WO2015093416A1

WO2015093416A1 - Heat-collecting receiver

Info

Publication number: WO2015093416A1
Application number: PCT/JP2014/083051
Authority: WO
Inventors: 伊藤　孝
Original assignee: イビデン株式会社
Priority date: 2013-12-20
Filing date: 2014-12-12
Publication date: 2015-06-25
Also published as: JP2017048926A

Abstract

This heat-collecting receiver has a first surface which receives solar heat, and a second surface which is on the side opposite the first surface and through which a heated gas is extracted. This heat-collecting receiver is characterized by comprising a ceramic porous body, with the first surface having multiple first bottomed holes extending toward the second surface, and the second surface having multiple second bottomed holes extending toward the first surface.

Description

Heat collecting receiver

The present invention relates to a heat collecting receiver used for solar power generation.

Solar power generation is known as a power generation method using the sun. In solar thermal power generation, light emitted from the sun is collected via a reflecting mirror or the like, and a steam turbine is driven using the obtained solar heat to generate electric power. Since this solar thermal power generation does not generate greenhouse gases such as carbon dioxide during power generation and can store heat, it can generate power even in cloudy weather or at night. Therefore, solar thermal power generation is attracting attention as a promising power generation method in the future.

There are two types of solar thermal power generation methods: trough type and tower type. Tower-type solar power generation is a power generation system that uses a number of plane mirrors called heliostats to concentrate sunlight by concentrating sunlight on a heat collection receiver in a tower installed in the center, and generate heat using that heat. . A heliostat is a flat mirror of several meters square, and tower-type solar power generation can concentrate sunlight collected from hundreds to thousands of heliostats in one place. Therefore, it is possible to heat the heat collecting receiver to about 1000 ° C., and the tower type solar thermal power generation has a feature of good thermal efficiency.

Patent Document 1 discloses a heat collection receiver used in a solar thermal power generation device as a tower-type solar power generation receiver, and the heat collection receiver has a plurality of flow paths for allowing a heat medium to pass therethrough. A heat absorber composed of one or a plurality of honeycomb units arranged side by side and a support that supports the heat absorber and circulates a heat medium, and the heat absorber includes silicon carbide. And a heat collecting receiver that is supported at a predetermined distance from the inner surface of the support.

JP 2012-93003 A

However, the heat collecting receiver described above has the following problems.
It is necessary to inhale air at a flow rate faster than the rising speed of the warmed air so that the warmed air in contact with the front surface of the heat collecting receiver does not diffuse out of the apparatus by convection. If the flow rate of air is high, the flow path necessary for heat exchange becomes naturally long, and the size of the heat collecting receiver becomes large. If a large temperature difference occurs in one heat collecting receiver, cracks are likely to occur due to thermal distortion. The frequency of occurrence of cracks due to this thermal strain becomes more conspicuous as the size of the heat collecting receiver increases. On the other hand, if the heat collecting receiver is short and small, the efficiency of heat exchange will deteriorate, and the heat collecting receiver will be overheated and the speed of deterioration will be increased.

An object of the present invention is to provide a heat collecting receiver capable of efficiently exchanging heat even with a small size, being less prone to cracking and ensuring long-term reliability.

The heat collection receiver of the present invention for solving the above-mentioned problem is a heat collection receiver having a first surface that receives solar heat and a second surface from which heated gas is extracted on the opposite side of the first surface, The heat collecting receiver is made of a ceramic porous body, and the first surface has a plurality of first bottomed holes extending toward the second surface, and the second surface faces the first surface. And a plurality of second bottomed holes extending in the direction.

The heat collecting receiver of the present invention is made of a ceramic porous body, and by sucking from the second surface side, gas is introduced from the first bottomed hole, and the first bottomed hole and the second bottomed hole The gas is discharged from the second bottomed hole through the ceramic porous body. At this time, the gas is heated by receiving heat from the heat collecting receiver heated by receiving sunlight. That is, heat exchange is performed in the process of gas passing through the porous body. Since the porous body has a large surface area, if the heat collecting receiver is a porous body, the area where the gas and the heat collecting receiver come into contact can be increased. Further, when passing through the porous body, the gas enters the pores of the porous body, so that the gas flow is disturbed. As a result, the moving distance of the gas when passing through the porous body becomes long. Therefore, heat can be exchanged efficiently in a short section. For this reason, without reducing the heat exchange performance of the heat collecting receiver, it is possible to reduce the size and to make it difficult to break, and to ensure long-term reliability.

Furthermore, the heat collecting receiver of the present invention is preferably in the following manner.
(1) When the said heat collection receiver is cut | disconnected in the direction perpendicular | vertical to a longitudinal direction, it has an area | region where the said 1st bottomed hole and the said 2nd bottomed hole exist.

When the heat collecting receiver is cut in a direction perpendicular to the longitudinal direction, the region having the first bottomed hole and the second bottomed hole is, for example, the bottom surface of the first bottomed hole. Extends to the vicinity of the second surface, and the bottom surface of the second bottomed hole extends to the vicinity of the first surface.
By extending the bottom surface of the first bottomed hole to the vicinity of the second surface, the gas before being heated can be spread over the entire heat collecting receiver. When the bottom surface of the second bottomed hole extends to the vicinity of the first surface, the heated gas can be drawn out from the entire heat collecting receiver.

