US20100000707A1

US20100000707A1 - Thermal storage device

Info

Publication number: US20100000707A1
Application number: US12/445,522
Authority: US
Inventors: Kenji Tsubone; Seiichi Hashi; Masahito Tsukahara; Masataka Fukuzawa; Kouji Narita
Original assignee: Individual
Current assignee: Toyota Motor Corp; T Rad Co Ltd
Priority date: 2006-10-25
Filing date: 2007-10-24
Publication date: 2010-01-07
Also published as: JP2008106996A; WO2008050221A3; DE112007002461B4; CN101529193A; JP4324187B2; WO2008050221A8; CN101529193B; WO2008050221A2; DE112007002461T5

Abstract

A thermal storage device having a plurality of tube-like first thermal medium branch pipes (5) into which a first thermal medium (3) flows and a thermal storage material (1) provided on the outer peripheries of the first thermal medium branch pipes (5) is characterized by including a first header (6) that communicates with the upper portions of the first thermal medium branch pipes (5) and allows the first thermal medium (3) to flow therethrough, a first upper reservoir (7) that communicates with the first header (6) and stores the first thermal medium (3), and a first inlet (8) that communicates with the first upper reservoir (7) and allows the first thermal medium (3) to flow therethrough. The first upper reservoir (7) is formed in a direction intersecting with the direction of streamline of the first inlet (8).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to a thermal storage device in which a first thermal medium and a second thermal medium flow through a thermal storage material, and more particularly to a thermal storage device that is able to temporarily store heat (or cool) possessed by a medium, such as a coolant.
2. Description of the Related Art
Japanese Patent Application Publication No. 2003-336974 (JP-A-2003-336974) discloses a thermal-storage device that stores heat or cool (thermal heating or thermal cooling) in a thermal storage material through contact of the thermal storage material with channels through which a first thermal medium and a second thermal medium flow. In the thermal storage device disclosed in JP-A-2003-336974, a plurality of first channels and a plurality of second channels are provided, and direct heat exchange takes place between a heat source fluid and a heat recovery fluid flowing through the first channels and the second channels, respectively. Since the thermal storage material is provided around the first channels and the second channels, heat of the heat source fluid is once stored in the thermal storage. material, and then transmitted to the heat recovery medium for effecting heat exchange.
Japanese Patent Application Publication No. 10-232093 (JP-A-10-232093) discloses a thermal storage device in which heat transfer plates are laminated or stacked together to form channels through which a first thermal medium and a second thermal medium are caused to flow, and heat exchange takes place between the first thermal medium and the second thermal medium within. the thermal storage device. In the thermal storage device disclosed in JP-A-10-232093, heat is transferred between the first thermal medium and the second thermal medium via the heat transfer plates.
In the thermal storage device disclosed in JP-A-2003-336974 as described above, a straight path that extends from an inlet to a tank is provided, and a plurality of channels are formed in a direction that intersects with the tank. Accordingly, when the amount of flow of the first thermal medium or second thermal medium introduced through the inlet is varied, the amounts of flow of the first thermal medium or second thermal medium that flows in the channels vary depending upon the mounting locations of the channels. Therefore, variations arise in the degree of heat transfer between the first thermal medium or second thermal medium and the thermal storage material, and variations are likely to arise in the temperature distribution in the thermal storage material.
Also, when the -amount of flow of the first thermal medium or second thermal medium introduced through the inlet is varied, air bubbles may appear in the tank or channels, in which a mixture of the bubbles (gas) and the thermal medium (liquid) is created, resulting in a reduction in the quantity of heat that can be directly transferred between the first thermal medium and the second thermal medium.
In the thermal storage device disclosed in JP-A-10-232093 as described above, the laminated heat transfer plates that effect heat exchange between the first thermal medium and the second thermal medium and a thermal storage tank that stores heat are separately provided, resulting in an increase in the size of the thermal storage device.

