31b and is guided to another first cold storage unit 30a located downstream. This causes heat exchange between the heat transfer liquid 5 and the first cold storage material. As a result, the temperature of the cold storage material in each cold storage unit 30, starting from the cold storage unit 30 located in the upstream region of the flow of the heat transfer liquid 5 in the multiple cold storage units 30, rises to a temperature above the melting point of the cold storage material. This causes the cold storage material in the multiple cold storage units 30 to change phase from solid to liquid, releasing cold energy. The heat transfer liquid 5 exchanges heat with the cold storage material, such as the first cold storage material, in the upstream and midstream regions of the flow of the heat transfer liquid 5 in the multiple cold storage units 30. This causes the heat of fusion required to melt the cold storage material to be transferred to the cold storage material, thereby lowering the temperature of the heat transfer liquid 5. As a result, in the downstream region 35d, a predetermined temperature distribution occurs in the heat transfer liquid 5 in the vertical direction, and the temperature of the heat transfer liquid 5 introduced to the lower end 35q of the downstream region 35d tends to be lower than the temperature of the heat transfer liquid 5 introduced to other parts of the downstream region 35d.

As in cold storage operation, the heat transfer liquid 5 cools the object to be cooled 90, causing the temperature of the heat transfer liquid 5 to rise. The heated heat transfer liquid 5 passes through the discharge port 72 and is returned to the inside of the heat storage tank 10. In the heat storage tank 10, the heat transfer liquid 5 that has passed through the multiple cold storage units 30 and been released to cool mixes with the heat transfer liquid 5 whose temperature has risen by cooling the object to be cooled 90. As a result, the temperature of the heat transfer liquid 5 near the recovery port 22 becomes higher than the temperature of the heat transfer liquid 5 immediately after passing through the multiple cold storage units 30. Therefore, the heat transfer liquid 5 having a higher temperature than the temperature of the heat transfer liquid 5 immediately after passing through the multiple cold storage units 30 is sent to the cooling device 50. On the other hand, the temperature of the heat transfer liquid 5 sent to the object to be cooled 90 is lower than the temperature of the heat transfer liquid 5 whose temperature has risen by cooling the object to be cooled 90. Therefore, the heat transfer liquid 5 sent to the object to be cooled 90 has a high density and so descends inside the heat storage tank 10, reaching the vicinity of the suction port 71, which is located lower than the discharge port 72, where it is taken in again through the suction port 71 and sent to the object to be cooled 90.

[1-3. Effects, etc.]
As described above, in this embodiment, the heat storage device 1a includes the heat storage tank 10, the supply port 21, the recovery port 22, and a plurality of cold storage units 30. The heat storage tank 10 stores the heat transfer liquid 5. The supply port 21 is disposed inside the heat storage tank 10 and guides the heat transfer liquid 5 into the heat storage tank 10. The recovery port 22 is disposed inside the heat storage tank 10 and guides the heat transfer liquid 5 toward the outside of the heat storage tank 10. The plurality of cold storage units 30 are disposed between the supply port 21 and the recovery port 22 inside the heat storage tank 10 and include a first cold storage unit 30a and a second cold storage unit 30b. The plurality of cold storage units 30 pass the heat transfer liquid 5 horizontally from the supply port 21 toward the recovery port 22. The first cold storage unit 30a includes a plurality of first containers 31a arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy. The second cold storage unit 30b includes a plurality of second containers 32a arranged parallel to one another and containing a second cold storage material that stores and releases cold by changing phase between liquid and solid. In the heat storage device 1a, the value V2 is smaller than the value V1. The value V2 is obtained by dividing the sum of the volumes occupied by the second containers 32a in the second cold storage unit 30b by the sum of the surface areas of the second containers 32a. The value V1 is obtained by dividing the sum of the volumes occupied by the first containers 31a in the first cold storage unit 30a by the sum of the surface areas of the first containers 31a. The second cold storage units 30b are arranged at both the upper end 35p and the lower end 35q of the plurality of cold storage units 30 in the vertical direction, in a downstream region 35d of the flow of the heat transfer liquid 5 in the plurality of cold storage units 30.

