U.S. patent application number 13/520403 was filed with the patent office on 2012-11-08 for method for automatic orientation of a solar panel device and device operating according to said method.
This patent application is currently assigned to Commissariat a L'Energie Atomique et aux Energies Alternatives. Invention is credited to Francois Boudehenn, Antoine Pineau.
Application Number | 20120279487 13/520403 |
Document ID | / |
Family ID | 42585390 |
Filed Date | 2012-11-08 |
United States Patent
Application |
20120279487 |
Kind Code |
A1 |
Pineau; Antoine ; et
al. |
November 8, 2012 |
METHOD FOR AUTOMATIC ORIENTATION OF A SOLAR PANEL DEVICE AND DEVICE
OPERATING ACCORDING TO SAID METHOD
Abstract
Method for orientation of a solar panel device (3), wherein the
solar panel device is oriented with respect to at least one axis
(5), in a first direction and in a second direction, using energy
from a first fluid reservoir (6) or a second fluid reservoir (8),
the energy being provided by the solar radiation and the two
reservoirs being independent, and wherein the solar panel device is
oriented with respect to the axis (5), in the first direction or in
the second direction, until a distributor valve (13, 14) prevents
feeding of one of the actuator chambers by one of the chambers of a
reservoir.
Inventors: |
Pineau; Antoine; (L'Alpe
D'Huez, FR) ; Boudehenn; Francois; (Saint Sauveur De
Montagut, FR) |
Assignee: |
Commissariat a L'Energie Atomique
et aux Energies Alternatives
Paris
FR
|
Family ID: |
42585390 |
Appl. No.: |
13/520403 |
Filed: |
December 31, 2010 |
PCT Filed: |
December 31, 2010 |
PCT NO: |
PCT/EP2010/070954 |
371 Date: |
July 3, 2012 |
Current U.S.
Class: |
126/604 |
Current CPC
Class: |
F24S 30/45 20180501;
F24S 30/425 20180501; F24S 2030/115 20180501; Y02E 10/47 20130101;
F24S 50/20 20180501 |
Class at
Publication: |
126/604 |
International
Class: |
F24J 2/38 20060101
F24J002/38; F24J 2/54 20060101 F24J002/54 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 4, 2010 |
FR |
1050017 |
Claims
1. Method for orientation of a solar panel device (3), wherein the
solar panel device is oriented with respect to at least one axis
(5), in a first direction and in a second direction, using energy
from a first fluid reservoir (6) or a second fluid reservoir (8),
the energy being provided by solar radiation and the two reservoirs
being independent, and wherein the solar panel device is oriented
with respect to the axis (5), in the first direction or in the
second direction, until a distributor valve (13, 14) prevents
feeding of one of the actuator chambers by one of the chambers of a
reservoir.
2. Orientation method according to claim 1, wherein the solar panel
device is oriented, with respect to the axis (5), in the first
direction, by pneumatically or hydraulically connecting a first
chamber (17) of the first reservoir (6) to a first chamber (15) of
the actuator (11) and wherein the solar panel device is oriented,
with respect to the axis (5), in the second direction, by
pneumatically or hydraulically connecting a second chamber (18) of
the second reservoir (8) to a second chamber (16) of the actuator
(12).
3. Orientation method according to claim 1, wherein a first
distributor valve (13) and a second distributor valve (14) are
controlled, respectively, by the pressure of a fluid contained in a
third chamber (19), notably in a third chamber (19) included in the
first reservoir (6), and by the pressure of a fluid contained in a
fourth chamber (20), notably in a fourth chamber (20) included in
the second reservoir (8).
4. Orientation method according to claim 3, wherein the solar panel
device is oriented, with respect to the axis (5), in the first
direction or in the second direction, until the third and fourth
chambers: are exposed minimally overall to the sun's rays, and/or
are exposed identically to the sun's rays, or are not exposed to
the sun's rays.