SUMMARY OF THE INVENTION

The invention is concerned with a thermal storage device that uses the same mechanism for effecting heat exchange between a first thermal medium and a second thermal medium and storing heat in a thermal storage material. It is an object of the invention to provide such a thermal storage device that is less likely to suffer from variations in the amount of flow of the first thermal medium or second thermal medium through a plurality of channels, depending upon the mounting locations of the channels, even when the amount of the first thermal medium or second thermal medium introduced into the device is varied. It is also an object of the invention to provide a thermal storage device in which tubes through which a thermal medium flows are provided in blades, assuring improved overall rigidity.
According to a first aspect of the invention, there is provided a thermal storage device including a plurality of tube-like first thermal medium branch pipes into which a first thermal medium flows, a thermal storage material provided on the outer peripheries of the first thermal medium branch pipes, a first header that communicates with upper portions of the first thermal medium branch pipes and allows the first thermal medium to flow therethrough, a first upper reservoir that communicates with the first header and stores the first thermal medium, and a first inlet that communicates with the first upper reservoir and allows the first thermal medium to flow therethrough, wherein the first upper reservoir is formed in a direction intersecting with a direction of streamline of the first inlet.
In the thermal storage device according to the above aspect of the invention, the upper reservoir may have a bottom face that is inclined upwards from a lower portion of the upper reservoir.
In the thermal storage device according to the above aspect of the invention, a cross-sectional area of the upper reservoir when cut in a direction parallel to a lower face of the first header may be smaller in a lower portion of the upper reservoir than in an upper portion thereof, and the cross-sectional area may increase from the lower portion toward the upper portion.
The thermal storage device according to the above aspect of the invention may further include a plurality of second thermal medium branch pipes through which a second thermal medium flows, a second header that communicates with upper portions of the second thermal medium branch pipes and allows the second thermal medium to flow therethrough, a second upper reservoir that communicates with the second header, and stores the second thermal medium, and a second outlet that communicates with the second upper reservoir and allows the second thermal medium to flow therethrough. In this device, the thermal storage material may be provided on the outer peripheries of the second thermal medium branch pipes, and the second upper reservoir may be formed in a direction intersecting with a direction of streamline of the second outlet, while the first upper reservoir and the second upper reservoir may be in contact with each other.
In the thermal storage device according to the above aspect of the invention, the first header and the second header may be in contact with each other.
The thermal storage device according to the above aspect of the invention may further include a plurality of first plate-like tubes that are arranged in parallel with each other to extend in a vertical direction of the thermal storage device. In this device, the first thermal medium branch pipes may be disposed in the vertical direction of the first plate-like tubes.
The thermal storage device according to the above aspect of the invention may further include a plurality of second plate-like tubes that are arranged in parallel with each other to extend in a vertical direction of the thermal storage device. In this device, the second thermal medium branch pipes may be disposed in a vertical direction of the second plate-like tubes.
The thermal storage device as described just above may further include a plurality of first plate-like tubes that are arranged in parallel with each other to extend in the vertical direction of the thermal storage device. In this device, the first thermal medium branch pipes may be disposed in a vertical direction of the first plate-like tubes, and the first plate-like tubes and the second plate-like tubes may be arranged in parallel with each other so as to be perpendicular to an inlet/outlet-side side face of the thermal storage device in which the first inlet and the second outlet are provided.
Each of the first plate-like tubes and the second plate-like tubes may be formed by joining two heat transfer plates to each other, and the first thermal medium branch pipes and the second thermal medium branch pipes may be inserted through grooves formed in mating faces of the two heat transfer plates.
The first plate-like tubes may extend through at least one of the second upper reservoir and a second lower reservoir, and at least one hole may be formed in the first plate-like tubes.
The second plate-like tubes may extend through at least one of the second upper reservoir and a second lower reservoir, and at least one hole may be formed in the second plate-like tubes.
In the thermal storage device according to the above aspect of the invention, the first thermal medium may be brine, and the second thermal medium may be a coolant.
According to a second aspect of the invention, there is provided a circulation system including the thermal storage device according to the first aspect of the invention, and a heat exchanger, wherein the first thermal medium circulates between the thermal storage device and the heat exchanger.
The circulation system according to the above aspect of the invention may further include a compressor, a condenser, a receiver tank and an expansion valve. In this system, the second thermal medium may circulate between the thermal storage device and the. compressor, and the condenser, the receiver tank and the expansion valve may be connected in the order of description between the compressor and the thermal storage device.
According to the first aspect of the invention, when the first thermal medium flows into the thermal storage device through the first inlet, the first thermal medium is stored in the first upper reservoir, and then flows from the first upper reservoir into the first header. Since a change in the amount of flow of the first thermal medium introduced through the first inlet is transmitted to the first header via the first upper reservoir, a change in the amount of flow of the first thermal medium in the first header is made smaller than the change in the amount of flow of the first thermal medium through the first inlet. Consequently, the amount of flow of the first thermal medium through the first thermal medium branch pipes is more stabilized, and variations in the temperature distribution in the thermal storage material in response to changes in the amount of flow of the first thermal medium are reduced.
With the arrangement in which the upper reservoir is formed with an inclined bottom face, pressure losses are reduced when the first thermal medium flows from the first inlet into the thermal storage device, and circulates in the interior of the thermal storage device.
In the embodiment having the second thermal medium branch pipes, the second thermal medium flows through the second thermal medium branch pipes and the second header, and is stored in the second upper reservoir. Since the first upper reservoir and the second upper reservoir are in contact with each other, direct heat exchange can be effected between the first thermal medium stored in the first upper reservoir and the second thermal medium stored in the. second upper reservoir even if no thermal energy is stored in the thermal storage material.
Also, when the first thermal medium is stored in the first header, and the second thermal medium is stored in the second header, direct heat exchange can be effected between the first thermal medium and the second thermal medium even if no thermal energy is stored in the thermal storage material.
In the arrangement where the first plate-like tubes are provided, the thermal storage device can be constructed by a simple means as a pressure-resistant structure that is resistant to pressure applied in a direction parallel to the planes of the first plate-like tubes. Thus, the size, weight and cost of the thermal storage device can be reduced.
In the arrangement where the second plate-like tubes are provided, the thermal storage device can be constructed by a simple means as a pressure-resistant structure that is resistant to pressure applied in a direction parallel to the planes of the second plate-like tubes. Thus, the size, weight and cost of the thermal storage device can be reduced.
In the arrangement where holes are formed in the first plate-like tubes that extend through the reservoir(s), a total cross-sectional area of channels in the reservoir through which the first plate-like tubes extend can be expanded or increased, resulting in a reduction in pressure loss of the first thermal medium or second thermal medium.
In the arrangement where holes are formed in the second plate-like tubes that extend through the reservoir(s), a total cross-sectional area of channels in the reservoir through which the second plate-like tubes extend can be expanded or increased, resulting in a reduction in pressure loss of the first thermal medium or second thermal medium.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements, and wherein:

FIG. 1 is a view schematically showing a thermal storage device according to a first embodiment of the invention;

FIG. 2 is a perspective view showing the outward appearance of the thermal storage device of FIG. 1;

FIG. 3 is a view schematically showing a circulation path of a first thermal medium;

FIG. 4 is a view schematically showing a circulation path of a second thermal medium;

FIG. 5 is a view schematically showing a thermal storage device provided with plate-like tubes according to a second embodiment of the invention;

FIG. 6 is an enlarged, lateral cross-sectional view showing principal parts of the plate-like tubes used in the thermal storage device of FIG. 5; and

FIG. 7 is a view schematically showing a modified example of the thermal storage device of FIG. 5 in which holes are formed in the plate-like tubes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be described in more detail. The thermal storage device of this invention is able to store both positive heat that increases energy and negative heat that reduces the energy. In the following description, specific examples will be illustrated which are arranged to store “cool” or thermal cooling for reduction of the energy.
Referring to FIG. 1 and FIG. 2, a thermal storage device 4 according to a first embodiment of the invention will be described. FIG. 2 is a perspective view of the thermal storage device 4 of this embodiment. As seen in FIG. 2, the thermal storage device 4 is in the form of a prism having a quadrangular bottom face. FIG. 1 is a view schematically showing the interior of the thermal storage device 4. As shown in FIG. 1, a coolant as a second thermal medium 2 introduces cool or thermal cooling into a thermal storage material 1, and brine as a first thermal medium 3 delivers or discharges the cool stored in the thermal storage material 1 out of the material 1. Thus, the thermal storage device 4 is constructed as a cool storage device that stores negative heat that reduces energy.
The thermal storage device 4 includes the thermal storage material 1, a plurality of first thermal medium branch pipes 5 that are inserted through the thermal storage material 1 and allow the first thermal medium 3 to flow therethrough, and a first header 6 that is located in the upper part of the thermal storage device 4 and defines a hollow in the interior thereof More specifically, the first thermal medium branch pipes 5 have respective hollows or bores formed in the inside thereof so as to allow the first thermal medium 3 to flow therethrough, and are arranged to extend in the vertical direction (perpendicular to the bottom face of the thermal storage device 4) within the thermal storage device 4. The thermal storage material 1 is formed so as to surround the outer peripheries of the first thermal medium branch pipes 5. The lower face of the first header 6 is formed in parallel with the bottom face of the thermal storage device 4, and the first thermal medium branch pipes 5 are evenly arranged over the lower face of the first header 6. With this arrangement, when the first thermal medium 3 in the form of brine for discharging cool is evenly passed through the respective first thermal medium branch pipes 5, the cool stored in the thermal storage material 1 is delivered evenly out of the material 1 in the thermal storage device 4. Since the thermal storage material 1 is in contact with the outer peripheries of the first thermal medium branch pipes 5, heat exchange or thermal energy exchange takes place between the first thermal medium 3 flowing through the first thermal medium branch pipes 5 and the thermal storage medium 1.
In the thermal storage device 4, the upper parts of the first thermal medium branch pipes 5 communicate with the first header 6. More specifically, the first header 6 has a hollows formed in the interior thereof, and is disposed in the upper portion of the thermal storage device 4 such that the lower face of the first header 6 is in parallel with the bottom face of the thermal storage device 4. Thus, the first thermal medium 3 is caused to flow substantially uniformly within the first header 6. Furthermore, the areas of the upper and lower faces of the first header 6 are made as large as possible. While the upper ends of the first thermal medium branch pipes 5 protrude upwards into the interior of the first header 6 in the example shown in FIG. 1, the upper ends of the first thermal medium branch pipes 5 may or may not protrude into the first header 6 as long as the first thermal medium 3 can flow between the first header 6 and the first thermal medium branch pipes 5. The first thermal medium branch pipes 5 and the first header 6 are joined to each other by, for example, welding.
The thermal storage device 4 is also provided with a first upper reservoir 7 that stores the first thermal medium 3. The first upper reservoir 7 is a hollow formed in the upper part of one side portion of the thermal storage device 4, and communicates with the first header 6. The thermal storage device 4 is further provided with a tube-like first inlet 8 through which the first thermal medium 3 flows into the first upper reservoir 7. The first upper reservoir 7 extends in a direction intersecting with the direction of streamline of the first inlet 8, toward the top of the thermal storage device 4. The area of a cross-section of the first upper reservoir 7 taken along the direction of streamline of the first inlet 8 is made as large as possible. As this cross-sectional area of the first upper reservoir 7 increases, the amount of a rise in the liquid level of the first thermal medium 3 flowing from the first inlet 8 is reduced in the first upper reservoir 7. The amount of the rise is based on the ratio between the cross-sectional area of the first inlet 8 when taken in a plane orthogonal to the direction of streamline and the above-indicated cross-sectional area of the first upper reservoir 7. If the cross-sectional area of the first inlet 8 is small, or the cross-sectional area of the first upper reservoir 7 is large, the amount of the rise in the liquid level of the first thermal medium 3 in the first upper reservoir 7 is reduced.
The first upper reservoir 7 has a hollow formed therein, and the first thermal medium 3 is stored in the first upper reservoir 7. The first inlet 8 is attached to one outside surface of the first upper reservoir 7, namely, to one side (or wall) of the thermal storage device 4 on which the first upper reservoir 7 is formed. The first upper reservoir 7 communicates with the first header 6 at a location above the face of the first upper reservoir 7 opposed to the face to which the first inlet 8 is attached. It is desirable that the first upper reservoir 7 is perpendicular to the lower face of the first header 6. However, the first reservoir 7 may be inclined downwards relative to the lower face of the first header 6, such that the first thermal medium 3 can be stored in the first reservoir 7. The first header 6 is provided above the lower face of the first upper reservoir 7.
