U.S. patent application number 13/395366 was filed with the patent office on 2012-07-05 for heat-storage device.
This patent application is currently assigned to Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.). Invention is credited to Kazuo Takahashi, Yuji Tanaka, Hiromiki Yagi.
Application Number | 20120168126 13/395366 |
Document ID | / |
Family ID | 43876203 |
Filed Date | 2012-07-05 |
United States Patent
Application |
20120168126 |
Kind Code |
A1 |
Tanaka; Yuji ; et
al. |
July 5, 2012 |
HEAT-STORAGE DEVICE
Abstract
Disclosed is a heat-storage device provided with a supply pipe,
a discharge pipe, and a heat-storage container that contains a
heat-storage material. A heat-storage material layer comprising
said heat-storage material is formed in the bottom of the
heat-storage container. The supply pipe supplies a heat-carrying
oil, which has a lower specific gravity than the heat-storage
material, from outside the heat-storage container to the inside of
the heat-storage material layer. The discharge pipe discharges the
heat-carrying oil, which had been supplied to the inside of the
heat-storage material layer, to the outside of the heat-storage
container. The heat-storage device is also provided with a
plurality of metal plates (members inside the heat-storage material
layer) arranged vertically inside the heat-storage material layer.
A metal plate is also disposed such that the upper end thereof is
at a height greater than or equal to the vicinity of the upper
surface level (L) of the heat-storage material layer. The disclosed
heat-storage device is better than conventional heat-storage
devices at preventing the heat-storage material from escaping the
heat-storage container.
Inventors: |
Tanaka; Yuji; (Kobe-shi,
JP) ; Takahashi; Kazuo; (Kobe-shi, JP) ; Yagi;
Hiromiki; (Kobe-shi, JP) |
Assignee: |
Kabushiki Kaisha Kobe Seiko Sho
(Kobe Steel, Ltd.)
Chuo-ku
JP
|
Family ID: |
43876203 |
Appl. No.: |
13/395366 |
Filed: |
October 13, 2010 |
PCT Filed: |
October 13, 2010 |
PCT NO: |
PCT/JP2010/067981 |
371 Date: |
March 9, 2012 |
Current U.S.
Class: |
165/104.11 |
Current CPC
Class: |
F28D 2020/0086 20130101;
Y02E 60/145 20130101; Y02E 60/14 20130101; F28D 20/025
20130101 |
Class at
Publication: |
165/104.11 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 13, 2009 |
JP |
2009-235868 |
Claims
1. A heat storage device comprising: a heat-storage container that
stores a heat-storage material used for latent heat storage, and
has a heat-storage material layer containing the heat-storage
material, and formed at a bottom portion thereof; a supply pipe
that supplies the heat-storage material layer with a heat exchange
medium smaller in specific gravity than the heat-storage material
from the outside of said heat-storage container into the
heat-storage layer; a discharge pipe that discharges the heat
exchange medium supplied into the heat-storage material layer to
the outside of said heat-storage container; and a plurality of
intra-heat-storage-material-layer members that are arranged in an
up/down direction in the heat-storage material layer, and are
formed by metal plates or pipes, wherein said
intra-heat-storage-material-layer members are arranged so that
upper ends of said intra-heat-storage-material-layer members are
disposed at a height equal to or more than a vicinity of an upper
surface level of the heat-storage material layer.
2. The heat-storage device according to claim 1, wherein a hole
passing through a wall surface of said
intra-heat-storage-material-layer member is formed.
3. The heat-storage device according to claim 1, comprising a
perforated plate that is horizontally attached to a lower end
portion of said heat-storage container so as to partition said
heat-storage container into two spaces delimited in an up/down
direction, wherein: a lower end of said supply pipe and said
perforated plate are connected with each other; and the heat
exchange medium is supplied to the inside of said heat-storage
container below said perforated plate via said supply pipe.
4. The heat-storage device according to claim 2, comprising a
perforated plate that is horizontally attached to a lower end
portion of said heat-storage container so as to partition said
heat-storage container into two spaces delimited in an up/down
direction, wherein: a lower end of said supply pipe and said
perforated plate are connected with each other; and the heat
exchange medium is supplied to the inside of said heat-storage
container below said perforated plate via said supply pipe.
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat-storage device of a
direct contact type capable of temporarily storing heat.
BACKGROUND ART
[0002] As a technology relating to the heat-storage device of the
direct contact type, there is a technology described in a patent
document 1, for example. The heat-storage unit (heat-storage
device) described in the patent document 1 includes a heat-storage
material such as erythritol that stores heat by means of a state
change between solid and liquid, a heat exchange medium such as oil
that is lower in specific gravity than the heat-storage material,
and is not mixed with the heat-storage material, a storage
container that stores the heat-storage material and the heat
exchange medium, a supply pipe that supplies the inside of the
storage container with the heat-exchange medium, and a discharge
pipe that discharges the heat-exchange medium to the outside of the
storage container.
[0003] An extreme end of the supply pipe (provided with supply
holes) is located in a bottom portion of a heat-storage material
layer in the storage container as shown in FIG. 2 of the patent
document 1. Moreover, an inlet opening of the discharge pipe is
located in an oil layer (heat-carrying oil layer) at a top portion
in the storage container. The heat exchange medium (heat-carrying
oil) is supplied to the heat-storage material layer in the storage
container via the supply pipe. The supplied heat-carrying oil is
lower in specific gravity than the heat-storage material, and rises
in the heat-storage material layer. The heat is transferred from
the heat-carrying oil to the heat-storage material (or from the
heat-storage material to the heat-carrying oil) by means of the
direct contact during this rise. Then, the heat-carrying oil exits
to the outside via the discharge pipe.
