U.S. patent application number 12/593855 was filed with the patent office on 2010-07-29 for inflatable solar collector.
This patent application is currently assigned to Heliovis AG. Invention is credited to Johannes Hoefler.
Application Number | 20100186733 12/593855 |
Document ID | / |
Family ID | 39808732 |
Filed Date | 2010-07-29 |
United States Patent
Application |
20100186733 |
Kind Code |
A1 |
Hoefler; Johannes |
July 29, 2010 |
Inflatable Solar Collector
Abstract
The invention relates to an inflatable solar collector (1)
comprising an at least partially transparent sleeve divided at
least into two chambers (3, 4) which are separated by a reflector
membrane (5) reflecting on one side and which can respectively
receive a gas, and at least one absorber (6) arranged opposite the
reflective side of each reflector membrane (5). The sleeve is a
cylindrical tube (2) and each reflector membrane (5) extends along
the length thereof. The absorber(s) (6) is/are arranged along at
least one focus line extending along the length thereof. Fillable
ballast chambers (10) can be provided beneath the reflector
membrane (5). Anchoring strips (12) are used for anchoring and
bearing rolls (13) for support.
Inventors: |
Hoefler; Johannes; (Wien,
AT) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER, EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
Heliovis AG
|
Family ID: |
39808732 |
Appl. No.: |
12/593855 |
Filed: |
March 28, 2008 |
PCT Filed: |
March 28, 2008 |
PCT NO: |
PCT/AT08/00117 |
371 Date: |
March 17, 2010 |
Current U.S.
Class: |
126/625 |
Current CPC
Class: |
F24S 23/745 20180501;
Y02E 10/47 20130101; F24S 10/45 20180501; Y02E 10/44 20130101; F24S
20/80 20180501; F24S 23/715 20180501; Y02E 10/40 20130101 |
Class at
Publication: |
126/625 |
International
Class: |
F24J 2/36 20060101
F24J002/36 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 30, 2007 |
AT |
A 512/2007 |
Claims
1. An inflatable solar collector comprising an at least partially
transparent sleeve divided into at least two chambers which are
separated by a reflector membrane that is reflective on one side,
and which can be independently acted on by a gas, and comprising at
least one absorber oppositely situated from the reflective side of
each reflector membrane, wherein the sleeve comprises a cylindrical
tube, and each reflector membrane extends in the direction of the
length of the tube, and the at least one absorber is situated along
at least one focus line extending in the direction of the length of
the tube.
2. An inflatable solar collector according to claim 1, including
wires stretched at defined intervals on a side of each reflector
membrane opposite the reflective side, transverse to the
longitudinal extension of the tube, and wherein each absorber is
situated essentially at a center between two wires.
3. An inflatable solar collector according to claim 1, including at
least one ballast chamber with a variable ballast on the side of
each reflector membrane opposite the reflective side.
4. An inflatable solar collector according to claim 3, wherein each
ballast chamber is divided into subchambers in the longitudinal
direction of the tube which are connected by lines.
5. An inflatable solar collector according to claim 1, including a
ballast which is adjustable in length positioned on the side of
each reflector membrane opposite the reflective side.
6. An inflatable solar collector according to claim 1, wherein each
reflector membrane is variably deflectable transverse to its
longitudinal extension, and in the state of use is curved in an
essentially parabolic or paraboloidal shape.
7. An inflatable solar collector according to claim 1, including
mutually intersecting anchoring bands secured at essentially
diametrically opposed, outer sides of the tube.
8. An inflatable solar collector according to claim 1, including
bearing rollers or the like on the exterior of the tube positioned
oppositely from each absorber.
9. An inflatable solar collector according to claim 1, wherein the
tube is filled with a buoyancy gas.
10. An inflatable solar collector according to claim 9, including
at least one conductor loop connected to a power source and
embedded in the tube.
Description
RELATED APPLICATIONS
[0001] This application claims the priorities of Austrian Patent
Applications Nos. AT 505,075 B1 and AT 504,916 B1 and of PCT
Application No. PCT/AT2008/000177, the disclosures of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates to an inflatable solar collector with
an at least partially transparent sleeve divided into at least two
chambers which are separated by a reflector membrane that is
reflective on one side, and which can be independently acted on by
a gas, and has at least one absorber that is oppositely situated
from the reflective side of each reflector membrane.
[0003] Such a spherical inflatable solar collector, which may be
used for terrestrial energy production, has become known from a
research report. All solar collectors of this type are based on the
principle that solar radiation is bundled by the reflector membrane
and directed to the absorber, which converts the solar radiation
into energy. As the result of differing pressure impingement on the
chambers, the reflector membrane is curved in such a way that the
solar rays are always focused on the absorber. Tubes, photovoltaic
elements, etc. through which media flow may be used as absorbers.