As a result, even if the temperature of the heat transfer liquid 5 introduced to the upper end 35p of the downstream area 35d is high when storing cold energy in the multiple cold storage units 30, the amount of heat exchanged between the second cold storage material and the heat transfer liquid 5 within a specified time is likely to be large. As a result, solidification of the cold storage material in the multiple cold storage units 30 is likely to be completed within a specified time. In addition, even if the temperature of the heat transfer liquid 5 introduced to the lower end 35q of the downstream area 35d is low when releasing cold energy from the multiple cold storage units 30, the amount of heat exchanged between the second cold storage material and the heat transfer liquid 5 within a specified time is likely to be large. As a result, melting of the cold storage material in the multiple cold storage units 30 is likely to be completed within a specified time.

As in this embodiment, the first cold storage unit 30a may be disposed in the downstream area 35d between the upper end 35p and the lower end 35q in the vertical direction.

As a result, a predetermined temperature distribution is more likely to occur in the heat transfer liquid 5 in the vertical direction in the downstream region 35d, and the temperature of the heat transfer liquid 5 introduced to the upper end 35p of the downstream region 35d is more likely to be higher than the temperature of the heat transfer liquid 5 introduced to other parts of the downstream region 35d. However, because the second cold storage units 30b are arranged at both the upper end 35p and the lower end 35q, solidification and melting of the cold storage material are more likely to be completed within a predetermined time. The second cold storage units 30b may be arranged throughout the entire downstream region 35d.

As in this embodiment, a heat exchange method can be provided that includes passing a heat transfer liquid 5 horizontally through multiple cold storage units 30 to store cold energy in the multiple cold storage units 30 or to release cold energy stored in the multiple cold storage units 30.

(Embodiment 2)
Hereinafter, the second embodiment will be described with reference to FIGS. 4, 5A, 5B, and 6. FIG.

[2-1. Configuration]
The heat storage device 1b according to the second embodiment is configured in the same manner as the heat storage device 1a according to the first embodiment, except for the parts that will be particularly described. The same reference numerals are used to designate the same or corresponding components of the heat storage device 1a, and detailed descriptions thereof will be omitted. The description of the heat storage device 1a also applies to the heat storage device 1b, provided that there is no technical contradiction.

As shown in FIG. 4, in the heat storage device 1b, the multiple cold storage units 30 include a first cold storage unit 30a and a second cold storage unit 30c. The second cold storage unit 30c is arranged in the downstream area 35d at the upper end 35p of the multiple cold storage units 30 in the vertical direction. The first cold storage unit 30a is arranged, for example, in a portion of the multiple cold storage units 30 other than the upper end 35p.

As shown in FIG. 5A, the second cold storage unit 30c includes multiple second containers 33a. The second containers 33a contain second cold storage material that changes phase between liquid and solid to store and release cold energy. In the second cold storage unit 30c, the multiple second containers 33a are arranged parallel to one another. As shown in FIG. 5B, the second containers 33a have, for example, the same shape and dimensions as the first containers 31a. In the heat storage device 1b, for example, the value V2 is equal to the value V1. The value V2 is the sum of the volumes occupied by the multiple second containers 33a in the second cold storage unit 30c divided by the sum of the surface areas of the multiple second containers 33a. The value V1 is the sum of the volumes occupied by the multiple first containers 31a in the first cold storage unit 30a divided by the sum of the surface areas of the multiple first containers 31a.

As shown in FIG. 6 , the second cold storage material of the second cold storage unit 30c has a melting point that is higher than the temperature of the heat transfer liquid 5 at the supply port 21 when cold energy is stored in the second cold storage material and higher than the melting point of the first cold storage material. The melting point of the second cold storage material is, for example, 8°C. The melting point of the first cold storage material is, for example, 7°C. The composition of the second cold storage material of the second cold storage unit 30c is, for example, different from the composition of the first cold storage material. The temperature of the heat transfer liquid 5 at the supply port 21 when cold energy is stored in the cold storage material is, for example, 5°C.

[2-2. Operation]
The operation of the heat storage device 1b configured as above will be described below, focusing on the differences from the operation of the heat storage device 1a according to the first embodiment.

During the cold storage operation of the heat storage device 1b, as with the heat storage device 1a, the temperature of the heat transfer liquid 5 introduced to the upper end 35p of the downstream area 35d tends to be higher than the temperature of the heat transfer liquid 5 introduced to other parts of the downstream area 35d. The heat transfer liquid 5 having such a temperature is introduced into the second cold storage unit 30c located at the upper end 35p.

