US20190353432A1

US20190353432A1 - Apparatus for filling heat storage material

Info

Publication number: US20190353432A1
Application number: US16/244,117
Authority: US
Inventors: Dong Cheol Kim; Kwang Doo Noh
Original assignee: HLB Life Science Co Ltd
Current assignee: HLB Life Science Co Ltd
Priority date: 2018-05-18
Filing date: 2019-01-10
Publication date: 2019-11-21
Also published as: KR101917573B1

Abstract

An apparatus for filling a heat storage material in a heat storage system for thermal energy delivery business is provided, wherein the heat storage system stores waste heat and is then moved a location where the heat is to be used, to dissipate the heat. According to the apparatus for filling a heat storage material, an accurate and uniform amount of a phase change material may be conveniently filled in the heat storage system while maintaining a liquid state of the heat storage material by melting the phase change material.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2018-0056864, filed on May 18, 2018, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

1. Field

One or more embodiments relate to an apparatus for filling a heat storage material, and more particularly, to an apparatus for filling a heat storage material in a heat storage system for thermal energy delivery business, wherein the heat storage system stores waste heat and is then moved a location where the heat is to be used, to dissipate the heat.

2. Description of the Related Art

A foray has been made into a thermal energy delivery business of storing waste heat generated in factories such as steel mills and supplying the heat to greenhouses or homes, and such heat has been used in some areas.
In the thermal energy delivery business, waste heat generated from heating furnaces or incinerator chimneys of a factory such as steel mills is stored for use. As a medium that stores waste heat, a phase change material (PCM) which is a latent heat storage material or a chemical heat storage material is used. By making a fluid such as a heat medium oil that is heated by using waste heat, to flow through a heat storage container storing the PCM, the PCM is changed to a liquid state, thereby storing heat.
An apparatus for storing heat by using the PCM is called a heat storage system. The heat storage system stores heat by using a PCM filled in the heat storage system. Thus, a manufacture of a heat storage system requires an operation of filling a PCM in the heat storage system.
The PCM described above is available as solid particles. When filling a PCM in a solid state in a heat storage system, a filling efficiency is low due to air gaps between solid particles. Thus, it is effective to fill a PCM in a heat storage system by melting the PCM in a solid state.
When melting a PCM in a solid state and individually injecting the PCM in a heat storage system, the PCM injected relatively early is cooled and changed to a solid state. There is a difference in a volume of a PCM between a solid state and a liquid state. Thus, it is difficult to fill an accurate amount of PCM in a heat storage system by using the above-described method.
Thus, there is a need for an apparatus for effectively filling a PCM in a heat storage system by effectively melting the PCM and maintaining a liquid state of the PCM.

SUMMARY

One or more embodiments include an apparatus for filling a heat storage material, wherein a uniform amount of a phase change material (PCM) may be filled in a plurality of heat storage systems by using the apparatus while maintaining the phase change material (PCM) in a liquid state.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments.
According to one or more embodiments, an apparatus for filling a heat storage material is provided, wherein the apparatus is formed in the form of a container for storing heat by using a thermal energy delivery method, wherein a heat storage material is filled in a heat storage unit having an injection inlet formed in an upper portion of the heat storage unit, the apparatus including: a heating case including a filling chamber having an opened upper portion, an inlet through which hot water is supplied to the filling chamber, and an outlet formed in the filling chamber, wherein the hot water that has flown into the filling chamber is discharged through the outlet; a holding frame including a holding portion on which the heat storage unit is held, wherein the holding frame enters an upper portion of the heating case to be seated in the filling chamber of the heating case; a cover plate including a filling hole communicating with the injection inlet of the heat storage unit so as to fill the heat storage material through the injection inlet of the heat storage unit, wherein the cover plate is coupled to the holding frame.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings in which:

FIG. 1 is a disassembled perspective view of an apparatus for filling a heat storage material, according to an embodiment of the present disclosure;

FIG. 2 is a perspective view of the apparatus for filling a heat storage material, illustrated in FIG. 1;

FIG. 3 is a perspective view of a holding frame of the apparatus for filling a heat storage material, illustrated in FIG. 1;

FIG. 4 is a cross-sectional view of the apparatus for filling a heat storage material illustrated in FIG. 2, taken along line IV-IV; and

FIG. 5 is a perspective view of a heat storage unit in which a heat storage material is filled by using the apparatus for filling a heat storage material illustrated in FIG. 1.