RELATED ART DOCUMENTS
Patent Document
[0004] [Patent Document 1] Japanese Patent Application Laid-open
No. 2005-188916
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0005] However, if a supply flow quantity of the heat-carrying oil
to the storage container is large, an upper surface of the
heat-storage material layer in the storage container rises, and the
heat-storage material may flow out from the discharge pipe to the
outside of the heat storage container in the heat-storage device
described in the patent document 1 as detailed later. Though the
upper surface of the heat-storage material layer can be prevented
from rising by decreasing the supply flow quantity of the
heat-carrying oil, high speed input (increase in heat storage
speed)/high speed output (increase of heat release speed) of the
heat cannot be attained.
(During Heat Storage)
[0006] The heat-storage material layer changes in state from solid
to liquid. If the heat-carrying oil is supplied to the heat-storage
material layer, bubbles of the heat-carrying oil (oil bubbles) are
formed in the heat-storage material layer. Though if the supply
flow quantity of the heat-carrying oil is relatively small, a
problem is less frequently generated, if the supply flow quantity
of the heat-carrying oil is large, the oil bubbles reach an
interface (upper surface of the heat-storage material layer)
between the heat-storage material layer and the heat-carrying oil
layer above thereof, and the oil bubbles subsequently may
accumulate without disappearing. As a result, the volume of the
heat-storage material layer (apparent volume) extends, the upper
surface of the heat-storage material layer rises, and the
heat-storage material can possibly flow out from the discharge pipe
to the outside of the storage container. It is understood that the
level of the discharge pipe is determined considering the quantity
of the heat-carrying oil flowing into the heat-storage material
layer in the storage container, and the rise of the upper surface
level of the heat-storage material layer caused by it. Nonetheless,
the heat-storage material may flow out from the discharge pipe to
the outside of the storage container. The heat-storage material,
which has flown out to the outside of the storage container, is
solidified in a circulation pipe for the heat-carrying oil, and
blocks the circulation pipe and the like causing a malfunction of a
system.
(During Heat Release)
[0007] The heat-storage material may flow out from the discharge
pipe to the outside of the storage container also during the heat
release as during the heat storage. The heat-storage material layer
changes in state from liquid to solid during the heat release. If
the heat-carrying oil is supplied to the heat-storage material
layer, bubbles of the heat-carrying oil (oil bubbles) are formed in
the heat-storage material layer. If the supply flow quantity of the
heat-carrying oil is large, the oil bubbles reach the upper surface
(interface) of the heat-storage material layer, and the oil bubbles
subsequently may accumulate without disappearing. The heat-storage
material around the oil bubbles accumulated at the interface
solidifies soon, and the oil bubbles come to join together. As a
result, the heat-storage material solidified in the vicinity of the
interface forms a lid or the like. The heat-storage material
remains in the liquid state below the lid, and the formation of the
oil bubbles thus continues. These oil bubbles lift up the lid, as a
result, the upper surface of the heat-storage material layer rises,
and the heat-storage material flows out from the discharge pipe to
the outside of the storage container. Though if the supply flow
quantity of the heat-carrying oil is relatively small as during the
heat storage, this problem is less frequently generated, if the
supply flow quantity of the heat-carrying oil increases, there
poses a problem that the heat-storage material flows out as
described before.
[0008] The present invention is devised in view of the above
mentioned state, and has an object of providing a heat-storage
device having a structure which can prevent more the heat-storage
material from flowing to the outside of the heat-storage container
than in a conventional case.
Means for Solving the Problem
[0009] As a result of diligent study to solve the above-mentioned
problem, the inventors have found that a state in which oil bubbles
are hardly formed in a vicinity of an interface between a
heat-storage material layer and a heat-carrying oil layer above
thereof (referred to as "interface of heat-storage material layer"
hereinafter), and bubbles tend to disappear even if they are formed
is brought about by providing multiple metal plates or multiple
pipes in an up/down direction in the heat-storage material layer so
that upper ends thereof are located at a height equal to or more
than a vicinity of an upper surface level of the
heat-storage-material layer in a bottom portion of a heat-storage
container, and this state can solve the above-mentioned problem,
and the present invention has been completed based on this
knowledge.
[0010] In other words, the present invention is a heat-storage
device including a heat-storage container that stores a
heat-storage material used for latent heat storage, and has a
heat-storage material layer containing the heat-storage material,
and formed at a bottom portion thereof, a supply pipe that supplies
the heat-storage material layer with a heat exchange medium smaller
in specific gravity than the heat-storage material from the outside
of the heat-storage container into the heat-storage layer, a
discharge pipe that discharges the heat exchange medium supplied
into the heat-storage material layer to the outside of the
heat-storage container, and a plurality of
intra-heat-storage-material-layer members that are arranged in an
up/down direction in the heat-storage material layer, and are
formed by metal plates or pipes, where the
intra-heat-storage-material-layer members are arranged so that
upper ends of the intra-heat-storage-material-layer members are
disposed at a height equal to or more than the vicinity of an upper
surface level of the heat-storage material layer.
[0011] Moreover, a hole passing through a wall surface of the
intra-heat-storage-material-layer member is preferably formed in
the present invention.
[0012] Further, the present invention preferably includes a
perforated plate that is horizontally attached to a lower end
portion of the heat-storage container so as to partition the
heat-storage container into two spaces delimited in an up/down
direction, where a lower end of the supply pipe and the perforated
plate are connected with each other, and the heat exchange medium
is supplied to the inside of the heat-storage container below the
perforated plate via the supply pipe.
Effects of the Invention
[0013] According to the present invention, the oil bubbles which
have reached the vicinity of the interface of the heat-storage
material layer are repelled by the upper end portions of the
intra-heat-storage-material-layer members, and thus tend to
disappear by disposing the multiple
intra-heat-storage-material-layer members, which are the components
according to the present invention, particularly the metal plates
or pipes, in an up/down direction in the heat-storage material
layer so that the upper ends thereof are disposed at a height equal
to or more than the vicinity of the top surface level of the
heat-storage material layer in the bottom portion of the heat
storage container. As a result, the state in which the oil bubbles
are hardly formed in the vicinity of the interface of the
heat-storage material layer, and even if the bubbles are formed,
the bubbles tend to disappear is brought about. As a result, the
rise of the upper surface of the heat-storage material layer is
restrained, and the heat storage material is more prevented from
flowing out from the heat storage container than in a conventional
case.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [FIG. 1] A block diagram showing a heat utilization system
provided with a heat storage device according to a first embodiment
of the present invention.