[2-3. Effects, etc.]
As described above, in this embodiment, the heat storage device 1b includes the heat storage tank 10, the supply port 21, the recovery port 22, and a plurality of cold storage units 30. The heat storage tank 10 stores the heat transfer liquid 5. The supply port 21 is disposed inside the heat storage tank 10 and guides the heat transfer liquid 5 into the heat storage tank 10. The recovery port 22 is disposed inside the heat storage tank 10 and guides the heat transfer liquid 5 toward the outside of the heat storage tank 10. The plurality of cold storage units 30 are disposed inside the heat storage tank 10 between the supply port 21 and the recovery port 22 and include a first cold storage unit 30a and a second cold storage unit 30c. The plurality of cold storage units 30 pass the heat transfer liquid 5 horizontally from the supply port 21 toward the recovery port 22. The first cold storage unit 30a includes a plurality of first containers 31a arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy. The second cold storage unit 30c includes a plurality of second containers 33a arranged parallel to one another and containing a second cold storage material that stores and releases cold by changing phase between liquid and solid. The second cold storage material has a higher temperature than the heat transfer liquid 5 at the supply port 21 when cold is stored in the second cold storage material and a higher melting point than the melting point of the first cold storage material. The second cold storage unit 30c is arranged at an upper end 35p of the plurality of cold storage units 30 in the vertical direction, in a downstream region 35d of the flow of the heat transfer liquid 5 in the plurality of cold storage units 30.

As a result, even if the temperature of the heat transfer liquid 5 introduced to the upper end 35p of the downstream area 35d is high when storing cold energy in multiple cold storage units 30, the difference between the melting point of the second cold storage material and the temperature of the heat transfer liquid 5 is likely to be large. This means that the amount of heat exchanged between the second cold storage material and the heat transfer liquid 5 in a given time period is likely to be large. As a result, solidification of the cold storage material in multiple cold storage units 30 is likely to be completed within the given time period.

As in this embodiment, the first cold storage unit 30a may be disposed in the downstream area 35d between the upper end 35p and the lower end 35q in the vertical direction.

As a result, a predetermined temperature distribution is more likely to occur in the heat transfer liquid 5 in the vertical direction in the downstream region 35d, and the temperature of the heat transfer liquid 5 introduced to the upper end 35p of the downstream region 35d is more likely to be higher than the temperature of the heat transfer liquid 5 introduced to other parts of the downstream region 35d. However, because the second cold storage unit 30c is located at the upper end 35p, solidification of the cold storage material is more likely to be completed within a predetermined time. The second cold storage unit 30c may be located throughout the entire downstream region 35d.

As in this embodiment, a heat exchange method can be provided that includes passing a heat transfer liquid 5 horizontally through multiple cold storage units 30 to store cold energy in the multiple cold storage units 30 or to release cold energy stored in the multiple cold storage units 30.

(Embodiment 3)
Hereinafter, the third embodiment will be described with reference to FIGS. 7, 8A, 8B, and 9. FIG.

[3-1. Configuration]
The heat storage device 1c according to the third embodiment is configured in the same manner as the heat storage device 1a according to the first embodiment, except for the parts that will be particularly described. The same reference numerals are used to designate the same or corresponding components of the heat storage device 1c as those of the heat storage device 1a, and detailed descriptions thereof will be omitted. The description of the heat storage device 1a also applies to the heat storage device 1c, provided that there is no technical contradiction.

As shown in FIG. 7, in the heat storage device 1c, the multiple cold storage units 30 include a first cold storage unit 30a and a second cold storage unit 30d. The second cold storage unit 30d is arranged in the downstream area 35d at the lower end 35q of the multiple cold storage units 30 in the vertical direction. The first cold storage unit 30a is arranged, for example, in a portion of the multiple cold storage units 30 other than the lower end 35q.

