Note: Descriptions are shown in the official language in which they were submitted.
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SUN-TRACKING SOLAR-COLLECTOR PANEL
SPECIFICATION
Field of the Invention
The present invention relates to a solar collector
panel. More particularly this invention concerns such a panel
which is set up to track the sun.
Backaround of the Invention
A standard solar panel comprises a pair of manifold
pipes extending longitudinally parallel to each other and a pla-
nar array of smaller-diameter collector tubes extending parallel
to each other between the tubes. The collector tubes lie on or
are imbedded in a planar light-absorbing panel so that all heat
radiation impinging on the panel is conducted by the panel to the
collector tubes and is there conducted to liquid flowing from one
of the manifold pipes to the other manifold pipe through these
tubes.
Clearly the panel should be perpendicular to the incom-
ing solar radiation to maximize energy collection. Thus it has
been suggested in US patents 4,542,737 and 4,632,091 to mount the
entire device so that it can pivot about at least one axis.
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Means is provided for trac~.ing the sun and operating the servomo-
tors that keep the panel aimed just right.
Clearly such an arrangement is fairly complex and in
fact uses up so much energy as to be of dubious efficiency. Even
if the panel is counterbalanced to pivot about a single axis,
moving the considerable mass of the structure is not a simple
task.
Objects of the Invention
It is therefore an object of the present invention to
provide an improved sun-tracking solar collector panel.
Another object is the provision of such an improved
sun-tracking solar collector panel which overcomes the above-
given disadvantages, that is which is of relatively simple con-
struction and where the energy needed to move it to traek the sun
is minimal.
Summary of the Invention
A sun-tracking solar collector has according to the
invention a stationary support, a pair of parallel, spaced, and
longitudinally extending manifold pipes, an array of parallel,
spaced, and transversely extending collector tubes hetween the
pipes ~nd each having one end at one of the pipes and another end
at the other pipe, and respective swivel joints conneeting each
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tube end to the respective pipe while permitting each tube to
pivot relative to the pipes about a respective transverse axis.
Respective generally planar subpanels are each mounted on and ex-
tend radially from a respective one of the collector tubes. A
heat-exchange liquid is fed to one of the pipes, then through the
tubes, and to the other pipe. A drive can rotate the collector
tubes about the respective transverse axes to maintain the sub-
panels generally perpendicular to incoming heat radiation.
Thus with this system it is not necessary to displace
the entire assembly. Instead the individual collector tubes are
pivoted to track the sun. Since the pressure inside the system
is normally very low, the swivel joints need not be so tight that
they make it difficult to rotate the collector tubes.
In accordance with the invention the drive includes a
respective wheel fixed on each collector tube and a flexible
drive element engaged over and coupled to the wheels so that the
drive element can be advanced to synchronously rotate the wheels
and thereby synchronously pivot the collector tubes. The stan-
dard prior-art sun-tracking system and drive motor is connected
to this drive belt or chain.
According to a further feature of the invention each
manifold pipe is provided at each respective tube end with a
respective transversely projecting tubular nipple projecting
along the respective transverse axis into the respective tube
end. Respective springs are braced transversely between each
manifold pipe and the tube ends to maintain the tubes centered.
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In addition each tube is provided at each nipple with an end cap
traversed by the respective nipple and provided internally with a
seal ring radially engaging the respective nipple. The drive
whee] on one of the ends of each of the collector tubes is
clamped axially between the respective tube end and the respec-
tive end cap.
The subpanels of this invention are radially extending
vanes integrally formed on the respective collector tubes. Each
subpanel has a back surface provided with a layer of insulating
material and the tubes are pivotal through about 180 between an
end collecting position with all the back surfaces turned upward
and shielding the respective collector tubes, and an opposite end
position with the back surfaces directed downward. This makes it
possible to close up the collector to prevent it from overheating
during the day or to conserve heat during the night or cloudy
times.
To make the system as big as possible each tube is
formed by a pair of tube sections joined together by a splice
sleeve. The housing has a longitudinally extending intermediate
partition wall in which the splice sleeves are journaled. This
makes it fairly easy for the collector tubes to be very long.
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Brief Description of the Drawina
The above and other objects, features, and advantages
will become more readily apparent from the following, reference
being made to the accompanying drawing in which:
Fig. l is a partly diagrammatic and sectional perspec-
tiye view of the solar collector according to the invention;
Figs. 2, 3, and 4 are sectional views of details of the
collector; and
Figs. 5 and 6 are sectional detail views illustrating
two end positions of the individual collector tubes and their
subpanels in accordance with this invention.
Specific Descri~tion
As seen in Fig. 1 a solar collector according to this
invention basically comprises a fixed housing 1 provided along
its longitudinal edges with large-diameter manifold pipes 2 and 3
connected to a conventicnal pump 10 for pumping a heat-exchange
fluid into the pipe 2 and withdrawing it from the pipe 3 in the
manner well known in the art. Bridging the pipes 2 and 3 and
passing through partition walls 6 of the housing 1 are small-
diameter collector tubes 4 that allow the liquid from the pump 10
to flow betwPen the pipes 2 and 3. The floor of the housing 1 is
formed by an insulating board 7 and the top i5 covered by a
transparent panel 11.
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As better seen in Figs. 2 and 3 each rod 2 and 3 is
provided at each tube 4 with a perpendicularly extending connec-
tor nipple or tube section 40 that extends along the respective
tube axis 4A into each tube 4. The nipples 40 are of a diameter
that is much smaller than the diameter of the tubes 4. Each tube
4 is provided at each end ~ith a liner sleeve 41 fi~ed in place,
sealed by O-rings 42, and spacedly internally surrounding the
respective feed nipple 40. The outer end of each liner sleeve 41
is threaded and carries an internally threaded cap 43 that holds
an 0-ring 44 snugly surrounding the respective feed nipple 40 and
that also clamps a sprocket 8 to an end face of a flange 46
formed on the liner sleeve 41. A compression spring 45 surround-
ing the nipple 40 presses the respective tube 4 axially of its
axis 4A away from the respective manifold tube 2 or 3. No
sprocket 8 is provided adjacent the manifold pipe 3, instead a
washer 47 takes its place.
Each tube 4 is actually formed of two tube sections
fitted as shown in Fig. 4 into the end of sleeve 4~ that is jour-
naled in the intermediate or center partition 5 of the housing 1.
Thus it is possible to make the collector of virtually any trans-
verse dimension.
In addition as best shown in Figs. 5 and 6 each tube 4
is integrally formed with two diametrically opposite vanes 5
~orming a respective collector subpanel. These vanes 5 are uni-
tarily formed of the same conductive material, normally a metal,as the respective tubes 4 so that sunlight striking them gener-
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ates heat that is conducted to the tubes 4 and thence to the
; liquid pumped through them. The undersides of the tubes 4 andtheir collector vanes 5 are covered by a layer 51 of an insulat-
ing material to minimize heat loss from the back of the collec-
tor.
A drive such as described in the abov~-cited US patents
has a chain 9 spanned over all the sproc~ets 8 and serves to
rotate the individual tubes 4 and their collector vanes 5 aimed
at the sun for best heat-collection efficiency. In addition the
tubes 4 can be rotated a half revolution as illustrated in Fig. 6
so that the insulating sides 51 are turned up and the tubes 4 are
enclosed in a space bounded on the one side by the insulating
floor 7 and on the other side by the longitudinally abutting
insulating layers 51. This Fig. 6 position is useful to prevent
the collector from overheating and to conserve heat when the sun
is not out.
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