5. Device (2) for orientation of a solar panel device (3) with
respect to an axis (5), the orientation device comprising at least
a first reservoir (6) and a second reservoir (8) independent of
each other and hydraulic or pneumatic means (13, 14, 21, 22, 23,
24) for connecting a first chamber (17) of the first reservoir and
a second chamber (18) of the second reservoir to a first chamber
(15) of an actuator (11) and to a second chamber (16) of an
actuator (12), respectively, so as to be able to feed the first
actuator chamber with fluid from the first chamber of the first
reservoir and to be able to feed the second actuator chamber with
fluid from the second chamber of the second reservoir, wherein it
comprises hydraulic or pneumatic means (13, 14, 23, 24, 25, 26, 27,
28) for hydraulically or pneumatically connecting the first chamber
(17) of the first reservoir (6) and the second chamber (18) of the
second reservoir (8) to the second chamber (16) of the actuator
(12) and to the first chamber (15) of the actuator (11),
respectively, so as to be able to feed the first chamber (17) of
the first reservoir (6) with fluid from the second chamber (16) of
the actuator (12) and to be able to feed the second chamber (18) of
the second reservoir (8) with fluid from the first chamber (15) of
the actuator (11).
6. Orientation device according to claim 5, wherein it comprises
two single-acting type actuators (11, 12).
7. Orientation device according to claim 5, wherein it comprises a
double-acting type actuator comprising the first actuator chamber
and the second actuator chamber.
8. Orientation device according to claim 5, wherein the hydraulic
or pneumatic connecting means comprise a first distributor valve
(13) and a second distributor valve (14) respectively controlled by
the pressure of a fluid contained in a third chamber (19), notably
in a third chamber (19) included in the first reservoir (6), and by
the pressure of a fluid contained in a fourth chamber (20), notably
in a fourth chamber (20) included in the second reservoir (8).
9. Orientation device according to claim 5, wherein it comprises
screens (7, 9) such that when the projections of the sun's rays in
a plane perpendicular to the axis (5) are perpendicular to the
solar panel device, the third and fourth chambers: are exposed
minimally overall to the sun's rays, and/or are exposed identically
to the sun's rays, or are not exposed to the sun's rays.
10. Solar energy conversion system (1) comprising an orientation
device (2) according to claim 5 and a solar panel device (3).
11. Solar energy conversion system (1) comprising a first
orientation device (2) according to claim 5, a second orientation
device (2) according to claim 5 and a solar panel device (3), the
first and second orientation devices being adapted to orient the
solar panel device with respect to two non-parallel axes and
preferably to orient the solar panel device with respect to two
orthogonal or substantially orthogonal axes.
Description
[0001] The present invention concerns a method for automatic
orientation of a solar panel and a device for orientation of a
solar panel, i.e. an orientation device operating according to such
a method. The invention further concerns a solar energy conversion
system comprising such a device for orientation of a solar panel
device and a solar panel device.
[0002] With worldwide energy demand increasing, one of the aims for
the next years is to find reliable and environmentally friendly
sources of energy. One of the first steps in this direction was the
production of systems able to convert solar energy either into
electricity by means of photovoltaic solar panels or into heat by
means of thermal solar panels. The installation of such systems
nevertheless remains costly and productivity is sometimes deemed
too low by consumers.
[0003] Research shows that a system of the above kind that is able
to track the course of the sun achieves a gain in productivity
averaging 15 to 30% depending on the technology employed. For the
system to be able to track the course of the sun, it is equipped
with an orientation device or "tracker" for automatically orienting
solar panels as a function of the position of the sun.
[0004] Orientation devices may be classified in two categories:
[0005] So-called active orientation devices, i.e. devices using
external energy, notably electrical energy, to enable the system to
track the course of the sun. These orientation devices often use
stepper motors to move the solar panels. [0006] So-called passive
orientation devices, i.e. devices using no external source of
energy to enable holding and orientation of the solar panels so
that they are positioned at least substantially perpendicular to
the sun's rays.
[0007] For installations of medium and high power, the energy
consumed by an active orientation device is low compared to the
quantity of energy converted by the solar panels that the
orientation device is designed to orient. On the other hand, for
installations of low power the energy consumed by an active
orientation device is no longer negligible compared to the quantity
of energy converted by the solar panels that the orientation device
is designed to orient and in particular is not negligible compared
to the energy savings produced by the orientation device compared
to a system with fixed solar panels. In such a context, passive
orientation devices are undoubtedly beneficial.
[0008] Various passive orientation devices are known already.