That is, when the heat collecting receiver of the present invention is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole and the second bottomed hole are configured so as to have a region. The gas absorbed in the wall surface of the bottomed hole is drawn out from the wall surface of the adjacent second bottomed hole. The heat exchange between the gas serving as the heat medium and the heat collecting receiver is performed inside the porous body between the first bottomed hole and the second bottomed hole, that is, the entire heat collecting receiver. A temperature difference between the surface and the second surface is unlikely to occur, and the heat collecting receiver can be made difficult to break.

(2) When the heat collecting receiver is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is the first bottomed hole. It has the area | region enclosed by the bottomed hole.
When the heat collecting receiver of the present invention is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole becomes the first bottomed hole. Since it has the area | region enclosed, it can arrange | position so that the distance between a 1st bottomed hole and a 2nd bottomed hole may not be biased in the whole heat collecting receiver, The gas taken in from the bottom hole can be quickly moved to the adjacent second bottomed hole.

(3) The first bottomed hole and the second bottomed hole are partitioned by a plate-like wall.
In the heat collecting receiver of the present invention, the first bottomed hole and the second bottomed hole are separated from each other by a plate-like wall, so that the gas as the heat medium is separated from the first bottomed hole and the second bottomed hole. The distance passing through between the bottomed holes can be made constant. For this reason, since the gas which is a heat medium can receive heat equally from the wall surface which separates the 1st bottomed hole and the 2nd bottomed hole, it makes it difficult to produce the bias | biasing of a heat at a heat collecting receiver. Can do.

(4) The aspect ratio of the first bottomed hole and the second bottomed hole is 10 ⁴ to 10 ⁶ m ⁻¹ .
The aspect ratio is a ratio defined as [the length of the bottomed hole in the longitudinal direction of the heat collecting receiver] / [the opening area of the bottomed hole].
In the heat collection receiver of the present invention, when the aspect ratio is 10 ⁴ m ⁻¹ or more, heat exchange in a plane direction parallel to the first surface becomes dominant, so the first surface and the second surface of the heat collection receiver The temperature difference generated between the two can be reduced, and the warp generated in the heat collecting receiver can be reduced. When the aspect ratio is 10 ⁶ m ⁻¹ or less, the pressure loss of the fluid generated in the first bottomed hole and the second bottomed hole can be reduced. For this reason, the temperature gradient generated with the pressure gradient is reduced, the temperature difference generated between the first surface and the second surface can be reduced, and the warp generated in the heat collecting receiver can be reduced.

(5) The ceramic is silicon carbide or alumina.
These ceramics have heat resistance, chemical stability, mechanical strength, and high thermal conductivity. Since the heat collecting receiver is exposed to high temperature, heat resistance is required. Further, the performance of the ceramic material needs to be non-reactive with the gas used as the heat medium. When air is used as the heat medium, the ceramic material is required to have no reactivity with oxygen and moisture, and silicon carbide and alumina satisfy these performances. In addition, the heat collecting receiver may be exposed to a rapid temperature difference such as a clear change in a clear sky, a cloudy weather, or a rain in a clear sky. Since these ceramics have a low coefficient of thermal expansion, high thermal conductivity, and high strength, they also have a performance against a rapid temperature change.

According to the present invention, the gas introduced from the first bottomed hole passes through the porous body and is exhausted from the second bottomed hole. And heat exchange is performed in the process in which gas passes a porous body. Since the porous body has a large surface area, if the heat collecting receiver is a porous body, the area where the gas and the heat collecting receiver come into contact can be increased. Further, when passing through the porous body, the gas enters the pores of the porous body, so that the gas flow is disturbed. As a result, the moving distance of the gas when passing through the porous body becomes long. Therefore, heat can be exchanged efficiently in a short section. For this reason, without reducing the heat exchange performance of the heat collecting receiver, it is possible to reduce the size and to make it difficult to break, and to ensure long-term reliability.

FIG. 1 is a schematic view schematically illustrating an example of a state in which the heat collecting receiver according to the first embodiment of the present invention is incorporated in a housing. Fig.2 (a) is a top view which shows typically an example of the heat collecting receiver of Example 1 which concerns on this invention, FIG.2 (b) is the side view. FIG. 3 is a cross-sectional view schematically showing an example of a cross section perpendicular to the longitudinal direction of the heat collecting receiver according to the first embodiment of the present invention. FIG. 4 is a plan view schematically showing an example of a mold for molding the heat collecting receiver of Example 1 according to the present invention. 5A is a cross-sectional view taken along the line A-A ′ of FIG. 4, and FIG. 5B is a cross-sectional view taken along the line B-B ′ of FIG. 4. FIG. 6A is a perspective view schematically showing an example of the heat collecting receiver of Example 2 according to the present invention, and FIG. 6B is a cross-sectional view parallel to the longitudinal direction of FIG. It is.

A solar thermal power generation device is composed of a large number of mirrors, a heat collecting receiver, a turbine, a generator, and the like.