DETAILED DESCRIPTION

Hereinafter, an apparatus for filling a heat storage material according to an embodiment of the present disclosure will be described in detail with reference to the attached drawings.
FIG. 1 is a disassembled perspective view of an apparatus for filling a heat storage material, according to an embodiment of the present disclosure. FIG. 2 is a perspective view of the apparatus for filling a heat storage material, illustrated in FIG. 1.
Referring to FIGS. 1 and 2, the apparatus for filling a heat storage material according to the present embodiment includes a heating case 200, a holding frame 300, and a cover plate 500.
As a heat storage material, materials generally known as a phase change material (PCM) are used. When a heat storage material has absorbed external heat and is thus at a high temperature, the heat storage material is in a liquid state. When a temperature of the heat storage material is lowered as heat stored in the heat storage material is dissipated to the outside, then the heat storage material is in a solid state.
According to the present embodiment, an apparatus for filling a heat storage material, which is capable of simultaneously filling a heat storage material into twelve heat storage units 100, will be described as an example.
The apparatus for filling a heat storage material, according to the present embodiment, is an apparatus for filling a heat storage material in the heat storage units 100 by melting a heat storage material in a solid state by using hot water filled in the heating case 200 after having inserted the holding frame 300, on which the twelve heat storage units 100 are held, into the heating case 200.
As illustrated in FIG. 1, the cover plate 500 is coupled to an upper portion of the holding frame 300, and the holding frame 300, to which the cover plate 500 is coupled, is inserted into the heating case 200.
The heating case 200 includes a filling chamber 210, an inlet 220, and an outlet 230. As illustrated in FIGS. 1 and 2, the filling chamber 210 has an opened upper portion. The filling chamber 210 has a shape in which hot water may be filled. The filling chamber 210 may preferably be formed of a heat-retaining material so as to maintain a constant temperature of the hot water filled in the filling chamber 210.
In the present embodiment, as illustrated in FIG. 2, the inlet 220 is arranged in a lower portion of the filling chamber 210, and the outlet 230 is arranged in an upper portion of the filling chamber 210. Hot water is supplied to the filling chamber 210 through the inlet 220, and the hot water filled in the filling chamber 210 is discharged through the outlet 230.
The holding frame 300 includes a holding portion 310 and a gap member 400. Referring to FIG. 1, the holding frame 300 is formed to enter the heating case 200 through an upper portion of the heating case 200 and to be seated in the filling chamber 210. Referring to FIG. 3, the holding frame 300 according to the present embodiment is formed of a metallic frame having a bar shape. Twelve heat storage units 100 are held inside the holding frame 300. The holding portion 310 is arranged in a lower portion of the holding frame 300 and supports lower surfaces of the heat storage units 100.
The holding portion 310 includes twelve unit guides 311, which is the same number as the heat storage units 100. As illustrated in FIG. 3, the unit guides 311 have a ring shape. A shape of the unit guides 311 corresponds to a shape of the lower surfaces of the heat storage units 100. A lower portion of the heat storage units 100 is inserted into the unit guides 311. The unit guides 311 are arranged at uniform distances to arrange the twelve heat storage units 100 at uniform distances. An inner diameter of the unit guides 311 is greater than a cross-section of the heat storage units 100 such that there is a distance between the heat storage units 100 inserted into the unit guides 311 and the unit guides 311.
As illustrated in FIG. 3, four gap members 400 are installed on an upper surface of the holding frame 300. The cover plate 500, which will be described later, is coupled to the holding frame 300 via the gap members 400. Due to the gap members 400, a constant distance is maintained between the holding frame 300 and the cover plate 500.
The cover plate 500 has a planar shape. To prevent distortion or bending, the cover plate 500 may preferably be formed of a rigid metallic material. As illustrated in FIG. 1, the cover plate 500 is coupled to the upper portion of the holding frame 300. As described above, due to the gap members 400 installed on the holding frame 300, the holding frame 300 and the cover plate 500 are maintained at a uniform distance.
A filling hole 510 and a coupling hole 520 are formed in the cover plate 500. One filling hole 510 and a plurality of coupling holes 520 are formed in the cover plate 500 at each of positions respectively corresponding to the heat storage units 100. As described above, twelve heat storage units 100 are held in the holding frame 300. A total of twelve filling holes 510 corresponding to the twelve heat storage units 100 are formed in the cover plate 500.
The filling hole 510 communicates with an injection inlet 160 of the heat storage units 100. The filling hole 510 is arranged at a position corresponding to the heat storage units 100 arranged via the unit guides 311 of the holding portion 310. Accordingly, when the cover plate 500 is coupled to the holding frame 300, a heat storage material may be injected into the injection inlet 160 of the heat storage units 100 through the filling hole 510 of the cover plate 500.
