U.S. patent application number 11/785301 was filed with the patent office on 2007-12-13 for solar radiation modular collector.
Invention is credited to Alexander Levin.
Application Number | 20070283949 11/785301 |
Document ID | / |
Family ID | 46327741 |
Filed Date | 2007-12-13 |
United States Patent
Application |
20070283949 |
Kind Code |
A1 |
Levin; Alexander |
December 13, 2007 |
Solar radiation modular collector
Abstract
The invention relates to the field of solar radiation collectors
intended to convert energy of solar radiation into thermal energy,
specifically, to the solar radiation collectors constructed as the
combination of a concentrated solar radiation receiver, a
single-curvature or compound-curvature concentrator and a tracking
mechanism. A thermal insulation of the concentrated solar radiation
receiver and the concentrated solar radiation receiver itself play
a role of parts in the tracking mechanism.
Inventors: |
Levin; Alexander;
(Binyamina, IL) |
Correspondence
Address: |
Dr. D. Graeser Ltd.;c/o The Discovery Dispatch
9003 Florin Way
Upper Marlboro
MD
20772
US
|
Family ID: |
46327741 |
Appl. No.: |
11/785301 |
Filed: |
April 17, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11081406 |
Mar 17, 2005 |
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11785301 |
Apr 17, 2007 |
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Current U.S.
Class: |
126/573 ;
126/670 |
Current CPC
Class: |
F24S 50/20 20180501;
Y02E 10/40 20130101; F24S 80/453 20180501; F24S 23/74 20180501;
F24S 25/10 20180501; F24S 40/80 20180501; F24S 2030/136 20180501;
F24S 30/425 20180501; Y02E 10/47 20130101; F24S 70/225
20180501 |
Class at
Publication: |
126/573 ;
126/670 |
International
Class: |
F24J 2/38 20060101
F24J002/38 |
Claims
1. A solar radiation modular collector comprising: a concentrating
unit of the single-curvature type; a receiver of concentrated solar
radiation, said receiver comprising: a metal pipe with inlet and
outlet connections, with a black or selective coating of the outer
surface of said metal pipe; a thermal insulation intended to
insulate thermally at least a portion of said metal pipe; said
thermal insulation comprising a metal envelope with a
vacuum-insulated internal cavity; said metal envelope comprising
elongated internal and external sections, which are joined by two
elongated connection straps and sealed at their ends by face
planes; said internal elongated section comprising a cylindrical
sub-section, which encloses a significant part of said metal pipe;
said cylindrical sub-section featuring flat or single-curved strips
with a certain angle of convergence with respect to said
cylindrical sub-section; wherein said elongated external section
encloses said metal pipe and the internal cavity between said
elongated internal and external sections is evacuated in order to
suppress convective and conductive losses of heat from said metal
pipe; wherein the gap between the distal longitudinal margins of
said flat or single-curved strips is glazed by a glazing; wherein
said internal and external sections of said metal envelope are
provided with corrugations, which decrease in dimension in the
vicinity of said connection straps; and wherein said receiver is
positioned in the zone of the focal line of said single-curvature
concentrator; and a set of truss struts joining said concentrating
unit with said metal envelope.
2. A solar radiation modular collector of claim 1, wherein said
metal pipe is provided at end sections with a plurality of flexible
sections in order to compensate for thermal expansion.
3. A solar radiation modular collector of claim 1, wherein said
metal pipe is provided with a set of low circular ribs in order to
prevent immediate contact of said black or selective coating with
the inner surface of said elongated internal section.
4. A solar radiation modular collector of claim 3, wherein the
cylindrical surfaces of said circular ribs are provided with an
antifriction coating.
5. A solar radiation modular collector of claim 1, wherein the ends
of said metal pipe are provided with flanges.
6. A solar radiation modular collector of claim 1, further
comprising an auxiliary means for installation of said
concentrating unit, said metal pipe and said metal envelope.
7. The collector of claim 6, wherein said metal pipe is installed
on two posts, which serve as said auxiliary means, and said metal
envelope can rotate around said metal pipe.
8. A solar radiation modular collector of claim 1, wherein the
outer surface of said external section of said metal envelope is
provided with a selective coating, which absorbs concentrated solar
radiation.
9. A solar radiation modular collector of claim 1, wherein
reflecting shields from metal foil are positioned in said internal
cavity of said metal envelope.
10. A solar radiation modular collector of claim 9, wherein said
internal cavity of said metal envelope is filled with gas.
11. A solar radiation modular collector of claim 10, wherein said
gas has low thermal conductivity.
12. A solar radiation modular collector of claim 1, wherein said
internal cavity is filled with powdered solid material.
13. A solar radiation modular collector of claim 1, wherein the
extreme sections of said metal pipe are provided with threads
instead of said flanges.
14. A solar radiation modular collector of claim 1, wherein there
are some said metal envelopes situated around one said metal pipe,
and, correspondingly, there are some said concentrating units,
which are joined with said metal envelopes.
15. A solar radiation modular collector of claim 1, further
comprising a tracking unit for tracking the sun by said
concentrating unit.
16. A solar radiation collector system comprising a plurality of
said solar radiation modular collectors of claim 1; said plurality
solar radiation modular collectors are placed in the form of
parallel rows and said metal pipes are interconnected in series in
each said row.
17. A solar radiation collector system of claim 16, further
comprising a common tracking unit for said collectors.