An example of a solar thermal power generation device will be described. Many mirrors are controlled so that sunlight can be collected in a heat collecting receiver by a tracking device that tracks the sun, and the collected light converts the collected light into heat energy. The converted thermal energy heats a heat medium such as a gas such as air or a liquid. The heated heat medium changes water into water vapor, for example, by heating water. Thereby, after obtaining a high pressure, electric energy can be obtained by rotating the turbine connected to the generator. The method for converting the thermal energy obtained by the heat collecting receiver into electrical energy is not limited to this, and a chemical reaction can be interposed in addition to direct conversion using a thermoelectric element. The heat collecting receiver of the present invention is a component that receives sunlight and converts it into heat energy.

The heat collection receiver of the present invention is a heat collection receiver having a first surface receiving solar heat and a second surface from which heated gas is taken out on the opposite side of the first surface, wherein the heat collection receiver is made of ceramic. The first surface includes a plurality of first bottomed holes extending toward the second surface, and the second surface includes a plurality of second holes extending toward the first surface. There is a bottomed hole.

When the heat collecting receiver of the present invention is cut in a direction perpendicular to the longitudinal direction, it is preferable to have a region where the first bottomed hole and the second bottomed hole exist.

When the heat collecting receiver is cut in a direction perpendicular to the longitudinal direction, the region having the first bottomed hole and the second bottomed hole is, for example, the bottom surface of the first bottomed hole. Extends to the vicinity of the second surface, and the bottom surface of the second bottomed hole extends to the vicinity of the first surface.

In the present invention, the vicinity of the first surface means a portion up to 30% of the length of the heat collecting receiver in the longitudinal direction from the first surface toward the second surface, and the vicinity of the second surface means the first surface. It means a part up to 30% of the length in the longitudinal direction of the heat collecting receiver from the second surface toward the first surface.
The bottom surface of the first bottomed hole is desirably in the vicinity of the second surface, and may be in a portion up to 10% of the length in the longitudinal direction of the heat collecting receiver from the second surface toward the first surface. More preferred.
Further, the bottom surface of the second bottomed hole is desirably in the vicinity of the first surface, and is in a portion up to 10% of the length in the longitudinal direction of the heat collecting receiver from the first surface toward the second surface. It is more preferable.
By extending the bottom surface of the first bottomed hole to the vicinity of the second surface, the gas before being heated can be spread over the entire heat collecting receiver. When the bottom surface of the second bottomed hole extends to the vicinity of the first surface, the heated gas can be drawn out from the entire heat collecting receiver.
That is, when the heat collecting receiver of the present invention is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole and the second bottomed hole are configured so as to have a region. The gas absorbed in the wall surface of the bottomed hole is drawn out from the wall surface of the adjacent second bottomed hole. The heat exchange between the gas serving as the heat medium and the heat collecting receiver is performed inside the porous body between the first bottomed hole and the second bottomed hole, that is, the entire heat collecting receiver. A temperature difference between the surface and the second surface is unlikely to occur, and the heat collecting receiver can be made difficult to break.

When the heat collecting receiver of the present invention is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is the first bottomed hole. It is preferable to have a region surrounded by the bottom hole.

When the heat collecting receiver of the present invention is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole becomes the first bottomed hole. Since it has the area | region enclosed, it can arrange | position so that the distance between a 1st bottomed hole and a 2nd bottomed hole may not be biased in the whole heat collecting receiver, The taken-in gas can be quickly moved to the adjacent second bottomed hole.

For example, the first bottomed hole is surrounded by the second bottomed hole and the second bottomed hole is surrounded by the first bottomed hole. The bottomed holes and the second bottomed holes are alternately arranged.

The first bottomed hole and the second bottomed hole of the present invention are preferably partitioned by a plate-like wall.
In the heat collecting receiver of the present invention, the first bottomed hole and the second bottomed hole are separated from each other by a plate-like wall, so that the gas as the heat medium is separated from the first bottomed hole and the second bottomed hole. The distance passing through between the bottomed holes can be made constant. For this reason, since the gas which is a heat medium can receive heat equally from the wall surface which separates the 1st bottomed hole and the 2nd bottomed hole, it makes it difficult to produce the bias | biasing of a heat at a heat collecting receiver. Can do.

The aspect ratio of the first bottomed hole and the second bottomed hole of the present invention is preferably 10 ⁴ to 10 ⁶ m ⁻¹ .
The aspect ratio is a ratio defined as [the length of the bottomed hole in the longitudinal direction of the heat collecting receiver] / [the opening area of the bottomed hole]. When the opening is a 1 mm square and the bottomed hole has a length of 100 mm, the aspect ratio is 10 ⁵ m ⁻¹ .
In the heat collection receiver of the present invention, when the aspect ratio is 10 ⁴ m ⁻¹ or more, heat exchange in a plane direction parallel to the first surface becomes dominant, so the first surface and the second surface of the heat collection receiver The temperature difference generated between the two can be reduced, and the warp generated in the heat collecting receiver can be reduced. When the aspect ratio is 10 ⁶ m ⁻¹ or less, the pressure loss of the fluid generated in the first bottomed hole and the second bottomed hole can be reduced. For this reason, the temperature gradient generated with the pressure gradient is reduced, the temperature difference generated between the first surface and the second surface can be reduced, and the warp generated in the heat collecting receiver can be reduced.