The coupling holes 520 are holes, through which a bolt for coupling the heat storage units 100 to the cover plate 500 passes. By inserting a bolt through the coupling holes 520 to fasten the bolt to the heat storage units 100, the heat storage units 100 are coupled to the cover plate 500. When coupling between the cover plate 500 and the heat storage units 100 is completed, upper surfaces of the heat storage units 100 and a lower surface of the cover plate 500 are closely adhered to each other. While coupling the cover plate 500 and the heat storage units 100 to each other via a bolt, the heat storage units 100 are lifted and the lower surfaces of the heat storage units 100 are separated from the holding portion 310.
Referring to FIG. 4, a distribution member 600 is installed in the filling chamber 210. The distribution member 600 includes a plurality of distribution holes 620 and a distribution flow passage 610.
The distribution flow passage 610 is a pipe formed inside the distribution member 600, and hot water may move through the distribution flow passage 610. The distribution flow passage 610 connects the inlet 220 of the heating case 200 and the distribution holes 620 of the distribution member 600. Hot water that has flown into the inlet 220 flows to the distribution holes 620 through the distribution flow passage 610. The distribution holes 620 are holes formed in the distribution member 600 to communicate with the filling chamber 210. Hot water is evenly distributed into the filling chamber 210 through the plurality of distribution holes 620. As illustrated in FIG. 4, an inner diameter of each of the distribution holes 620 may preferably increase away from the inlet 220.
A checking member 700 has a bar shape. Measurement is marked on the checking member 700 in a length direction. The checking member 700 may be inserted into the injection inlet 160 of the heat storage units 100 through the filling hole 510 of the cover plate 500.
Next, referring to FIG. 5, a structure of the heat storage units 100 used in the apparatus for filling a heat storage material, according to the present embodiment, will be described.
The heat storage units 100 include a unit main body 110 having a cylindrical shape and extending in a length direction. A heat storage chamber formed as a closed space is formed inside the unit main body 110. A heat storage material is filled in the heat storage chamber. The injection inlet 160 communicating with the heat storage chamber is formed in the unit main body 110. Accordingly, a heat storage material may be filled in the heat storage chamber through the injection inlet 160. A coupling port 170, to which a bolt inserted through the coupling holes 520 of the cover plate 500 is fastened, is formed in the upper surfaces of the heat storage units 100.
Meanwhile, a plurality of internal pins are installed in the heat storage chamber. The internal pins are formed to protrude and extend from an inner surface of the heat storage chamber toward a center of the heat storage chamber. The internal pins are arranged radially with respect to the unit main body 110 to protrude. In addition, a plurality of uneven structures may be formed on surfaces of the internal pins to increase an area of contact between a heat storage material and the internal pins, thereby enhancing heat exchange efficiency. A plurality of external pins 140 are installed on an external surface of the unit main body 110. The external pins 140 may be arranged in a circumferential direction along the external surface of the unit main body 110 to protrude in a radial direction.
Hereinafter, an operation of filling a heat storage material in the heat storage units 100 by using the apparatus for filling a heat storage material configured as described above will be described.
First, the twelve heat storage units 100 are placed in the holding frame 300. A user places the heat storage units 100 such that the lower surfaces of the heat storage units 100 meet the holding portion 310 of the holding frame 300. Here, some of the heat storage units 100 are inserted into the unit guide 311 of the holding portion 310 as described above. Accordingly, the twelve heat storage units 100 are held in the holding frame 300 while they are in an arrangement as illustrated in FIG. 1.
After placing the twelve heat storage units 100 in the holding frame 300, the cover plate 500 is coupled to the upper portion of the holding frame 300. Due to the gap members 400, there is a distance between the cover plate 500 and the holding frame 300.
As described above, the filling hole 510 and the coupling holes 520 of the cover plate 500 are arranged at positions corresponding to the heat storage units 100 aligned via the unit guides 311. When the cover plate 500 and the holding frame 300 are coupled to each other, one filling hole 510 and a plurality of coupling holes 520 correspond to each of the heat storage units 100.
When a bolt is fastened to the coupling port 170 of the heat storage units 100 via the coupling holes 520 of the cover plate 500, the cover plate 500 and the heat storage units 100 are coupled to each other. As described above, as there is a distance between the cover plate 500 and the holding frame 300 due to the gap members 400, the heat storage units 100 are lifted while coupling the heat storage units 100 to the cover plate 500. Accordingly, when the heat storage units 100 are completely coupled to the cover plate 500, the lower surfaces of the heat storage units 100 are spaced apart from the holding portion 310 of the holding frame 300.
Due to the action of the gap members 400 as described above, the heat storage units 100 are firmly fixed to the cover plate 500, and space accommodating changes in the measurement of the heat storage units 100 due to thermal expansion is also provided.
Next, an operation of filling hot water in the filling chamber 210 of the heating case 200 will be described.
Hot water is supplied to the heating case 200 by using a pump (not shown) and a heater (not shown). Hot water flows through the inlet 220 to the distribution flow passage 610 of the distribution member 600 connected to the inlet 220. The hot water flowing through the distribution flow passage 610 is distributed into the filling chamber 210 of the heating case 200 through the plurality of distribution holes 620 connected to the distribution flow passage 610. As described above, as hot water flowing in the distribution flow passage 610 is supplied to the filling chamber 210 through the plurality of distribution holes 620, the hot water may be evenly distributed into the filling chamber 210.