The first inlet 8 is shaped-like a tube, and its one end communicates with the first upper reservoir 7. More specifically, the first inlet 8 communicates with a lower portion of the first upper reservoir 7, and is provided below the lower face of the first header 6. While it is desirable that the first upper reservoir 7 is formed in a direction perpendicular to the direction of streamline of the first inlet 8, the first upper reservoir 7 may be inclined and extend upwards relative to the direction of streamline of the first inlet 8. With this arrangement, when the first thermal medium 3 flows into the first upper reservoir 7 through the first inlet 8, pulsation of the first thermal medium 3, which would occur when the amount of the introduced first thermal medium 3 increases or decreases, is absorbed in the first upper reservoir 7.
The thermal storage device 4 is further provided with a first footer 9 that communicates with the lower end portions of the first thermal medium branch pipes 5. More specifically, the first footer 9 is provided in the lower part of the thermal storage device 4 such that a hollow is formed in the interior of the first footer 9, and such that the lower face of the first footer 9 is parallel with the bottom face of the thermal storage device 4. With this arrangement, the first thermal medium 3 is stored in the first footer 9. Here, the areas of the upper and lower faces of the first footer 9 are made as large as possible.
Since the first footer 9 communicates at its upper face with the first thermal medium branch pipes 5, and the first thermal medium branch pipes 5 are evenly arranged over the upper face of the first footer 9 within the thermal storage device 4, the stored cool can be uniformly delivered out of the thermal storage material 1 in the thermal storage device 4 via the first thermal medium 3 flowing through the first thermal medium branch pipes 5. The lower end portions of the first thermal medium branch pipes 5 may or may not protrude downwards into the first footer 9 as long as the first thermal medium 3 can flow between the first thermal medium branch pipes 5 and the first footer 9. The first thermal medium branch pipes 5 and the first footer 9 are joined to each other by, for example, welding.
The thermal storage device 4 is also provided with a first lower reservoir 10 that communicates with the first footer 9, and a first outlet 11 that communicates with the first lower reservoir 10. More specifically, the first lower reservoir 10 is a hollow formed in a lower part of the above-indicated one side portion of the thermal storage device 4 in which the first upper reservoir 7 is formed. The first outlet 11 is attached to one outside surface of the first lower reservoir 10, namely, to a side wall of the thermal storage device 4 which partially defines the first upper reservoir 7 and the first lower reservoir 10. The first lower reservoir 10 communicates with the first footer 9 at a location below the face of the first lower reservoir 10 opposed to the face to which the first outlet 11 is attached. While it is desirable that the first lower reservoir 10 is perpendicular to the lower face of the first footer 9, the first lower reservoir 10 may be inclined upwards relative to the lower face of the first footer 9. With this arrangement, the first thermal medium 3 can be stored in the first lower reservoir 10. The first footer 9 is provided below the upper face of the first lower reservoir 10.
The first outlet 11 is shaped like a tube, and communicates at one end thereof with the first lower reservoir 10. In this thermal storage device 4, it is desirable that the first lower reservoir 10 is formed in a direction perpendicular to the direction of streamline of the first outlet 11. However, the first lower reservoir 10 may not necessarily be formed in this direction, but may be inclined and extends downwards relative to the direction of streamline of the first outlet 11.
As shown in FIG. 2, an inclined face 12 is formed within the first upper reservoir 7, such that the inclined face 12 extends from a lower portion of the first upper reservoir 7 to an upper portion thereof. The inclined face 12 is provided by a slope that is formed in the bottom face of the first upper reservoir 7 so as to extend from the vicinity of a point at which the first inlet 8 is attached, toward the top of the thermal storage device 4, along the side face to which the first inlet 8 is attached. In other words, the area of a cross-section of the first upper reservoir 7 taken in a direction parallel to the lower face of the first header 6 is relatively small on the lower side of the reservoir 7, and increases toward the upper side thereof. Accordingly, as the amount of storage of the first thermal medium 3 introduced from the first inlet 8 increases, the amount of a rise in the liquid level of the first thermal medium 3 in the first upper reservoir 7 is reduced. Thus, a change in the amount of flow of the first thermal medium 3 fed from the first inlet is reduced when the medium 3 flows into the first header 6. Also, the provision of the inclined face 12 makes it possible to reduce a loss (pressure loss) encountered when the liquid level of the first thermal medium 3 introduced from the first inlet 8 rises in the first upper reservoir 7.
Next, passages through which the second thermal medium 2 in the form of a coolant circulates will be explained. The thermal storage device 4 is provided with a plurality of second thermal medium branch pipes 13 through which the second thermal medium 2 flows, such that the branch pipes 13 are inserted through the thermal storage material 1, and such that the outer peripheries of the branch pipes 13 are surrounded by the thermal storage material 1. More specifically, the plurality of second thermal medium branch pipes 13 are arranged to extend in directions perpendicular to the bottom face of the thermal storage device 4 so as to allow the second thermal medium 2 to flow in the vertical direction of the thermal storage device 4. Since the thermal storage material 1 is in contact with the outer peripheries of the second thermal medium branch pipes 13, heat (or thermal energy) exchange takes place between the thermal storage material 1 and the second thermal medium 2 flowing though the second thermal medium branch pipes 13.