18. A solar radiation modular collector comprising: a concentrating
unit of the compound-curvature type with a frame; a bearing pipe
with an inlet and outlet connections and flexible joints at its
extreme sections for compensation of its thermal expansion, for
transport of heat by a working medium; wherein said bearing pipe is
provided with a thermal insulation layer; posts for mounting said
bearing pipe; wherein said bearing pipe comprises tubular members
and T-pieces, installed between each pair of the neighboring
tubular members; wherein the lower branch of each said T-piece is
sealed by a metal convex spherical cap and a part of its outer
surface of the T-piece is covered with a thermal insulation layer;
a solar radiation receiving unit, which is constructed from a
dish-type plate and a double-wall funnel; wherein the upper side of
said dish-type plate has the concave surface in the form of a
spherical segment with the radius commensurate with that of said
metal convex spherical cap, thereby forming a spherical joint;
wherein the lower surface of said dish-type plate is covered with a
layer of solar radiation absorption coating; wherein the upper edge
of the internal wall of said double-wall funnel is joined with the
edge of said dish-type plate and the edge of its outer wall is
provided with a flange; a glazing of the distal (lower) aperture of
said double-wall funnel; a bearing housing with a split lower
flange and two longitudinal slots; said bearing housing being
mounted on said thermal insulation layer of said T-piece; a clamp,
which closes the open sections of said bearing housing; a flexible
joint that joins said split lower flange of said bearing housing
and said flange of said double-wall funnel; and a tracking unit for
tracking the sun by said concentrating unit of the
compound-curvature type; said tracking unit comprising tracking
rods, which are joined by hinges with said frame.
19. A solar radiation modular collector of claim 18, wherein the
internal surface of said internal wall of said double-wall funnel
has a high value of light reflection coefficient.
20. A solar radiation modular collector comprising: a concentrating
unit of the compound-curvature type with a frame; a bearing pipe
with an inlet and outlet connections and flexible joints at its
extreme sections for compensation of its thermal expansion, for
transport of heat by a working medium; wherein said bearing pipe is
provided with a thermal insulation layer; posts for mounting said
bearing pipe; wherein said bearing pipe comprises tubular members
and T-pieces, installed between each pair of the neighboring
tubular members; wherein the lower branch of each said T-piece is
sealed by a metal convex spherical cap and a part of its outer
surface of the T-piece is covered with a thermal insulation layer;
a solar radiation receiving unit, which is constructed from a
double-wall funnel; wherein the upper side of said dish-type plate
has the concave surface in the form of a spherical segment with the
radius commensurate with that of said metal convex spherical cap,
thereby forming a spherical joint; wherein the lower surface of
said dish-type plate is covered with a layer of solar radiation
absorption coating; wherein the upper edge of the internal wall of
said double-wall funnel is joined with the edge of said dish-type
plate and the edge of its outer wall is provided with a flange; and
wherein the outer surface of said metal convex spherical cap is
provided with a radiation absorption coating and said radiation
absorption coating is stable against friction with the upper edge
of said double-wall funnel; a glazing of the distal (lower)
aperture of said double-wall funnel; a bearing housing with a split
lower flange and two longitudinal slots; said bearing housing being
mounted on said thermal insulation layer of said T-piece; a clamp,
which closes the open sections of said bearing housing; a flexible
joint that joins said split lower flange of said bearing housing
and said flange of said double-wall funnel; and a tracking unit for
tracking the sun by said concentrating unit of the
compound-curvature type; said tracking unit comprising tracking
rods, which are joined by hinges with said frame.
21. A solar radiation modular collector comprising, a concentrating
unit of the compound-curvature type with a frame; a bearing pipe
with an inlet and outlet connections and flexible joints at its
extreme sections for compensation of its thermal expansion, for
transport of heat by a working medium; wherein said bearing pipe is
provided with a thermal insulation layer; posts for mounting said
bearing pipe; wherein said bearing pipe comprises tubular members
and T-pieces, installed between each pair of the neighboring
tubular members; wherein the lower branch of each said T-piece is
sealed by a metal convex spherical cap and a part of its outer
surface of the T-piece is covered with a thermal insulation layer;
a solar radiation receiving unit, which is constructed from a
dish-type plate and a single-wall funnel; wherein the upper side of
said dish-type plate has the concave surface in the form of a
spherical segment with the radius commensurate with that of said
metal convex spherical cap, thereby forming a spherical joint;
wherein the lower surface of said dish-type plate is covered with a
layer of solar radiation absorption coating; a glazing of the
distal (lower) aperture of said double-wall funnel; a bearing
housing with a split lower flange and two longitudinal slots; said
bearing housing being mounted on said thermal insulation layer of
said T-piece; a clamp, which closes the open sections of said
bearing housing; a flexible joint that joins said split lower
flange of said bearing housing and said flange of said double-wall
funnel; and a tracking unit for tracking the sun by said
concentrating unit of the compound-curvature type; said tracking
unit comprising tracking rods, which are joined by hinges with said
frame; wherein the lower edge of said single-wall funnel is joined
with the lower flange of said flexible joint; said truss struts are
joined in this case with said connecting branch.
22. A solar radiation collector system comprising a plurality of
said solar radiation modular collectors of claim 18; wherein said
plurality of solar radiation modular collectors are in parallel
rows; said bearing pipes are interconnected in series in each said
row; said solar radiation modular collectors, which are positioned
in parallel or belong to said one set of interconnected serial
bearing pipes have common tracking units.