[0009] In a first orientation device, two identical cylinders
subjected to the same pressure are disposed on each side of a solar
panel and at the same distance from the centre of rotation of that
solar panel. They are filled with a fluid having a low boiling
point. The device further provides screens judiciously dispose so
that if the sun's rays are not perpendicular to the surface of the
solar panel, most of the radiation reaches one of the two
cylinders, which causes the fluid therein to boil and a transfer of
fluid from one cylinder to the other. It follows that the
respective weights of the two cylinders are no longer the same, and
that the solar panel therefore tilts. Although such an orientation
device has advantages (notably an improvement in the performance of
the solar panel comparable to that obtained with an active
orientation device, a simple structure and thus a low cost), it has
some drawbacks that may be unacceptable: [0010] the orientation
device is not resistant to external elements such as gusts of wind,
because its equilibrium about the ideal position is precarious and
because the forces that it employs are low compared to the forces
produced by a gust of wind, for example; [0011] there exists a risk
of a phenomenon of oscillation about the ideal position occurring:
because of inertia, during a phase of modification of the
orientation of the solar panel, the orientation device will
overshoot the ideal position and then seek to correct this
overshoot by an orientation in the opposite direction, but will
again overshoot the ideal orientation; this leads to a phenomenon
of oscillation about the ideal position.
[0012] There is also known from the document US 2005/284 467 a
passive orientation device for orienting solar panels as a function
of the position of the sun. In this orientation device, a liquid
fills a chamber that is connected to a piston and cylinder
actuator. The expansion of the liquid moves the piston rod of the
actuator and consequently moves the solar panels. Thus in this
orientation device the orientation of the solar panels is a
function of the temperature of the liquid and not necessarily a
function of the orientation of the sun's rays. In particular,
during the first part of the day, the chamber is not exposed to the
sun's rays and the temperature of the liquid is a function only of
the temperature of the surrounding air. It follows that the sun's
rays are not necessarily perpendicular to the solar panels during
this first part of the day. Similarly, during the second part of
the day, the chamber is progressively exposed to the sun's rays,
and is consequently more exposed to the sun's rays at the end of
the day than in the middle of the day. It follows that the sun's
rays cannot have a constant angle of incidence relative to the
solar panels during the second part of the day and that the sun's
rays are therefore not perpendicular to the solar panels throughout
this second part of the day. Moreover, the ambient temperature
necessarily influences the orientation of the solar panels.
Consequently, if under certain conditions the sun's rays are
perpendicular to the solar panels, under those same conditions but
with a different ambient temperature the sun's rays will not be
perpendicular to the solar panels. Moreover, if the device is
completely shaded from the sun in cloudy weather, it reverts to a
position defined only by the ambient temperature, which position
may be very far from the position occupied just before the clouds
appear.
[0013] The object of the invention is to provide an orientation
method and an orientation device enabling the problems referred to
above to be solved and improving the orientation methods and the
orientation devices known in the prior art. In particular, the
invention proposes an orientation method and an orientation device
enabling the accuracy of the orientation of the solar panels to be
improved.
[0014] According to the invention, the method makes it possible to
orient a solar panel device. It is characterized in that the solar
panel device is oriented with respect to at least one axis, in a
first direction and in a second direction, using energy from a
first fluid reservoir or a second fluid reservoir, the energy being
provided by solar radiation and the two reservoirs being
independent. The solar panel device is oriented with respect to the
axis, in the first direction or in the second direction, until a
distributor valve prevents feeding of one of the actuator chambers
by one of the chambers of a reservoir.
[0015] The solar panel device may be oriented, with respect to the
axis, in the first direction, by pneumatically or hydraulically
connecting a first chamber of the first reservoir to a first
chamber of the actuator and the solar panel device may be oriented,
with respect to the axis, in the second direction, by pneumatically
or hydraulically connecting a second chamber of the second
reservoir to a second chamber of the actuator.
[0016] A first distributor valve and a second distributor valve may
be controlled, respectively, by the pressure of a fluid contained
in a third chamber, notably in a third chamber included in the
first reservoir, and by the pressure of a fluid contained in a
fourth chamber, notably in a fourth chamber included in the second
reservoir.
