{DESCRIPTION}
{Title of Invention}
SOLAR THERMAL RECEIVER AND SOLAR THERMAL POWER GENERATION
FACILITY
{Technical Field}
{0001}
The present invention relates to solar thermal receivers
and solar thermal power generation facilities.
{Background Art}
{0002}
Various types of power generation facilities utilizing
solar heat have been conventionally proposed. For example,
power generation facilities have been proposed in which fluid
compressed by a compressor is heated by absorbing solar heat,
the heated fluid is supplied to a turbine section to extract a
rotary drive force, and a power generator is rotationally
driven (for example, see Patent Literatures 1 and 2).
{0003}
Since solar thermal receivers that make fluid absorb
solar heat are required to make the fluid absorb heat from
sunlight efficiently, various configurations have been
proposed (for example, see Patent Literatures 3 and 4).
In Patent Literatures 3 and 4, in order to improve solar
heat absorption efficiency, a layer made of a highly
endothermic material is disposed in an area to be irradiated
with sunlight.
{0004}
For example, a solar thermal receiver is also known in
which porous ceramic is disposed in a silica-glass tube, and
air passes through the porous ceramic.
In this solar thermal receiver, the heat of sunlight is
first absorbed into the porous ceramic. Then, when air passes
through the porous ceramic, the heat of the porous ceramic is
absorbed into the air, thus heating the air.
{Citation List}
{Patent Literature}
{0005}
{PTL 1}
PCT International Publication No. WO 2006-025449 Pamphlet
{PTL 2}
United States Patent No. 4268319
{PTL 3}
European Patent Application, Publication No. 1746363
{PTL 4}
The Publication of Japanese Patent No. 3331518
{Summary of Invention}
{Technical Problem}
{0006}
In order to improve power generation efficiency in solar
thermal power generation, it is necessary to more efficiently
heat fluid to a high temperature in the solar thermal
receiver.
However, merely with a method of improving the solar heat
absorption efficiency, there is an upper limit to the
absorption efficiency, and thus there is also an upper limit
to the improvement in fluid heating efficiency, leading to a
problem of difficulty in further improving the power
generation efficiency.
{0007}
When a solar thermal receiver is made of porous ceramic
etc., there is a problem in that it is easily damaged because
the porous ceramic has low thermal shock resistance, and the
cost is high.
Further, there is a problem in that the production cost
is high when the solar thermal receiver is made of porous
ceramic etc.
{0008}
The present invention has been made to solve the above-
described problems, and an object thereof is to provide a
solar thermal receiver that improves power generation
efficiency in solar thermal power generation, that reduces the
production cost, that enhances the resistance to thermal shock
caused by intermittent blocking of sunlight because of clouds,
and that eliminates oxidative damage of the thermal receiver,
and a solar thermal power generation facility using the solar
thermal receiver.
{Solution to Problem}
{0009}
In order to achieve the above-described object, the
present invention provides the following solutions.
A first aspect of the present invention is a solar
thermal receiver that receives solar radiation to heat fluid,
including: a heat-receiving section that is made of metal and
that constitutes a flow path in which at least the fluid
flows; and a coating layer that is disposed on at least a
surface of an area of the heat-receiving section irradiated
with the sunlight, that absorbs energy of the sunlight, and
that has heat resistance.
{0010}
According to the first aspect of the present invention,
since the coating layer is provided, the temperature
difference, in other words, the heat drop, between a surface
irradiated with sunlight and a surface in contact with fluid
can be increased. Therefore, the fluid can be efficiently
heated to a high temperature.
{0011}
Specifically, since the coating layer having a higher
heat-resistant temperature than other members made of metal
etc. is provided, the surface irradiated with sunlight can be
heated to a high temperature. As a result, it is possible to
increase the above-described temperature difference to
increase the heat flux density from the surface irradiated
with sunlight to the surface in contact with fluid and to
efficiently heat the fluid to a high temperature.
{0012}
On the other hand, compared with a case where the coating
layer is not provided, it is possible to suppress the heat
resistance required for a member constituting the heat-
receiving section. Therefore, the heat-receiving section can
be formed using metal, for example, a heat-resistant alloy,
which is highly resistant to thermal shock compared with
porous ceramic etc.
{0013}
Specifically, because the surface of the coating layer is
irradiated with sunlight, the temperature is the highest
thereat, and decreases therefrom in a contact surface between
the coating layer and the heat-receiving section and a contact
surface between the heat-receiving section and fluid in that
order. Therefore, compared with a case where the coating
layer is not provided and the surface irradiated with sunlight
has an identical temperature, it is possible to reduce the
temperature of the heat-receiving section, thereby suppressing
the heat resistance required for a member constituting the
heat-receiving section.