[0015] [FIG. 2] A lengthwise cross sectional view of the heat
storage device shown in FIG. 1.
[0016] [FIG. 3] (a) is a cross sectional view made on a plane and
in a direction indicated by A in FIG. 2, and (b) is a cross
sectional view made on a plane and in a direction indicated by B in
FIG. 2.
[0017] [FIG. 4] A lengthwise cross sectional view showing a
variation of the heat storage device shown in FIG. 2.
[0018] [FIG. 5] A lengthwise cross sectional view showing the heat
storage device according to a second embodiment of the present
invention.
[0019] [FIG. 6] (a) is a cross sectional view made on a plane and
in a direction indicated by C in FIG. 5, and (b) is a cross
sectional view made on a plane and in a direction indicated by D in
FIG. 5.
[0020] [FIG. 7] A lengthwise partial cross sectional view showing a
variation of the heat storage device shown in FIG. 5.
[0021] [FIG. 8] (a) and (b) are charts showing performance
comparison test results for heat storage and heat release
operations.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0022] A description will now be given of embodiments of the
present invention referring to drawings. The description is given
of an example in which a heat storage device according to the
present invention is used as a stationary heat storage device in
the following description. The stationary heat storage means heat
storage without transfer of heat to the outside, namely in a state
in which a heat storage device is always fixed.
(Configuration of Heat Utilization System)
[0023] FIG. 1 is a block diagram showing a heat utilization system
100 provided with a heat storage device 1 according to a first
embodiment of the present invention. The heat utilization system
100 includes a heat source 2, a heat utilization device 3, and the
heat storage device 1 which accumulates heat collected from the
heat source 2, and supplies the heat utilization device 3 with the
accumulated heat as shown in FIG. 1.
(Heat Source and Heat Utilization Device)
[0024] If the heat storage device 1 is fixed (permanently
installed) in an iron mill, for example, the heat source 2 is a
blast furnace, a converter furnace, a rolling facility, or the
like. The heat utilization device 3 is a heated water generation
device, an air conditioning facility, or the like in the iron
mill.
(Heat Storage Device) (First Embodiment)
[0025] FIG. 2 is a lengthwise cross sectional view of the heat
storage device 1 shown in FIG. 1. FIG. 3(a) is a cross sectional
view made on a plane and in a direction indicated by A in FIG. 2,
and FIG. 3(b) is a cross sectional view made on a plane and in a
direction indicated by B in FIG. 2.
[0026] As shown in FIGS. 1-3, the heat storage device 1 includes a
heat storage container 4 which stores a heat storage material 22
used for latent heat storage, a supply pipe 6 which supplies the
inside of the heat storage container 4 with a heat-carrying oil 21
(heat exchange medium), a discharge pipe 7 which discharges the
heat-carrying oil 21 to the outside of the heat storage container
4, and multiple metal plates 8 (intra-heat-storage-material-layer
members) which are vertically disposed in the heat storage
container 4 from an approximately center portion to the lower end
portion of the heat storage container 4.
(Heat Storage Material and Heat Exchange Medium)
[0027] As the heat storage material 22, it is preferred to employ a
material having a large latent heat (heat of fusion), and sugar
alcohols such as erythritol, mannitol, galactitol, and xylitol can
be mentioned as this material. For example, erythritol is a
material having a melting point: approximately 119.degree. C., and
heat of fusion: approximately 340 kJ/kg, and mannitol is a material
having a melting point: approximately 167.degree. C., and a heat of
fusion: approximately 300 kJ/kg. It is assumed that erythritol is
employed as the heat storage material 22 unless otherwise specified
in the following description. Moreover, the heat-carrying oil 21
(heat exchange material) is a material smaller in specific gravity
than the heat storage material 22. A material which can maintain a
state in which the material is completely separated from the heat
storage material 22 is preferably employed as the heat-carrying oil
21, and mineral oil can be mentioned as such a material, for
example. It is assumed that mineral oil is employed as the
heat-carrying oil 21 unless otherwise specified in the following
description.
(Heat Storage Container)
[0028] The heat storage container 4 is a cylindrical container
(such a metal container) having a bottom plate portion 4a, and top
plate portion 4b. Shapes of the bottom plate portion 4a and the top
plate portion 4b are both disk shapes. Moreover, the heat storage
container 4 is covered with a heat insulation layer 5. The heat
insulation layer 5 may be formed by winding a heat insulation
material such as glass wool around the heat storage container 4,
the heat insulation layer 5 may be formed by constructing the heat
storage container 4 as a double-shell container, and forming the
heat insulation layer 5 using a heat insulation material such as
glass wool, or the heat insulation layer 5 may be a vacuum heat
insulation layer as a method of forming the heat insulation layer
5. Wasteful heat emission to the outside via a wall surface of the
heat storage container 4 can be prevented by forming the heat
insulation layer 5 around the heat storage container 4, and the
heat collected via the heat-carrying oil 21 can be efficiently used
to heat the heat utilization device 3. It should be noted that the
heat storage container 4 is not limited to the cylindrical shape,
and may be a rectangular parallelepiped or cubic shape.
[0029] A circular perforated plate 9 is horizontally attached to
the lower end portion of the heat storage container 4 so as to
partition the inside of the heat storage container 4 into two
spaces delimited in an up/down direction. An outer peripheral
surface of the perforated plate 9 and an inner wall surface of the
heat storage container 4 are brought into contact with each other,
and the perforated plate 9 is fixed to the heat storage container 4
by means of welding or the like. A predetermined interval is
provided between the bottom plate portion 4a of the heat storage
container 4 and the perforated plate 9. Multiple through holes 9a
are formed in the perforated plate 9 in the thickness direction
thereof. It should be noted that even if the heat storage material
22 is in liquid state, the heat storage material 22 does not move
down below the perforated plate 9 due to the surface tensions
(surface tensions of the heat storage material 22 and the
heat-carrying oil 21) by properly designing the diameter of the
through holes 9a of the perforated plate 9. The perforated plate 9
is made of a metal material, for example. When the heat storage
container 4 is viewed from above, the perforated plate 9 is
disposed across an overall planar cross section (entire surface) in
the heat storage container 4 as shown in FIG. 3(b). In other words,
the inner diameter of the heat storage container 4 and the outer
diameter of the perforated plate 9 are approximately the same.
