HEAT EXCHANGE DEVICE

BACKGROUND OF THE INVENTION 1. Field of the Invention [000l3 The invention relates to a heat exchange device in which heat exchange takes place between a first thermal medium or a second thermal medium flowing through channels formed in plate-shaped tubes, and a thermal storage material that is in contact with the channels.

2. Description of the Related Art

[0002] Heat exchange devices in which heat transfer plates in the form of corrugated plates are laminated on each other to form channels for thermal media are disclosed in, for example, Japanese Patent Application Publication No.

10-232093 (JP-A-10-232093), Japanese Patent Application Publication No. 11-173771 (JP-A-11-173771) and Japanese Patent Application Publication No.

10-122770 (JP-A-10-122770). More specifically, JP-A- 10-232093 discloses a thermal storage device in which heat transfer plates having protrusions and recesses in the form of sine waves are formed of copper or aluminum, and the heat transfer plates are laminated or stacked together. In the device disclosed in JP- A- 10-232093, channels are formed within the corrugated heat transfer plates

(namely, the channels are defined by the protrusions and recesses), and a thermal medium is caused to flow through the channels. JP-A-11-173771 discloses a heat exchanger in which heat transfer plates are laminated on one another, and channels for a thermal medium are formed between the heat transfer plates. The heat transfer plates have protrusions that contact with each other so as to define coolant channels through which a coolant flows, and protrusions that contact with each other so as to define thermal-medium channels through which a thermal medium, such as water, flows. The protrusions that define the coolant channels are joined or bonded to each other, and the protrusions that define the

thermal-medium channels are not joined or bonded to each other. With this arrangement, when the volume of the thermal medium expands, certain parts of the heat transfer plates can be easily deformed since the mutually contacting protrusions that define the thermal-medium channels are not joined to each other. As a result, the volume expansion of the thermal medium is absorbed, and deformation of the heat exchanger is prevented. JP-A- 10- 122770 discloses a heat exchanger similar to that of JP-A- 11-173771, in which heat transfer plates are laminated on one another to form channels.

[0003] In the heat exchanger or thermal storage device as disclosed in each of the above-identified publications, the heat transfer plates are laminated or stacked together to provide a multi-layered assembly in which channels for heat transfer media (thermal media) are formed. Tb make it easy to join the heat transfer plates together when forming the channels, the recesses formed by press molding in the heat transfer plates are opposed to each other and joined to each other. However, since the recesses of the upper and lower heat transfer plates are opposed to each other to form a single channel, only one channel is formed with respect to two protrusions of the upper and lower heat transfer plates, resulting in a relatively small number of channels that can be formed by each pair of plates.

Accordingly, the area of heat exchange between the thermal medium flowing through the channels and the thermal medium around the heat transfer plates is reduced.

[0004) There is also known a thermal storage device constructed such that a cool storage material or heat storage material is interposed between plate-shaped tubes in which channels through which a heat transfer fluid flows are formed by laminated heat transfer plates. In this type of thermal storage device, however, the plate-shaped tubes are likely to receive stress due to expansion and contraction that occur when the cool storage material or heat storage material interposed between the plate-shaped tubes repeatedly fuses (or freezes) and coagulates (or thaws), which may result in deformation of the plate-shaped tubes.

SUMMARY OF THE INVENTION

[0005] It is an object of the invention to provide a heat exchange device that is able to easily expand the area of heat exchange of heat transfer plates that are joined to each other to form channels for a thermal medium.

[0006] According to a first aspect of the invention, there is provided a heat exchange device including a plate-shaped tube in which a plurality of channels through which a first thermal medium or a second thermal medium flows are formed, and a thermal storage material that exchanges heat with the first thermal medium or the second thermal medium. In this device, the plate-shaped tube is disposed in the thermal storage material, and is formed by joining two plates into a laminated form. Also, each of the plates has a plurality of elongated projections that protrude in a direction opposite to mating faces of the plates and have respective hollows formed therein, and a plurality of flat portions located between the elongated projections, and openings of the hollows formed in one of the two plates are closed by the corresponding flat portions of the other plate so that the hollows provide the above -indicated plurality of channels.