When the hot water filled in the filling chamber 210 exceeds a certain level, the hot water is discharged through the outlet 230 arranged in the upper portion of the filling chamber 210 and flows to a pump (not shown). In sum, the hot water that has flown into the filling chamber 210 through the inlet 220 is discharged to the outside through the outlet 230. As described above, as the hot water filled in the filling chamber 210 of the heating case 200 is continuously circulated, the hot water filled in the filling chamber 210 may be maintained at a certain temperature.
Meanwhile, in order to evenly supply hot water not only into the distribution holes 620 adjacent to the inlet 220 but also to the distribution holes 620 that are relatively far from the inlet 220, an inner diameter of the distribution holes 620 that are relatively far from the inlet 220 may preferably be larger than an inner diameter of the distribution holes 620 that are relatively close to the inlet 220. By using this method, an internal temperature of the filling chamber 210 may be maintained uniform.
When hot water is filled in the filling chamber 210 of the heating case 200 according to this process, an assembly in which the heat storage units 100 are held and the holding frame 300 and the cover plate 500 are coupled to each other is inserted into the filling chamber 210 of the heating case 200. The assembly including the heat storage units 100, the holding frame 300, and the cover plate 500 may be inserted into the filling chamber 210 of the heating case 200 by using various methods. In the present embodiment, the assembly is inserted into the filling chamber 210 by using a crane.
When the holding frame 300 is seated in the filling chamber 210 of the heating case 200, the twelve heat storage units 100 held in the holding frame 300 are arranged inside the filling chamber 210 of the heating case 200. The heat storage units 100 are heated by hot water filled in the filling chamber 210 of the heating case 200. After the heat storage units 100 are sufficiently heated, a heat storage material in a solid state is injected into each of the heat storage units 100 through the filling hole 510 of the cover plate 500. The heat storage material that has passed through the filling hole 510 is filled in the heat storage chamber through the injection inlet 160 of the heat storage units 100.
The heat storage material filled in the heat storage chamber is heated by the hot water filled in the filling chamber 210 of the heating case 200, and when a temperature of the heat storage material increases to a melting point or higher, the heat storage material is melted to a liquid state. Temperatures of the heat storage units 100 and the heat storage material in the heat storage units 100 are maintained at a high temperature due to the hot water in the filling chamber 210. Accordingly, a heat storage material that has been injected into the heat storage chamber relatively early is not cooled and maintains its liquid state. Thus, the filling operation may be performed while maintaining the liquid state of the heat storage material until the heat storage chamber is completely filled with the heat storage material. In addition, as the filling operation may be performed while simultaneously heating the twelve heat storage units 100, the filling operation of the heat storage units 100 may be performed quickly and efficiently.
As described above, when the heat storage units 100 are heated and the heat storage material is simultaneously melted, due to thermal expansion of a material, of which the heat storage units 100 are formed, and an increase in a volume of the heat storage material filled in the heat storage units 100, the volume of the heat storage units 100 may increase. As described above, the heat storage units 100 are coupled to the cover plate 500 while they are spaced apart from the holding portion 310, and the inner diameter of the unit guides 311, into which some of the heat storage units 100 are inserted, is also greater than a cross-section of the heat storage units 100. This configuration is provided in consideration of the increase in the volume of the heat storage units 100 occurring during the filling operation. That is, according to the apparatus for filling a heat storage material of the present embodiment, damages to elements adjacent to the heat storage units 100 due to the increase in the volume of the heat storage units 100 when the elements come into contact with the heat storage units 100 may be effectively prevented.
The user may use a checking member 700 to check a filling level of a heat storage material. When the checking member 700 is inserted into the filling hole 510 of the cover plate 500, a surface of the checking member 700 is smeared with the heat storage material. The user may check a level of filling of the heat storage material by identifying the measurement marked on the surface of the checking member 700 and a portion smeared with the heat storage material.
Meanwhile, an additional apparatus for injecting a heat storage material simultaneously into the twelve filling holes 510 may be used to use the apparatus for filling a heat storage material according to the present embodiment.
When filling the heat storage units 100 with a heat storage material is completed according to this process, a fixed-type crane is operated to lift the holding frame 300 to separate the holding frame 300 from the heating case 200.