The thermal storage device 4 is also provided with a second header 14 that communicates with the upper portions of the second thermal medium branch pipes 13 and allows the second thermal medium to flow therethrough. More specifically, the second header 14 has a hollow formed therein, and the second thermal medium 2 is stored in the second header 14. The second header 14 that communicates with the upper portions of the second thermal medium branch pipes 13 is provided in the upper portion of the thermal storage device 4, such that the lower face of the second header 14 is in parallel with the lower face of the thermal storage device 4. Thus, the second thermal medium 2 flows substantially uniformly in the second header 14.
The second thermal medium branch pipes 13 communicate with the second header 14. While the upper ends of the second thermal medium branch pipes 13 protrude upwards into the second header 14 in the example shown in FIG. 1, the upper ends of the second thermal medium branch pipes 13 may not protrude into the second header 14 as long as the second thermal medium 2 can flow between the second header 14 and the second thermal medium branch pipes 13. The second header 14 and the second thermal medium branch pipes 13 are joined to each other by, for example, welding. Where the second header 14 is disposed under the first header 6, the first thermal medium branch pipes 5 extend through the second header 14 and communicate with the first header 6.
Here, the first header 6 and the second header 14 are in contact with each other in the upper portion of the. thermal storage device 4. More specifically, the second header 14 is disposed under the first header 6, and the lower face of the first header 6 and the upper face of the second header 14 are in contact with each other. With this arrangement, heat (or thermal energy) exchange takes place between the first thermal medium 3 stored in the first header 6 and the second thermal medium 2 stored in the second header 14.
The thermal storage device 4 is further provided with a second upper reservoir 15 that communicates with the second header 14 and stores the second thermal medium, and a second outlet 16 that communicates with the second upper reservoir 15 and allows the second thermal medium to flow therethrough. The second upper reservoir 15 extends upwards in a direction intersecting with the direction of streamline of the second outlet 16. More specifically, the second upper reservoir 15 has a hollow formed therein, and the second thermal medium 2 is stored in the second upper reservoir 15.
The second upper reservoir 15 communicates with the second header 6 at a location above the face of the second upper reservoir 15 to which the second outlet 16 is not attached, namely, the face opposed to the face to which the second outlet 16 is attached. While it is desirable that the second upper reservoir 15 is perpendicular to the lower face of the second header 14, the second upper reservoir 15 may be inclined downwards relative to the lower face of the second header 14. The second header 14 is provided above the lower face of the second upper reservoir 15.
In the thermal storage device 4, the first upper reservoir 7 and the second upper reservoir 15 are arranged to be in contact with each other. More specifically, the second upper reservoir 15 is provided inside the first upper reservoir 7, and the inner side face of the first upper reservoir 7 and the outer side face of the second upper reservoir 15 are in contact with each other. In other words, the side face of the first upper reservoir 7 closer to the first header 6 and the side face of the second upper reservoir 15 remote from the second header 14 are in contact with each other. With this arrangement, heat exchange takes place between the first thermal medium 3 stored in the first upper reservoir 7 and the second thermal medium 2 stored in the second upper reservoir 15.
The second outlet 16 is shaped like a tube, and is provided at the lower side of the second upper reservoir 15 such that one end of the second outlet 16 communicates with the second upper reservoir 15. While it is desirable that the second upper reservoir 15 extends in a direction perpendicular to the direction of streamline of the second outlet 16, the second upper reservoir 15 may be inclined and extend upwards relative to the direction of streamline of the second outlet 16.
The thermal storage device 4 is further provided with a second footer 17 that communicates with the lower portions of the second thermal medium branch pipes 13. More specifically, the second footer 17 is provided in a lower portion of the thermal storage device 4, such that a hollow is formed in the interior of the second footer 17 and the lower face of the second footer 17 is in parallel with the bottom face of the thermal storage device 4. Thus, the second thermal medium 2 flows into the second footer 17.
The upper face of the second footer 17 is given a large area, and the second thermal medium branch pipes 13 are evenly arranged over the upper face of the second footer 17, so that thermal energy of the coolant is evenly or uniformly stored in the interior of the thermal storage device 4. Thus, the second thermal medium 2 flows substantially uniformly in the second footer 17. The lower end portions of the second thermal medium branch pipes 13 may or may not protrude downwards into the second footer 17 as long as the second thermal medium 2 can flow between the second thermal medium branch pipes 13 and the second footer 17 that communicate with each other.
The second footer 17 and the second thermal medium branch pipes 13 are joined to each other by, for example, welding. In the present embodiment, the second footer 17 is disposed above the first footer 9. In this case, the first thermal medium branch pipes 5 extend through the second footer 17, and communicate with the first footer 9.
The thermal storage device 4 is also provided with a second lower reservoir 18 that communicates with the second footer 17, and a second inlet 19 that communicates with the second lower reservoir 18. The second lower reservoir 18 has a hollow formed therein, and the second inlet 19 communicates with the upper portion of the second lower reservoir 18. The second lower reservoir 18 communicates with the second footer 17 at an end portion of the second lower reservoir 18 on the side where the second inlet 19 is not attached, in other words, at a location below the face of the second lower reservoir 18 opposed to the face to which the second inlet 19 is attached. While it is desirable that the second lower reservoir 18 is perpendicular to the lower face of the second footer 17, the second lower reservoir 18 may be inclined upwards relative to the lower face of the second footer 17.