{0014}
As the coating layer, examples thereof include a coating
layer having a high thermal barrier property, such as a
thermal barrier coating (hereinafter, referred to as "TBC"),
which is provided by a spraying method or a vapor deposition
method, on an M, Cr, Al, and Y metal-binding layer (M: Ni, Co,
Fe) that has superior high-temperature oxidation resistance
and structural stability than a heat-resistant alloy matrix
consisting primarily of Ni, Co, or Fe, the metal-binding layer
being formed on the matrix.
By using TBC endowed with the thermal barrier property,
as a coating layer, as described above, it is possible to
further increase the temperature difference between the
surface of the coating layer irradiated with sunlight and the
contact surface between the coating layer and the heat-
receiving section and to increase the temperature difference
between the surface irradiated with sunlight and the surface
in contact with fluid.
{0015}
In the above-described first aspect of the invention, it
is preferable to have a configuration in which the coating
layer be made of ceramic thermally sprayed on the heat-
receiving section.
By doing so, a coating layer made of ceramic can easily
formed.
{0016}
In the above-described configuration, it is preferable
that the ceramic be ZrO2 ceramic obtained by stabilizing or
partially stabilizing a solid solution of at least one of
Sm2O3, MgO, CaO, and Y2O3.
In the above-described configuration, it is preferable
that the ceramic be ZrO2 ceramic obtained by partially
stabilizing a solid solution of Y2O3.
{0017}
By doing so, it is possible to form the coating layer
that improves the absorption properties for absorbing energy
of sunlight and that has high heat resistance, compared with
metals. Further, compared with coating layers made of other
materials, it is possible to increase the temperature
difference between the surface of the coating layer irradiated
with sunlight and the surface of the heat-receiving section
that is in contact with fluid.
{0018}
In the above-described first aspect, it is preferable
that a heat-receiving section according to the above-described
first aspect be a heat-receiving pipe having a flow path in
which the fluid flows; a coating layer according to the above-
described first aspect be disposed on an outer circumferential
surface of the heat-receiving pipe; and the heat-receiving
pipe have a light-incident part for guiding the sunlight to
the inside thereof and be accommodated in a housing whose
inner circumferential surface reflects the sunlight.
{0019}
By doing so, sunlight guided to the inside of the housing
is reflected at the inner circumferential surface of the
housing, so that the heat-receiving pipe is irradiated with
the sunlight from all directions. Therefore, fluid can be
efficiently heated compared with a case where the heat-
receiving pipe is irradiated with sunlight only from a
predetermined direction. Further, the pipe experiences
neither cracking nor peeling caused by the difference in
linear expansion due to the temperature difference from a
portion of the heat-receiving pipe that is not directly
irradiated with sunlight.
On the other hand, since the heat-receiving pipe is
irradiated with sunlight from all directions, it is possible
to suppress the occurrence of a temperature difference along
the circumferential direction of the heat-receiving pipe and
to suppress damage to the heat-receiving pipe.
{0020}
In a case where a large number of heat-receiving pipes
are provided and thus less light is reflected from a rear
surface, the temperature of a surface of the pipe that is
directly irradiated with sunlight is approximately 900 °C, and
the temperature of a rear surface of the pipe is approximately
600 °C. If this temperature difference occurs every day,
cracking is likely to occur on the pipe due to thermal
fatigue, and therefore a coating layer may be provided on a
portion irradiated with sunlight, as shown in FIG. 7.
{0021}
In the above-described first aspect, it is preferable
that a transparent housing that accommodates a heat-receiving
section according to the above-described first aspect and
through which the sunlight passes be provided; a coating layer
according to the above-described first aspect be disposed on
at least a surface of the heat-receiving section that faces
the transparent housing; the flow path have a first flow path
in which the fluid flows, between the heat-receiving section
and the transparent housing, and a second flow path in which
the fluid flows, at an opposite side of the heat-receiving
section from the first flow path; and the fluid flow in the
first flow path and the second flow path.
{0022}
By doing so, sunlight passing through the transparent
housing irradiates the coating layer to heat it. Fluid
flowing in the first flow path adjacent to the coating layer
is heated by absorbing the heat of the coating layer.