The ceramic of the present invention is preferably silicon carbide or alumina.
These ceramics have heat resistance, chemical stability, mechanical strength, and high thermal conductivity. Since the heat collecting receiver is exposed to high temperature, heat resistance is required. Further, the performance of the ceramic material needs to be non-reactive with the gas used as the heat medium. When air is used as the heat medium, the ceramic material is required to have no reactivity with oxygen and moisture, and silicon carbide and alumina satisfy these performances. In addition, the heat collecting receiver may be exposed to a rapid temperature difference such as a clear change in a clear sky, a cloudy weather, or a rain in a clear sky. Since these ceramics have a low coefficient of thermal expansion, high thermal conductivity, and high strength, they also have a performance against a rapid temperature change.

Hereinafter, the first and second embodiments, which are specific embodiments of the present invention, will be described. Embodiment 1 is a thick plate-shaped heat collecting receiver made of a porous body of alumina, and is used by being housed in a light receiving unit housing of a solar thermal power generation apparatus. The second embodiment is a honeycomb-shaped heat collecting receiver made of a porous body of silicon carbide, and is used by being housed in a light receiving unit housing of a solar thermal power generation apparatus.

<Embodiment 1>
The heat collecting receiver according to the first embodiment of the present invention will be described below. The heat collecting receiver of this embodiment is a thick plate-shaped heat collecting receiver made of a porous body of alumina, and is used by being housed in a housing of a light receiving part of a solar thermal power generation apparatus.

In the heat collecting receiver of this embodiment, the side receiving sunlight is the first surface, and the back surface thereof is the second surface. The first surface is formed with a plurality of first bottomed holes that are regularly arranged and extend toward the second surface, and the bottom surface of the first bottomed hole extends to the vicinity of the second surface. The first bottomed holes have the same shape. In addition, on the first surface, the plurality of first bottomed holes are evenly arranged in columns and rows. That is, the first bottomed holes are arranged in a lattice shape, and the first bottomed holes are located at the lattice points of the lattice.

The second surface is formed with a plurality of second bottomed holes that are regularly arranged and extend toward the first surface, and the bottom surface of the second bottomed hole extends to the vicinity of the first surface. Yes. The second bottomed holes have the same shape. In addition, on the second surface, the plurality of second bottomed holes are evenly arranged in columns and rows. That is, the second bottomed holes are arranged in a lattice shape, and the second bottomed holes are located at the lattice points of the lattice.
Further, when the second bottomed hole is projected onto the first surface, there is no overlapping portion between the first bottomed hole and the second bottomed hole on the first surface.
The heat collecting receiver of this embodiment does not have a through hole that connects the first surface side and the second surface side. The first bottomed hole and the second bottomed hole are tapered bottomed holes.

Thus, the heat collection receiver of the present embodiment is a heat collection receiver having a first surface that receives solar heat and a second surface from which heated gas is extracted on the opposite side of the first surface, and the heat collection receiver is The first surface has a plurality of first bottomed holes extending toward the second surface, and the second surface has a plurality of second holes extending toward the first surface. There is a bottom hole.

The heat collecting receiver of the present embodiment is made of a ceramic porous body, and by sucking from the second surface side, gas is introduced from the first bottomed hole, and the first bottomed hole and the second bottomed The gas is discharged from the second bottomed hole through the ceramic porous body between the holes. At this time, the gas is heated by receiving heat from the heat collecting receiver heated by receiving sunlight. That is, heat exchange is performed in the process of gas passing through the porous body. Since the porous body has a large surface area, if the heat collecting receiver is a porous body, the area where the gas and the heat collecting receiver come into contact can be increased. Further, when passing through the porous body, the gas enters the pores of the porous body, so that the gas flow is disturbed. As a result, the moving distance of the gas when passing through the porous body becomes long. Therefore, heat can be exchanged efficiently in a short section. For this reason, without reducing the heat exchange performance of the heat collecting receiver, it is possible to reduce the size and to make it difficult to break, and to ensure long-term reliability.
The porous body is not particularly limited, but the porosity is preferably 38 to 70%. When the porosity is 38% or more, gas can be easily circulated from the first surface side to the second surface side. When the porosity is 70% or less, the gas passes while contacting the pore surfaces of many ceramic porous bodies, so that heat exchange can be performed efficiently.

The gas used as the heat medium is not particularly limited, but for example, air can be used. When air is used as the heat medium, it is not necessary to shield the outside air, so that the apparatus can be simplified.

The first bottomed hole and the second bottomed hole are not limited to the scope of the present embodiment, and the size, arrangement, number, depth, and the like can be changed as appropriate. Further, the size, material, and the like of the entire heat collecting receiver can be appropriately changed.

It is preferable that the first bottomed hole and the second bottomed hole of the present embodiment are arranged so as not to be connected to each other. When arranged so as not to be connected to each other, all the gas introduced from the first bottomed hole is guided to the second bottomed hole while moving inside the ceramic porous body, and thus passes through the porous body. In this case, heat exchange is performed efficiently, and a high-temperature gas can be obtained.