Description
[0001] This Application is a Continuation-in-Part Application of
U.S. patent application Ser. No. 11/081,406 filed on 17 Mar. 2005,
which is hereby incorporated by reference as if fully set forth
herein.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of solar
radiation collectors intended to convert energy of solar radiation
into thermal energy.
BACKGROUND OF THE INVENTION
[0003] Solar radiation collectors which convert energy of solar
radiation into thermal energy are known. Some types of such
collectors include those which incorporate single-curvature or
compound-curvature concentrators.
[0004] If single-curvature parabolic mirrors are used as the
concentrators, the modular solar radiation collector is constructed
as a combination of an elongated receiver, the single-curvature
concentrator and a tracking mechanism, which ensures steady
positioning of the elongated receiver in the focal zone of the
single-curvature concentrator.
[0005] It is known that such solar collectors can result in
temperatures of a working fluid which are significantly higher than
100.degree. C.; this in turn gives the possibility of applying the
obtained thermal energy to different industrial processes or to
convert this thermal energy into electricity with sufficiently high
efficiency. In the most cases, the single-curvature concentrator is
constructed as a trough-wise parabolic mirror or a single-curvature
Fresnel lens.
[0006] The elongated receiver is usually constructed as a pipe with
an outer coating intended to absorb concentrated and direct solar
radiation, and a transparent (glass) elongated envelope positioned
around the pipe. The transparent envelope is sealed with the pipe
at its ends and the gap between the pipe and the elongated envelope
is vacuum-insulated in order to suppress convective losses of
thermal energy from the outer surface of the pipe.
[0007] There are some drawbacks of this construction, a few of
which are listed below.
[0008] 1. Concentrated solar radiation illuminates only a part of
the whole surface of the radiation receiving pipe; at the same
time, heat loss by radiation occurs from the entire outer surface
of this pipe.
[0009] 2. Sealing the metal pipe of the receiver with the glass
envelope is very expensive and complicated from the technological
point of view.
[0010] 3. It is impossible to insulate thermally the radiation
receiving pipe in a modular manner.
[0011] 4. Low strength of the glass envelope does not permit this
glass envelope to be used as a carrying element of the construction
of a solar collector.
[0012] These same drawbacks are also true for solar collectors
which feature compound-curvature dish-type concentrators.
[0013] There are some US patents related to the area of this
invention, none of which completely solve the above problems. U.S.
Pat. No. 4,078,549 to McKeen describes a solar energy collector
which concentrates the sun's rays on a liquid medium that is used
to power a mechanical energy device such as a positive displacement
steam engine. A reflective surface of the solar energy collector is
made from an arcuate portion of a circle having a trough-like
surface to reflect and concentrate the sun's rays in a plane. A
collector having a liquid medium flowing therethrough is located in
the plane. The collector is constructed to extend across the entire
plane for complete absorption by the liquid medium of the sun's
rays reflected from the reflective surface. The collector and
reflective surface are connected together for pivotal movement by
an appropriate tracking apparatus so that the sun's rays are
continually reflected during normal daylight hours through the
plane in which the collector is located.
[0014] However, this patent has numerous drawbacks, a few of which
are listed below It does prevent heat loss from the receiving pipe
due to infrared radiation.
[0015] It does not permit enclosure of the majority of the
receiving pipe by the thermo-insulating envelope (in fact, the
thermo-insulating envelope encloses less than 50% of the surface of
the receiving pipe).
[0016] It does not permit the internal reflecting surface of the
envelope to be used as a secondary non-imaging concentrator.
[0017] U.S. Pat. No. 4,048,982 to Pei describes a bulb-type solar
energy collector comprising a hollow glass body shaped with a
parabolic interior surface that is coated with specular finish of a
metal, e.g. silver, and includes an apex aperture and integral
hollow yoke. A hollow glass, bulb-shaped absorber element is
exteriorly coated with a wave length selective coating. The
bulb-shaped element includes a tubular hollow stem dependent from
the bulbar portion and fixed in the yoke of the glass body so that
the central axis of the stem and bulbar end portion is along the
focal axis of the parabolic reflecting surface. A cover plate is
sealed over the enlarged end of the reflecting surface enclosing
the interior mirror surface in a chamber which is evacuated to
substantial vacuum, e.g. 10.sup.-4 torr or greater vacuum. A
working liquid is circulated from a source in a manifold through
the interior volume of the absorber element to remove the solar
energy absorbed thereby as heat and the media is returned to the
manifold. The solar energy laden liquid is available for heating,
cooling or power generating uses.
[0018] Pei does not teach any technical solution of tracking the
reflector after the sun motion.
BRIEF SUMMARY OF THE INVENTION
[0019] The background art does not teach or suggest a solar
collector device for both providing sufficient insulation of a
solar radiation receiver so as to decrease significantly or prevent
heat loss (thereby increasing efficiency of collection of solar
energy) and also for most efficiently tracking the sun in order to
obtain the most efficient amount of solar exposure.
[0020] The present invention overcomes these deficiencies of the
background art by providing (in a first embodiment) a solar
radiation modular collector with a concentrating unit of the
single-curvature type (one-axis sun tracking concentrator) and with
a receiver of concentrated solar radiation in the form of a
radiation receiving pipe.