[0007] According to a second aspect of the invention, there is provided a heat exchange device including a plate-shaped tube in which a plurality of channels through which a first thermal medium or a second thermal medium flows are formed, and a thermal storage material that exchanges heat with the first thermal medium or the second thermal medium. In this device, the plate-shaped tube is disposed in the thermal storage material, and is formed by joining two plates into a laminated form. Also, each of the plates has a plurality of elongated projections that protrude in a direction opposite to mating faces of the plates and have respective hollows formed therein, and a plurality of flat portions located between the elongated projections, and openings of the hollows formed in one of the two plates face those of the hollows formed in the other plate, so that the hollows defined by the elongated protrusions of the two plates provide the above-indicated plurality of channels.

[0008] In the heat exchange device according to the first or second aspect of the invention, a plurality of plate-shaped tubes each provided by the plate-shaped tube as described above may be arranged in parallel with each other at predetermined intervals, and the thermal storage material that fills space between the plate-shaped tubes may be a thermal storage material that fuses when heated and coagulates when cooled. The plate-shaped tubes may be arranged such that the elongated projections of one of the plate-shaped tubes are opposed to the flat portions of an adjacent one of the plate-shaped tubes which is located adjacent to the above -indicated one of the plate-shaped tubes.

[0009] In the heat exchange device as described above, the plate-shaped tubes may include first plate-shaped tubes through which the first thermal medium flows and second plate-shaped tubes through which the second thermal medium flows. At least one of the first plate-shaped tubes and at least one of the second plate-shaped tubes may be adjacent.

^■ [OOIO] In the heat exchange device according to the first or second aspect of the invention, the elongated projections of one of the plate-shaped tubes have outside faces that are inclined relative to the flat portions of an adjacent one of the plate-shaped tubes.

[0011] In the heat exchange device according to the first aspect of the invention, each of the elongated projections of one of the two plates may be shaped like a triangle in cross section, and the corresponding flat portion of the other plate may provide a bottom of the triangle.

[0012] According to the first aspect of the invention, the channels defined by the elongated projections and the flat portions are disposed in the thermal storage material, and therefore, one channel is formed with respect to each of the projections of the plates. Thus, the area of contact between the channels and the thermal storage material becomes larger than that in the case where the recesses of the upper and lower plates are opposed to each other to form a single channel. Accordingly, heat exchange between the thermal storage material and the first

thermal medium or second thermal medium flowing through the channels is effected with improved efficiency. Typical examples of the plates are heat transfer plates.

[0013] According to the first or second aspect of the invention, heat exchange between the first thermal medium or second thermal medium and the thermal storage material takes place at the elongated projections and the flat portions. Therefore, the thermal storage material coagulates (or freezes) along the elongated projections and the flat portions when a coolant as the second thermal medium flows through the channels, and the thermal storage material fuses (or thaws) along the elongated projections and the flat portions when brine as the first thermal medium flows through the channels and the thermal storage material is coagulated (or frozen). Here, the elongated projections of one of the plate-shaped tubes are arranged so as to be opposed to the flat portions of an adjacent one of the plate-shaped tubes located adjacent to the above-indicated one plate-shaped tube. Therefore, stress that arises from coagulation and fusion of the thermal storage material along the flat portions of the above-indicated one plate -shaped tube is applied to the elongated projections of the other (or adjacent) plate-shaped tube, so that the stress applied to the other plate-shaped tube at the elongated projections can be alleviated or reduced. [0014] Furthermore, part of stress that arises from coagulation and fusion of the thermal storage material along the elongated projections of one of the plate-shaped tubes is applied to an adjacent one of the plate-shaped tubes in the horizontal direction, and therefore, the stress applied to the other (or adjacent) plate-shaped tube can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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 perspective view showing the outward appearance of a heat exchange device according to a first embodiment of the invention;