[0030] Though the example in which one perforated plate 9 is placed
at a lower end portion of the heat storage container 4 is shown in
the present embodiment, a box-shape body including an internal
space may horizontally be disposed at (attached to) the lower end
portion of the heat storage container 4. In this case, an upper
surface (surface on the side of the heat-storage material layer) of
the box-shape body is formed into a perforated plate, for example.
This box-shape body is preferably disposed across the overall
planar cross section (entire surface) of the heat storage container
4. In other words, the inner diameter of the heat storage container
4 and the outer diameter of the box-shape body are preferably
approximately equal. Moreover, the heat-carrying oil 21 which has
flown through the supply pipe 6 flows through the box-shape body
(internal space), and then flows into the heat-storage material
layer from the holes of the perforated plate constituting the
box-shape body. It should be noted that a bottom surface (surface
on the side of the bottom plate portion 4a of the heat storage
container 4) of the box-shape body may be a perforated plate. In
this case, an interval is formed between the box-shape body and the
heat storage container 4, and the heat-carrying oil 21 exiting from
the perforated plate of the bottom surface of the box-shape body is
fed through the interval to a top portion of the box-shape
body.
[0031] The supply pipe 6 and the discharge pipe 7 are attached to
the heat storage container 4. The supply pipe 6 is arranged from
above the heat storage container 4 into the inside thereof in the
vertical direction so that the center of the top plate portion 4b
of the heat storage container 4 is penetrated. A lower end of the
supply pipe 6 and the perforated plate 9 are connected with each
other at a center portion of the perforated plate 9. The supply
pipe 6 is opened inside the heat storage container 4 at the lower
end portion of the heat storage container 4. The discharge pipe 7
is arranged from above the heat storage container 4 into the inside
thereof in the vertical direction so that the top plate portion 4b
of the heat storage container 4 is penetrated. The discharge pipe 7
is opened inside the heat storage container 4 at the top portion of
the heat storage container 4.
[0032] The layer of the heat storage material 22 (heat-storage
material layer) the specific gravity of which is larger than that
of the heat-carrying oil 21 is formed in the bottom portion of the
heat storage container 4. The layer of the heat-carrying oil 21
(heat-carrying oil layer) which is smaller in specific gravity than
the heat storage material 22 is formed above the heat-storage
material layer (in the top portion in the heat storage container
4). Moreover, as a result of the supply of the heat-carrying oil 21
from the outside of the heat storage container 4 into the inside
thereof via the supply pipe 6, a layer of the heat-carrying oil 21
(heat-carrying oil layer) is formed at the lower end portion of the
heat storage container 4 (between the bottom plate portion 4a of
the heat storage container 4 and the perforated plate 9). Though
the heat-carrying oil 21 is smaller in specific gravity than the
heat storage material 22, the heat-carrying oil 21 will not enter
the heat-storage material layer due to the surface tensions
(surface tensions of the heat storage material 22 and the
heat-carrying oil 21) by properly designing the diameter of the
through holes 9a of the perforated plate 9 even if the heat-storage
material layer (heat storage material 22) is in the liquid state as
long as a heat carrier circulation pump (not shown) is not
operated.
(Intra-Heat-Storage-Material-Layer Members)
[0033] The multiple metal plates 8 are vertically disposed at the
bottom portion in the heat storage container 4 (in the heat-storage
material layer formed in the heat storage container 4). The metal
plates 8 are disposed so that the direction orthogonal to the
thickness direction of the metal plates 8 is the vertical
direction. It should be noted that the direction of disposing the
metal plates 8 is not necessarily the strictly vertical direction.
The direction may be slightly inclined with respect to the vertical
direction. In other words, it is only necessary for the metal
plates 8 to be disposed in an up/down direction in the heat storage
material layer. Moreover, the metal plates 8 may not be formed by a
single plate member such as one according to this embodiment, but
may be a hollow form (box shape) constructed by combining multiple
plate members.
[0034] The supply pipe 6 is disposed at the center of the heat
storage container 4 when the heat storage container 4 is viewed
from above as shown in FIG. 3(a). Eight metal plates 8 are disposed
so that the metal plates 8 extend radially from the supply pipe 6
as the center. Side surfaces of the metal plates 8 on the supply
pipe 6 side are in contact with an outer peripheral surface of the
supply pipe 6, and are fixed to the supply pipe 6 by means of
welding or the like. Side surfaces of the metal plates 8 on the
heat storage container 4 side are in contact with the inner surface
of the heat storage container 4, and are fixed to the heat storage
container 4 by means of welding or the like. The bottom portion
(heat-storage material layer) of the heat storage container 4 is
delimited into eight sectors by the eight metal plates 8. Moreover,
lower ends of the metal plates 8 are in contact with an upper
surface of the perforated plate 9 as shown in FIG. 2.
[0035] Moreover, the metal plates 8 are arranged so that upper ends
of the metal plates 8 are located at a position slightly higher
than an upper surface level L of the heat-storage material layer as
shown in FIG. 2. It should be noted that it is only necessary for
the upper ends of the metal plates 8 to be located at a height
equal to or more than a vicinity of the upper surface level L of
the heat-storage material layer. For example, the upper ends of the
metal plates 8 may be located at a position slightly lower than the
upper surface level L. However, the upper ends of the metal plates
8 are preferably located at a height equal to or more than the
upper surface level L of the heat-storage material layer in order
to increase a bubble extinguishing (oil bubble extinguishing)
effect by the metal plates 8. Further, the upper ends of the metal
plates 8 are preferably located at a position higher than the upper
surface level L, namely the metal plates 8 are preferably disposed
across the interface of the heat-storage material layer as in this
embodiment.