On the other hand, the heat of the coating layer is
transferred to the heat-receiving section to heat the heat-
receiving section. The fluid flowing in the second flow path
adjacent to the heat-receiving section is further heated by
absorbing the heat of the heat-receiving section. Therefore,
the fluid can be efficiently heated.
{0023}
For example, since fluid flows in the first flow path and
the second flow path in that order, it is possible to heat the
fluid more efficiently than in a case where it flows in
reverse order.
Specifically, the fluid is immediately heated by
absorbing the heat from the heated coating layer while flowing
in the first flow path, and is further heated by absorbing the
heat from the heat-receiving section, which has a lower
temperature than the coating layer but has a higher
temperature than the fluid, while flowing in the second flow
path. In this way, the fluid is heated in two steps, thereby
efficiently heating the fluid.
{0024}
A second aspect of the present invention is a solar
thermal power generation facility including: a reflecting
section that reflects sunlight; a compressor that compresses
fluid; a solar thermal receiver according to one of the solar
thermal receivers of the above-described first aspect that
receives the sunlight reflected by the reflecting section to
heat the fluid compressed by the compressor; a turbine section
that extracts a rotary drive force from the fluid heated by
the solar thermal receiver; and a power generator that is
rotationally driven by the turbine section.
{0025}
According to the second aspect of the present invention,
since the solar thermal receiver according to the first aspect
is provided, it is possible to improve power generation
efficiency in solar thermal power generation, to reduce the
production cost, and to enhance the thermal shock resistance.
{Advantageous Effects of Invention}
{0026}
According to the solar thermal receiver of the first
aspect of the present invention and the solar thermal power
generation facility of the second aspect thereof, because a
coating layer having a thermal barrier property is provided,
an advantage is afforded in that it is possible to improve
power generation efficiency in solar thermal power generation,
to reduce the production cost, and to enhance the thermal
shock resistance.
{Brief Description of Drawings}
{0027}
{Fig. 1}
FIG. 1 is a schematic diagram for explaining, in outline,
a solar thermal power generation facility according to a first
embodiment of the present invention.
{Fig. 2}
FIG. 2 is a schematic diagram for explaining the
configuration of a power generating section shown in FIG. 1.
{Fig. 3}
FIG. 3 is a schematic diagram for explaining the
configuration of a thermal receiver shown in FIG. 2.
{Fig. 4}
FIG. 4 is a sectional view for explaining the
configuration of a pipe shown in FIG. 3.
{Fig. 5}
FIG. 5 is a schematic diagram for explaining the
configuration of a thermal receiver in a solar thermal power
generation facility according to a second embodiment of the
present invention.
{Fig. 6}
FIG. 6 is a sectional view for explaining another
embodiment of the thermal receiver shown in FIG. 5.
{Fig. 7}
FIG. 7 is a sectional view for explaining one
modification of the embodiment of FIG. 4.
{Description of Embodiments}
{0028}
A culturing processing apparatus and an automatic
culturing apparatus according to one embodiment of the
invention will be described with reference to FIGS. 1 to 6.
{0029}
First Embodiment
A solar thermal power generation facility according to a
first embodiment of the present invention will be described
below with reference to FIGS. 1 to 4.
FIG. 1 is a schematic diagram for explaining, in outline,
the solar thermal power generation facility according to this
embodiment.
As shown in FIG. 1, a solar thermal power generation
facility 1 converts energy of sunlight into heat (solar heat)
and generates power by utilizing the heat. In this
embodiment, a description will be given of the solar thermal
power generation facility 1 that is a so-called solar thermal
gas turbine obtained when a configuration in which a power
generator 5 is driven by using a gas turbine is combined with
a configuration in which power is generated by utilizing solar
heat.
{0030}
Note that the solar thermal power generation facility 1
may be of the solar thermal gas turbine type, as described
above, or may be another type using a steam turbine or the
like; the type thereof is not particularly limited.
{0031}
As shown in FIG. 1, the solar thermal power generation
facility 1 includes a tower T, reflecting mirrors (reflecting
sections) H, and a power generating section 2.
{0032}
As shown in FIG. 1, the tower T extends upward from the
ground G and collects sunlight reflected at the reflecting
mirrors H.
A thermal receiver 7 of the power generating section 2,
to be described later, is disposed at a portion in the tower T
where sunlight is collected, for example, at the end of the
tower T.
{0033}
FIG. 1 shows a configuration in which the whole of the
power generating section 2 is disposed in the tower T;
however, it is only necessary to dispose the thermal receiver
7 of the power generating section 2 at least at the portion in
the tower T where sunlight is collected, and the configuration
thereof is not particularly limited.