When the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, it is preferable to have a region where the first bottomed hole and the second bottomed hole exist.
By extending the bottom surface of the first bottomed hole to the vicinity of the second surface, the gas before being heated can be spread over the entire heat collecting receiver. When the bottom surface of the second bottomed hole extends to the vicinity of the first surface, the heated gas can be drawn from the entire heat collecting receiver.

That is, when the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, the heat collecting receiver is configured to have a region in which the first bottomed hole and the second bottomed hole are present. The gas absorbed by the wall surface of one bottomed hole is drawn out from the wall surface of the adjacent second bottomed hole. The heat exchange between the gas serving as the heat medium and the heat collecting receiver is performed inside the porous body between the first bottomed hole and the second bottomed hole, that is, the entire heat collecting receiver. A temperature difference between the surface and the second surface is unlikely to occur, and the heat collecting receiver can be made difficult to break.

When the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is the first bottomed hole. It is preferable to have a region surrounded by
The first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is surrounded by the first bottomed hole, for example, in a cross section perpendicular to the longitudinal direction of the heat collecting receiver. The first bottomed hole and the second bottomed hole constitute a honeycomb-like regular repeating pattern, and the first bottomed hole and the second bottomed hole appear alternately in the vertical and horizontal rows of the pattern. Shape. Examples of the honeycomb shape include a rectangle, a hexagon, and a combination of a rectangle and an octagon.
When the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is the first bottomed hole. The first bottomed hole can be arranged so that the distance between the first bottomed hole and the second bottomed hole is not biased in the entire heat collecting receiver. The gas taken in can be quickly moved to the adjacent second bottomed hole.

In the heat collecting receiver of the present embodiment, the first bottomed hole and the second bottomed hole may be partitioned by a plate-like wall. The first bottomed hole and the second bottomed hole are separated from each other by a plate-like wall, so that the gas as the heat medium passes between the first bottomed hole and the second bottomed hole. The passing distance can be made constant. For this reason, since the gas which is a heat medium can receive heat equally from the wall surface which separates the 1st bottomed hole and the 2nd bottomed hole, it makes it difficult to produce the bias | biasing of a heat at a heat collecting receiver. Can do.

In the heat collecting receiver of this embodiment, it is preferable that the first bottomed hole and the second bottomed hole have an aspect ratio of 10 ⁴ to 10 ⁶ m ⁻¹ . In the present specification, the aspect ratio is a ratio defined as [the length of the bottomed hole in the longitudinal direction of the heat collecting receiver] / [the opening area of the bottomed hole]. When the aspect ratio is 10 ⁴ m ⁻¹ or more, the heat exchange in the plane direction parallel to the first surface becomes dominant, so that the temperature difference generated between the first surface and the second surface of the heat collecting receiver Can be reduced, and the warpage generated in the heat collecting receiver can be reduced. When the aspect ratio is 10 ⁶ m ⁻¹ or less, the pressure loss of the fluid generated in the first bottomed hole and the second bottomed hole can be reduced. For this reason, the temperature gradient generated with the pressure gradient is reduced, the temperature difference generated between the first surface and the second surface can be reduced, and the warp generated in the heat collecting receiver can be reduced.

In the heat collecting receiver of the present embodiment, the ceramic porous body is preferably silicon carbide or alumina. These ceramics have heat resistance, chemical stability, mechanical strength, and high thermal conductivity. Since the heat collecting receiver is exposed to high temperature, heat resistance is required. Further, the performance of the ceramic material needs to be non-reactive with the gas used as the heat medium. When air is used as the heat medium, the ceramic material is required to have no reactivity with oxygen and moisture, and silicon carbide and alumina satisfy these performances. In addition, the heat collecting receiver may be exposed to a rapid temperature difference such as a clear change in a clear sky, a cloudy weather, or a rain in a clear sky. Since these ceramics have a low coefficient of thermal expansion, high thermal conductivity, and high strength, they also have a performance against a rapid temperature change. For example, the thermal expansion coefficient of silicon carbide is 4.2 to 5.2 × 10 ⁻⁶ / ° C., the thermal conductivity is 25 to 200 W / mK, and the tensile strength is 20 to 100 MPa. Alumina has a thermal expansion coefficient of 7.0 to 8.0 × 10 ⁻⁶ / ° C., a thermal conductivity of 10 to 30 W / mK, and a tensile strength of 20 to 100 MPa.

As described above, in the heat collecting receiver of the present embodiment, the gas introduced from the first bottomed hole passes through the porous body and is exhausted from the second bottomed hole. And heat exchange is performed in the process in which gas passes a porous body. Since the porous body has a large surface area, if the heat collecting receiver is a porous body, the area where the gas and the heat collecting receiver come into contact can be increased. Further, when passing through the porous body, the gas enters the pores of the porous body, so that the gas flow is disturbed. As a result, the moving distance of the gas when passing through the porous body becomes long. Therefore, heat can be exchanged efficiently in a short section. For this reason, without reducing the heat exchange performance of the heat collecting receiver, it is possible to reduce the size and to make it difficult to break, and to ensure long-term reliability. Such an effect is not limited to the present embodiment, and can be obtained by appropriately combining the elements described in the present invention.