FIG. 2 is an enlarged, lateral cross-sectional view showing a principal part of a plate-shaped tube used in the heat exchange device of FIG. 1»

FIG. 3 is an enlarged, lateral cross-sectional view showing a principal part of the main body of the heat exchange device;

FIG. 4 is a lateral cross-sectional view illustrating an example of operating condition of the heat exchange device when it stores cook FIG. 5 is a lateral cross-sectional view illustrating another example of operating condition of the heat exchange device when it stores cooL

FIG. 6 is a lateral cross-sectional view illustrating an operating condition of a heat exchange device according to another embodiment of the invention when the device stores cool; FIG. 7 is a lateral cross-sectional view showing a modified example of the plate-shaped tube used in the heat exchange device according to the first embodiment of the invention _* and

FIG. 8 is a lateral cross-sectional view showing another modified example of the plate-shaped tube used in the heat exchange device according to the first embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] Some exemplary embodiments of the invention will be described.

The heat exchange device of this invention is able to store both positive heat (or heat) that increases thermal energy and negative heat (cool) that reduces thermal energy. In the following description, specific examples arranged to store cool or thermal cooling will be illustrated. FIG. 1 is a schematic perspective view of a heat exchange device 1 according to a first embodiment of the invention. The heat exchange device 1 as shown in FIG. 1 includes plate-shaped tubes 4 in each of

which a plurality of channels through which a first thermal medium 2 or a second thermal medium 3 flows are formed. The plate-shaped tubes 4 are disposed in a heat storage material 5 that exchanges heat with the first thermal medium 2 or the second thermal medium 3. The plate-shaped tubes 4, which are provided in the interior of the heat exchange device 1, are arranged in parallel with each other at certain intervals in one of the lateral (width) direction α, vertical (depth) direction β, and the height direction γ.

[0017] Referring to FIG. 1, an inlet tube 6a for a coolant as the first thermal medium 2 is provided on one side of the heat exchange device 1 so as to extend through an outer wall of the heat exchange device 1 and communicate with a space (not shown) provided at one of the opposite ends of the plate-shaped tubes 4.

Also, an outlet tube 7a for the coolant as the first thermal medium 2 is provided on the same side of the heat exchange device 1 so as to extend through the outer wall of the device 1 and communicate with a space (not shown) provided at the other end of the plate-shaped tubes 4 located opposite to the above-indicated one end of the plate -shaped tubes 4. Furthermore, an inlet tube 6b for brine as the second thermal medium 3 is provided on the same side of the heat exchange device 1 so as to extend through the outer wall of the device 1 and communicate with a space (not shown) that is provided at the other end of the plate-shaped tubes 4 and is not in fluid communication with the outlet pipe 7a. Moreover, an outlet tube 7b for brine is provided on the same side of the heat exchange device 1 so as to extend through the outer wall of the device 1 and communicate with a space (not shown) that is provided at the above-indicated one end of the plate-shaped tubes 4 and is not in fluid communication with the inlet tube 6a. [0018] FIG. 2 is a cross-sectional view showing one example of plate-shaped tube 4 disposed inside the heat exchange device 1 as described above. The plate-shaped tube 4 shown in FIG. 2 consists of two heat transfer plates 8, 9 corresponding to the plates of the invention, which are opposed to and joined to each other. Each of the heat transfer plates 8, 9 has elongated projections 8A, 9A

that are formed by bending at predetermined intervals, substantially in parallel with each other, such that hollows are.formed within the respective projections 8A,