[0036] It should be noted that there is brought about a state in
which not a small amount of the heat-carrying oil 21 is contained
in the heat-storage material layer by the supply of the
heat-carrying oil 21 to the heat-storage material layer in the heat
storage container 4, and the change in the state (liquid/solid) of
the heat-storage material layer caused by this supply. The
dimensions of the metal plates 8 are determined so that the upper
ends of the metal plates 8 are located at a height equal to or more
than a vicinity of the upper surface level L of the heat-storage
material layer considering an increase in volume of the heat
storage metal layer by the heat-carrying oil 21.
(Heat Carrier Circulation Path)
[0037] Pipes 33-36 (heat carrier circulation paths) connect between
the heat source 2 and the heat storage device 1, and between the
heat storage device 1 and the heat utilization device 3 as shown in
FIG. 1. The heat carrier circulation path on the heat source 2 side
is constructed by the pipes 33 and 35, and the heat carrier
circulation path on the heat utilization device 3 side is
constructed by the pipes 33, 34, and 36. The pipe 33 is connected
to an upper end of the supply pipe 6 of the heat storage device 1.
The pipe 34 is connected to an upper end of the discharge pipe 7 of
the heat storage device 1. The pipe 33, the pipe 35a, and the pipe
36a are connected with one another via a three-way valve 31. The
pipe 34, the pipe 35b, and the pipe 36b are connected with one
another via a three-way valve 32. A heat carrier circulation pump
(not shown) is attached to the pipe 34. The heat-carrying oil 21 is
circulated either one of the heat carrier circulation path (pipes
33 and 35) on the heat source 2 side and the heat carrier
circulation path (pipes 33, 34, and 36) on the heat utilization
device 3 side by operating the heat carrier circulation pump. The
switching between the circulation on the heat source 2 side and the
circulation on the heat utilization device 3 side is carried out by
the three-way valves 31 and 32. The three-way valves 31 and 32 are
generally electrically operated.
(Operation of Heat Utilization System)
[0038] A description will now be given of an operation of the heat
utilization system 100. The operation of the heat utilization
system 100 (operation of the heat storage device 1) is roughly
separated into a heat storage operation and a heat release
operation.
(Heat Storage Operation)
[0039] First, a description is given of the heat storage operation.
The three-way valves 31 and 32 are switched (or are confirmed to be
in intended states) so that the heat-carrying oil 21 circulates in
the heat carrier circulation path (pipes 33 and 35) on the heat
source 2 side. The heat carrier circulation pump (not shown) is
then started, thereby circulating the heat-carrying oil 21 between
the heat storage device 1 and the heat source 2.
[0040] The heat-carrying oil 21 flows through the heat source 2,
and the heat-carrying oil 21 is consequently heated by the heat
from the heat source 2, resulting in the collection of the heat
(waste heat) from the heat source 2. The heat-carrying oil 21
heated by the heat source 2 is returned to the heat storage
container 4 from the supply pipe 6 via the pipe 35a and the pipe
33. On this occasion, the heat-carrying oil 21 is returned to the
heat storage container 4 below the perforated plate 9 via the
supply pipe 6. Then, the heat-carrying oil 21 enters from the
multiple through holes 9a formed on the perforated plate 9 into the
heat-storage material layer. The heat-carrying oil 21 rises (floats
upward) in the heat storage container 4 due to a difference in
specific gravity between the heat storage material 22 and the
heat-carrying oil 21 in the form of the oil bubbles while the
heat-carrying oil 21 supplies the heat storage material 22 with the
heat (exchanges heat with the heat storage material 22) by the
direct contact with the heat storage material 22. The heat-carrying
oil 21 rises (floats upward) in the gaps delimited into the sectors
between the eight metal plates 8. The heat-carrying oil 21 then
reaches the layer of the heat-carrying oil 21 (heat-carrying oil
layer) formed above the heat storage material 22.
[0041] The heat-carrying oil 21 which has reached the heat-carrying
oil layer, and has released the heat is sucked from the discharge
pipe 7 by the heat carrier circulation pump (not shown) for being
heated again by the heat source 2, and is supplied again to the
heat source 2 via the pipe 34 and the pipe 35b. The heat-storage
material layer changes in state from solid to liquid during the
heat storage operation.
(Heat Release Operation)
[0042] A description will now be given of the heat release
operation. The three-way valves 31 and 32 are switched so that the
heat-carrying oil 21 circulates through the heat carrier
circulation path (pipes 33, 34, and 36) on the heat utilization
device 3 side. The heat carrier circulation pump (not shown) is
then started, thereby circulating the heat-carrying oil 21 between
the heat storage device 1 and the heat utilization device 3.
[0043] When the heat-carrying oil 21 in the heat storage container
4 enters the heat utilization device 3, the heat is removed from
the heat-carrying oil 21. The heat-carrying oil 21 the heat of
which has been removed by the heat utilization device 3 is returned
to the heat storage container 4 from the supply pipe 6 via the pipe
36a and the pipe 33. On this occasion, the heat-carrying oil 21 is
returned to the heat storage container 4 below the perforated plate
9 via the supply pipe 6. Then, the heat-carrying oil 21 enters from
the multiple through holes 9a formed on the perforated plate 9 into
the heat-storage material layer.
[0044] A layer of the heat-carrying oil in contact with the entire
bottom surface of the perforated plate 9 is formed between the
bottom plate portion 4a of the heat storage container 4 and the
perforated plate 9 (below the perforated plate 9). As a result, the
heat exchange by the heat transmission via the perforated plate 9
is promoted.