[0021] The radiation receiving pipe is provided with a thermal
insulation layer which is preferably in the form of a metal
envelope, which may optionally be vacuum-insulated and/or filled
with material with low thermal conductivity. In addition, the
internal cavity of this metal envelope may optionally feature one
or more radiant shields from metal foil with high reflection
coefficient in the infrared range. The single-curvature
concentrator can optionally be constructed as a parabolic
trough-wise reflector, or alternatively as a single-curvature
Fresnel mirror.
[0022] The metal envelope insulates most of the outer surface of
the radiation receiving pipe with significant reduction of heat
losses caused by convection and radiation from this part of the
outer surface.
[0023] The metal envelope of the radiation receiving pipe is
preferably constructed from two elongated internal and external
sections, which are joined by two elongated connection straps and
sealed at their ends by face planes.
[0024] The internal elongated section comprises a cylindrical
sub-section, which encloses a significant part of the radiation
receiving pipe; this cylindrical sub-section is transformed at its
longitudinal margins to flat or single-curved strips with a certain
angle of convergence with respect to the cylindrical sub-section.
In such a way, the cross-section of the internal section is
somewhat similar to the vertical cross-section of a jug. The
external section encloses the internal one.
[0025] The internal cavity between the internal and external
sections of the metal envelope is preferably evacuated (to form a
vacuum) in order to suppress convective loss of heat. In addition,
this space can be filled with a porous material and/or layers of
metal foil in order to diminish heat loss by radiation.
[0026] It is possible to apply filling the internal cavity of the
metal envelope with a gas having low thermal conductivity, for
example, krypton.
[0027] The gap between the elongated connection straps is
preferably glazed in order to diminish heat losses, which occur
from the part of the radiation receiving pipe that is not enclosed
by the cylindrical sub-section of the internal elongated
section.
[0028] According to preferred embodiments, a plurality of metal
envelopes may optionally be installed sequentially around a
radiation receiving pipe in place of a single envelope. Each such
envelope is preferably constructed as described previously. This
simplifies the manufacturing process of the metal envelopes.
[0029] Without wishing to be limited by a single hypothesis,
thermal losses in the proposed construction of the thermal
insulation may be expected to occur one of three ways:
[0030] By thermal conductivity of the walls of the metal
envelope.
[0031] By radiation from the illuminated surface of the radiation
receiving pipe.
[0032] By convection via the internal cavity between the internal
flat strips, the glazing and the radiation receiving pipe.
[0033] By way of example only and without wishing to be limited in
any way, the above problems may optionally be solved as follows.
The optional but preferred glazing of the internal cavity between
the internal flat strips significantly reduces thermal losses
occurring by convection. In addition, the glazing may optionally be
provided with a transparent coating, which reflects back infrared
radiation from the radiation receiving pipe.
[0034] The limited thermal conductivity of the walls of the metal
envelope may cause temperature gradient to occur within the
envelope and in turn this can cause deformation of the metal
envelope.
[0035] In order to prevent this, the internal and external sections
of the metal envelope are optionally and preferably provided with
corrugations, which decrease in dimension to zero (ie are narrowed)
in the vicinity of the connection straps. These corrugations can be
directed inwards or outwards with respect to the internal cavity of
the metal envelope.
[0036] The outer surface of the external section of the metal
envelope can be coated with a coating, for example by being painted
with black paint or pigment, and/or with paint or pigment having a
very low emittance coefficient in the infrared range; it enables
the temperature of the external section of the metal envelope to be
raised due to the direct solar radiation falling on its surface. It
in turn diminishes heat losses caused by thermal conductivity of
the metal envelope and by radiation and thermal conductivity
through the internal cavity of the metal envelope.
[0037] The proposed receiver of the solar radiation may optionally
be rigidly joined by a set of truss struts with the
single-curvature concentrator, which should be rotated by a
tracking mechanism in accordance with the sun motion. In this case,
the receiver rotates by turning the single-curvature
concentrator.
[0038] According to some embodiments of the present invention, the
mechanical strength of the metal envelope also optionally and
preferably enables the modular solar collector to feature a
stationary metal radiation receiving pipe. In this case, the metal
envelope with the single-curvature concentrator is rigidly joined
to the metal envelope by the truss struts and is rotated around the
metal radiation receiving pipe by the tracking mechanism. In such a
way, the radiation receiving pipe plays the role of a bearing
element and an axle.
[0039] The radiation receiving pipe may optionally be provided in
this case with a set of ribs in order to prevent contact of the
internal surface of the metal envelope with the black or selective
coating of the radiation receiving pipe. In addition, the
cylindrical surface of these ribs may optionally be provided with
an antifriction coating.
[0040] The proposed construction of the thermal insulation of the
radiation receiving pipe allows the solar radiation collector to be
assembled in a modular manner without requiring complicated and
expensive sealing means between a glass cylindrical envelope and
the radiation receiving pipe, as is known in the art.
[0041] According to other preferred embodiments of the present
invention, a plurality of solar radiation modular collectors may
optionally be located in parallel rows and provided with common
tracking mechanisms.
[0042] According to another embodiment of the solar collector
according to the present invention, compound-curvature
concentrators and, particularly, dish-type parabolic mirrors, are
used as the concentrators of solar radiation.
[0043] If the compound-curvature concentrators are in the form of
the dish-type mirrors, a module of the present invention preferably
features a bearing pipe that is mounted on vertical posts. A heat
transfer medium (working fluid) flows in the bearing pipe. The
bearing pipe is provided with a layer of thermal insulation.