9A. Each heat transfer plate 8, 9 also has flat portions 8B, 9B formed between the elongated projections 8A, 9A, respectively. While the cross-sectional shape of each of the elongated projections 8A, 9A is a triangle whose bottom is provided by the corresponding flat portion 9B or 8B of the other heat transfer plate 9, 8 in the example of FIG. 2, the projection 8A, 9A may have any desired cross-sectional shape, such as a rectangle or a semicircle, as shown in FIG. 7 and FIG. 8. The hollow formed inside each of the elongated projections 8A, 9A is open to the mating faces of the heat transfer plates 8, 9, to thus provide a groove that extends in the longitudinal direction of the elongated projection 8A, 9A. The heat transfer plates

8, 9 are joined to each other such that the elongated projections of one of the heat transfer plates 8, 9 are opposed to the flat portions of the other heat transfer plate

9, 8. Accordingly, the opening of the hollow formed in each elongated projection of the above-indicated one heat transfer plate is closed by the flat portion of the opposite (other) heat transfer plate. In this manner, a channel 10 is formed inside each of the elongated projections 8A, 9A.

[0019] The channels 10 formed in the plate-shaped tubes 4 communicate with the space (not shown) that communicates with the inlet tube 6a at the above -indicated one end of the plate-shaped tubes 4, and communicate with the space (not shown) that communicates with the outlet tube 7a at the other end of the plate-shaped tubes 4. Also, the channels 10 communicate with the space (not shown) that communicates with the outlet tube 7b at the above-indicated one end of the plate-shaped tubes 4, and communicate with the space (not shown) that communicates with the inlet tube 6b at the other end of the plate-shaped tubes 4. With this arrangement, the coolant introduced into the heat exchange device 1 through the inlet tube 6a flows toward the outlet tube 7a via the channels 10 formed inside the elongated projections 8A ₁ 9A. Also, the brine introduced into the heat exchange device 1 through the inlet tube 6b flows toward the outlet tube

7b via the channels 10 formed inside the elongated projections 8A, 9A.

[0020] FIG. 3 is an enlarged, lateral cross-sectional view showing the internal construction of the heat exchange device 1 that incorporates the plate-shaped tubes 4. The plate-shaped tubes 4 shown in FIG. 3 are arranged in parallel with each other at predetermined intervals. More specifically, the thermal storage material 5 as another thermal medium different from the coolant and brine is sandwiched by and between the adjacent plate-shaped tubes 4 such that the material 5 is in contact with the plate-shaped tubes 4, and the plate-shaped tubes 4 are arranged in parallel with each other while being spaced at certain intervals. The coolant as the first thermal medium 2 or brine as the second thermal medium 3 flows through the channels 10 of the plate-shaped tubes

4, so that heat exchange takes place between the coolant and the brine via the thermal storage medium 5. Where the coolant flows through the channels 10 of selected one of the plate-shaped tubes 4 and the brine flows through the channels 10 of the plate-shaped tubes 4 located adjacent to the selected plate*shaped tubes 4, heat exchange takes place between the coolant and the brine via the thermal storage material 5.

[0021] The plate-shaped tubes 4 as shown in FIG. 3 are arranged such that the elongated projections 8A, 9A of one of the plate-shaped tubes 4 are opposed to the flat portions 9B, 8B of adjacent plate-shaped tubes 4 located on the opposite sides of the above-indicated one plate-shaped tube 4. More specifically, the elongated projections 8A formed in the heat transfer plate 8 are open to the mating faces of the heat transfer plates 8 and 9, and the heat transfer plates 8, 9 are joined together such that the elongated projections 8A of the heat transfer plate 8 are opposed to the flat portions 9B of the other heat transfer plate 9. Therefore, the plate-shaped tubes 4 are arranged such that the elongated projections 8A formed in a certain heat transfer plate 8 are opposed to the flat portions 9B formed in the heat transfer plate 9 of the adjacent plate-shaped tube 4.

