US20160282014A1

US20160282014A1 - Thermal energy storage device

Info

Publication number: US20160282014A1
Application number: US15/036,105
Authority: US
Inventors: Sungkoo PARK
Original assignee: Individual
Current assignee: Individual
Priority date: 2013-11-13
Filing date: 2014-11-11
Publication date: 2016-09-29
Also published as: WO2015072719A1; JP2016537608A; CN105765318A; KR101499357B1

Abstract

The present invention relates to a thermal heat storage device. According to one aspect of the present invention, the thermal heat storage device comprises: a Fresnel lens for concentrating incident light to output the same; a heat collection port located at a lower part of the Fresnel lens to receive the incident light concentrated by the Fresnel lens; a heat pipe of which a portion is inserted into the heat collection port, and which has a heating medium, changing from a liquid state to a gaseous state by the heat collected by the heat collection port, filled therein; a heat-dissipation plate mounted on the outer surface of a portion of the heat pipe to radiate, to the outside, the heat of the heat pipe heated by the heating medium in the gaseous state; a heat exchange unit having the heat-dissipation plate therein and has a heat transfer liquid, which is heated by the heat radiated by the heat-dissipation plate, filled therein; and a heat storage tank connected to the heat exchange unit to receive and store the heated heat transfer liquid of the heat exchange unit and to output, to the heat exchange unit, the heat transfer liquid of which the heat is lost.

Description

TECHNICAL FIELD

The present invention relates to a thermal energy storage device.

BACKGROUND ART

A device which uses a solar energy, in general, may be categorized into a sunlight power generator which is configured to use sunlight, and a heat storage device which is configured to use a solar heat.
The sunlight power generator is a device which is able to directly convert a solar energy into an electric energy using a solar cell, and the solar heat storage device is a device which is able to obtain heat in such a way to concentrate sunlight with the aid of a light collection device, wherein water or a heat medium is heated using the thusly obtained heat, and is stored at a heat storage tank, and the thusly stored heat can be used later, if necessary.
The conventional solar heat storage device has a configuration wherein a sunlight is focused using a reflection mirror, and the focused sunlight is directly emitted toward an end of a heat pipe, whereby heat can be stored at the heat storage tank based on an efficient heat transfer effect of the heat pipe.
In case where only a reflection mirror is used, it is possible to use only the sunlight which is reflected off the reflection mirror, so a light collection efficiency may be degraded, which may result in a decreased light condensation efficiency. In case of a method wherein sunlight is directly collected at a heat pipe and is emitted, it is not easy to adjust focuses, and since the heat pipe is made of a metal material, a heat collection effect may be disadvantageously degraded.
An example of the aforementioned conventional technology is described in the Korean patent registration number 10-0720926 (the registration date is Jun. 16, 2007).

DISCLOSURE OF INVENTION

Technical Problem

Accordingly, it is an object of the present invention to provide a thermal energy storage device wherein the installation space of a heat storage device can be decreased since a heat storage operation can be carried out in such a way to collect sunlight by using a Fresnel lens the focusing distance of which is short.
It is another object of the present invention to provide a thermal energy storage device wherein the performance of a heat storage device can be enhanced by improving a light collection efficiency.

Technical Solution

To achieve the above objects, there is provided a thermal energy storage device, which may include, but is not limited to, a Fresnel lens which is able to collect and output an incident light; a heat collection unit which is disposed below the Fresnel lens and is configured to receive the incident light which is collected by the Fresnel lens; a heat pipe an end of which is partially inserted inside the heat collection unit, wherein the heat pipe is filled with a heat transfer medium which converts from a liquid state to a gaseous state by the heat collected by the heat collection unit; a heat-dissipation plate which is installed at an outer surface of a part of the heat pipe and is configured to radiate the heat of the heat pipe which is heated by the heat transfer medium which is in the vaporized state; a heat exchange unit which is provided with the heat-dissipation plate and is filled with a heat transfer liquid which is heated by the heat radiated from the heat-dissipation plate; and a heat storage tank which is connected to the heat exchange unit and is configured to receive and store the heat transfer liquid of the heat exchange unit and output the heat-lost heat transfer liquid to the heat exchange unit.
It is preferred that the heat pipe is disposed slanted upward toward the heat-dissipation plate and between the heat collection unit and the heat-dissipation plate.
It is preferred that the heat collection unit is installed at a focal position of the Fresnel lens.
There may be further provided first and second circulation pipes which are connected between the heat exchange unit and the heat storage tank and are configured to circulate the heat transfer liquid between the heat exchange unit and the heat storage tank.
The heat collection unit may be coated with an aluminum nitride.
There may be further provided a concave reflection mirror which is disposed below the heat collection unit and is configured to cover the heat collection unit and reflect the light which has passed through the Fresnel lens, toward the heat collection unit.