[0017] The solar panel device may be oriented, with respect to the
axis, in the first direction or in the second direction, until the
third and fourth chambers: [0018] are exposed minimally overall to
the sun's rays, and/or [0019] are exposed identically to the sun's
rays, or [0020] are not exposed to the sun's rays.
[0021] The device of the invention is for orientation of a solar
panel device with respect to an axis. The orientation device
comprises at least a first reservoir and a second reservoir
independent of each other and hydraulic or pneumatic means for
connecting a first chamber of the first reservoir and a second
chamber of the second reservoir to a first actuator chamber and to
a second actuator chamber, respectively, so as to be able to feed
the first actuator chamber with fluid from the first chamber of the
first reservoir and to be able to feed the second actuator chamber
with fluid from the second chamber of the second reservoir. The
orientation device comprises hydraulic or pneumatic means for
hydraulically or pneumatically connecting the first chamber of the
first reservoir and the second chamber of the second reservoir to
the second actuator chamber and to the first actuator chamber,
respectively, so as to be able to feed the first chamber of the
first reservoir with fluid from the second actuator chamber and to
be able to feed the second chamber of the second reservoir with
fluid from the first actuator chamber.
[0022] The orientation device may comprise two single-acting type
actuators.
[0023] The orientation device may comprise a double-acting type
actuator comprising the first actuator chamber and the second
actuator chamber.
[0024] The hydraulic or pneumatic connecting means may comprise a
first distributor valve and a second distributor valve respectively
controlled by the pressure of a fluid contained in a third chamber,
notably in a third chamber included in the first reservoir, and by
the pressure of a fluid contained in a fourth chamber, notably in a
fourth chamber included in the second reservoir.
[0025] The orientation device may comprise screens such that when
the projections of the sun's rays in a plane perpendicular to the
axis are perpendicular to the solar panel device, the third and
fourth chambers: [0026] are exposed minimally overall to the sun's
rays, and/or [0027] are exposed identically to the sun's rays, or
[0028] are not exposed to the sun's rays.
[0029] In another aspect, the device is for orienting a solar panel
device about an axis and comprises at least first and second
independent reservoirs and hydraulic or pneumatic connecting means
for connecting a first chamber of the first reservoir and a second
chamber of the second reservoir to a first actuator chamber and a
second actuator chamber, respectively, so as to be able to feed the
first actuator chamber with fluid from the first chamber of the
first reservoir and to be able to feed the second actuator chamber
with fluid from the second chamber of the second reservoir. The
hydraulic or pneumatic connecting means comprise a first
distributor valve and a second distributor valve respectively
controlled by the pressure of a fluid contained in a third chamber,
notably in a third chamber included in the first reservoir, and by
the pressure of a fluid contained in a fourth chamber, notably in a
fourth chamber included in the second reservoir.
[0030] The solar energy conversion system of the invention
comprises an orientation device as defined above and a solar panel
device.
[0031] The solar energy conversion system may comprise a first
orientation device as defined above, a second orientation device as
defined above and a solar panel device, the first and second
orientation devices being adapted to orient the solar panel device
with respect to two non-parallel axes and preferably to orient the
solar panel device with respect to two orthogonal or substantially
orthogonal axes.
[0032] The appended drawings represent by way of example a solar
energy conversion system of one embodiment of the invention.
[0033] FIG. 1 is a mechanical diagram of a solar energy conversion
system of one embodiment of the invention, the orientation device
being represented in a situation of equilibrium.
[0034] FIG. 2 is a hydraulic or pneumatic diagram of the solar
energy conversion system of this embodiment of the invention, the
orientation device being represented in a situation of
equilibrium.
[0035] FIG. 3 is a mechanical diagram of the solar energy
conversion system of this embodiment of the invention, the
orientation system being represented in a transient situation.
[0036] FIG. 4 is a hydraulic or pneumatic diagram of the solar
energy conversion system of this embodiment of the invention, the
orientation device being represented in a transient situation.
[0037] The theory of the invention is based on the use of the fluid
expansion phenomenon and on the actions that the expansion of the
fluid may produce in chambers of one or more actuators used to
orient a solar panel with respect to one or more axes.
[0038] Generally speaking, the theory of the invention is to use
solar energy to expand a fluid. This expansion generates mechanical
actions for orienting the solar panel via one or more
actuators.