[0045] The heat-carrying oil 21 rises (floats upward) in the heat
storage container 4 due to the difference in specific gravity
between the heat storage material 22 and the heat-carrying oil 21
in the form of the oil bubbles while the heat-carrying oil 21
receives the heat from the heat storage material 22 (exchanges heat
with the heat storage material 22) by the direct contact with the
heat storage material 22. The heat-carrying oil 21 rises (floats
upward) in the gaps delimited into the sectors between the eight
metal plates 8. The heat-carrying oil 21 then reaches the layer of
the heat-carrying oil 21 (heat-carrying oil layer) formed above the
heat storage material 22.
[0046] The heat-carrying oil 21 which has reached the heat-carrying
oil layer, and has received the heat is sucked from the discharge
pipe 7 by the heat carrier circulation pump (not shown), and is
supplied again to the heat utilization device 3 via the pipe 34 and
the pipe 36b. The heat-storage material layer changes in state from
liquid to solid during the heat release operation.
[0047] As the description has been given of the heat storage device
1 while the description is being given of the heat utilization
system 100 provided with the heat storage device 1 according to the
present invention, the heat-storage material layer is brought into
the state in which the heat-storage material layer is delimited
into the multiple portions by vertically disposing the multiple
metal plates 8 (intra-heat-storage-material-layer members) in the
heat-storage material layer in the heat storage container 4 by
means of the heat storage device 1. The oil bubbles which have
reached the vicinity of the interface of the heat-storage material
layer are repelled by the upper end portions of the metal plates 8
and tend to disappear by locating the upper ends of the metal
plates 8 at a height equal to or more than the vicinity of the
upper surface level L of the heat-storage material layer. As a
result, there is brought about the state in which oil bubbles are
hardly formed in the vicinity of the interface of the heat-storage
material layer, and tend to disappear even if the oil bubbles are
formed, resulting in the restraint of the rise of the upper surface
of the heat-storage material layer. In other words, a separation
property between the heat-carrying oil 21 and the heat storage
material 22 increases at the interface of the heat-storage material
layer. This prevents more the heat storage material 22 from flowing
to the outside of the heat storage container 4 than in a
conventional case. Moreover, this can increase the quantity of the
heat-carrying oil 21 supplied into the heat storage container 4
compared with the conventional case, resulting in heat exchange at
a higher speed.
[0048] Moreover, the solidification of the heat storage material 22
starts from portions along the metal plates 8 during the heat
release operation (heat transfer from the heat storage material 22
to the heat-carrying oil 21 in the heat storage container 4). The
heat-carrying oil 21 lower in temperature than the heat storage
material 22 enters into the heat storage container 4 below the
perforated plate 9 via the supply pipe 6. On this occasion, the
supply pipe 6 and the perforated plate 9 are cooled by the
heat-carrying oil 21. The metal plates 8 are in contact with the
supply pipe 6 and the perforated plate 9, and the metal plates 8
are also cooled by the supply pipe 6 and the perforated plate 9
being cooled by the heat-carrying oil 21. As a result, the
solidification of the heat storage material 22 starts from the
portions along the metal plates 8 during the heat release
operation. Flow passages of the heat-carrying oil 21 are secured in
an up/down direction (along the floating direction of the
heat-carrying oil 21) between the metal plates 8 by the
solidification of the heat storage material 22 starting from the
portions along the metal plates 8. This also prevents the
heat-storage material layer from swelling upward, thereby
preventing the upper surface of the heat-storage material layer
from rising even if the flow quantity of the heat-carrying oil 21
supplied into the heat storage container 4 increases. This prevents
the heat storage material 22 from flowing to the outside of the
heat storage container 4.
(Variation)
[0049] FIG. 4 is a lengthwise cross sectional view showing a
variation of the heat storage device 1 shown in FIG. 2. It should
be noted that like components are denoted by like numerals as of
the heat storage device 1 shown in FIG. 2 in a heat storage device
101 according to the variation in FIG. 4.
[0050] Multiple through holes 10a are formed in the thickness
direction on the side surfaces of metal plates 10
(intra-heat-storage-material-layer members) of the heat storage
device 101 as shown in FIG. 4. This point is different from the
metal plates 8 of the heat storage device 1. The metal plates 8 of
the heat storage device 1 and the metal plates 10 of the heat
storage device 101 according to this variation are the same in
shape, arrangement, and number except for the fact that the
multiple holes are formed on the side surfaces of the metal plates.
The hole 10a is larger than the through holes 9a of the perforated
plate 9.
[0051] The shape of the holes 10a is not limited to a circle, and
may be in another shape such as a rectangle. However, the metal
plates 10 are used under a severe temperature condition, and
repeatedly receive thermal stress. On the other hand, the circular
hole 10a does not have a corner, and the stress hardly
concentrates. Thus, the circular hole 10a can prevent the metal
plate 10 from being damaged. In other words, the forming circular
hole 10a is preferred.
[0052] Contact area between the metal plates 10 and the heat
storage material 22 is increased by forming multiple holes 10a
passing through the metal plates 10, and a solidified quantity of
the heat storage material 22 starting from the portions along the
metal plates 10 thus increases during the heat release operation.
As a result, more flow passages for the heat-carrying oil 21 are
secured in the heat-storage material layer in an up/down direction
(along the floating direction of the heat-carrying oil 21).
[0053] Moreover, the holes 10a cause the neighboring sections to
communicate with each other. As a result, the holes 10a constitute
escape routes for the rising heat-carrying oil 21, thereby further
preventing the heat-storage material layer from swelling
upward.
Second Embodiment
[0054] FIG. 5 is a lengthwise cross sectional view showing a heat
storage device 102 according to a second embodiment of the present
invention. FIG. 6(a) is a cross sectional view made on a plane and
in a direction indicated by C in FIG. 5, and FIG. 6(b) is a cross
sectional view made on a plane and in a direction indicated by D in
FIG. 5. Like components are denoted by like numerals as of the heat
storage device 1 according to the first embodiment shown in FIG. 2
in the description of this embodiment.