<Embodiment 2>
Next, a second embodiment of the present invention will be described.
The heat collection receiver of the present embodiment is a honeycomb-shaped heat collection receiver made of a porous body of silicon carbide, and is used by being housed in a light receiving unit housing of a solar thermal power generation apparatus.

In the heat collecting receiver of this embodiment, the side receiving sunlight is the first surface, and the back surface thereof is the second surface. The heat collection receiver of this embodiment is formed between a first surface and a second surface, and is configured by regularly arranging holes having a square cross section perpendicular to the longitudinal direction of the heat collection receiver. These holes are sealed on either the first surface side or the second surface side. That is, the hole opened on the first surface side is sealed on the second surface side, and the hole opened on the second surface side is sealed on the first surface side.

Thus, the hole sealed on the first surface side is the second bottomed hole, and the hole sealed on the second surface side is the first bottomed hole. Further, when the second bottomed hole is projected onto the first surface, the first bottomed hole and the second bottomed hole do not overlap each other. Furthermore, the heat collecting receiver of the present embodiment does not have a through hole that connects the first surface side and the second surface side.

The heat collecting receiver of the present embodiment is made of a ceramic porous body, and by sucking from the second surface side, gas is introduced from the first bottomed hole, and the first bottomed hole and the second bottomed The gas is discharged from the second bottomed hole through the ceramic porous body between the holes. At this time, the gas is heated by receiving heat from the heat collecting receiver heated by receiving sunlight. That is, heat exchange is performed in the process of gas passing through the porous body. Since the porous body has a large surface area, if the heat collecting receiver is a porous body, the area where the gas and the heat collecting receiver come into contact can be increased. Further, when passing through the porous body, the gas enters the pores of the porous body, so that the gas flow is disturbed. As a result, the moving distance of the gas when passing through the porous body becomes long. Therefore, heat can be exchanged efficiently in a short section. For this reason, without reducing the heat exchange performance of the heat collecting receiver, it is possible to reduce the size and to make it difficult to break, and to ensure long-term reliability.

Further, the porous body is not particularly limited, but the porosity is preferably 38 to 70%. When the porosity is 38% or more, gas can be easily circulated from the first surface side to the second surface side. When the porosity is 70% or less, the gas passes while contacting the pore surfaces of many ceramic porous bodies, so that heat exchange can be performed efficiently.

When the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, it is preferable to have a region where the first bottomed hole and the second bottomed hole exist.
When the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, the region having the first bottomed hole and the second bottomed hole means that the first bottomed hole is, for example, The form which extends to the vicinity of the 2nd surface and the 2nd bottomed hole extends to the vicinity of the 1st surface is mentioned.

The bottom surface of the first bottomed hole extends to the vicinity of the second surface, so that the gas before being heated can be spread over the entire heat collecting receiver. When the bottom surface of the second bottomed hole extends to the vicinity of the first surface, the heated gas can be drawn from the entire heat collecting receiver.

That is, when the heat collecting receiver is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is configured to have a region where the first bottomed hole and the second bottomed hole exist. The gas absorbed by the wall surface of the hole is drawn out from the wall surface of the adjacent second bottomed hole. The heat exchange between the gas serving as the heat medium and the heat collecting receiver is performed inside the porous body between the first bottomed hole and the second bottomed hole, that is, the entire heat collecting receiver. A temperature difference between the surface and the second surface is unlikely to occur, and the heat collecting receiver can be made difficult to break.

When the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is the first bottomed hole. It is preferable to have a region surrounded by.
The first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is surrounded by the first bottomed hole, for example, in a cross section perpendicular to the longitudinal direction of the heat collecting receiver. The first bottomed hole and the second bottomed hole constitute a honeycomb-like regular repeating pattern, and the first bottomed hole and the second bottomed hole appear alternately in the vertical and horizontal rows of the pattern. Shape. Examples of the honeycomb shape include a rectangle, a hexagon, and a combination of a rectangle and an octagon.

When the heat collecting receiver of the present embodiment is cut in a direction perpendicular to the longitudinal direction, the first bottomed hole is surrounded by the second bottomed hole, and the second bottomed hole is the first bottomed hole. Therefore, the distance between the first bottomed hole and the second bottomed hole can be arranged so as not to be biased in the whole heat collecting receiver, and is taken from the first bottomed hole. The generated gas can be quickly moved to the adjacent second bottomed hole.

In the heat collecting receiver of this embodiment, the first bottomed hole and the second bottomed hole are partitioned by a plate-like wall. The first bottomed hole and the second bottomed hole are separated from each other by a plate-like wall, so that the gas as the heat medium passes between the first bottomed hole and the second bottomed hole. The passing distance can be made constant. For this reason, since the gas which is a heat medium can receive heat equally from the wall surface which separates the 1st bottomed hole and the 2nd bottomed hole, it makes it difficult to produce the bias | biasing of a heat at a heat collecting receiver. Can do.