[0039] The aim is therefore to use solar energy to generate
pressure differences between a plurality of chambers so as to
enable movement of at least one actuator piston rod and thus to
move the solar panel.
[0040] The pressure difference is created when fluid trapped in a
reservoir is heated by the sun. The fluid expands and therefore
occupies a greater volume by pushing an actuator piston rod. Fluid
enclosed in another reservoir is held at the same temperature and
pressure conditions to prevent it exerting an antagonistic
mechanical action. A pneumatic or hydraulic circuit can achieve
this objective.
[0041] A solar energy conversion system 1 of a first embodiment of
the invention, shown in FIGS. 1 to 4, mainly comprises a solar
panel device 3 and a device 2 for orienting that solar panel
device. The orientation devices of the passive type and enables the
solar panel device to be oriented automatically so that the solar
radiation 10 is at least substantially perpendicular to the surface
of the solar panel device.
[0042] The solar panel device enables conversion of solar energy
into another form of energy. It may comprise a plurality of solar
energy conversion elements. The solar panel device may notably
comprise one or more elements for conversion of solar energy into
electrical energy and/or may comprise one or more elements for
conversion of solar energy into thermal energy transported by a
fluid.
[0043] The orientation device 2 mainly comprises a support 4 at the
end of which the solar panel device is mounted so as to be mobile
relative to an axis 5 and two single-acting piston-and-cylinder
actuators 11, 12, mounted for example symmetrically with respect to
the axis 5 with respect to which the solar panel device is
articulated. First ends of the actuators are articulated to the
solar panel device and the other ends of the actuators are
articulated to the support or to a structure to which the support
is fixed. Accordingly, deployment of the piston rod of the first
actuator 11 leads to rotation of the solar panel device about the
axis 5 in a first direction and retraction of the piston rod of the
second actuator 12. Symmetrically, deployment of the piston rod of
the second actuator 12 leads to rotation of the solar panel device
about the axis 5 in a second direction and retraction of the piston
rod of the first actuator 11. It is the actions of these actuators
that enable the solar panel device to be oriented optimally with
respect to the solar radiation, i.e. to be oriented so that the
sun's rays are as perpendicular as possible to the surface of the
solar panel device.
[0044] The orientation device 2 also comprises reservoirs 6, 8 and
hydraulic or pneumatic means for connecting the reservoirs to the
actuators. Accordingly, the actuators are fed with fluid under
pressure by the reservoirs 6, 8 via the hydraulic or pneumatic
connecting means and the mechanical energy applied by the actuators
to the solar panel device comes from the reservoirs 6, 8.
[0045] Furthermore, the orientation device 2 comprises screens 7
and 9. The reservoirs and the screens are kinematically connected
to the solar panel device. The reservoirs and the screens are
preferably (directly or indirectly) fastened to the solar panel
device. The screens may consist of simple pieces of sheet metal or
of metal or synthetic material structural sections.
[0046] The screens are arranged so that the reservoirs 6, 8 are
protected from the sun's rays when the sun's rays are in a required
direction relative to the surface of the solar panel device, i.e.
notably when the projections of the sun's rays in a plane
perpendicular to the axis 5 are perpendicular or substantially
perpendicular to the surface of the solar panel device.
Alternatively, the screens are arranged so that the reservoirs are
at their most protected from the sun's rays and/or protected in
identical manner from the sun's rays when the sun's rays are in a
required direction relative to the surface of the solar panel
device, i.e. notably when the projections of the sun's rays in a
plane perpendicular to the axis 5 are perpendicular or
substantially perpendicular to the surface of the solar panel
device. Moreover, the screens are arranged so that the reservoirs
are not protected in the same manner from the sun's rays when the
sun's rays are not in the required direction relative to the
surface of the solar panel device, i.e. notably when the
projections of the sun's rays in a plane perpendicular to the axis
5 are not perpendicular or substantially perpendicular to the
surface of the solar panel device.
[0047] Consequently, when the reservoirs are not protected in the
same manner from the sun's rays, one of the reservoirs is heated
more than the other, for example the first reservoir 6 is heated
more than the second reservoir 8, the consequence of which is an
increase in the fluid pressure in a first chamber 17 of the first
reservoir 6. This increase in pressure constitutes energy that will
be used, as explained hereinafter, in one of the actuators for
orienting the solar panel device so that the latter has an
orientation such that the sun's rays are as perpendicular as
possible to its surface.