[0055] A different point between the heat storage device 102
according to this embodiment and the heat storage device 1
according to the first embodiment is the
intra-heat-storage-material-layer members as shown in FIG. 5 and
FIG. 6.
[0056] Multiple cylindrical circular pipes 11
(intra-heat-storage-material-layer members) are disposed in the
vertical direction in a bottom portion (in the heat-storage
material layer formed in the heat storage container 4) of the heat
storage container 4. The circular pipes 11 are disposed so that the
lengthwise direction orthogonal to the radial direction of the
circular pipes 11 is the vertical direction. It should be noted
that the direction of the arrangement of the pipes 11 may not be
strictly vertical direction. The direction may be slightly inclined
with respect to the vertical direction. In other words, it is only
necessary for the circular pipes 11 to be disposed in an up/down
direction in the heat-storage material layer. Moreover, both ends
of the circular pipes 11 are opened.
[0057] When the heat storage container 4 is viewed from above, the
supply pipe 6 is disposed at the center of the heat storage
container 4 as shown in FIG. 6(a). The multiple circular pipes 11
are disposed around the supply pipe 6. The bottom portion
(heat-storage material layer) of the heat storage container 4 is
partitioned into smaller sections by the multiple circular pipes
11. Moreover, the lower ends of the circular pipes 11 are brought
into contact with the upper surface of the perforated plate 9 as
shown in FIG. 5. It should be noted that the through holes 9a are
formed so that the through holes 9a are disposed outside and inside
the circular pipes 11 if the heat storage container 4 is viewed
from above.
[0058] Moreover, the circular pipes 11 are disposed so that the
upper ends of the circular pipes 11 are located at a position
slightly higher than the upper surface level L of the heat storage
material layer as shown in FIG. 5. It should be noted that it is
only necessary for the top ends of the circular pipes 11 to be
located at a height equal to or more than a vicinity of the upper
surface level L of the heat-storage material layer. For example,
the top ends of the circular pipes 11 may be located at a position
slightly lower than the upper surface level L. However, the upper
ends of the circular pipes 11 are preferably located at a height
equal to or more than the upper surface level L of the heat-storage
material layer in order to increase the bubble extinguishing (oil
bubble extinguishing) effect by the circular pipes 11. Further, the
upper ends of the circular piles 11 are preferably located at a
position higher than the upper surface level L, namely, the
circular pipes 11 are preferably disposed so as to cross the
interface of the heat-storage material layer as in this
embodiment.
[0059] It should be noted that there is brought about a state in
which not a small amount of the heat-carrying oil 21 is contained
in the heat-storage material layer by the supply of the
heat-carrying oil 21 to the heat-storage material layer in the heat
storage container 4, and the change in the state (liquid/solid) of
the heat-storage material layer caused by this supply. The
dimensions of the circular pipes 11 are determined so that the
upper ends of the circular pipes 11 are located at a height equal
to or more than the upper surface level L of the heat-storage
material layer considering an increase in volume of the
heat-storage material layer by the heat-carrying oil 21.
[0060] The heat storage device 102 brings about the state in which
the heat-storage material layer is partitioned into the multiple
sections by vertically disposing the multiple circular pipes 11
(intra-heat-storage-material-layer members) in the heat-storage
material layer in the heat storage container 4. The oil bubbles
which have reached the vicinity of the interface of the
heat-storage material layer are repelled by the upper end portions
of the circular pipes 11 and tend to disappear by locating the
upper ends of the circular pipes 11 at a height equal to or more
than the vicinity of the upper surface level L of the heat-storage
material layer. As a result, there is brought about the state in
which oil bubbles are hardly formed in the vicinity of the
interface of the heat-storage material layer, and tend to disappear
even if the oil bubbles are formed, resulting in the restraint of
the rise of the upper surface of the heat-storage material layer.
In other words, a separation property between the heat-carrying oil
21 and the heat storage material 22 increases at the interface of
the heat-storage material layer. This prevents more the heat
storage material 22 from flowing to the outside of the heat storage
container 4 than in a conventional case. Moreover, this can
increase the flow quantity of the heat-carrying oil 21 supplied
into the heat storage container 4 compared with the conventional
case, resulting in heat exchange at a higher speed.
[0061] Moreover, any of the multiple circular pipes 11 are in
contact with the perforated plate 9. As a result, flow passages of
the heat-carrying oil 21 are secured in an up/down direction (along
the floating direction of the heat-carrying oil 21) by the multiple
circular pipes 11 in the heat storage container 4 as mentioned in
the description of the first embodiment. As a result, even if the
flow quantity of the heat-carrying oil 21 supplied into the heat
storage container 4 increases, this prevents the heat storage
material 22 from flowing to the outside of the heat storage
container 4. The circular pipe 11 is preferably made of a material
high in heat conductivity, namely, the material of the circular
pipes 11 is preferably metal such as stainless steel.
[0062] It should be noted that the pipe may not be the circular
pipe 11, and may be a rectangular pipe the cross sectional shape of
which is a rectangle, for example. However, the pipes
(intra-heat-storage-material-layer members) of the heat storage
container 4 are used under a severe temperature condition,
repeatedly receive thermal stress, and are preferably formed into
the circular pipes 11 in which the stress hardly concentrates.
(Variation)
[0063] FIG. 7 is a partial lengthwise cross sectional view showing
a variation of the heat storage device 102 shown in FIG. 5. It
should be noted that like components are denoted by like numerals
as of the heat storage device 102 shown in FIG. 5 in a heat storage
device 103 according to the variation in FIG. 7.
[0064] Circular through holes 12a are formed passing through wall
surfaces of the circular pipes 12
(intra-heat-storage-material-layer members) of the heat storage
device 103 in a line in the lengthwise direction thereof as shown
in FIG. 7. This point is different from the circular pipes 11 of
the heat storage device 102. The circular pipes 11 of the heat
storage device 102 and the circular pipes 12 of the heat storage
device 103 according to this variation are the same in shape,
arrangement, and number except for the fact that the multiple holes
are formed on the circular pipes. It should be noted that the holes
12a may be formed in two or more lines on the circular pipes 12, or
may be disposed in a staggered manner. The hole 12a is larger than
the through holes 9a of the perforated plate 9.