As shown in FIG. 8A, the second cold storage unit 30d includes multiple second containers 34a. The second containers 34a contain second cold storage material that changes phase between liquid and solid to store and release cold energy. In the second cold storage unit 30d, the multiple second containers 34a are arranged parallel to one another. As shown in FIG. 8B, the second containers 34a have, for example, the same shape and dimensions as the first container 31a. In the heat storage device 1c, for example, the value V2 is equal to the value V1. The value V2 is the sum of the volumes occupied by the multiple second containers 34a in the second cold storage unit 30d divided by the sum of the surface areas of the multiple second containers 34a. The value V1 is the sum of the volumes occupied by the multiple first containers 31a in the first cold storage unit 30a divided by the sum of the surface areas of the multiple first containers 31a.

As shown in FIG. 9 , the second cold storage material of the second cold storage unit 30d has a melting point that is lower than the temperature of the heat transfer liquid 5 at the supply port 21 when cold is released from the second cold storage material and lower than the melting point of the first cold storage material. The melting point of the second cold storage material is, for example, 6°C. The melting point of the first cold storage material is, for example, 7°C. The temperature of the heat transfer liquid 5 at the supply port 21 when cold is released from the cold storage material is, for example, 12°C.

[3-2. Operation]
The operation of the heat storage device 1c configured as above will be described below, focusing on the differences from the operation of the heat storage device 1a according to the first embodiment.

During the cold-discharge operation of the heat storage device 1c, as with the heat storage device 1a, the temperature of the heat transfer liquid 5 introduced to the lower end 35q of the downstream area 35d tends to be lower than the temperature of the heat transfer liquid 5 introduced to other parts of the downstream area 35d. The heat transfer liquid 5 having such a temperature is introduced into the second cold storage unit 30d located at the lower end 35q.

[3-3. Effects, etc.]
As described above, in this embodiment, the heat storage device 1c includes the heat storage tank 10, the supply port 21, the recovery port 22, and a plurality of cold storage units 30. The heat storage tank 10 stores the heat transfer liquid 5. The supply port 21 is disposed inside the heat storage tank 10 and guides the heat transfer liquid 5 into the heat storage tank 10. The recovery port 22 is disposed inside the heat storage tank 10 and guides the heat transfer liquid 5 toward the outside of the heat storage tank 10. The plurality of cold storage units 30 are disposed inside the heat storage tank 10 between the supply port 21 and the recovery port 22 and include a first cold storage unit 30a and a second cold storage unit 30d. The plurality of cold storage units 30 pass the heat transfer liquid 5 horizontally from the supply port 21 toward the recovery port 22. The first cold storage unit 30a includes a plurality of first containers 31a arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy. The second cold storage unit 30d includes a plurality of second containers 34a arranged parallel to one another and containing a second cold storage material that changes phase between liquid and solid to store and release cold. The second cold storage material has a melting point that is lower than the temperature of the heat transfer liquid 5 at the supply port 21 when cold is released from the second cold storage material and lower than the melting point of the first cold storage material. The second cold storage unit 30d is arranged in the downstream region 35d at a lower end 35q of the plurality of cold storage units 30 in the vertical direction.

As a result, even if the temperature of the heat transfer liquid 5 introduced to the lower end 35q of the downstream area 35d is low when cold energy is released from the multiple cold storage units 30, the difference between the melting point of the second cold storage material and the temperature of the heat transfer liquid 5 tends to be large. Therefore, the amount of heat exchanged between the second cold storage material and the heat transfer liquid 5 in a given time tends to be large. As a result, the melting of the cold storage materials in the multiple cold storage units 30 tends to be completed within the given time.

As in this embodiment, the first cold storage unit 30a may be disposed in the downstream area 35d between the upper end 35p and the lower end 35q in the vertical direction.

As a result, in the downstream region 35d, a predetermined temperature distribution is more likely to occur in the heat transfer liquid 5 in the vertical direction, and the temperature of the heat transfer liquid 5 introduced to the lower end 35q of the downstream region 35d is more likely to be lower than the temperature of the heat transfer liquid 5 introduced to other parts of the downstream region 35d. However, because the second cold storage unit 30d is located at the lower end 35q, melting of the cold storage material is more likely to be completed within a predetermined time. The second cold storage unit 30d may be located throughout the entire downstream region 35d.

As in this embodiment, a heat exchange method can be provided that includes passing a heat transfer liquid 5 horizontally through multiple cold storage units 30 to store cold energy in the multiple cold storage units 30 or to release cold energy stored in the multiple cold storage units 30.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to FIGS. 10, 11A, 11B, 12A, and 12B.