{0034}
The reflecting mirrors H are disposed at a plurality of
places around the tower T and reflect sunlight toward the
tower T to collect the sunlight on the thermal receiver 7.
A heliostat or the like that controls the direction of a
planner mirror in accordance with the movement of the sun to
reflect sunlight toward a predetermined location can be used
as each of the reflecting mirrors H; the type thereof is not
particularly limited.
{0035}
FIG. 2 is a schematic diagram for explaining the
configuration of the power generating section shown in FIG. 1.
The power generating section 2 generates power by using
energy of sunlight reflected by the reflecting mirrors H.
As shown in FIG. 2, the power generating section 2
includes a compressor 3, a turbine section 4, the power
generator 5, a heat exchanger 6, and the thermal receiver
(solar thermal receiver) 7.
{0036}
As shown in FIG. 2, the compressor 3 constitutes the gas
turbine together with the turbine section 4, the thermal
receiver 7, etc. to drive the power generator 5 and compresses
fluid such as air.
The compressor 3 is disposed around a rotary shaft 8 that
receives a rotary drive force from the turbine section 4, so
as to receive the rotary drive force.
{0037}
Further, a pipe 10A and a pipe 10B in which compressed
air flows are provided between the compressor 3 and the heat
exchanger 6 and between the compressor 3 and the turbine
section 4, respectively.
{0038}
Note that a known axial flow compressor, a known
centrifugal compressor, or the like can be used as the
compressor 3; the type thereof is not particularly limited.
{0039}
As shown in FIG. 2, the turbine section 4 is supplied
with heated air from the thermal receiver 7 and converts heat
energy etc. of the air into a rotary drive force. The turbine
section 4 is disposed around the rotary shaft 8 so as to
transfer the rotary drive force thereto.
{0040}
Further, a pipe 10C in which air discharged from the
turbine section 4 flows is provided between the turbine
section 4 and the heat exchanger 6.
Note that a known turbine section can be used as the
turbine section 4; the type thereof is not particularly
limited.
{0041}
As shown in FIG. 2, the power generator 5 is rotationally
driven by the rotary shaft 8 to generate power.
Note that a known power generator can be used as the
power generator 5; the type thereof is not particularly
limited.
{0042}
As shown in FIG. 2, the heat exchanger 6 causes air that
has been compressed and increased in temperature by the
compressor 3 to further absorb the heat of the air discharged
from the turbine section 4.
A pipe 10D in which the compressed air heated by the heat
exchanger 6 flows is provided between the heat exchanger 6 and
the thermal receiver 7.
Note that a known heat exchanger can be used as the heat
exchanger 6; the type thereof is not particularly limited.
{0043}
FIG. 3 is a schematic diagram for explaining the
configuration of the thermal receiver shown in FIG. 2.
As shown in FIG. 1, the thermal receiver 7 is disposed at
a location on the tower T where sunlight is collected,
converts the energy of irradiating sunlight into heat, and
heats air.
As shown in FIGS. 2 and 3, the thermal receiver 7
includes a housing 71 and a heat-receiving pipe (heat-
receiving section) 72.
{0044}
As shown in FIG. 3, the housing 71 forms the outer shape
of the thermal receiver 7 and accommodates the heat-receiving
pipe 72.
The housing 71 has a light-incident part 73 at an area
irradiated with sunlight. Further, the inner surfaces of the
housing 71 are formed to have mirror surfaces for reflecting
the sunlight introduced from the light-incident part 73.
Note that the housing 71 may have a cubic shape, as shown
in FIG. 3, or may have another shape; the shape thereof is not
particularly limited.
{0045}
As shown in FIG. 3, the light-incident part 73 guides
sunlight to the inside of the housing 71.
The light-incident part 73 is disposed on a surface of
the housing 71 irradiated with sunlight and is a member formed
in an approximately conical shape whose diameter expands from
the housing 71 in a direction from which the sunlight is
radiated. The inner circumferential surface of the light-
incident part 73, formed in the approximately conical shape,
is formed to have a mirror surface for reflecting sunlight.
{0046}
A connecting part between the housing 71 and the light-
incident part 73 is configured such that sunlight passes
therethrough, and the sunlight irradiating the inside of the
light-incident part 73 is guided into the housing 71.
Note that a known structure can be used for the light-
incident part 73; the structure thereof is not particularly
limited.
{0047}
As shown in FIGS. 2 and 3, the heat-receiving pipe 72
converts energy of the sunlight into heat and heats air.