[0048] As shown in FIGS. 2 and 4, the means for hydraulically or
pneumatically connecting the reservoirs to the actuators comprise
pipes 21, 22, 23, 24, 25 and 26 and distributor valves 13 and 14.
The pipe 21 connects the first chamber 17 of the first reservoir 6
to the distributor valve 13, the pipe 23 connects the distributor
valve 13 to the first chamber 15 of the actuator 11 and the pipe 25
connects the distributor valve 13 to the second chamber 18 of the
second reservoir 8 via a check valve 27 allowing the fluid to flow
only from the distributor valve to the second chamber of the second
reservoir. Symmetrically, the pipe 22 connects the second chamber
18 of the second reservoir 8 to the distributor valve 14, the pipe
24 connects the distributor valve 14 to the second chamber 16 of
the actuator 12 and the pipe 26 connects the distributor valve 14
to the first chamber 17 of the first reservoir 6 via a check valve
28 allowing the fluid to flow only from the distributor valve to
the first chamber of the first reservoir.
[0049] The first distributor valve 13 is controlled by the fluid
pressure in a third chamber 19 of the first reservoir 6 and is
spring-loaded into a rest position. In the rest position, flow of
the fluid between the first chamber 17 of the first reservoir 6 and
the first chamber 15 of the actuator 11 is prevented and flow of
the fluid between the first chamber 15 of the actuator 11 and the
second chamber 18 of the second reservoir 8 is allowed. When the
first reservoir 6 is subjected to the sun's rays, the fluid
pressure in the third chamber 19 increases and, via a pipe 31,
commands a change of position of the distributor valve 13, the
latter going from its rest position to a second position in which
flow of the fluid between the first chamber 17 of the first
reservoir 6 and the first chamber 15 of the actuator 11 is allowed
and flow of the fluid between the first chamber 15 of the actuator
11 and the second chamber 18 of the second reservoir 8 is
prevented.
[0050] Symmetrically, the second distributor valve 14 is controlled
by the fluid pressure in a fourth chamber 20 of the first reservoir
8 and is spring-loaded into a rest position. In the rest position,
flow of the fluid between the second chamber 18 of the second
reservoir 8 and the second chamber 16 of the actuator 12 is
prevented and flow of the fluid between the second chamber 16 of
the actuator 12 and the first chamber 17 of the first reservoir 6
is allowed. When the second reservoir 8 is subjected to the sun's
rays, the fluid pressure in the fourth chamber 20 increases and,
via a pipe 32, commands a change of position of the distributor
valve 14, the latter going from its rest position to a second
position, represented in FIG. 4, in which flow of the fluid between
the second chamber 18 of the first reservoir 8 and the first
chamber 15 of the actuator 11 is allowed and flow of the fluid
between the first chamber 15 of the actuator 11 and the second
chamber 18 of the second reservoir 8 is prevented.
[0051] An orientation method of one embodiment of the invention is
described hereinafter. This embodiment of the orientation method
corresponds to one embodiment of a method of operating a solar
panel orientation device.
[0052] In these embodiments, the solar panel device is oriented
with respect to the axis 5, in a first direction and in a second
direction, using energy obtained from solar radiation from a first
fluid reservoir or a second fluid reservoir, the two reservoirs
being independent.
[0053] As explained above, when the fourth chamber 20 of the second
reservoir 8 is subjected to the solar radiation (see FIG. 3) the
fluid contained in this fourth chamber is heated and expands, which
leads to an increase in pressure in the chamber 20 and movement of
the distributor valve 14 to its second position shown in FIG. 4.
This enables the fluid contained in the second chamber 18 of the
second reservoir 8 to feed the second chamber 16 of the actuator
12, the fluid in the second chamber 18 being at a pressure higher
than that of the second chamber 16 because, in the second chamber
18, the fluid is heated by the solar radiation and therefore under
pressure. The piston rod of the actuator 12 is therefore deployed,
the solar panel device rotates about the axis 5, and the piston rod
of the actuator 11 is retracted into it. This retraction of the
piston rod 11 is made possible by the compression of the fluid
contained in the chamber 15 of the actuator 11 and, where
applicable, by return of this fluid to the first chamber 18 of the
second reservoir 8 via the distributor valve 13 and the check valve
27. This operation continues until the pressures in the chambers
18, 16 and 15 equalize or until the distributor valve returns to
its rest position.