The second inlet 19 is shaped like a tube, and communicates at one end thereof with the second lower reservoir 18. In the thermal storage device 4, the second lower reservoir 18 is formed in a direction intersecting with the direction of streamline of the second inlet 19. While it is desirable that the second lower reservoir 18 is formed in a direction perpendicular to the direction of streamline of the second inlet 19, the invention is not limited to this arrangement, but the second lower reservoir 18 may be inclined and extend downwards relative to the direction of streamline of the second inlet 19.
In the thermal storage device 4, the first thermal medium branch pipes 5 and the second thermal medium branch pipes 13 are arranged in parallel with each other, and the thermal storage material 1 is provided between the first thermal medium branch pipes 5 and the second thermal medium branch pipes 13. Therefore, cool is transmitted from the second thermal medium 2 flowing through the second thermal medium branch pipes 13 to the thermal storage material 1, and is stored in the thermal storage material 1. At this time, the thermal storage material 1 takes cool out of the second thermal medium 2, and the state of the second thermal medium 2 changes from a liquid state to a gaseous or vapor state. Also, the cool stored in the thermal storage material 1 is transmitted to the first thermal medium 3 flowing through the first thermal medium branch pipes 5.
The first thermal medium branch pipes 5 and the second thermal medium branch pipes 13 may contact with each other within the thermal storage device 4. In this case, direct heat (or thermal energy) exchange takes place between the first thermal medium 3 flowing through the first thermal medium branch pipes 5 and the second thermal medium 2 flowing through the second thermal medium branch pipes 13, at portions where the first thermal medium branch pipes 5 contact with the second thermal medium branch pipes 13.
FIG. 3 is a schematic view illustrating a circulation system through which the first thermal medium 3 in the form of brine circulates. A flow passage through which the first thermal medium 3 flows within the thermal storage device 4 forms a part of a circulation path through which the first thermal medium 3 circulates between the thermal storage device 4 and a heat exchanger 24, such as a heat exchanger installed on the vehicle-compartment side. A pump 25 is interposed between the thermal storage device 4 and the heat exchanger 24 in the circulation path. The flow passage specifically refers to a passage that extends from the first inlet 8 to the first outlet 11 via the first upper reservoir 7, first header 6, each of the first thermal medium branch pipes 5, first footer 9, and the first lower reservoir 10.
FIG. 4 is a schematic view illustrating a circulation system through which the second thermal medium 2 in the form of a coolant circulates. The circulation system includes a compressor 20 driven by a power source (not shown), such as an engine of the vehicle, and a condenser 21, a receiver tank 22 and an expansion valve 23 which are connected in this order to the discharge side of the compressor 20. The second inlet 19 is connected to the discharge side of the expansion valve 23, and the second outlet 16 that is not connected to the discharge side of the expansion valve 23 is connected to the inlet side of the compressor 20.
FIG. 5 illustrates a thermal storage device 24 according to a second embodiment of the invention, in which the first thermal medium 3 in the form of brine delivers cool or thermal cooling out of the thermal storage material 1, and the second thermal medium 2 in the form of a coolant introduces cool into the thermal storage material 1, as in the thermal storage device 4 of FIG. 1. In the thermal storage device 24, a plurality of plate-like tubes are arranged to extend in a direction (vertical direction) substantially perpendicular to the bottom face of the thermal storage device 24, and the thermal storage material 1 is provided between the plate-like tubes. The first thermal medium branch pipes 5 and the second thermal medium branch pipes 13 extend along the vertical direction of the plate-like tubes. In FIG. 5, the same reference numerals as used in FIG. 1 are used for identifying the same or corresponding constituent elements as those of the thermal storage device 4 as shown in FIG. 1, and explanation of these elements not he provided.
In the thermal storage device 24, the first thermal medium branch pipes 5 are formed in the vertical direction of first plate-like tubes 26, and the second thermal medium branch pipes 13 are formed in the vertical direction of second plate-like tubes 27. As shown in FIG. 6, each of the first plate-like tubes 26 and the second plate-like tubes 27 is fabricated by joining mutually opposed, two heat transfer plates 28, 29 to each other. Each of the heat transfer plates 28, 29 have elongated projections 28A, 29A that are formed by bending at certain intervals in substantially parallel with the vertical direction, and a hollow is formed inside each elongated projection 28A, 29A. Each of the heat transfer plates 28, 29 also includes flat portions 28B, 29B located between the corresponding elongated projections 28A, 29A. Each of the elongated projections 28A, 29A may have any desired cross-sectional shape, such as a triangle, a quadrangle, or a semicircle. In the example of FIG. 6, the cross-sectional shape of each elongated projection 28A, 29A is a triangle whose bottom is provided by the corresponding flat portion 29B, 28B of the heat transfer plate 29, 28 that is opposed to the heat transfer plate 28, 29 having the elongated projection 28A, 29A. Namely, the hollow formed in each of the elongated projections 28A, 29A is open to the mating faces of the corresponding heat transfer plates 28, 29. Since the heat transfer plates 28, 29 are joined to each other such that the elongated projections 28A, 29A of one of the heat transfer plates 28, 29 are opposed to the flat portions 29B, 28B of the other heat transfer plate 29, 28, the hollows formed in the elongated projections 28A, 29A of the above-indicated one heat transfer plate 28, 29 are respectively closed by the flat portions 29B, 28B of the other heat transfer plate 29, 28. The hollows thus formed provide grooves that extend in the vertical direction of the thermal storage device 24. The first thermal medium branch pipes 5 and the second thermal medium branch pipes 13 are disposed in the grooves thus formed inside the respective elongated projections 28A, 29A.