[0044] A plurality of T-pieces are built into the bearing pipe,
i.e. the bearing pipe comprises a set of tubular sections with
T-pieces installed between two neighboring tubular sections to
connect them. The lower branch of each T-piece is sealed by a metal
convex spherical cap and at least a portion of the outer surface of
the T-piece is covered with a layer of thermal insulation.
[0045] In addition, there is a solar radiation receiving member,
which is constructed from a dish-type plate and a double-wall
funnel. The upper side of the dish-type plate has the concave
surface in the form of a spherical segment with the radius almost
identical to that of the metal convex spherical cap. In such a way,
the pair of the spherical cap of the T-piece and the concave
surface of the dish-type plate together presents a spherical joint.
The lower surface of the dish-type plate is preferably covered with
a layer of a solar radiation absorption coating.
[0046] The upper surface of the dish-type plate and the outer
surface of the metal convex spherical cap may optionally be
provided with antifriction coating.
[0047] The upper edge of the internal wall of the double-wall
funnel is joined with the edge of the dish-type plate and the edge
of its outer wall is provided with a flange.
[0048] The distal (lower) aperture of the double-wall funnel can be
glazed in order to diminish heat losses via its internal cavity. In
addition, this glazing can be provided with a transparent coating,
which reflects back infrared radiation from the layer of the solar
radiation absorption coating of the dish-type plate.
[0049] The internal surface of the internal wall of the double-wall
funnel is preferably constructed of one or more materials with the
property of high reflectivity for solar radiation; in such a way,
this internal wall plays a role of an additional non-imaging
concentrator of the solar radiation.
[0050] There is a bearing housing with a split lower flange and two
longitudinal slots; this housing is mounted on the thermal
insulation of the T-piece. The open sections of the longitudinal
slots are closed by a clamp. The flanges of the bearing housing and
the outer wall of the double-wall funnel are joined by a flexible
joint, which plays at the same time a role of a thermal
insulator.
[0051] The outer wall of the double-wall funnel serves at the same
time for mounting truss struts, which serve in turn for
installation of a dish-type concentrating mirror with its
frame.
[0052] The frame of the dish-type mirror is joined through
cylindrical hinges with tracking rods.
[0053] The internal cavity between the walls of the double-wall
funnel and between the flexible joint and the lower branch of the
T-piece may optionally be filled with thermo-insulating material
with low thermal conductivity.
[0054] It should be noted that heat transfer from the internal
surface of the spherical cap to the working medium is performed
mainly by natural convection, conduction and boiling. In order to
diminish temperature drop between this internal surface and the
working medium, the internal surface of the spherical cap may be
provided with fins and/or a porous coating from metal powder; this
porous coating has open porosity.
[0055] It is possible to use a funnel with a single wall instead of
the aforementioned double-wall funnel; in this case the lower edge
of the funnel is joined with a connecting branch with a flange;
this connecting branch is joined in turn with the lower flange of
the flexible joint. The truss struts are joined in this case with
the connecting branch.
[0056] In addition, it is possible to obviate use of the dish-type
plate. The outer surface of the metal convex spherical cap is
provided in this embodiment with a radiation absorption coating.
This coating is preferably stable against friction with the upper
edge of the aforementioned double- or single-wall funnel.
[0057] A solar radiation collector may optionally be assembled from
a plurality of solar radiation modular collectors, which are
described above; this plurality of solar radiation modular
collectors is preferably placed in the form of parallel rows and
bearing pipes are interconnected in series in each row.
[0058] Solar radiation modular collectors, which are positioned in
parallel and/or belong to one set of interconnected serial bearing
pipes, preferably have common tracking units.
[0059] Without wishing to be limited to a single set of advantages,
it should be noted that the technical solutions described above
have a number of advantages, a few of which are listed below.
[0060] In the first described embodiment of the proposed solar
collector with a trough-wise concentrator, the metal thermal
insulation of the receiver has a number of functions, which are not
known in the background art:
[0061] It serves as an non-imaging concentrator;
[0062] Its corrugations prevent its thermal deformation and serve
as elements of the tracking mechanism;
[0063] It is supporting the concentrators.
[0064] This is true as well regarding the receiver, which also has
some additional functions:
[0065] It is a bearing element for the thermal insulation and for
the concentrators;
[0066] It is an element in a tracking mechanism.
[0067] In the second embodiment of the invention with a dish-wise
concentrator, T-pieces with their caps of the bearing pipe also
have a variety of functions:
[0068] 1. They are bearing elements for double-wall funnels and the
concentrators;
[0069] 2. They serve for heat transfer to a medium flowing in the
bearing pipes;
[0070] 3. They serve as elements in the tracking mechanism.
[0071] On the other hand, the double-wall funnels with their
dish-type plates also have additional functions:
[0072] Their dish-type plates serve for heat transfer to the
spherical caps of the T-pieces;
[0073] The double-wall funnels serves as non-imaging
concentrators;
[0074] The double-wall funnels with their dish-type plates are
elements in the tracking mechanism;
[0075] The double-wall funnels are the bearing elements for the
dish-type concentrators.
BRIEF DESCRIPTION OF THE DRAWINGS
[0076] FIG. 1a is a transverse cross-section of a receiver of a
concentrated solar radiation collector module with a concentrating
single-curvature unit.
[0077] FIG. 1b is an exploded transverse cross-section of the metal
envelope of the receiver and its glazing.
[0078] FIG. 1c is an exploded transverse cross-section of a
radiation receiving pipe of the receiver.