However, the spherical shape is disadvantageous for these solar
collectors, since manufacturing it is complex, and complicated
biaxial tracking is necessary. Use as spherical heliostats
represents a further disadvantage, since due to the shading problem
caused by solar tower power plants it is not possible to position
such solar collectors relatively closely together. Therefore, the
area yield for energy production is not optimal.
SUMMARY OF THE INVENTION
[0004] It is an object of the invention to eliminate the
above-mentioned disadvantages, i.e. to simplify the manufacture and
the tracking, and to increase the area yield for energy
production.
[0005] This object is achieved according to the invention using an
inflatable solar collector of the aforementioned type, by the fact
that the sleeve is designed as a cylindrical tube, and each
reflector membrane extends over the length thereof. The absorber(s)
is/are situated along at least one focus line extending over the
length of the tube.
[0006] The cylindrical shape of the solar collector according to
the invention allows such collectors to be positioned closely next
to one another, thereby maximizing the area yield for energy
production. Accordingly, each reflector membrane extends over the
entire length of the solar collector. In such a cylindrical tube it
is in fact possible to provide multiple reflector membranes, which
cooperate either with a single absorber or with absorbers that are
individually assigned to them. These absorbers are situated on at
least one focus line extending in the longitudinal direction of the
tube. The feeding gas line connections to the individual chambers
as well as the absorber connections to the further energy
utilization equipment correspond to the prior art.
[0007] One preferred embodiment of the inflatable solar collector
according to the invention is characterized in that wires or the
like are stretched at defined intervals on the side of each
reflector membrane opposite its reflective side. The wires extend
transverse to the longitudinal extension of the tube, and each
absorber is effectively situated at the center between two wires.
As a result of this design, due to the fact that a lower pressure
is generated on the side of the reflector membrane opposite the
reflective side than on the top side when the solar collector is
acted on by pressure, the membrane is not cylindrically curved.
Since the membrane is supported by the wires, it assumes the shape
of spherical dome shell surfaces arranged in a row. Accordingly,
one absorber is provided above the center of each individual
section, thus achieving intensive bundling of the incoming solar
energy.
[0008] It is useful to provide at least one ballast chamber with a
variable ballast on the side of each reflector membrane opposite
its reflective side. For solar collectors according to the
invention this is particularly favorable for terrestrial energy
production, since on the one hand position stabilization and on the
other hand alignment with the sun may be achieved by sequentially
filling and/or emptying the ballast chamber(s). For inflatable
solar collectors which are anchored in the ground but which project
into or float in the air, it is advantageous for each ballast
chamber to be divided into subchambers that extend in the
longitudinal direction of the tube and which are interconnected by
conduit lines. Continuous alignment with the sun is achieved by
varying the filling or emptying of the subchambers.
[0009] Instead of ballast chambers which may be filled or emptied,
a ballast which is adjustable in length may be accommodated on the
side of each reflector membrane opposite the reflective side.
[0010] Because of their low weight and the intrinsic rigidity, the
solar collector may be affixed at (at least) one end to (at least)
one pole in order to keep the area therebeneath shaded and/or free
of snow or rain, and/or to act as noise protection. For an inclined
installation, the cross-section inclined toward the sun may be
optimally adjusted for the season. (The inclination is a function
of the geographical latitude.) The solar collector may also be
slidably or otherwise movably mounted on a swivel pole, and in this
manner may biaxially track the sun with the use of only one motor.
Alternatively, instead of the pole a buoyancy gas may provide the
inclined position. In this case, biaxial tracking may be achieved
with the variable length of the guy wire for the collector.
[0011] The solar collector may also be set up vertically, and
braced and operated in the manner of a pole. In this operating mode
the solar collector is able to collect a large amount of sunlight,
particularly in the winter months when low-angle incidence of solar
radiation is encountered. Furthermore, snow cannot collect on the
surface, only a small base surface area is required, and the back
side may be used for advertising, for example. The pole could also
be used for various other areas of use such as mobile wireless
telephone providers, for example.
[0012] When the reflector membrane is made of a homogeneous
material, its concave curvature in the state of use essentially
follows a catenary or circular line. Since this is not always
adequate for optimal focusing, it is advisable for each reflector
membrane to be variably deflectable transverse to its length, and
in the state of use to be curved in an essentially parabolic or
paraboloidal shape.
[0013] For terrestrial use of the inflatable solar collector
according to the invention, to allow ground anchoring on the one
hand, and simple tracking of the sun's position on the other hand,
it has proven advantageous to fasten preferably mutually
intersecting anchoring bands at essentially diametrically opposed
outer sides of the tube. When such oppositely situated, and
preferably also mutually intersecting, bands are anchored to the
ground at their free ends, mounting is ensured, and the solar
collector can be rotated corresponding to the solar trajectory.
[0014] To facilitate the above-referenced rotary motion in solar
collectors according to the invention for terrestrial applications,
bearing rollers or the like may be provided on the exterior of the
tube opposite each absorber.