As shown in FIG. 3, the heat-receiving pipe 72 is
disposed inside the housing 71 in a spiral form, and the heat-
receiving pipe 72 disposed in a spiral form is disposed with
space between each spiral.
{0048}
FIG. 4 is a sectional view for explaining the
configuration of the pipe shown in FIG. 3.
As shown in FIG. 4, the heat-receiving pipe 72 includes a
pipe main body (heat-receiving section) 74 formed of a heat-
resistant alloy in a cylindrical shape, a coating layer 75
formed on the outer circumferential surface of the pipe main
body 74, and turbulators 7 6 disposed inside the pipe main body
74.
{0049}
As shown in FIG. 4, the pipe main body 74 is formed of a
heat-resistant alloy in a cylindrical shape, and air flows
therein.
Known alloy can be used as the heat-resistant alloy
forming the pipe main body 74; the type thereof is not
particularly limited.
{0050}
As shown in FIG. 4, the coating layer 75 is provided on
the outer circumferential surface of the pipe main body 74 and
is TBC (Thermal Barrier Coating) formed by thermally spraying
ZrO2(Y2O3-ZrO2) ceramic that is obtained by partially
stabilizing a solid solution of Y2O3 of 7wt% to 20wt%.
{0051}
Note that, as the ceramic for forming the coating layer
75, ZrO2 ceramic obtained by partially stabilizing a solid
solution of Y2O3 may be used, as described above, or ZrO2
ceramic obtained by stabilizing or partially stabilizing a
solid solution of at least one of MgO, CaO, and Y2O3 may be
used.
{0052}
In this way, it is possible to form the coating layer 75
that improves the absorption properties for absorbing the
energy of sunlight and that has high thermal barrier
properties, compared with metals. Further, compared with
coating layers made of other materials, it is possible to
increase the temperature difference between a surface of the
coating layer 75 irradiated with sunlight and a surface of the
pipe main body 74 that is in contact with compressed air, so
that more sunlight can be reflected from the reflecting
mirrors H to the light-incident part 73 than in conventional
technologies, and thus the heat-receiving section 7 provided
on the top of the tower T can be reduced in size and improved
in performance.
{0053}
As shown in FIG. 4, the turbulators 7 6 are provided on an
inner circumferential surface of the pipe main body 74 and
facilitate heat exchange between the pipe main body 74 and
air.
The turbulators 76 protrude inward from the inner
circumferential surface of the pipe main body 74, produce
turbulence in the airflow in the pipe main body 74, and
increase the area for heat exchange between the pipe main body
74 and air.
{0054}
Note that, for the turbulators 76, a known configuration
such as that in which they extend from the inner
circumferential surface of the pipe main body 74 in a spiral
manner can be used; the configuration thereof is not
particularly limited. Also, the duration of contact of fluid
with the inner surface of the pipe main body may be made
longer by providing concave portions on the outer surface
(convex portions on the inner surface) by pressing from the
outer surface of the pipe, or by providing, instead of
turbulators, spiral fins on the inner surface.
{0055}
Next, power generation in the thus-configured solar
thermal power generation facility 1 will be described.
An outline of power generation in the solar thermal power
generation facility 1 will be described first, and the
operation of the thermal receiver 7, which is a feature of
this embodiment, will be described thereafter.
{0056}
As shown in FIG. 1, sunlight is incident on the
reflecting mirrors H disposed around the tower T and is
reflected by the reflecting mirrors H toward the thermal
receiver 7 disposed on the tower T.
Note that a known method can be used to control the
sunlight reflection directions of the reflecting mirrors H;
the method is not particularly limited.
{0057}
As shown in FIG. 2, the reflected sunlight heats air
compressed by the compressor 3, in the thermal receiver 7.
The heated air is supplied to the turbine section 4 through a
pipe 10E, and the turbine section 4 converts heat energy etc.
of the heated air into a rotary drive force.
The air discharged from the turbine section 4 flows into
the heat exchanger 6 through the pipe 10C, is used to heat air
compressed by the compressor 3, and is then discharged to the
outside.
{0058}
The turbine section 4 transfers the rotary drive force to
the rotary shaft 8, and the rotary shaft 8 rotationally drives
the power generator 5 and the compressor 3.
The power generator 5 is rotationally driven by the
rotary shaft 8 to generate power and supplies the power to the
outside.
{0059}
On the other hand, the compressor 3 rotationally driven
by the rotary shaft 8 sucks air in from the outside and
compresses it. The compressed air flows from the compressor 3
into the pipe 10A and the pipe 10B.