[4-1. Configuration]
The heat storage device 1d according to the fourth embodiment is configured in the same manner as the heat storage device 1a according to the first embodiment, except for the parts that will be particularly described. The same reference numerals are used to designate components of the heat storage device 1d that are the same as or correspond to the components of the heat storage device 1a, and detailed descriptions thereof will be omitted. The descriptions of the heat storage device 1a also apply to the heat storage device 1d as long as there is no technical contradiction.

As shown in FIG. 10, in the heat storage device 1d, the multiple cold storage units 30 include a first cold storage unit 30a and a second cold storage unit 30b.

As shown in Figures 11A, 11B, 12A, and 12B, the first container 31a and the second container 32a are each cylindrical. The diameter of the second container 32a in a direction perpendicular to the axis is smaller than the diameter of the first container 31a in a direction perpendicular to the axis. As a result, in the thermal storage device 1d, value V2 is smaller than value V1. Value V2 is the sum of the volumes occupied by the multiple second containers 32a in the second cold storage unit 30b divided by the sum of the surface areas of the multiple second containers 32a. V1 is the sum of the volumes occupied by the multiple first containers 31a in the first cold storage unit 30a divided by the sum of the surface areas of the multiple first containers 31a.

[4-2. Operation]
The heat storage device 1d configured as above can operate in the same manner as the heat storage device 1a according to the first embodiment.

[4-3. Effects, etc.]
As described above, in this embodiment, the value V2 is smaller than the value V1. In addition, the second cold storage units 30b are disposed in the downstream region 35d at both the upper end 35p and the lower end 35q of the plurality of cold storage units 30 in the vertical direction. This arrangement makes it easier to increase the amount of heat exchanged between the second cold storage material and the heat transfer liquid 5 within a predetermined time, even if the temperature of the heat transfer liquid 5 introduced to the upper end 35p of the downstream region 35d is high when cold energy is stored in the plurality of cold storage units 30. As a result, solidification of the cold storage material in the plurality of cold storage units 30 is easier to complete within a predetermined time. In addition, when cold energy is released from the plurality of cold storage units 30, even if the temperature of the heat transfer liquid 5 introduced to the lower end 35q of the downstream region 35d is low, the amount of heat exchanged between the second cold storage material and the heat transfer liquid 5 within a predetermined time is easier to complete. As a result, melting of the cold storage material in the plurality of cold storage units 30 is easier to complete within a predetermined time.

(Other embodiments)
As described above, the first, second, third, and fourth embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the first, second, third, and fourth embodiments to create new embodiments.

Therefore, other embodiments will be described below. In embodiments 1, 2, 3, and 4, water is used as an example of heat transfer liquid 5. The heat transfer liquid 5 may be any liquid that can flow in the temperature range in which it is used. Therefore, the heat transfer liquid 5 is not limited to water. However, if water is used as the heat transfer liquid 5, the heat transfer liquid 5 can be obtained in large quantities at low cost.

In embodiments 1, 2, 3, and 4, a cold storage material containing a substance capable of forming clathrate hydrate is given as an example of the first cold storage material and the second cold storage material. The first cold storage material and the second cold storage material may store cold by changing phase from liquid to solid at a predetermined temperature, and release cold by changing phase from solid to liquid. Therefore, the cold storage material is not limited to one containing a substance capable of forming clathrate hydrate. However, if a cold storage material containing a substance capable of forming clathrate hydrate is used, it is easier to store and release cold at temperatures close to the operating temperature range by selecting the guest substance in the clathrate hydrate. In this case, the cold storage material changes phase from liquid to solid when storing cold, and changes phase from solid to liquid when releasing cold.

In embodiments 1 and 4, the second cold storage units 30b are arranged in the downstream area 35d at both the upper ends 35p and the lower ends 35q of the multiple cold storage units 30 in the vertical direction. The second cold storage units 30b may be arranged only at the upper ends 35p or only at the lower ends 35q. When the second cold storage units 30b are arranged only at the upper ends 35p, the first cold storage units 30a may be arranged at the lower ends 35q. When the second cold storage units 30b are arranged only at the lower ends 35q, the first cold storage units 30a may be arranged at the upper ends 35p.