[0079] FIG. 2 is an isometric view of an internal section of a
metal envelope of the receiver, which is shown in FIG. 1a and FIG.
1b, with corrugations directed inwards.
[0080] FIG. 3 is an isometric view of an external section of the
metal envelope of the receiver, which is shown in FIG. 1a and FIG.
1b, with corrugations directed outwards.
[0081] FIG. 4 is an axial cross-section of the radiation receiving
pipe of the receiver, which is shown in FIG. 1a and FIG. 1c.
[0082] FIG. 5 is a transverse cross-section of the solar radiation
collector modules for concentrating single-curvature units and with
some elements of a tracking mechanism.
[0083] FIG. 6 demonstrates an isometric view of the section of the
receiver of concentrated solar radiation for the case of
application a concentrating single-curvature mirrors.
[0084] FIG. 7 is a cross-section of a combined unit: a
T-piece--solar radiation receiver with application of a double-wall
funnel and a dish-type radiation absorption plate.
[0085] FIG. 8 is a cross-section of a combined unit: a
T-piece--solar radiation receiver with application of a single-wall
funnel and a dish-type radiation absorption plate.
[0086] FIG. 9 is a cross-section of a combined unit: a
T-piece--solar radiation receiver with application of a metal
convex spherical cap for absorption of concentrated solar
radiation.
[0087] FIG. 10 is a longitudinal cross-section of the solar
radiation collector module with a concentrating compound-curvature
unit and with some elements of a tracking mechanism.
DETAILED DESCRIPTION OF THE INVENTION
[0088] FIG. 1a, FIG. 1b and FIG. 1c show the transverse
cross-sections of the receiver of concentrated solar radiation for
the embodiment of the present invention featuring a concentrating
single-curvature unit. The figures show an exploded transverse
cross-section of the metal envelope of the receiver and its glazing
and an exploded transverse cross-section of a radiation receiving
pipe of the receiver.
[0089] This embodiment of the device according to the present
invention includes a radiation receiving pipe 101 with a selective
coating 102 of its outer surface and low circular ribs 103, and a
metal envelope 104. Preferably coating 102 is made of selective
coating material (preferably absorbing strongly in the visible
range but only weakly emitting in the infra-red range of light). As
previously described, radiation receiving pipe 101 receives
radiation and is insulated by metal envelope 104.
[0090] Metal envelope 104 includes an internal elongated section
105 and an external elongated section 106, which are joined by two
elongated connection straps 107 and sealed at their ends by face
planes; the internal elongated section 105 comprises in turn a
cylindrical sub-section 108, which encloses a significant part of
the radiation receiving pipe 101 for insulating it from heat loss.
Cylindrical sub-section 108 features at its longitudinal margins a
plurality of flat strips 109 with a defined angle of convergence
with respect to the cylindrical sub-section 108.
[0091] The external elongated section 106 comprises a cylindrical
sub-section 110, which encloses the cylindrical sub-section 108;
cylindrical sub-section 110 features at its longitudinal margins a
plurality of flat strips 111 with the same angle of convergence as
for flat strips 109. The angle of convergence preferably enables
additional radiation reflected from the surface of the flat strips
109 to be collected by the radiation receiving pipe 101 and also
for heat to be maintained in the area of the radiation receiving
pipe 101, further increasing the efficiency of energy
collection.
[0092] Two elongated connection straps 112 join the flat strips 109
and flat strips 111.
[0093] The internal space between the internal and external
sections (108 and 110, respectively) is preferably evacuated in
order to reduce convective losses of heat. In addition, this space
may optionally be filled with a porous filler 113 to further reduce
heat loss.
[0094] In addition, radiation shields in the form of metal foils
114 are situated in the internal cavity of the metal envelope 104
to reduce heat loss and to increase the efficiency of energy
collection.
[0095] The flat strips 109 are provided with longitudinal clamps
115, which serve for fastening glazing 116. Glazing 116 preferably
increases the efficiency of energy collection and also reduces
radiant and convective heat loss.
[0096] FIG.2 shows an isometric view of the internal section of the
metal envelope alone according to an optional embodiment with
corrugations directed inwards.
[0097] It comprises a cylindrical sub-section 201, which features
flat strips 202 at the longitudinal margin as previously
described.
[0098] The cylindrical sub-section 201 and the flat strips 202 are
preferably provided with corrugations 203, which decrease in
dimension at their lower margins. These corrugations 203 are
preferably directed inwards with respect to the cylindrical
sub-section 201. The lower edges of the flat strips 202 are
provided with elongated connection straps 204. Dimensions of
corrugations 203 are a function of the mechanical properties of the
envelope (material and dimensions) and also depends on the
temperature differential. Corrugations 203 preferably are
constructed so as to prevent distortion due to a temperature
gradient on the metal envelope and mechanical stresses caused by
this temperature gradient, as previously described.
[0099] FIG. 3 is an isometric view of an external section of the
metal envelope alone according to an embodiment featuring
corrugations directed outwards.
[0100] It comprises a cylindrical sub-section 301, which also
features flat strips 302 as previously described.
[0101] The cylindrical sub-section 301 and the flat strips 302 are
preferably provided with corrugations 303, which decrease in
dimension at their lower margins. Corrugations 303 are directed
outwards with respect to the cylindrical sub-section 301.