The compressed air flowing into the pipe 10A flows into
the turbine section 4 together with air flowing through the
pipe 10E.
{0060}
The compressed air flowing into the pipe 10B is heated in
the heat exchanger 6 by the air discharged from the turbine
section 4. The heated compressed air flows into the thermal
receiver 7 through the pipe 10D and is further heated in the
thermal receiver 7.
{0061}
Next, heating of compressed air in the thermal receiver
7, which is a feature of this embodiment, will be described.
{0062}
As shown in FIG. 3, sunlight enters the housing 71 from
the light-incident part 73 and is repeatedly reflected at the
inner circumferential surface of the housing 71. The sunlight
entering the housing 71 and the reflected sunlight are
incident on the coating layer 75 of the heat-receiving pipe
72, as shown in FIGS. 3 and 4, and energy of the sunlight is
converted into heat.
{0063}
The outer circumferential surface of the coating layer 75
on which the sunlight is incident is heated to a high
temperature by the incident sunlight. The temperature of the
outer circumferential surface of the coating layer 75 is
transferred toward the center of the heat-receiving pipe 72
according to the heat transfer coefficients of the coating
layer 75 and the pipe main body 74.
{0064}
The heat transferred to the inner circumferential surface
of the pipe main body 74 is absorbed by compressed air flowing
in the pipe main body 74 and is used to heat the compressed
air.
At this time, since the flow of the compressed air is
diffused by the turbulators 76 and the heat transfer area is
expanded, the compressed air is heated with high efficiency,
compared with a case where the turbulators 7 6 are not
provided.
{0065}
On the other hand, a temperature difference, a so-called
heat drop, is produced between the outer circumferential
surface of the coating layer 75 and the inner circumferential
surface of the pipe main body 74. Since the coating layer 75
is TBC, compared with layers made of other materials, the
heat-resistant temperature thereof is high (for example,
approximately 850 °C or more and approximately 1,320 °C or
less, more preferably, approximately 1,150 °C or more and
approximately 1,320 °C or less), and has a thermal barrier
property, thereby producing a large heat drop.
As a result, the heat flux density transferred from the
outer circumferential surface of the coating layer 75 to the
inner circumferential surface of the pipe main body 74 becomes
high, so that compressed air flowing in the pipe main body 74
can be efficiently heated.
{0066}
According to the above-described configuration, by
providing the coating layer 75, it is possible to increase the
temperature difference, in other words, the heat drop, between
the surface irradiated with sunlight and the surface in
contact with fluid such as air. Therefore, the air can be
efficiently heated to a high temperature. Thus, the power
generation efficiency of the solar thermal power generation
facility 1 of this embodiment can be improved.
{0067}
In other words, since the coating layer 75 having a
higher heat-resistant temperature than other members made of
metal etc. is provided, the surface irradiated with sunlight
can be heated to a high temperature. As a result, it is
possible to increase the above-described temperature
difference to increase the heat flux density from the surface
irradiated with sunlight to the surface in contact with air
and to efficiently heat the air to a high temperature.
{0068}
On the other hand, compared with a case where the coating
layer 75 is not provided, it is possible to suppress the heat
resistance required for a member constituting the pipe main
body 74. Therefore, the pipe main body 74 can be formed by
using a heat-resistant alloy, which is highly resistant to
thermal shock compared with porous ceramic etc. As a result,
compared with a case where porous ceramic or the like is used,
it is possible to enhance the thermal shock resistance of the
thermal receiver 7 of the solar thermal power generation
facility 1 of this embodiment and to reduce the production
cost thereof.
{0069}
Specifically, because the surface of the coating layer 75
is irradiated with sunlight, the temperature is the highest
thereat, and decreases therefrom in the contact surface
between the coating layer 75 and the pipe main body 74 and the
contact surface between the pipe main body 74 and fluid in
that order. Therefore, compared with a case where the coating
layer is not provided and the surface irradiated with sunlight
has an identical temperature, it is possible to reduce the
temperature of the pipe main body 74, thereby suppressing the
heat resistance required for the member constituting the pipe
main body 74.
{0070}
Since sunlight guided to the inside of the housing 71 is
reflected at the inner circumferential surface of the housing
71, the heat-receiving pipe 72 is irradiated with the sunlight
from all directions. Therefore, air can be efficiently
heated, compared with a case where the heat-receiving pipe 72
is irradiated with sunlight only from a predetermined
direction.