[0022] FIG. 4 and FIG. 5 are enlarged, lateral cross-sectional views

showing the internal construction of the heat exchange device 1 when it stores cool. The construction of the heat exchange device shown in FIG. 4 and FIG. 5 is identical with that of FIG. 3, and therefore, the same reference numerals as used in FIG. 3 are vised for identifying the same constituent elements, of which no further explanation will be provided. The thermal storage material 5 as shown in FIG. 4 is comprised of a thermal storage material that fuses (or thaws) when it is heated, and coagulates (or freezes) when it is cooled. More specifically, the thermal storage material 5 may be selected from latent-heat thermal storage materials, such as water, an aqueous solution of ethylene glycol, and an aqueous solution of ammonium chloride, having low fusing points and relatively large heat of fusion. In the example of FIG. 4 in which the elongated projections 8A, 9A are arranged alternately or in a staggered configuration, when the coolant flows through the channels 10, congelation 11 is formed in the thermal storage material around the elongated projections 8A, 9A and the flat portions 8B, 9B, that define the channels 10 through which the coolant flows. Since the congelation 11 formed around the elongated projections 8A, 9A grows along the inclined outside faces of the projections 8A, 9A, stress applied to be the opposed heat transfer plates 9, 8 is alleviated or reduced. While the congelation 11 formed on the flat portions 8B, 9B grows along the planes of the flat portions 8B, 9B ₁ the opposed elongated projections 9A, 8A that protrude away from the flat portions 8B, 9B serve to alleviate or reduce stress applied to the opposed heat transfer plates 9, 8.

[0023] When the coolant flows through the channels 10, thermal energy (thermal cooling) is transferred from the elongated projections 8A, 9A and flat portions 8B, 9B to the thermal storage material 5, so that the thermal storage material 5 located around the projections 8A, 9A and flat portions 8B, 9B is cooled, and congelation 11 is produced. The congelation 11 formed around the flat portions 8B, 9B grows toward the elongated projections 9A, 8A that are opposed to the flat portions 8B, 9B via the thermal storage material 5. Also, the congelation 11 formed around the elongated projections 8A, 9A grows toward the flat portions

9B, 8B that are opposed to the projections 8A, 9A via the thermal storage material 5.

[0024] When the congelation 11 formed around the elongated projections

8A, 9A grows and approaches the flat portions 9B, 8B opposed to the projections 8A, 9A via the thermal storage material 5, cool (thermal cooling) of the congelation 11 formed around the projections 8A, 9Ais captured by the opposed (or adjacent) heat transfer plates 9, 8 of the adjacent plate-shaped tubes 4 in which brine flows through the channels 10, and the congelation 11 is cut off at around the tips of the projections 8A, 9A. Also, cool (thermal cooling) of the congelation 11 formed around the flat portions 8B, 9B is captured by the elongated projections 9A, 8A of the opposed (or adjacent) heat transfer plates 9, 8 of the adjacent plate-shaped tubes 4, and therefore, the congelation 11 is cut off at around the tips of the projections 9A, 8A.

[0025] As a result, the congelation 11 is peeled off with the thermal storage material 5 in a liquid state, and is separated or moved away from the surfaces of the heat transfer plates 8, 9 due to natural convection induced by differences in the temperature of the thermal storage material 5. Therefore, the congelation 11 is prevented from being fixed to or sticking to the surfaces of the heat transfer plates

8, 9 and hampering transfer of cool (thermal cooling) carried by the coolant to the thermal storage material 5. Also, congelation 11 of the thermal storage material 5 is newly formed on the surface of the plate-shaped tube 4, and cool (thermal cooling) carried by the coolant is efficiently transferred to the thermal storage material in its entirety.