Advantageous Effects

According to the aforementioned features of the present invention, since a sunlight can be inputted into a heat collection unit by using a Fresnel lens the focusing distance of which is short, the distance between the Fresnel lens and the heat collection unit can be decreased, by which the installation space of the heat storage device can be decreased.
Moreover, since the heat collection unit is installed at a focusing position of the Fresnel lens, the light collection efficiency of the heat collection unit can be enhanced.
Furthermore, since the light which has passed through the Fresnel lens is reflected back toward the heat collection unit by providing a concave reflection mirror installed at a lower portion of the heat collection unit, the light collection efficiency of the heat collection unit can be more improved, thus enhancing the performance of the heat storage device.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a solar heat storage device according to an embodiment of the present invention.

FIG. 2 is a cross sectional view illustrating a solar heat storage device in FIG. 1.

FIG. 3 is a conception view for describing a state where a sunlight is collected at a heat collection unit with the aid of a Fresnel lens and a concave reflection mirror according to an embodiment of the present invention.

FIG. 4 is a view for describing another example of a concave reflection mirror according to an embodiment of the present invention.

FIG. 5 is a plane view illustrating a part of a Fresnel lens.

FIG. 6 is a view illustrating a configuration wherein a heat transfer liquid heated by a plurality of heat exchange units is stored at one regenerative furnace according to an embodiment of the present invention.