In the heat collecting receiver of the present embodiment, the ceramic porous body is preferably silicon carbide or alumina. These ceramics have heat resistance, chemical stability, mechanical strength, and high thermal conductivity. Since the heat collecting receiver is exposed to high temperature, heat resistance is required. Further, as the performance of the ceramic material, it is also necessary that there is no reactivity with the gas used as the heat medium. When air is used as the heat medium, the ceramic material is required to have no reactivity with oxygen and moisture, and silicon carbide and alumina satisfy these performances. In addition, the heat collecting receiver may be exposed to a rapid temperature difference such as a clear change in a clear sky, a cloudy weather, or a rain in a clear sky. Since these ceramics have a low coefficient of thermal expansion, high thermal conductivity, and high strength, they also have a performance against a rapid temperature change. For example, the thermal expansion coefficient of silicon carbide is 4.2 to 5.2 × 10 ⁻⁶ / ° C., the thermal conductivity is 25 to 200 W / mK, and the tensile strength is 20 to 100 MPa. Alumina has a thermal expansion coefficient of 7.0 to 8.0 × 10 ⁻⁶ / ° C., a thermal conductivity of 10 to 30 W / mK, and a tensile strength of 20 to 100 MPa.

As described above, in the heat collecting receiver of the present embodiment, the gas introduced from the first bottomed hole passes through the porous body and is exhausted from the second bottomed hole. And heat exchange is performed in the process in which gas passes a porous body. Since the porous body has a large surface area, if the heat collecting receiver is a porous body, the area where the gas and the heat collecting receiver come into contact can be increased. Furthermore, when the gas passes through the porous body, the gas enters the pores of the porous body, so that the gas flow is disturbed. As a result, the moving distance of the gas when passing through the porous body becomes long. Therefore, heat can be exchanged efficiently in a short section. For this reason, without reducing the heat exchange performance of the heat collecting receiver, it is possible to reduce the size and to make it difficult to break, and to ensure long-term reliability. Such an effect is not limited to the present embodiment, and can be obtained by appropriately combining the elements described in the present invention. *

<Example 1>
Next, Embodiment 1 according to the present invention will be described with reference to the drawings. Example 1 relates to Embodiment 1 of the present invention.
FIG. 1 is a schematic view schematically illustrating an example of a state in which the heat collecting receiver according to the first embodiment of the present invention is incorporated in a housing. Fig.2 (a) is a top view which shows typically an example of the heat collecting receiver of Example 1 which concerns on this invention, FIG.2 (b) is the side view. FIG. 3 is a cross-sectional view schematically showing an example of a cross section perpendicular to the longitudinal direction of the heat collecting receiver according to the first embodiment of the present invention. FIG. 4 is a plan view schematically showing an example of a mold for molding the heat collecting receiver of Example 1 according to the present invention. 5A is a cross-sectional view taken along line AA ′ of FIG. 4, and FIG. 5B is a cross-sectional view taken along line BB ′ of FIG.
In Example 1, a heat collecting receiver made of alumina formed by press molding will be described in order from the manufacturing method.

As shown in FIG. 4 and FIGS. 5 (a) and 5 (b), the mold cavity that is the upper punch 6, the lower punch 7, and the die 8 is filled with a molding raw material that is a raw material for the porous body of the heat collecting receiver. And pressurize to form. The forming raw material is not particularly limited as long as it is a raw material capable of forming alumina. For example, the forming raw material includes alumina powder, an organic binder, a sintering aid, a lubricant, and the like. The mixing ratio and average particle size are not particularly limited, and other additives may be added.

The upper punch 6 has a plurality of cylindrical first protrusions 61 that are regularly arranged with a draft angle. The lower punch 7 has a plurality of cylindrical second protrusions 71 having draft angles, and each of the second protrusions 71 is disposed so as to be surrounded by the plurality of first protrusions 61. ing. The draft angle is 1/30 for both the first protrusion 61 and the second protrusion 71, but the inclination is not particularly limited as long as the molded body can be pulled out without being damaged. The individual sizes of the first protrusion and the second protrusion are the same, but may not be the same.

The heat collecting receiver 10 can be obtained by degreasing and sintering the obtained molded body. The sintering temperature is 1500 ° C. The sintering temperature is not particularly limited, but is preferably 1000 ° C. or higher so as not to shrink when used as a heat collecting receiver.

As shown in FIGS. 1, 2 (a) and 2 (b) and FIG. 3, in the heat collecting receiver 10 of the present embodiment, the side receiving sunlight is the first surface 1 and the back surface is the second surface 2. is there. The first surface 1 is formed with a plurality of first bottomed holes 3 that extend toward the second surface 2 and are regularly arranged. The bottom surface 31 of the first bottomed hole extends to the vicinity of the second surface 2. It extends. The first bottomed holes 3 have the same shape. In the first surface 1, the first bottomed holes 3 are evenly arranged in columns and rows. That is, the 1st bottomed hole 3 is arrange | positioned so that it may become a grid | lattice form, and the 1st bottomed hole 3 is located in the lattice point of the said grid | lattice.

The second surface 2 is formed with a plurality of second bottomed holes 4 that extend toward the first surface 1 and are regularly arranged. A bottom surface 41 of the second bottomed hole is formed on the first surface 1. It extends to the vicinity. The second bottomed holes 4 have the same shape. In the second surface 2, the second bottomed holes 4 are evenly arranged in columns and rows. That is, the second bottomed holes 4 are arranged in a lattice shape, and the second bottomed holes 4 are located at the lattice points of the lattice.
Further, when the second bottomed hole 4 is projected onto the first surface 1, the first bottomed hole 3 and the second bottomed hole 4 do not overlap each other.
The heat collecting receiver 10 of the present embodiment does not have a through hole that connects the first surface 1 side and the second surface 2 side. The first bottomed hole 3 and the second bottomed hole 4 are tapered bottomed holes.