Note that the above-described embodiments are intended to illustrate the technology disclosed herein, and various modifications, substitutions, additions, omissions, etc. may be made within the scope of the claims or their equivalents.

This disclosure is applicable to heat storage devices that include a heat storage tank in which a cold storage unit containing cold storage material is immersed in a heat transfer liquid in order to shift the time period in which cold energy is used, and that supply the heat transfer liquid used for air conditioning or cooling in manufacturing processes.

1a, 1b, 1c, 1d Heat storage device 5 Heat transfer liquid 10 Heat storage tank 21 Supply port 22 Recovery port 30 Cold storage unit 30a First cold storage unit 30b, 30c, 30d Second cold storage unit 31a First container 32a, 33a, 34a Second container 35d Downstream region 35p Upper end 35q Lower end

Claims (10)

a heat storage tank for storing a heat transfer liquid;
a supply port disposed inside the heat storage tank and configured to introduce the heat transfer liquid into the heat storage tank;
a recovery port disposed inside the heat storage tank and directing the heat transfer liquid toward the outside of the heat storage tank;
a plurality of cold storage units including a first cold storage unit and a second cold storage unit, the cold storage unit being disposed between the supply port and the recovery port inside the heat storage tank;
the plurality of cold storage units pass the heat transfer liquid horizontally from the supply port toward the recovery port;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
a value obtained by dividing the sum of the volumes occupied by the plurality of second containers in the second cold storage unit by the sum of the surface areas of the plurality of second containers is smaller than a value obtained by dividing the sum of the volumes occupied by the plurality of first containers in the first cold storage unit by the sum of the surface areas of the plurality of first containers;
the second cold storage unit is disposed at an upper end of the plurality of cold storage units in a vertical direction, in a downstream region of the flow of the heat transfer liquid in the plurality of cold storage units;
Heat storage device. a heat storage tank for storing a heat transfer liquid;
a supply port disposed inside the heat storage tank and configured to introduce the heat transfer liquid into the heat storage tank;
a recovery port disposed inside the heat storage tank and directing the heat transfer liquid toward the outside of the heat storage tank;
a plurality of cold storage units including a first cold storage unit and a second cold storage unit, the cold storage unit being disposed between the supply port and the recovery port inside the heat storage tank;
the plurality of cold storage units pass the heat transfer liquid horizontally from the supply port toward the recovery port;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
a value obtained by dividing the sum of the volumes occupied by the plurality of second containers in the second cold storage unit by the sum of the surface areas of the plurality of second containers is smaller than a value obtained by dividing the sum of the volumes occupied by the plurality of first containers in the first cold storage unit by the sum of the surface areas of the plurality of first containers;
the second cold storage unit is disposed at a lower end of the plurality of cold storage units in a vertical direction, in a downstream region of the flow of the heat transfer liquid in the plurality of cold storage units;
Heat storage device. The heat storage device according to claim 1 or 2, wherein the first cold storage unit is arranged in the downstream area between upper ends of the plurality of cold storage units in the vertical direction and lower ends of the plurality of cold storage units in the vertical direction . a heat storage tank for storing a heat transfer liquid;
a supply port disposed inside the heat storage tank and configured to introduce the heat transfer liquid into the heat storage tank;
a recovery port disposed inside the heat storage tank and directing the heat transfer liquid toward the outside of the heat storage tank;
a plurality of cold storage units including a first cold storage unit and a second cold storage unit, the cold storage unit being disposed between the supply port and the recovery port inside the heat storage tank;
the plurality of cold storage units pass the heat transfer liquid horizontally from the supply port toward the recovery port;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
The second cold storage unit satisfies the following conditions (Ia) and (Ib):
Heat storage device.
(Ia) The second cold storage material has a melting point that is higher than the temperature of the heat transfer liquid at the supply port when cold is stored in the second cold storage material and higher than the melting point of the first cold storage material.
(Ib) The second cold storage unit is disposed at the upper end of the cold storage units in the vertical direction, in a downstream region of the flow of the heat transfer liquid in the cold storage units. a heat storage tank for storing a heat transfer liquid;
a supply port disposed inside the heat storage tank and configured to introduce the heat transfer liquid into the heat storage tank;
a recovery port disposed inside the heat storage tank and directing the heat transfer liquid toward the outside of the heat storage tank;