MODES FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will be described in detail so that a person having ordinary skill in the art can easily carry out with reference to the accompanying drawings. It is obvious that the present invention may be carried out into various different forms, and is not limited to the embodiments to be described herein. In addition, in the drawing, the portions which are not directly related with the descriptions of the invention will be omitted in an effort to clearly describe the present invention. Moreover, the terms used herein are used to mention only a specific embodiment, not intended to limit the present invention. Moreover, unless otherwise stated, a singular form used herein should be interrupted as including a plural meaning. The term “comprise” used in the specification is used to specify a predetermined characteristic, a region, an integer, a step, an operation, a component and/or a composition, not excluding any of presence or addition of other predetermined characteristics, regions, integers, steps, operations, components, composition and/or groups. Not defined different herein, all the terms used herein including technical and science terms should be interpreted as having the same meaning as the meaning that a person having ordinary skill in the art, in general, can understand. The terms defined on an ordinary dictionary should be interpreted as having the meanings matching with the related technology documents and the currently disclosed contents, and unless otherwise defined, they should not be interrupted as ideal or official meanings.
The embodiments of the present invention described with reference to the perspective views may show in detail an ideal embodiment of the present invention. Consequently, various modifications from the drawings, for example, a change in a manufacturing method and/or a specification, may be expected. For this reason, the embodiments are not limited to a specific form within an illustrated region, for example, any modifications based on the manufacturing may be included. The portions which are illustrated or described as being flat may have a tough or touch and nonlinear characteristic. Moreover, the portions which are illustrated as having a sharp angle may be presented rounded. The portions illustrated in the drawings correspond to a schematic configuration, and such forms are not intended to illustrate an accurate form of a corresponding region, not intended to narrow the scope of the present invention.
The solar heat storage device according to an embodiment of the present invention will be described with reference to the accompanying drawings.
It is noted that the same components or parts are illustrated with the same reference numbers. Moreover, throughout the descriptions of the present invention, the detailed descriptions on the related functions or configuration will be omitted in an effort to avoid any confusions over the subject matters of the present invention.
As illustrated in FIGS. 1 to 6, the solar heat storage device 100 according to an embodiment of the present invention may include, but is not limited to, a concave reflection mirror 110 which is able to reflect an incident light, for example, a sunlight; a Fresnel lens 120 which is disposed above the concave reflection mirror 110 and is employed to collect the sunlight which is inputted, and output it; a heat collection unit 140 disposed in a space formed between the concave reflection mirror 110 and the Fresnel lens 120; a heat pipe 130 an end of which is inserted in the heat collection unit 140 and obliquely and rectilinearly extends and passes through the concave reflection mirror 110; a heat exchange unit 150 wherein the other end of the heat pipe 130 passes and is inserted into the inside thereof; a heat-dissipation plate 160 which is connected to the heat pipe 130 inserted passing through the heat exchange unit 150 and is disposed inside the heat exchange unit 150; first and second circulation pipes 171 and 172 which are connected to the other side surface of the heat exchange unit 150 which is opposite to one side surface; and a heat storage tank 180 which is connected to the first and second heat circulation pipes 171 and 172.
As illustrated in FIG. 1, the concave reflection mirror 110 has a concave inner surface, wherein the inner space of the former is empty, so the concave reflection mirror 110 is disposed covering the heat collection unit which positions inside the inner space.
The sunlight which is inputted through the Fresnel lens 120 is reflected off the concave inner surface and is emitted toward the heat collection unit 140 which positions inside the concave reflection mirror 110.
The concave reflection mirror 110 may have a semispherical shape wherein the side surface of the former is shaped in a semispherical shape as illustrated in FIG. 1 or may have a semi-cylindrical shape the plane of the former may be shaped in a quadrangular shape as illustrated in FIG. 4, and the front thereof may be shaped in a semicircular shape.
As described before, the Fresnel lens 120 may be installed at the top of the concave reflection mirror 110, for which the top of the open state concave reflection mirror 110 may be completely covered by the Fresnel lens 120, so the inner space of the concave reflection mirror 110 may become a sealed space except for the portion which is connected to the heat pipe 130.
The Fresnel lens 120, in general, is formed of a plurality of circular band-shaped lenses so as to reduce the thickness of the lens, so a lens the diameter of which is large can be made without considering the thickness of the lens. For this reason, the aforementioned Fresnel lens 120 is used so as to condense light toward a narrow region.
As for the plane of the Fresnel lens 120, as illustrated in FIG. 5, a plurality of concentric circles 6 having different diameters are disposed at regular intervals on the upper surface of the lens about a central portion 5, namely, on the plane, so a focal distance shorter than that of the concave lens can be formed.
If a sunlight is inputted into the Fresnel lens 120, it will pass through the Fresnel lens 120 and will be inputted whole focusing at a predetermined distance.
As illustrated in FIG. 2, the heat collection unit 140 may be disposed inside the inner space of the concave reflection mirror 110 which is below the Fresnel lens 120 via a connection to the heat pipe 130 without using any support member. The inside of the heat collection unit 140 is empty, and a partial side portion of the heat pipe 130 is inserted in the empty space.
The aforementioned heat collection unit 140 may position where a focus is formed by the Fresnel lens 120, thus collecting to the maximum the sunlight which has collected by the Fresnel lens 120.
The Fresnel lens 120 may have a focal distance which is much shorter than that of the concave lens having the same thickness as that of the Fresnel lens 120, the distance between the Fresnel lens 120 and the heat collection unit 140, namely, the distance based on the focal distance, can be greatly reduced as compared to when the concave lens, etc. is used.
If the sunlight is emitted through the Fresnel lens 120 toward the heat collection unit 140, the installation space of the heat collection unit 140 can be greatly reduced, and the thickness, the weight, etc. of the lens used for collecting the light toward the heat collection unit 140 can be reduced.
If the sunlight is primarily emitted through the Fresnel lens 120 toward the heat collection unit 140, the sunlight reflected by the concave reflection mirror 110 which positions covering the heat collection unit 140 is secondarily emitted toward the heat collection unit 140, whereby the intensity of the sunlight which is inputted toward the heat collection unit 140 may increase, thus greatly increasing the efficiency of the heat collection unit 140.
Alternatively, the concave reflection mirror 110 may be omitted. In this case, the Fresnel lens 120 and the heat collection unit 140 may be installed using a separate support member.
The heat collection unit 140 is made of a material and is configured in a structure to absorb to the maximum the heat source from the sunlight while minimizing the reflection of the sunlight.