[0026] FIG. 6 is an enlarged, lateral cross-sectional view showing the internal construction of another embodiment of heat exchange device 1 when it stores cool. Each of the plate-shaped tubes 4 shown in FIG. 6 consists of two heat transfer plates 8, 9 corresponding to the plates of the invention, which are opposed to and joined to each other. Each of the heat transfer plates 8, 9 has elongated projections 8A, 9A that are formed by bending at predetermined intervals,

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12 substantially in parallel with each other, such that hollows are formed within the respective projections 8A, 9A. Each heat transfer plate 8, 9 also has flat portions

8B, 9B formed between the elongated projections 8A, 9A, respectively. The elongated projections 8A, 9Amay have any desired cross-sectional shape, such as a triangle, a rectangle or a semi-circle. The hollow formed in each of the elongated projections 8A, 9A is open to the mating faces of the heat transfer plates 8, 9, to thus provide a groove that extends in the longitudinal direction of the elongated projection 8A, 9A. The heat transfer plates 8, 9 are joined together such that the elongated projections 8A, 9A of one of the heat transfer plates 8, 9 are opposed to the elongated projections 9A, 8A of the other heat transfer plate ^' 9, 8. Thus, the hollow formed in each elongated projection 8A, 9A of the above-indicated one heat transfer plate 8, 9 is open to the hollow of the corresponding elongated projection

9A, 8Aof the other heat transfer plate 9, 8, and these hollows cooperate to form a single groove or channel 12 that is defined by the opposed elongated projections 8A, 9A and extend in the longitudinal direction of the projections 8A, 9A.

[0027] Like the plate-shaped tubes 4 as shown in FIG. 2, the channels 12 formed in the plate-shaped tubes 4 of FIG. 6 communicate with a space (not shown) that communicates with the inlet tube 6a ^' at one end of the plate-shaped tubes 4, and communicate with a space (not shown) that communicates with the outlet tube 7a at the other end of the plate-shaped tubes 4. Also, the channels 12 communicate with a space (not shown) that communicates with the outlet tube 7b at the above-indicated one end of the plate-shaped tubes 4, and communicate with a space (not shown) that communicates with the inlet tube 6b at the other end of the plate-shaped tubes 4. With this arrangement, the coolant introduced from the inlet tube 6a flows toward the outlet tube 7a via the channels 12 formed in the elongated projections 8A, 9A. Also, brine introduced from the inlet tube 6b flows toward the outlet tube 7b via the channels 12 formed in the elongated projections

8A. 9A.

[0028] When the first thermal medium 2 flowing through the channels 12

is a coolant, heat (or thermal energy) exchange takes place between the elongated projections 8A, 9A and the thermal storage material 5, and congelation 11 is formed around the projections 8A, 9A of the plate-shaped tubes 4 through which the coolant flows. The cool (thermal cooling) carried by the coolant flowing through the channels 12 is also transferred to the flat portions 8B, 9B, and congelation 11 is also formed on the flat portions 8B, 9B. As the congelation 11 keeps growing toward the elongated projections 9A, 8Aof the heat transfer plates 9, 8 opposed to the heat transfer plates 8, 9 via the thermal storage material 5, stress is applied to the opposed heat transfer plates 9, 8 due to volume expansion caused by the growth of the congelation 11. However, since the elongated projections 8A, 9A are formed in a triangular cross-sectional shape, the stress applied to the opposed heat transfer plates 9, 8 is dispersed laterally as indicated by arrows in FIG. 6. Thus, the stress applied to the heat transfer plates 9, 8 is alleviated or reduced. [0029] Further, in the aforementioned exemplary embodiments, the example in that the plate-shaped tube through which the coolant flows and the plate-shaped tube through which the brine flows are adjacent is described. However the invention is not limited to the arrangement in which the plate-shaped tubes for coolant and the plate-shaped tubes for brine are alternately arranged. For example, the plate-shaped tubes for the coolant and the plate-shaped tubes for the brine may be arranged alternately or two plate-shaped tubes for coolant or two plate-shaped tubes for the brine may be arranged continuously. These plate-shaped tubes may be arranged flexibly for controlling distribution of temperature in the heat exchange device. [0030] While the invention has been described with reference to what are considered to be preferred embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments and constructions. On the contrary, the invention is intended to cover various modifications and equivalent arrangements. In addition, while the various elements of the disclosed invention

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.