On the other hand, since the heat-receiving pipe 72 is
irradiated with sunlight from all directions, it is possible
to suppress the occurrence of a temperature difference along
the circumferential direction of the heat-receiving pipe 72
and to suppress damage to the heat-receiving pipe 72.
{0071}
Second Embodiment
Next, a second embodiment of the present invention will
be described with reference to FIGS. 5 and 6.
In a solar thermal power generation facility of this
embodiment, the basic configuration is the same as that of the
first embodiment but the configuration of a thermal receiver
is different from that of the first embodiment. Therefore, in
this embodiment, a description will be given of only the
thermal receiver and its surroundings by using FIGS. 5 and 6,
and a description of the other components etc. will be
omitted.
FIG. 5 is a schematic diagram for explaining the
configuration of the thermal receiver in the solar thermal
power generation facility according to this embodiment.
Note that identical reference numerals are assigned to
the same components as those of the first embodiment, and a
description thereof will be omitted.
{0072}
As in the first embodiment, a thermal receiver 107 of a
solar thermal power generation facility 101 of this embodiment
is disposed at a location in the tower T where sunlight is
collected, converts energy of irradiating sunlight into heat,
and heats air (see FIG. 1).
As shown in FIG. 5, the thermal receiver 107 includes a
transparent housing 171, an outer wall (heat-receiving
section) 172, and an inner wall 173.
{0073}
The transparent housing 171 is a cylindrical container
that is made of a sunlight-transmissive transparent material
such as silica glass and one end of which is closed. Further,
as shown in FIG. 5, the transparent housing 171 is also a
container forming the outer shape of the thermal receiver 107
and accommodating the outer wall 172, the inner wall 173, and
the like.
{0074}
The outer wall 172 is a cylindrical container that is
made of a material having heat resistance and thermal shock
resistance, such as a heat-resistant alloy, and one end of
which is closed. Further, as shown in FIG. 5, a first flow
path 174 is formed between the outer wall 172 and the
transparent housing 171, and a second flow path 175 is formed
between the outer wall 172 and the inner wall 173.
{0075}
As shown in FIG. 5, the coating layer 75 is provided on
surfaces of the outer wall 172.
Note that the coating layer 75 may be provided on a
surface of the outer wall 172 that faces the transparent
housing 171 and on a surface thereof that faces the inner wall
173, as shown in FIG. 5, or may be provided only on the
surface thereof that faces the transparent housing 171; the
location thereof is not particularly limited.
{0076}
The first flow path 174 is a flow path in which
compressed air supplied from the pipe 10D flows, and forms a
compressed-air flow path in the thermal receiver 107 together
with the second flow path 175.
The first flow path 174 is connected to the second flow
path 175 via a communicating hole 17 6 formed on the outer wall
172 such that the compressed air can flow therethrough.
{0077}
The second flow path 175 is a flow path into which the
heated compressed air flows from the first flow path 174, and
forms the compressed-air flow path in the thermal receiver 107
together with the first flow path 174.
The second flow path 175 is connected to the pipe 10E
such that the compressed air can flow therethrough.
{0078}
The inner wall 173 is a cylindrical container that is
made of a material having heat resistance and thermal shock
resistance, such as a heat-resistant alloy, and one end of
which is closed. Further, as shown in FIG. 5, the inner wall
173 is disposed inside the outer wall 172, and the second flow
path 175 is formed between the inner wall 173 and the outer
wall 172.
{0079}
The operation of the thus-configured thermal receiver 107
will be described.
Note that since the outline of power generation in the
solar thermal power generation facility 101 is the same as
that of the first embodiment, a description thereof will be
omitted.
{0080}
As shown in FIG. 5, sunlight passes through the
transparent housing 171 and irradiates the coating layer 75 to
heat it. Compressed air supplied from the pipe 10D flows into
the first flow path 174 adjacent to the coating layer 75 and
is heated by absorbing the heat of the coating layer 75.
On the other hand, the heat of the coating layer 75 is
transferred to the outer wall 172, thus heating the outer wall
172.
{0081}
After the compressed air is heated in the first flow path
174, it flows into the second flow path 175 between the outer
wall 172 and the inner wall 173. The compressed air is
further heated by absorbing the heat of the outer wall 172
while flowing in the second flow path 175 adjacent to the
outer wall 172.
The compressed air further heated in the second flow path
175 flows into the pipe 10E and is guided to the turbine
section 4.