When a temperature is varied during the operation of filling a heat storage material, due to a change in a density of the heat storage material, a filling level of the heat storage material in each of the heat storage units 100 may be different. Thus, in order to fill an equal amount of heat storage material, it is important to inject a heat storage material in a constant temperature state. According to the apparatus for filling a heat storage material of the present embodiment, a heat storage material is filled while a temperature is maintained as described above, and thus, a uniform amount of heat storage material may be filled.
In addition, according to the apparatus for filling a heat storage material of the present disclosure, as a heat storage material may be filled into a plurality of heat storage units 100 at the same time, time and costs needed for a filling operation may be remarkably saved. Thus, the unit cost of the heat storage units 100 may be reduced.
According to the apparatus for filling a heat storage material of the present disclosure, a method of melting a heat storage material by using hot water is used, and thus, the method is safe compared to a method of directly injecting a melted heat storage material. In addition, according to the apparatus for filling a heat storage material of the present disclosure, a filling apparatus and a filling process may be configured relatively simply.
While the present disclosure has been described with reference to preferred embodiments, the scope of the present disclosure is not limited to the above described and illustrated forms.
For example, while the inlet 220 of the heating case 200 is described as being arranged in the lower portion of the filling chamber 210, and the outlet 230 is described as being arranged in the upper portion of the filling chamber 210 above, the opposite is also possible. That is, an outlet may be arranged in a lower portion of a filing chamber, and an inlet may be arranged in an upper portion of the filling chamber. Moreover, an apparatus for filling a heat storage material according to the present disclosure may also be configured by installing an outlet and an inlet at a same height.
In addition, while the heat storage units 100 and the cover plate 500 are described above as being coupled via a bolt passing through the coupling holes 520, heat storage units and a cover plate may be coupled using various well-known methods other than a bolt coupling method.
In addition, twelve heat storage units 100 held in the holding frame 300 are described above as an example. Accordingly, twelve unit guides 311 included in the holding portion 310 and twelve filling holes 510 of the cover plate 500 are described. However, the number of heat storage units to be held in a holding frame may be modified in various manners, and the number of unit guides, filling holes, and coupling holes may also be modified in various manners.
In addition, while the unit guides 311 of the holding portion 310 are described as being formed to simply correspond to a cross-section of the heat storage units 100 such that the heat storage units 100 are inserted into the unit guides 311, unit guides may also be configured to fix heat storage units inserted into the unit guides so that the heat storage units are not rotated about a length direction as an axis. For example, grooves of unit guides and protrusions of heat storage units may be configured to be coupled to each other so as to fix a position of the heat storage units inserted into the unit guides. In addition, unit guides may also be omitted.
In addition, while the gap members 400 are described as being coupled to the holding frame 300, an apparatus for filling a heat storage material according to the present disclosure may also be configured such that a gap member is coupled to a cover plate. An apparatus for filling as heat storage material according to the present disclosure may also be configured by omitting a gap member.
In addition, while the heat storage units 100 coupled to the cover plate 500 are described above to be separated from a holding portion of a holding frame via the gap members 400, the same effects may also be obtained by adjusting heights of a cover plate and heat storage units. For example, a holding frame may be configured to have a higher height than heat storage units. In this case, when the heat storage units are coupled to the cover plate, the heat storage units are lifted in a coupling operation, and thus, the heat storage units are separated from the holding portion of the holding frame.
In addition, the form of the holding frame 300 described and illustrated above is merely an example, and the form of a holding frame of the apparatus for filling a heat storage material according to the present disclosure may be modified in various manners.
In addition, while the distribution holes 620 of the distribution member 600 are described above to have different inner diameters from each other, a distribution member including distribution holes having a uniform inner diameter may also be configured. In addition, an apparatus for filling a heat storage material according to the present disclosure may also be configured by omitting a distribution member.
In addition, a structure of the heat storage units 100 described above is merely an example, and the apparatus for filling a heat storage material according to the present disclosure may be used to fill various types of heat storage systems.
According to the apparatus for filling a heat storage material of the present disclosure, an accurate and uniform amount of a heat storage material may be conveniently filled in a heat storage system while maintaining a liquid state of the heat storage material by melting heat storage material.
In addition, according to the apparatus for filling a heat storage material according to the present disclosure, the time and costs needed for an operation of filling a heat storage material in a plurality of heat storage systems may be saved.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments.
While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the inventive concept as defined by the following claims.