Thus, the heat collecting receiver of the present embodiment is the heat collecting receiver 10 having the first surface 1 that receives solar heat and the second surface 2 from which the heated gas is taken out on the opposite side of the first surface 1, The heat collecting receiver 10 is made of a ceramic porous body. The first surface 1 has a plurality of first bottomed holes 3 extending toward the second surface 2, and the second surface 2 has the first surface 1. There are a plurality of second bottomed holes 4 extending toward.

<Example 2>
Next, a second embodiment according to the present invention will be described with reference to the drawings. Example 2 relates to Embodiment 2 of the present invention.
FIG. 6A is a perspective view schematically showing an example of the heat collecting receiver of Example 2 according to the present invention, and FIG. 6B is a cross-sectional view parallel to the longitudinal direction of FIG. It is.
In Example 2, a heat collecting receiver 10 made of honeycomb-shaped silicon carbide formed by extrusion will be described in order from the manufacturing method.

A nozzle for forming a square honeycomb is used as a plunger nozzle, and a silicon carbide forming raw material is extruded. The forming raw material is not particularly limited as long as it is a raw material capable of forming silicon carbide. For example, the forming raw material includes silicon carbide powder, an organic binder, a sintering aid, a lubricant, and the like. The mixing ratio and average particle diameter are not particularly limited. Other additives may be added.
The extruded molded body can be obtained by cutting to a certain length, sealing the communicating holes alternately, degreasing, and sintering. The sintering temperature is 2000 ° C. The sintering temperature is not particularly limited, but is preferably 1800 ° C. or higher so as not to shrink when used as a heat collecting receiver.

6 (a) and 6 (b), in the heat collecting receiver 10 formed in this manner, the side receiving sunlight is the first surface 1 and the back surface thereof is the second surface 2. The heat collection receiver 10 of the present embodiment is formed between a first surface and a second surface, and is configured by regularly arranging holes having a quadrangular cross section perpendicular to the longitudinal direction of the heat collection receiver 10. Yes. These holes are sealed on either the first surface 1 side or the second surface 2 side. That is, the hole opened on the first surface 1 side is sealed on the second surface 2 side, and the hole opened on the second surface 2 side is sealed on the first surface 1 side.

Thus, the hole sealed on the first surface 1 side is the second bottomed hole 4, and the hole sealed on the second surface 2 side is the first bottomed hole 3. Further, when the second bottomed hole 4 is projected onto the first surface 1, the first bottomed hole 3 and the second bottomed hole 4 do not overlap each other. Furthermore, the heat collecting receiver 10 of the present embodiment does not have a through hole that connects the first surface 1 side and the second surface 2 side.

Thus, the heat collecting receiver of the present embodiment is the heat collecting receiver 10 having the first surface 1 that receives solar heat and the second surface 2 from which the heated gas is taken out on the opposite side of the first surface 1, The heat collecting receiver is made of a ceramic porous body. The first surface 1 has a plurality of first bottomed holes 3 extending toward the second surface 2, and the second surface 2 has the first surface 1. There are a plurality of second bottomed holes 3 extending toward the bottom.
The heat collecting receiver 10 of the present embodiment is joined so as to be arranged in a plurality, and is housed in a housing and used for a light receiving portion of solar thermal power generation.

DESCRIPTION OF SYMBOLS 1 1st surface 2 2nd surface 3 1st bottomed hole 4 2nd bottomed hole 5 Plate-shaped wall 6 Upper punch 7 Lower punch 8 Dice 9 The 1st bottomed hole and the 2nd bottomed hole Existing area 10 Heat collecting receiver 31 Bottom surface 41 of the first bottomed hole Bottom surface of the second bottomed hole

Claims

A heat collection receiver having a first surface for receiving solar heat and a second surface for extracting heated gas on the opposite side of the first surface,
The heat collecting receiver is made of a ceramic porous body,
The first surface has a plurality of first bottomed holes extending toward the second surface,
The heat collecting receiver, wherein the second surface has a plurality of second bottomed holes extending toward the first surface.
2. The collector according to claim 1, comprising a region where the first bottomed hole and the second bottomed hole exist when the heat collecting receiver is cut in a direction perpendicular to a longitudinal direction. Thermal receiver.
When cutting the heat collecting receiver in a direction perpendicular to the longitudinal direction,
The first bottomed hole is surrounded by the second bottomed hole;
The second bottomed hole is surrounded by the first bottomed hole;
The heat collecting receiver according to claim 1, wherein the heat collecting receiver has a region.
The heat collecting receiver according to claim 3, wherein the first bottomed hole and the second bottomed hole are partitioned by a plate-like wall.
The heat collection according to any one of claims 1 to 4, wherein an aspect ratio of the first bottomed hole and the second bottomed hole is 10 4 to 10 6 m -1. receiver.
The heat collecting receiver according to any one of claims 1 to 5, wherein the ceramic is silicon carbide or alumina.