[0065] The shape of the holes 12a is not limited to a circle, and
may be other shapes such as a rectangle. However, the circular
pipes 12 are used under a severe temperature condition, and
repeatedly receive thermal stress. On the other hand, the circular
hole 12a does not have a corner, and the stress hardly
concentrates. Thus, the circular hole 12a can prevent the circular
pipes 12 from being damaged. In other words, the forming circular
hole 12a is preferred.
[0066] Contact area between the circular pipes 12 and the heat
storage material 22 is increased by forming multiple holes 12a in
the circular pipes 12, thereby a solidified quantity of the heat
storage material 22 starting from the portions along the circular
pipes 12 increases during the heat release operation. As a result,
more flow passages for the heat-carrying oil 21 are secured in the
heat-storage material layer in an up/down direction (along the
floating direction of the heat-carrying oil 21).
[0067] Moreover, the holes 12a communicate the inside of the
circular pipes 12 and the outside of the circular pipes 12 with
each other. As a result, the holes 12a constitute escape routes for
the rising heat-carrying oil 21, thereby further preventing the
heat-storage material layer from swelling upward.
EXAMPLE
[0068] FIGS. 8(a) and (b) are charts showing performance comparison
test results for the heat storage and heat release operations. FIG.
8(a) shows a performance comparison test result during the heat
storage operation, and FIG. 8(b) shows a performance comparison
test result during the heat release operation. A test result of the
heat storage device according to the present invention was brought
about by the heat storage device 102 having the structure shown in
FIG. 5, and a test result of the heat storage device relating to a
comparative example is brought about by a heat storage device
without the circular pipes 11.
[0069] A cumulative input heat quantity (or cumulative released
heat quantity) Q (kJ) assigned to the vertical axis of the charts
is obtained by the following equation.
Q=.SIGMA.(m.times.Cp.times..DELTA.T)
[0070] m: flow quantity of heat-carrying oil (kg/sec)
[0071] Cp: Specific heat of heat-carrying oil (kJ/kg.degree.
C.)
[0072] .DELTA.T: Difference in temperature of heat-carrying oil
between at the entrance and at the exit of heat storage
container
(Heat Storage Operation Test Result)
[0073] The heat storage device according to the present invention
could store heat of 1135 kJ for approximately 27 minutes as shown
in FIG. 8(a). It should be noted that the internal temperature of
the heat storage device rose from 8.degree. C. to 140.degree. C. On
the other hand, the heat storage quantity was 1057 kJ for
approximately 48 minutes for the heat storage device according to
the comparative example. In the heat storage device of the
comparative example, if the supplied flow quantity m of the
heat-carrying oil is increased, the oil bubbles accumulate at the
interface of the heat-storage material layer, the upper surface of
the heat-storage material layer rises, and the supplied flow
quantity m of the heat-carrying oil could not be increased. In
contrast, in the heat storage device according to the present
invention, the oil bubbles hardly be generated in a vicinity of the
interface of the heat-storage material layer (separation property
between the heat-carrying oil and the heat storage material at the
interface of the heat-storage material layer is excellent), and the
supplied flow quantity m of the heat-carrying oil could be
increased compared with the heat storage device of the comparative
example. As a result, the heat storage device according to the
present invention could store heat at a higher speed.
(Heat Release Operation Test Result)
[0074] As appreciated from a test result in a vicinity of a heat
release operation time 250 (sec) in FIG. 8(b), the heat release
operation could start faster if the heat storage device according
to the present invention was used. Moreover, the cumulative heat
release quantity until approximately 25 minutes after the start of
the heat release was 782 kJ if the heat storage device according to
the present invention was used, while that was 760 kJ if the heat
storage device of the comparative example was used. The difference
therebetween was caused by a larger supply flow quantity m of the
heat-carrying oil realized by the heat storage device according to
the present invention as in the heat storage operation test. It
should be noted that the internal temperature of the heat storage
device according to the present invention decreased from
110.degree. C. to 35.degree. C.
[0075] The description has been given of the embodiments of the
present invention, and the present invention is not limited to the
above-mentioned embodiments, and can be changed in various ways,
and can be embodied within the scope of claims.
[0076] The present application is based on Japanese Patent
Application Laid-open No. 2009-235868 filed on Oct. 13, 2009, the
contents of which are incorporated herein by reference.
INDUSTRIAL APPLICABILITY
[0077] The heat storage device according to the present invention
is a device which can be applied to utilities such as the stored
heat transport. Refer to the patent document 1 (Japanese Patent
Application Laid-open No. 2005-188916) as an example of the stored
heat transport. The heat storage device according to the present
invention can be used as a device for transporting waste heat
generated in an iron mill and an incineration plant to a heated
swimming pool, an air conditioner (such as a heating facility for a
building), and a public bath. Heat sources are waste heat generated
in an iron mill and an incineration plant and cogeneration waste
heat, and the heat utilizing destinations are a heated swimming
pool, an air conditioner (such as a heating facility for a
building), a public bath for the stored heat transport.
[0078] Further, the heat storage device according to the present
invention can be used for warming up engines of motor vehicles
(including passenger vehicles and construction vehicles). If the
heat storage device according to the present invention is used as a
heat storage device for warming up an engine, the heat storage
device is to be mounted on a motor vehicle. The heat source thereof
is waste heat of the engine, and the heat is used for the engine
(for warming up the engine).
DESCRIPTION OF THE NUMERALS
[0079] 1: Heat storage device [0080] 2: Heat source [0081] 3: Heat
utilization device [0082] 4: Heat storage container [0083] 6:
Supply pipe [0084] 7: Discharge pipe [0085] 8: Metal plate
(intra-heat-storage-material-layer member) [0086] 21: Heat-carrying
oil (heat exchange medium) [0087] 22: Heat storage material [0088]
100: Heat utilization system
* * * * *