[0015] For floating use, attachment at the two tube ends may be
sufficient. The tracking may be achieved either by means of the
above-mentioned ballast technique(s), or by using motors or the
like mounted on pivots. Biaxial tracking is made possible by
rotation of the tube about the vertical axis.
[0016] When using the inflatable solar collector according to the
invention in the air, it is advantageous for the tube to be filled
with a buoyancy gas. In this case the solar collector may be
floated above the ground without additional auxiliary means. To
allow a solar collector filled in such a manner with buoyancy gas
to track the solar position in each case, it has proven
advantageous to embed in the tube at least one conductor loop which
is connected to an electrical power source. By use of such a
conductor loop, i.e. multiple windings together with a coil, a
magnetic field may be generated which allows positioning of the
solar collector by interaction with the earth's magnetic field.
[0017] The invention is explained in greater detail below with
reference to two exemplary embodiments schematically illustrated in
the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view that shows a first embodiment
of the solar collector of the present invention; and
[0019] FIG. 2 is a perspective view that shows a second
embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Referring to FIG. 1, the inflatable solar collector 1 has a
cylindrical tube 2 as a sleeve. The tube is transparent, at least
above a reflector membrane 5 which divides the tube 2 into two
chambers 3, 4. In the illustrated example, the reflector membrane 5
is reflective on the top, upwardly facing side and extends
essentially diametrically across the tube over the entire length of
tube 2. An elongated absorber 6 is situated above the reflector
membrane 5, approximately in the region of the lateral surface of
the tube 2. This may be, for example, a pipe through which media
flow. The chambers 3, 4 and the absorber 6 are connected to
corresponding connecting lines 7, 8, 9. Two ballast chambers 10 are
situated below the reflector membrane, and may be filled or emptied
through lines 11 as needed. As shown in FIG. 1, the ballast
chambers may be further divided into subchambers 18 which are
connected via lines. Anchoring bands 12 are fastened at
diametrically opposed outer sides of the tube 2 and, as shown, they
intersect each other. These bands may be used to fasten the
inflatable solar collector according to the invention to the
ground; a rotary motion about the axis of the cylindrical tube 2 is
still possible. Bearing rollers 13 are also provided for supporting
the inflatable solar collector 1 according to the invention.
[0021] When the inflatable solar collector according to the
invention is used for terrestrial energy production, the solar
collector is mounted on the ground in a favorable position with
respect to the solar trajectory with the anchoring bands 12, and
tracks the solar trajectory with the help of the ballast chambers
10 and with support from the bearing rollers 13. The emitted solar
radiation is reflected by the reflector membrane 5 and is focused
on the absorber 6. As a result, the medium flowing therein
undergoes intense heating and can be subsequently utilized for
energy production.
[0022] Instead of a single reflector membrane 5 and the two
chambers 3, 4 thus formed, two or more reflector membranes may by
accommodated. In each case, in the state of use the chamber must be
filled with less pressure than the chamber thereabove to achieve
the desired curvature of the reflector membrane. If a curvature of
the reflector membrane 5 is desired which most closely approximates
a parabolic shape, the deflectability of the reflector membrane
transverse to the longitudinal extension is different.
[0023] FIG. 2 shows an inflatable solar collector 14. In FIG. 2,
identical features are denoted by the same reference numerals as in
FIG. 1. In contrast to FIG. 1, in FIG. 2 wires or the like 15 are
stretched at defined intervals in the transverse direction of the
tube and below the reflector membrane 5. In the state of use of the
solar collector 14, the reflector membrane 5 does not have a mere
cylindrical curvature as illustrated in FIG. 1, but instead has an
individual, approximately spherical or paraboloidal dome shell
curvature. To avoid the formation of creases, etc., the reflector
membrane between the stretched wires may have a convex curvature at
the borders. Suitable gussets may also be provided. Accordingly,
separate absorbers 16 are situated on a common focus line,
approximately at the center above these individual sections; these
may be photovoltaic elements, for example. Instead of the finable
ballast chambers 10, a ballast 17 of adjustable length is arranged
below the reflector membrane 5 which performs the same functions as
ballast chambers 10. All the other features used for anchoring
purposes may likewise be provided, but for the sake of simplicity
are not shown in FIG. 2. The operating principle of the solar
collector 14 corresponds to that of the solar collector 1, except
that the focusing in each case is approximately punctiform, not
linear as in FIG. 1.
[0024] Besides the illustrated embodiments for terrestrial energy
production, which by means of conventional adaptations are also
suitable for use as floating solar collectors, it is also possible
to fill solar collectors with a buoyancy gas, allowing the solar
collectors to float in the air in the manner of a dirigible. The
connections and anchors necessary for this purpose are of the
conventional type. For positioning, however, and in keeping with
the invention, the earth's magnetic field may be utilized when a
coil encloses the tube or is embedded therein which, when current
passes through it, generates a magnetic field which interacts with
the earth's magnetic field.
* * * * *