To this end, the heat collection unit 140 may be equipped with an insertion groove into which the heat pipe 130 can be inserted, and may have a hexahedron shape all sides of which are sealed, except for a metallic box on an outer surface of which is coated with an aluminum nitride, namely, a portion where the insertion groove is formed.
The heat pipe 130 may be a metallic pipe which is made of a metallic material, wherein the inner space of the heat pipe 130 is sealed. In this example, the heat pipe 130 has a circular pole shape, which is not limited thereto. It may have various shapes.
An end of the heat pipe 130 may be inserted into one side surface of the neighboring heat collection unit 140. As illustrated in FIG. 2, an end of the heat pipe 130 is partially inserted into the inside of the heat collection unit 140.
Moreover, the heat pipe 130 may be installed slanted more upwardly in the direction where it becomes farther from the heat collection unit 140. For this reason, it is slanted upward from the heat collection unit 140 to the heat-dissipation plate 160.
A heat medium (a heat transfer medium) (HL1) having a low boiling point and a good heat transfer function is disposed inside the heat pipe 130.
Since the heat pipe 130 is slanted downward toward the heat collection unit 140, the heat medium (HL1) disposed inside the heat pipe 130, as illustrated in FIG. 2, will gather at a side end portion of the heat pipe 130 inserted inside the heat collection unit 140.
The heat medium (HL1) stored inside the heat pipe 130 may expand when it receives heat, so it will be converted from a liquid state into a vaporized state.
The heat exchange unit 150 may include a heat-dissipation plate 160 into which an end of the heat pipe 160 is partially inserted.
All the portions of the heat exchange unit 150 are sealed except for the portion where the heat pipe 130 and the first and second circulation pipes 171 and 172 are inserted, and a heat transfer liquid (HL2) is filled in the inner space of the heat exchange unit 150.
The heat transfer liquid (HL2) may be water or oil.
The heat-dissipation plate 160 disposed inside the heat exchange unit 150 is configured to radiate heat, and as illustrated in FIG. 2, the heat pipe 130 is passing through the heat-dissipation plate 160 while crossing the center thereof in the longitudinal direction.
The heat-dissipation plate 160 may position at an outer surface of the heat pipe 130 which is passing through the heat-dissipation plate 160 and may radiate the heat of the heat pipe 130 to the outside, namely, toward the heat transfer liquid (HL2) filled in the heat exchange unit 150.
The heat-dissipation plate 160 may be disposed inside the heat exchange unit 150 with the air of the support function of the heat pipe 130 without using any support member.
The first and second circulation pipes 171 and 172 may be disposed spaced apart from each other parallel in the vertical direction and may be connected between the other side surface of the heat exchange unit 150 and the heat storage tank 180.
The heat exchange unit 150 and the heat storage tank 180 are communicating with each other via the first and second circulation pipes 171 and 172.
The first circulation pipe 171 which is disposed lower between the two circulation pipes 171 and 172 is a drainage pipe for discharging the heat transfer liquid (HL2) in the heat exchange unit 150 toward the heat storage tank 180, and the second circulation pipe 172 is a water intake pipe for receiving, into the heat exchange unit 150, the heat transfer liquid (HL2) the heat of which is lost after being discharged toward the heat storage tank 180.
The heat transfer liquid (HL2) of the heat exchange unit 150 can circulate between the heat exchange unit 150 and the heat storage tank 180 by the first and second circulation pipe 171, 172.
The heat storage tank 180 is a space for storing heat by storing the heat transfer liquid (HL2) which is transferred from the heat exchange unit 150 through the circulation operation of the heat transfer liquid (HL2).
The operation of the solar heat storage device 100 having the aforementioned configuration according to an embodiment of the present invention will be described.
First, the solar heat collected by the Fresnel lens 120 and the solar heat reflected by the concave reflection mirror 110 are emitted toward the heat collection unit 140 disposed between the Fresnel lens 120 and the concave reflection mirror 110, so the heat collection unit 140 can be heated by the thusly transferred heat.
As the heat collection unit 140 is heated, the heat medium (HL1) filled inside the heat pipe 130 inserted inside the heat collection unit 140 is also heated, so the liquid state heat medium (HL1) will be vaporized and change into a gaseous state.
The vaporized heat medium (HL1) will ascend, and since the heat pipe 130 is installed slanted upward toward the heat-dissipation plate 160, the vaporized heat medium (HL1) will move toward the other end of the heat pipe 130, which is the heat-dissipation plate 160, along the heat pipe 130.
The whole portions of the heat pipe 130 will be heated by the moving operation of the heat medium (HL1), and the heat can be transferred via the heat pipe 130 which is contacting with the heat-dissipation plate 160 disposed covering the outer surfaces of the heat pipe 130.
For this reason, the heat-dissipation plate 160 will receive the heat which has been collected by the heat collection unit 140 via the heat pipe 130, and the heat which has been transferred to the heat-dissipation plate 160 will be radiated to the outside of the heat-dissipation plate 160 with the aid of the heat-dissipation plate 160.
As described before, since the heat-dissipation plate 160 is disposed inside the heat exchange unit 150, the heat radiated from the heat-dissipation plate 160 will be transferred to the heat transfer liquid (HL2) filled inside the heat exchange unit 150.
The heat medium (HL1) which has been vaporized by the heat of the heat collection unit 140 and has transferred heat to the heat transfer liquid (HL2) of the heat exchange unit 150 via the heat pipe 130 will be liquefied.
Since the heat pipe 130 is formed slanted upward from the heat-dissipation plate 150 to the heat collection unit 140, the heat medium (HL1) which has been changed into the liquid state will move toward the heat collection unit 140 along the heat pipe 130 and will gather at the side end portion of the heat pipe 130 inserted inside the heat collection unit 140 and then will vaporized by the heat collection unit 140.
Due to the change of the heat medium (HL1) from the vaporized state to the liquid state, the solar heat collected by the heat collection unit 140 will be transferred as the heat transfer liquid (HL2) of the heat exchange unit 150, so the heating operation of the heat transfer liquid (HL2) is carried out.
The heat transfer liquid (HL2) heated by the circulation operation of the heat medium (HL1) will be transferred to the heat storage tank 180 via the first circulation pipe 171 and will be stored in the heat storage tank 180, thus storing heating therein.
A pump (not illustrated) is installed inside the heat storage tank 180. The heat transfer liquid (HL2) the heat of which has been lost will be inputted into the heat exchange unit 150 via the second circulation pipe 172, so the heating operation will be carried out by the revaporized heat medium (HL1).
The temperature of the heat stored in the heat storage tank 180 through the circulation operation of the heat transfer liquid (HL2) will increase through the first and second circulation pipes 171 and 172.
In this case, in order to prevent any heat loss while heat is being transferred through the heat pipe 130, the heat exchange unit 150, the heat storage tank 180 and the first and second circulation pipes 171 and 172, such devices 130, 150, 171, 172 and 180 are thermally insulated using a heat insulation material, thus minimizing any heat loss.
When the heat which is transferred to the heat exchange unit 150 is stored, as illustrated in FIG. 6, since the heat transferred from a plurality of the heat exchange units 150 can be stored using one regenerative furnace 180, the heat storage time can be decreased, while improving a heat storage efficiency.
As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described examples are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