As shown in FIG. 5, the first plate-like tubes 26 and the second plate-like tubes 27 are arranged in parallel with each other, to extend in a direction substantially perpendicular to the bottom face of the thermal storage device 24, and in a direction perpendicular to a side face (which will be referred to as “inlet/outlet-side side face”) of the thermal storage device 24 which is provided with the first inlet 8, second inlet 19, first outlet 11 and the second outlet 16. The first plate-like tubes 26 extend through the lower face of the first header 9 and the upper face of the first footer 9. When viewed from above the thermal storage device 24, the upper end portions of the first plate-like tubes 26 that extend through the lower face of the first header 6 are oriented so as to be in parallel with the direction of the flow path of the first thermal medium 3 that flows in the first header 6. Thus, the thermal storage device 24 incorporating the first plate-like tubes 26 provides a pressure-resistant structure that is resistant to pressures in the vertical direction and the direction of the flow path of the first thermal medium 3 flowing in the first header 6. The direction of the flow path of the first thermal medium 3 flowing in the first header 6 refers to a direction of stream-like flow from the inlet/outlet-side side face of the thermal storage device 24 toward the opposite side face.
The first plate-like tubes 26 may extend through at least one of the second upper reservoir 15 and the second lower reservoir 18. More specifically, since the planes of the first plate-like tubes 26 are perpendicular to the bottom face of the thermal storage device 24 and are perpendicular to the inlet/outlet-side side face, the first plate-like tubes 26 extend through at least one of the second upper reservoir 15 and the second lower reservoir 18 in a direction substantially perpendicular to the bottom face of the thermal storage device 24 and perpendicular to the inlet/outlet-side side face. The reservoirs and the first plate-like tubes 26 are joined to each other by, for example, welding.
Where the second header 14 is disposed under the first header 6, the first plate-like tubes 26 extend through the second header 14 as well as the lower face of the first header 6. Furthermore, where the second footer 17 is disposed above the first footer 9, the first plate-like tubes 26 extend through the second footer 17 as well as the upper face of the first footer 9.
FIG. 7 shows a modified example of the thermal storage device 24 in which a plurality of holes 30 are formed in a part of the first plate-like tubes 26 that extend through at least one of the reservoirs. As described above, the first plate-like tubes 26 extend through at least one of the second upper reservoir 15 and the second lower reservoir 18, in the direction perpendicular to the bottom face of the thermal storage device 24 and perpendicular to the inlet/outlet-side side face. With the plurality of holes 30 thus provided, the second thermal medium stored in the reservoir(s) can move in the reservoir(s). The holes 30 may have a circular, triangular, rectangular, or any other shape, provided that the second thermal medium stored in the reservoir(s) can flow through the holes 30. Since the first plate-like tubes 26 extend through the reservoirs, the thermal storage device 24 provides a pressure-resistant structure that is resistant to pressures in the vertical direction and the direction of the flow path of the first thermal medium 3 flowing in the first header 6.
Also, the second plate-like tubes 27 extend through the lower face of the second header 14 and the upper face of the second footer 17. When viewed from above the thermal storage device 24, the upper end portions of the second plate-like tubes 27 that extend through the lower face of the second header 14 are oriented so as to be in parallel with the direction of the flow path of the second thermal medium 2 flowing in the second header 14. Thus, the thermal storage device 24 incorporating the second plate-like tubes 26 provides a pressure-resistant structure that is resistant to pressures in the vertical direction and the direction of the flow path of the second thermal medium 2 flowing in the second header 14. The direction of the flow path of the second thermal medium 2 flowing in the second header 14 refers to a direction of stream-like flow from the inlet/outlet-side side face of the thermal storage device 24 toward the opposite side face.
The second plate-like tubes 27 may extend through at least one of the second upper reservoir 15 and the second lower reservoir 18. More specifically, since the planes of the second plate-like tubes 27 are perpendicular to the bottom face and inlet/outlet-side side face of the thermal storage device 24, the second plate-like tubes 27 extend through at least one of the second upper reservoir 15 and the second lower reservoir 18 in the direction perpendicular to the bottom face and inlet/outlet-side side face of the thermal storage device 24. The reservoirs and the second plate-like tubes 27 are joined to each other by, for example, welding.
The second plate-like tubes 27 that extend through at least one of the reservoirs is provided with a plurality of holes 30. The holes 30 may have a circular, triangular, rectangular, or any other shape, provided that the second thermal medium 2 stored in the reservoir(s) can flow through the holes 30. Since the second plate-like tubes 27 extend through the reservoir(s), the thermal storage device 24 provides a pressure-resistant structure that is resistant to pressures in the vertical direction and the direction of the flow path of the second thermal medium 2 that flows in the second header 14.
In the embodiments described above, carbon dioxide may be used as a coolant, which may serve as the second thermal medium 2, for example, and sodium chloride fluid can be used as brine, which may serve as the first thermal medium 3, for example.
In the embodiments described above, the thermal storage device being in the form of a prism having a quadrangular bottom face is explained with an example. However the thermal storage device of the invention is not limited to such form. For example, the thermal storage device may be formed in a cylindrical shape.
While the invention has been described with reference to the exemplary embodiments thereof, it is to be understood that the invention is not limited to the exemplary embodiments and constructions. To the contrary, the invention is intended to cover various modifications and equivalent arrangements.
In addition, while the various elements of the exemplary embodiments are shown in various combinations and configurations, which are exemplary, other combinations and configurations, including more, less or only a single element, are also within the scope of the invention.