Claims

What is claimed is:

1. An apparatus for filling a heat storage material, the apparatus being formed in a form of a container for storing heat by using a thermal energy delivery method, wherein the heat storage material is filled in a heat storage unit having an injection inlet formed in an upper portion of the heat storage unit, the apparatus comprising:

a heating case comprising a filling chamber having an opened upper portion, an inlet through which hot water is supplied to the filling chamber, and an outlet formed in the filling chamber, wherein the hot water that has flown into the filling chamber is discharged through the outlet;

a holding frame comprising a holding portion on which the heat storage unit is held, wherein the holding frame enters the upper portion of the heating case to be seated in the filling chamber of the heating case;

a cover plate comprising a filling hole communicating with the injection inlet of the heat storage unit so as to fill the heat storage material through the injection inlet of the heat storage unit, wherein the cover plate is coupled to the holding frame; and

a gap member disposed between the holding frame and the cover plate and installed on one of the holding frame and the cover plate, such that the cover plate is coupled to the holding frame while maintaining a distance with respect to the holding frame,

wherein the holding portion of the holding frame comprises a unit guide having a shape corresponding to a lower surface of the heat storage unit such that a position of the heat storage unit with respect to the cover plate is aligned.

2. The apparatus of claim 1, wherein a coupling hole, through which a bolt coupling the heat storage unit held on the holding portion of the holding frame and the cover plate to each other passes through, is formed in the cover plate.

3. The apparatus of claim 1, wherein the inlet of the heating case is arranged in a lower portion of the filing chamber, and the outlet of the heating case is arranged in an upper portion of the filing chamber.

4. The apparatus of claim 3, further comprising a distribution member installed in the filling chamber and comprising a plurality of distribution holes, through which the hot water flowing through the inlet is distributed into the filling chamber, and a distribution flow passage connecting the plurality of distribution holes and the inlet of the heating case.

5. The apparatus of claim 4, wherein an inner diameter of the plurality of distribution holes of the distribution member increases away from the inlet of the filling chamber.

6. The apparatus of claim 1, further comprising a checking member inserted into the heat storage unit through the filling hole of the cover plate to check a level of filling of the heat storage material.

7. The apparatus of claim 6, wherein a measurement is marked on the checking member in a length direction.