What is claimed is:

1. A thermal energy storage device, comprising:

a Fresnel lens which is able to collect and output an incident light;

a heat collection unit which is disposed below the Fresnel lens and is configured to receive the incident light which is collected by the Fresnel lens;

a heat pipe an end of which is partially inserted inside the heat collection unit, wherein the heat pipe is filled with a heat transfer medium which converts from a liquid state to a gaseous state by the heat collected by the heat collection unit;

a heat-dissipation plate which is installed at an outer surface of a part of the heat pipe and is configured to radiate the heat of the heat pipe which is heated by the heat transfer medium which is in the vaporized state;

a heat exchange unit which is provided with the heat-dissipation plate and is filled with a heat transfer liquid which is heated by the heat radiated from the heat-dissipation plate; and

a heat storage tank which is connected to the heat exchange unit and is configured to receive and store the heat transfer liquid of the heat exchange unit and output the heat-lost heat transfer liquid to the heat exchange unit.

2. The device of claim 1, wherein the heat pipe is disposed slanted upward toward the heat-dissipation plate and between the heat collection unit and the heat-dissipation plate.

3. The device of claim 1, wherein the heat collection unit is installed at a focal position of the Fresnel lens.

4. The device of claim 1, further comprising:

first and second circulation pipes which are connected between the heat exchange unit and the heat storage tank and are configured to circulate the heat transfer liquid between the heat exchange unit and the heat storage tank.

5. The device of claim 1, wherein the heat collection unit is coated with an aluminum nitride.

6. The device of claim 1, further comprising:

a concave reflection mirror which is disposed below the heat collection unit and is configured to cover the heat collection unit and reflect the light which has passed through the Fresnel lens, toward the heat collection unit.