[0102] FIG. 4 shows an axial cross-section of an embodiment of the
radiation receiving pipe alone. It comprises a metal pipe 401 that
is provided with two bellows 402 at its extreme sections. Bellows
402 are intended to compensate thermal expansion of the metal pipe
401. The outer surface of the metal pipe 401 is provided with a
selective coating 403 which preferentially absorbs solar radiation
and has a low emittance of infra-red energy. Selective coating 403
may optionally cover only the part of the outer surface of pipe
401, which is irradiated by the concentrated solar radiation. In
addition, the metal pipe 401 is preferably provided with low ribs
404, which prevent immediate contact of the selective coating 403
with the surface of the internal section of the metal envelope (not
shown) when the envelope rotates around the metal pipe 401. The
cylindrical surfaces of the low ribs are preferably coated
separately with antifriction coating 405 also to prevent friction
during rotation.
[0103] Flanges 406 are installed on the ends of the metal pipe
401.
[0104] Bellows 402 may optionally be made of the same material as
metal pipe 401; the material is preferably selected according to
the dimensions of bellows 402 and the plasticity of the
material.
[0105] FIG. 5 is a transverse cross-section of two solar radiation
collectors positioned in parallel with a common tracking rod and
with a concentrating single-curvature unit.
[0106] It shows posts 501 with pipes 502 installed on their upper
sections. A metal envelope 503, which is provided with glazing 504,
is situated on pipe 502 and can rotate around pipe 502. Truss
struts 505 serve for fastening frames 506, which in turn serve for
installation of parabolic trough-wise mirrors 507. A common
tracking rod 508 is joined by hinged units 509 with frames 506.
This enables the unit to follow the motion of the sun through
movement by a common tracking unit (not shown; may optionally
employ a motor to power movement of the unit). Pipes 502, metal
envelope 503 and glazing 504 preferably operate together are as for
FIG. 1. Metal envelope 503 also collects energy through heating due
to some radiation falling onto it. Glazing 504 preferably
diminishes heat loss through natural convection.
[0107] FIG. 6 demonstrates an isometric view of the section of the
receiver of concentrated solar radiation for the embodiment
featuring a single-curvature concentrating mirror.
[0108] It comprises: a radiation receiving pipe 601 with a
selective coating, and a metal envelope that includes an internal
elongated section 602 and an external elongated section 603. These
sections 602 and 603 are joined together to elongated connection
straps 604. The internal elongated section 602 comprises, in turn,
a cylindrical sub-section 605, which encloses a majority of the
radiation receiving pipe 601; this cylindrical sub-section 605 is
transformed at its longitudinal margins to flat strips 606 with a
certain angle of convergence with respect to the cylindrical
sub-section 605.
[0109] The external elongated section 607 comprises a cylindrical
sub-section 608; this cylindrical sub-section 608 is transformed at
its longitudinal margins to flat strips 609 with the same angle of
convergence as the flat strips 606.
[0110] The internal space between the internal and external
sections (sections 602 and 603 respectively) is preferably
evacuated in order to reduce convective losses of heat.
[0111] The flat strips 609 are provided with clamps 600, which
serve for installation of glazing 611.
[0112] The cylindrical sub-section 605 and the flat strips 606 are
provided with corrugations 612, which decrease in dimension at
their lower margins. These corrugations 612 are directed inwards
with respect to the internal elongated section 602.
[0113] Truss struts 613 are installed on the outer surface of the
flat strip 609.
[0114] The function of these elements is similar to that of the
corresponding elements of FIGS. 1-5.
[0115] FIG. 7 demonstrates a cross-section of a combined unit
(which is another embodiment according to the present invention),
featuring a T-piece--solar radiation receiver with a double-wall
funnel and a dish-type radiation absorption plate.
[0116] It comprises: bearing pipes 701 and 702 with insulting
layers 703 and 704, and a T-piece 705 with an insulating layer 706.
The lower branch of this T-piece 705 is sealed by a metal convex
spherical cap 707. In addition, there is a solar radiation
receiving member, which is constructed from a dish-type plate 708
and a double-wall funnel 709.
[0117] The upper side of the dish-type plate 708 has a concave
surface in the form of a spherical segment with the radius almost
identical to that of the metal convex spherical cap 707. In such a
way, the metal convex spherical cap 707 of T-piece 705 and the
concave surface of the dish-type plate 708 together forms a
spherical joint.
[0118] The lower surface of the dish-type plate 708 is covered with
layer 710 of solar radiation absorption coating.
[0119] The upper edge of the internal wall of the double-wall
funnel 709 is joined with the edge of the dish-type plate 708 and
the edge of its outer wall is provided with flange 711.
[0120] The distal (lower) aperture of the double-wall funnel 709 is
glazed with glazing 712.
[0121] There is a bearing housing 713 with a split lower flange 714
and two longitudinal slots; this bearing housing 713 is mounted on
the thermal insulation 706 of T-piece 705.
[0122] Flanges 714 and 711 of the bearing housing 713 and of the
outer wall of the double-wall funnel 709 are joined by a flexible
joint 715, which plays at the same time a role of a thermal
insulator.
[0123] The outer wall of the double-wall funnel 709 serves at the
same time for mounting truss struts 716, which in turn serve for
installation of a dish-type concentrating mirror with its
frame.
[0124] FIG. 8 shows a cross-section of a combined unit of a
T-piece--solar radiation receiver with application of a single-wall
funnel and a dish-type radiation absorption plate.