a plurality of cold storage units including a first cold storage unit and a second cold storage unit, the cold storage unit being disposed between the supply port and the recovery port inside the heat storage tank;
the plurality of cold storage units pass the heat transfer liquid horizontally from the supply port toward the recovery port;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
The second cold storage unit satisfies the following conditions (IIa) and (IIb):
Heat storage device.
(IIa) The second cold storage material has a melting point that is lower than the temperature of the heat transfer liquid at the supply port when cold is released from the second cold storage material and lower than the melting point of the first cold storage material.
(IIb) The second cold storage unit is disposed at a lower end of the cold storage units in the vertical direction, in a downstream region of the flow of the heat transfer liquid in the cold storage units. The heat storage device according to claim 4 or 5, wherein the first cold storage unit is arranged in the downstream area between upper ends of the plurality of cold storage units in a direction perpendicular to the horizontal direction and lower ends of the plurality of cold storage units in a direction perpendicular to the horizontal direction . a heat transfer liquid passing through a plurality of cold storage units including a first cold storage unit and a second cold storage unit in a horizontal direction to store cold energy in the plurality of cold storage units or to release cold energy stored in the plurality of cold storage units;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
a value obtained by dividing the sum of the volumes occupied by the plurality of second containers in the second cold storage unit by the sum of the surface areas of the plurality of second containers is smaller than a value obtained by dividing the sum of the volumes occupied by the plurality of first containers in the first cold storage unit by the sum of the surface areas of the plurality of first containers;
the second cold storage unit is disposed at an upper end of the plurality of cold storage units in a vertical direction, in a downstream region of the flow of the heat transfer liquid in the plurality of cold storage units;
Heat exchange method. a heat transfer liquid passing through a plurality of cold storage units including a first cold storage unit and a second cold storage unit in a horizontal direction to store cold energy in the plurality of cold storage units or to release cold energy stored in the plurality of cold storage units;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
a value obtained by dividing the sum of the volumes occupied by the plurality of second containers in the second cold storage unit by the sum of the surface areas of the plurality of second containers is smaller than a value obtained by dividing the sum of the volumes occupied by the plurality of first containers in the first cold storage unit by the sum of the surface areas of the plurality of first containers;
the second cold storage unit is disposed at a lower end of the plurality of cold storage units in a vertical direction, in a downstream region of the flow of the heat transfer liquid in the plurality of cold storage units;
Heat exchange method. a heat transfer liquid is passed in a horizontal direction from a supply port to a recovery port in a plurality of cold storage units including a first cold storage unit and a second cold storage unit, to store cold energy in the plurality of cold storage units or to release the cold energy stored in the plurality of cold storage units;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
The second cold storage unit satisfies the following conditions (Ia) and (Ib):
Heat exchange method.
(Ia) The second cold storage material has a melting point that is higher than the temperature of the heat transfer liquid at the supply port when cold is stored in the second cold storage material and higher than the melting point of the first cold storage material.
(Ib) The second cold storage unit is disposed at the upper end of the cold storage units in the vertical direction, in a downstream region of the flow of the heat transfer liquid in the cold storage units. a heat transfer liquid is passed in a horizontal direction from a supply port to a recovery port in a plurality of cold storage units including a first cold storage unit and a second cold storage unit, to store cold energy in the plurality of cold storage units or to release the cold energy stored in the plurality of cold storage units;
the first cold storage unit includes a plurality of first containers arranged parallel to one another and containing a first cold storage material that changes phase between liquid and solid to store and release cold energy;
the second cold storage unit includes a plurality of second containers arranged parallel to each other and containing a second cold storage material that changes phase between liquid and solid to store and release cold energy;
The second cold storage unit satisfies the following conditions (IIa) and (IIb):
Heat exchange method.
(IIa) The second cold storage material has a melting point that is lower than the temperature of the heat transfer liquid at the supply port when cold is released from the second cold storage material and lower than the melting point of the first cold storage material.
(IIb) The second cold storage unit is disposed at a lower end of the cold storage units in the vertical direction, in a downstream region of the flow of the heat transfer liquid in the cold storage units.