[0054] Symmetrically, when the third chamber 19 of the first
reservoir 6 is subjected to the solar radiation, the fluid
contained in this third chamber is heated and expands, which leads
to an increase in pressure in the chamber 19 and movement of the
distributor valve 13 to its second position. This enables the fluid
contained in the first chamber 17 of the first reservoir 6 to feed
the first chamber 15 of the actuator 11, the fluid in the first
chamber 17 being at a pressure higher than that of the first
chamber 15 because, in the first chamber 17, the fluid is heated by
the solar radiation and is therefore under pressure. Thus the
piston rod of the actuator 11 is deployed, the solar panel device
rotates about the axis 5 and the piston rod of the actuator 12 is
retracted into it. This retraction of the piston rod of the
actuator 12 is made possible by the compression of the fluid
contained in the chamber 16 of the actuator 12 and, where
applicable, by return of this fluid to the first chamber 17 of the
first reservoir 6 via the distributor valve 14 and the check valve
28. This operation continues until the pressures in the chambers
17, 16 and 15 equalize or until the distributor valve returns to
its rest position.
[0055] In the embodiment described above, the fluid the expansion
of which is used is a gas. There may nevertheless be imagined a
device for orientation of a solar panel device operating in
accordance with the same principle and in which the expansion of a
liquid is used.
[0056] Finally, in the embodiment described, the chambers 19 and 20
are part of the reservoirs 6 and 8. These chambers may nevertheless
be independent of the reservoirs, notably to solve thermal inertia
problems. They are preferably exposed to the solar radiation in
accordance with an exposure logic similar to the logic of exposure
to the solar radiation of the first and second reservoirs.
[0057] In an embodiment that is not shown the single-acting type
piston-and-cylinder actuators 11 and 12 are replaced by a single
double-acting actuator of this type. The double-acting actuator
used is preferably of the through-rod type (i.e. the piston rod of
the actuator passes through the whole of the actuator so that the
area of the piston of the actuator seen from each of the chambers
is the same and so that the piston is immobile if the two chambers
are subjected to the same pressure).
[0058] The articulation axis 5 of the solar panel device and the
axes or centres about which the ends of the actuators 11 and 12 are
articulated to the solar panel device are preferably contained or
substantially contained in the same plane.
[0059] The screens may have reflecting surfaces; they may notably
have a parabolic cross section and be disposed so that the focal
axis of each screen is situated in or in the vicinity of each of
the reservoirs. Thus the sun's rays reaching the internal surface
of the screens are reflected toward the reservoirs.
[0060] The invention concerns a solar energy conversion device
comprising an orientation device and a solar panel device. It
concerns in particular a solar energy conversion device comprising
a first orientation device and a second orientation device, the
first and second orientation devices being adapted to orient the
solar panel device with respect to two non-parallel axes, and
preferably to orient the solar panel device with respect to two
orthogonal or substantially orthogonal axes. A first axis may
enable daily orientation while a second axis may enable seasonal
orientation.
[0061] The orientation device of the invention enables the problems
of the devices known in the prior art to be solved. In particular,
it enables good retention of the solar panel device to be assured
even in the event of wind. A prototype that has been constructed
and enabling orientation of the solar panel device with a pressure
of three bar resists winds of 70 km/h.
[0062] The responsiveness of the orientation device may be defined
in terms of various construction parameters, notably the nature of
the fluid used.
[0063] The orientation device enables a rapid return to an ideal
position after a cloudy period or at the start of the day. For
example, in the case of the prototype that has been constructed, 7
minutes are required to return to the ideal position after a cloudy
period of 2 hours duration.
[0064] In contrast to the device described in the document US
2005/284 467, a cloudy period does not lead to modification of the
orientation of the solar panel device.
[0065] In the present document the two reservoirs are referred to
as independent. By "independent" is meant that the two reservoirs
may be subjected to different pressures.
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