[0125] It comprises bearing pipes 801 and 802 with insulting layers
803 and 804; and T-piece 805 with an insulating layer 806. The
lower branch of T-piece 805 is sealed by a metal convex spherical
cap 807. In addition, there is a solar radiation receiving member,
which constructed from a dish-type plate 808 and a single-wall
funnel 809.
[0126] The upper side of the dish-type plate 808 has the concave
surface in the form of a spherical segment with the radius almost
identical to that of the metal convex spherical cap 807. In such a
way, the combination of the metal convex spherical cap 807 of the
T-piece and the concave surface of the dish-type plate 808 together
form a spherical joint.
[0127] The lower surface of the dish-type plate 808 is covered with
layer 810 of a solar radiation absorption coating.
[0128] The lower edge of the single-wall funnel 809 is joined with
a connecting branch 811 with flange 812, which is joined in turn
with the lower flange of a flexible joint 813. Truss struts 814 are
joined in this case with the connecting branch 811, which serve in
turn for installation of a dish-type concentrating mirror with its
frame (not shown).
[0129] The distal (lower) aperture of the single-wall funnel 809 is
glazed with glazing 815.
[0130] There is a bearing housing 816 with a split lower flange 817
and two longitudinal slots; this bearing housing 816 is mounted on
the thermal insulation 806. The split lower flange 817 of the
bearing housing 816 is joined with the flexible joint 813, which
plays at the same time a role of a thermal insulator serving in
turn for installation of a dish-type concentrating mirror with its
frame (not shown).
[0131] FIG. 9 is a cross-section of a combined unit featuring a
T-piece--solar radiation receiver with application of a metal
convex spherical cap for absorption of concentrated solar
radiation.
[0132] It comprises bearing pipes 901 and 902 with insulting layers
903 and 904; T-piece 905 with an insulating layer 906, the lower
branch of T-piece 905 is sealed by a metal convex spherical cap
907.
[0133] The outer surface of the metal convex spherical cap 907 is
provided with a radiation absorption coating 908.
[0134] There is a double-wall funnel 909; the upper edge of this
double-wall funnel is in immediate contact with the radiation
absorption coating 908 of the metal convex spherical cap 907, and
the double wall funnel 909 can be turned in two directions around
this metal convex spherical cap 907.
[0135] In such a way, the combination of the metal convex spherical
cap 907 of T-piece 905 and the double-wall funnel 909 forms a
spherical joint.
[0136] The outer edge of the outer wall of the double-wall funnel
909 is. provided with flange 910.
[0137] The distal (lower) aperture of the double-wall funnel 909 is
glazed with glazing 911.
[0138] There is a bearing housing 912 with a split lower flange 913
and two longitudinal slots; this bearing housing 912 is mounted on
the thermal insulation 906 of T-piece 905.
[0139] Flanges 913 and 910 of the bearing housing 912 and of the
outer wall of the double-wall funnel 909 are joined by a flexible
joint 914, which plays at the same time a role of a thermal
insulator. The outer wall of the double-wall funnel 909 serves at
the same time for mounting truss struts 915, which serve in turn
for installation of a dish-type concentrating mirror with its
frame.
[0140] FIG. 10 shows a longitudinal cross-section of the solar
radiation collector module with a concentrating compound-curvature
unit and with some elements of a tracking mechanism.
[0141] It comprises bearing pipes 1001 with expansion units 1021,
which are mounted on vertical posts 1002. A working medium flows in
the bearing pipes 1001. The bearing pipes 1001 are provided with
layers 1003 of a thermal insulation.
[0142] T-piece 1004 is built into the bearing pipes 1001. The lower
branch of T-piece 1004 is sealed by a metal convex spherical cap
1005.
[0143] T-piece 1004 is covered with layer 1006 of a thermal
insulation.
[0144] In addition, there is a solar radiation receiving member,
which constructed from a dish-type plate 1007 and a double-wall
funnel 1008.
[0145] The upper side of the dish-type plate 1007 has the concave
surface in the form of a spherical segment with the radius almost
identical to that of the metal convex spherical cap 1005. In such a
way, the combination of the metal convex spherical cap 1005 and the
concave surface of the dish-type plate 1007 forms a spherical
joint.
[0146] The lower surface of the dish-type plate 1007 is covered
with layer 608 of a solar radiation absorption coating.
[0147] The upper edge of the internal wall of the double-wall
funnel 1008 is joined with the edge of the dish-type plate 1007 and
the edge of its outer wall is provided with flange 1009.
[0148] The distal (lower) aperture of the double-wall funnel 1008
is glazed by glazing 1010 in order to diminish heat losses via its
internal cavity.
[0149] There is a bearing housing 1011 with a split lower flange
1012 and two longitudinal slots; this bearing housing 1011 is
mounted on the thermal insulation 1006 of T-piece 1004.
[0150] The open sections of the longitudinal slots of the bearing
housing 1011 are closed. The flanges 1012 and 1009 of the bearing
housing 1011 and of the outer wall of the double-wall funnel 1008
are joined by a flexible joint 1013, which plays at the same time a
role of a thermal insulator.
[0151] The outer wall of the double-wall funnel 1008 serves at the
same time for mounting truss struts 1014, which in turn serve for
installation of a dish-type concentrating mirror 1015 with its
frame 1016.
[0152] Frame 1016 of the dish-type concentrating mirror 1015 is
joined through cylindrical hinges 1019 and 1020 with tracking rods
1017 and 1018.
[0153] Other embodiments and configurations may be devised without
departing from the spirit of the invention and the scope of
appended claims.
* * * * *