Claims

1. A thermal storage device comprising:

a plurality of tube-like first thermal medium branch pipes into which a first thermal medium flows;

a thermal storage material provided on the outer peripheries of the first thermal medium branch pipes;

a first header that communicates with upper portions of the first thermal medium branch pipes and allows the first thermal medium to flow therethrough;

a first upper reservoir that communicates with the first header and stores the first thermal medium; and

a first inlet that communicates with the first upper reservoir and allows the first thermal medium to flow therethrough,

wherein the first upper reservoir is formed in a direction intersecting with a direction of streamline of the first inlet,

the first header is provided above a lower face of the first upper reservoir, and

the first upper reservoir is perpendicular to or inclined downwards relative to a lower face of the first header.

2. A thermal storage device comprising:

the first upper reservoir is formed in the upper part of the thermal storage device and in a direction intersecting with a direction of streamline of the first inlet, and

the first header is disposed in the upper part of the thermal storage device above a lower face of the first upper reservoir and the first upper reservoir is located in one side portion of the thermal storage device.

3. The thermal storage device according to claim 1, wherein

the first upper reservoir has a bottom face that is inclined upwards from a lower portion of the upper reservoir.

4. The thermal storage device according to claim 3, wherein

a cross-sectional area of the first upper reservoir when cut in a direction parallel to a lower face of the first header is smaller in a lower portion of the first upper reservoir than in an upper portion thereof, and the cross-sectional area increases from the lower portion toward the upper portion.

5. The thermal storage device according to claim 1, further comprising:

a plurality of second thermal medium branch pipes through which a second thermal medium flows;

a second header that communicates with upper portions of the second thermal medium branch pipes and allows the second thermal medium to flow therethrough;

a second upper reservoir that communicates with the second header, and stores the second thermal medium; and

a second outlet that communicates with the second upper reservoir and allows the second thermal medium to flow therethrough,

wherein the thermal storage material is provided on the outer peripheries of the second thermal medium branch pipes, and the second upper reservoir is formed in a direction intersecting with a direction of streamline of the second outlet, while the first upper reservoir and the second upper reservoir are in contact with each other.

6. The thermal storage device according to claim 5, wherein the first header and the second header are in contact with each other.

7. The thermal storage device according to claim 1, further comprising:

a plurality of first plate-like tubes that are arranged in parallel with each other to extend in a vertical direction of the thermal storage device, wherein

the first thermal medium branch pipes are disposed in the vertical direction of the first plate-like tubes.

8. The thermal storage device according to claim 5, further comprising:

a plurality of second plate-like tubes that are arranged In parallel with each other to extend in a vertical direction of the thermal storage device, wherein

the second thermal medium branch pipes are disposed in a vertical direction of the second plate-like tubes.

9. The thermal storage device according to claim 8, further comprising:

a plurality of first plate-like tubes that are arranged in parallel with each other to extend in the vertical direction of the thermal storage device, wherein

the first thermal medium branch pipes are disposed in a vertical direction of the first plate-like tubes, and

the first plate-like tubes and the second plate-like tubes are arranged in parallel with each other so as to be perpendicular to an inlet/outlet-side side face of the thermal storage device in which the first inlet and the second outlet are provided.

10. The thermal storage device according to claim 9, wherein

each of the first plate-like tubes and the second plate-like tubes is formed by joining two heat transfer plates to each other; and

the first thermal medium branch pipes and the second thermal medium branch pipes are inserted through grooves formed in mating faces of the two heat transfer plates.

11. The thermal storage device according to claim 9, further comprising:

a second footer that communicates with lower portions of the second thermal medium branch pipes and allows the second thermal medium to flow therethrough;

a second lower reservoir that communicates with the second footer, and stores the second thermal medium; wherein

the first plate-like tubes extend through at least one of the second upper reservoir and the second lower reservoir, and at least one hole is formed in the first plate-like tubes.

12. The thermal storage device according to claim 9, further comprising:

the second plate-like tubes extend through at least one of the second upper reservoir and the second lower reservoir, and at least one hole is formed in the second plate-like tubes.

13. The thermal storage device according to claim 11, wherein

14. The thermal storage device according to claim 1, wherein the first thermal medium comprises brine, and the second thermal medium comprises a coolant.

15. A circulation system comprising:

the thermal storage device according to claim 1; and

a heat exchanger, wherein

the first thermal medium circulates between the thermal storage device and the heat exchanger.

16. The circulation system according to claim 15, further comprising:

a compressor;

a condenser;

a receiver tank; and

an expansion valve, wherein

the second thermal medium circulates between the thermal storage device and the compressor, and the condenser, the receiver tank and the expansion valve are connected in the order of description between the compressor and the thermal storage device.

17. The thermal storage device according to claim 2, wherein

18. The thermal storage device according to claim 2, further comprising:

19. The thermal storage device according to claim 2, further comprising:

20. The thermal storage device according to claim 2, wherein the first thermal medium comprises brine, and the second thermal medium comprises a coolant.

21. A circulation system comprising:

the thermal storage device according to claim 2; and

a heat exchanger, wherein