Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BAC~CGROUND OF TE~E INVENTION
This in~ention relates generally to a system to convert
solar energy to thermal energy for heating purposes and more
particularly to an improved solar heating panel.
In the past, a variety of solar collectors have been
constructed to conduct a thermal transfer fluid. A common type
is ormed of black plastic which converts solar energy to thermal
energy at its outer surface and the heat is then transferred
through the plastic to the thermal carrier, which is usualIy
1~ water. This structure has the disadvantage that there is con-
siderable heat loss to outside air due to the insulation pro-
perties of the plastic, thereby resulting in very ineicient
heat trans~er.
More recently, a more sophisticated and expensive
system has been provided using a transparent~ planar front
surface, usually formed of glass. In this system, incoming
radiation passes through the glass to strike a black fluid carry-
ing tube system where it is converted to thermal energy and carried
away by the circulating ~luid. This system has improved efficiency-,
but it is more expensive to construct and maintain, particularly
if it is to be attached to a household or house trailer pressure
system. This system has the disadvantage that the transparent
surface becomes increasingly reflective of incident radiation as
the angle of incidence departs from normal to the surface o the
solar panel. This results in lowered eficiency and has led
to costly efforts to have the collector located so that its
surface is at right angles to incoming solar energy. In
view of the fact that the position o the sun is constantly
- changing relative to a point on earth, such efforts are of
marginal value
6UMMARY OF THE INVENTION
Accordingly, it is an object of the present invention
to at least partially overcome these disadvantages by providing
an improved solar heating panel which receives the solar energy
through a transparent front side which is uneven shaped, such as
semitu~ular or dome shaped.
A solar heating panel having a flow channel through
which a fluid flows to be heated by solar energy comprising: -
(a) a first dark opaque shset, and (b3 a second transparent sheet
facing the sun, the second sheet being shaped to form a plùrality
of interconnected adjacent protruding transparent portions, the
first and second sheets being joined together to define the
fluid flow channel therebetween which extends through hollow
areas formed between the protruding portions of the second
sheet and the first sheet, the protruding portions being shaped
to reflect a portion of the incident energy from the sun to the
adjacent portions.
A solar heating panel having a flow channel through
which a liquid flows to be heated by solar energy, the panel
havi~g a flat dark opaque surface with a transparent plastic
film secured thereto, the film being shaped to form a series
of outwardly projecting interconnected domes, the dark surface
and the transparent film thereby defining a continuous liquid
flow channel connecting a liquid inlet and a liquid outlet,
the panel being oriented whereby the sun's rays will pass through
the transparent film and the liquid to strike the opaque surface.
With this structure, the loss of energy through
reflection is minimized in that radiation striking the transparent
; side or film will be partially transmitted by refraction towards
the black opaque surface or side and will be partially reflected.
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1 In most cases, the reflected portion of the energy will strikeanother portion of the transparent film wherein some of it will
be converted to thermal energy. This action may be repeated :
several times with each angle o~ incidence varying until a
considerable portion of the solar energy is converted to thermal
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1 energy in the carrier fluid. Thus, the loss of efficiency as the
sun assumes different positions in the sky as the days and
se~sons pass is minimized. Furthermore, this structure reduces
loss due to reradiation of energy from the solar panel. This
structure provides for conversion of radiant solar energ~ to
thermal energy at the surface of the opaque side which is in
contact with the carrier fluid. This, combined with the in-
creased efficiency due to reduced reflection losses enables
smaller, less costly panels to be used and eliminates the costly
attempts to arrange the panels to intercept the solar energy at
right angles.
Furthermore, because of the relief factor of the
present structure, when the sun is not at right angles to the
panel, energy will be captured along the edges of the panel which
would not otherwise strike the panel.
Further objects and advantages of the invention will
- appear from the following description taken together with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a solar panel accord-
ing to a first embodiment of the invention;
Figure 2 is a sectional view taken along line II-II in
Figure l;
Figure 3 shows a portion of the sectional view seen in
Figure 2;
Figure 4 is a perspective view of a solar panel accord-
ing to a second embodiment of the invention; and
Figure 5 (located on page with Figures 1-3) is a
; 3~ sectional view taken along line V-V in Figure 4.
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DESCRIPTION OF THE PRE:FERRED EMBODIMENTS
Reference is first made to Figures 1 to 3 which show the
first embodiment of a solar panel 10 formed by an upper trans-
parent side or film 12 secured to a lower dark opaque side 14. The
lower side 14 is a flat rectangular sheet, while the upper side 12
is molded of plastic to form series of interconnected domes 16.
As may be seen, adjacent domes 16 intersect each other at necks
26, while the end domes of adjacent rows are interconnected by
arch portions 18, and a fluid inlet ~0 and a fluid outlet 22 are
1o provided to form a continuous fluid channel 24 between the upper
and lower sides. The lower side 14 is normally black and the
upper transparent side 12 is cemented to it to prevent leakage
of the fluid.
In use, the fluid inlet 20 and fluid outlet 22 are
connected to a source of thermal fluid, usually water, which cir-
culates through the solar panel 10 to transfer heat as required.
Referring in more detail to Figure 3, an incoming ray of solar
radiation 28 strikes the surface of one of the domes 16 and a
portion of it is refracted to strike the black lower side 14 where
20 it is converted to thermal energy and transferred to the circula-
ting fluid ~ A portion of the solar radiation will be reflected
at 30 to strike an adjacent dome, where a portion of it in turn
will be transmitted to the thermal conversion side 1~ and another
portion reflected back to the first dome. Thus, the shape of the
upper transparent side 12 provides a significant increase in the
efficiency of absorption of solar energy over the previously known
planar surface.
Figures 4 and 5 illustrate a second embodiment of the
invention, and as many of the features are identical to those of
30 the first embodiment, features common to both embodiments are
described and illustrated using the same reference numerals. In
this second embodiment, the solar panel 10 is similarly formed
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1 of a transparent side or film 12 secured to a lower dark opaque
side 14. However, in this embodiment, the upper side 12 is
shaped to form a series of semitubular portions 32. As may be
seen, these semitubular portions 32 are interconnected at alter-
na-te ends by arch portions 18 and are provided with a fluid
inlet 20 and a fluid outlet 22 to also form a continuous fluid
channel 24. It will be appreciated that ~his embodiment also
provides considerably improved energy conversion efficiency over
a solar panel with a flat planar front surface for solar radiation
with a low angle of incidence in that some o~ the solar energy
re~lected from one semitubular portion 32 will be received by an
adjacent semitubular portion~ The importance of this will be
appreciated when it is considered the small percentage of time
that the sun is located perpendicular to the plane of the solar
panel. Operation of this second embodiment is similar to that
of the first embodiment and its description need not be repeated.
Although the description of this invention has been
given with respect to particular embodiments, it is not to be
con~trued in a limiting sense. Many variations and modifications
will now occur to those skilled in the art. For instance, the
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; domes might be formed to have polygonal or elliptical bases.
Alternatively r the domes might be replaced by pyramids or the
semitubular portions ~ be of another modified tubular shape.
As well, the opaque side 14 could be provided with fluid channels
on both the front and rear. Thus, in the higher latitudes
advantage might be gained from the act that the sun rises north
of east and sets north of west in the summer months. Further-
more, although the solar panel is preferably formed of plastic,
other materials such as glass and metals might be combined.
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