{0082}
According to the above-described configuration, since the
compressed air flows in the first flow path 174 and the second
flow path 175 in that order, it is possible to heat the
compressed air more efficiently than in a case where it flows
in reverse order, for example.
The compressed air is immediately heated by absorbing the
heat from the heated coating layer 75 while flowing in the
first flow path 174, and is further heated by absorbing the
heat from the outer wall 172, which has a lower temperature
than the coating layer 75 but has a higher temperature than
the compressed air, while flowing in the second flow path 175.
In this way, the compressed air is heated in two steps,
thereby efficiently heating the compressed air.
{0083}
FIG. 6 is a sectional view for explaining another
embodiment of the thermal receiver shown in FIG. 5.
Note that, as in the above-described embodiment, the
thermal receiver 107 may be formed by using the cylindrically-
formed transparent container 171 one end of which is closed,
the outer container 172, and the inner container 173; or, as
shown in FIG. 6, a thermal receiver 207 may be formed by using
a cylindrically-formed transparent container 271 and an outer
container 272, so as to form the first flow path 174 and the
second flow path 175; the configuration thereof is not
particularly limited.
{Reference Signs List}
{0084}
1, 101 solar thermal power generation facility
3 compressor
4 turbine section
5 power generator
7, 107, 207 thermal receiver (solar thermal receiver)
71 housing
72 heat-receiving pipe (heat-receiving section)
73 light-incident part
74 pipe main body (heat-receiving section)
75 coating layer
171, 271 transparent housing
172, 272 outer wall (heat-receiving section)
H reflecting mirror (reflecting section)
{CLAIMS}
{Claim 1}
A solar thermal receiver that receives solar radiation to
heat fluid, comprising:
a heat-receiving section that is made of metal and that
constitutes a flow path in which at least the fluid flows; and
a coating layer that is disposed on at least a surface of
an area of the heat-receiving section irradiated with the
sunlight, that absorbs energy of the sunlight, and that has
heat resistance.
{Claim 2}
A solar thermal receiver according to claim 1, wherein
the coating layer is made of ceramic thermally sprayed on the
heat-receiving section.
{Claim 3}
A solar thermal receiver according to claim 2, wherein
the coating layer is provided on a heat-receiving portion
irradiated with the sunlight.
{Claim 4}
A solar thermal receiver according to claim 2, wherein
the ceramic is ZrO2 ceramic obtained by stabilizing or
partially stabilizing a solid solution of at least one of MgO,
CaO, and Y2O3.
{Claim 5}
A solar thermal receiver according to claim 2, wherein
the ceramic is ZrO2 ceramic obtained by partially stabilizing
a solid solution of Y2O3.
{Claim 6}
A solar thermal receiver, wherein:
a heat-receiving section according to claim 1 is a heat-
receiving pipe having a flow path in which the fluid flows;
a coating layer according to one of claims 1 to 5 is
disposed on an outer circumferential surface of the heat-
receiving pipe; and
the heat-receiving pipe has a light-incident part for
guiding the sunlight to the inside thereof and is accommodated
in a housing whose inner circumferential surface reflects the
sunlight.
{Claim 7}
A solar thermal receiver comprising a transparent housing
that accommodates a heat-receiving section according to claim
1 and through which the sunlight passes, wherein:
a coating layer according to one of claims 1 to 5 is
disposed on at least a surface of the heat-receiving section
that faces the transparent housing;
the flow path has a first flow path in which the fluid
flows, between the heat-receiving section and the transparent
housing, and a second flow path in which the fluid flows, at
an opposite side of the heat-receiving section from the first
flow path; and
the fluid flows in the first flow path and the second
flow path.
{Claim 8}
A solar thermal power generation facility comprising:
a reflecting section that reflects sunlight;
a compressor that compresses fluid;
a solar thermal receiver according to one of claims 1 to
7 that receives the sunlight reflected by the reflecting
section to heat the fluid compressed by the compressor;
a turbine section that extracts a rotary drive force from
the fluid heated by the solar thermal receiver; and
a power generator that is rotationally driven by the
turbine section.

Provided is a solar heat receiver, which improves power generating efficiency in solar thermal power generation
and has a reduced manufacturing cost and improved thermal shock resistance. A solar thermal power generating system using the
solar heat receiver is also provided. The solar heat receiver which receives radiation of solar light and heats a fluid is provided
with: a metal heat receiving section (72), which configures at least a channel wherein the fluid flows; and a heat-resistant coating
layer (75), which is arranged at least on the surface of the heat receiving section (72) in a region irradiated with solar light and absorbs
energy of the solar light.