Note: Descriptions are shown in the official language in which they were submitted.
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LIGHT ~ALL PANELS FOR CONTROL OF THE TRANSMISSIO~
THERETHROUGH OF INCIDENT LIGHT ENERGY
The invention pertains to improvements in wall panels
able to control the transmission therethrough of incident light
energy in accordance with its angle of incidence thereon,
particularly solar radiation. The panels of the invention
provide control of their heat-flow-through resistance while also
providing a visual barrier.
lt is known how to design light wall panels with high
heat-flow-through resistance and opaqueness. For example,
opacity to vision can be produced by tinting, but this results
in an opaqueness in regard to all forms of solar energy, which
is not always desired. An increase in the heat-flow-through
resistance can be achieved by a multi-layer panel construction
and/or through reinforcement by use of specific insulating
material, i.e. air layers. Increase of the thickness of the
air~layer is effective as an insulating measure only up to a
cer~ain limiting value. Multi-layer panels can produce the
required opacity but an increased energy absorption or
reflection takes place because of the multiple layers, so that
the amount of solar energy transmitted is reduced.
In accordance with the present invention there is
provided a panel providing for the control of the transmission
therethrough of incident light energy in accordance with the
angle of incidence of the light energy thereon comprising two
spaced light transmitting sheets constituting respectively a ray
penetrating panel outer side and a ray emerging panel inner side
and between which sheets are disposed a plurality of pairs of
light impervious elements arranged parallel and spaced from one
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another, wherein adjacent elements of successive pairs of light
impervious elements form between themselves an ingoinq
irradiation cross~section which is a section in which the light
enters a hollow section between the two spaced sheets and an
outgoing emission cross-section which is a section in which
liqht exits from this hollow section.
characterised in that the upper side of a first li~ht
impervious element of a pair thereof is reflective and forms
with the underside of a second liqht impervious element of the
pair, which underside is also reflective, a liqht enerqy
concentration cross-section space which is a section in which
the light energy rays are concentrated disposed between the said
ingoing irradiation and outgoinq emission cross-section, and
that the contour of the said upper side of the said first
element of a pair differs in curvature from that of the said
underside of the said second element of a pair so that an energy
irradiation density substantially independent of the light
incident angle is obtained.
Panels of the invention are able to provide integrated
sun protection and increased heat-flow-through resistance while
providing a visual barrier in such a manner, that, by arangement
of the panels in coordination with the heating demands of a
building, solar heatina of the building takes place in the
winter by solar energy transmitted through the light wall
panels, while shading and conse~uent cooling of the building
occurs in the summer by the same panels.
In the panels of the invention the said liqht
impervious elements may constitute reflector systems of
reflecting-profile-strip-type installed within the space between
the spaced liqht transmitting sheets.
rrhese reflector systems accomplish the followinq;
l. Due to design of the reflecting surfaces, the amount of
penetrating rays of solar energy can be controlled, based on the
elevation angle of the sun.
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2. The reflecting surfaces represent a visual protection
towards the inner space of the panel.
3. Due to the reflecting surfaces, a concentration effect
can be achieved at particular locations within the panel through
which it is possible to provide the light wall panel with a heat
insulation factor in predetermined relation to its concentration
factor.
In acldition the light wall panels represent the
following advantages when functioning as reflector systems:
lo The reflectors may be disposed in an insulated air
space. Therefore, firstly contamination and secondly static
load of the reflectors by wind forces are both prevented. This
allows a very simple design of reflectors.
2. The wall or flange surfaces of the panels represent a
simple possibility for fastening the reflectors over their
entire length. This permits a very precise and inexpensive
positioning of the reflectors as e.g. through laying-on or
gluing.
3. The reflector profile strips are themselves a very
rigid construction element, through which, by statically
effective gluing to the wall surfaces, less material is used and
a high degree of rigidity of the panels can be achieved.
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The integration of reflectors into the light wall panel
cal~ses a very small scale development of the reflecting
surfaces. Ihis requires a multitude of reflecting strips which
must be properly hung and adjusted. The inven-tion thereore
provides for the development of several reflecting surfaces in
-the form of a profile strip~ This design is of special
importance with respect to the manwfacturing process. The
reflector profile strips are manufactured from reflecting thin
strip, in a forming machine with a high production speed, and
installed in the light wall panel, so that on location only a
horizontal adjustment is required. Individual positioning of
the reflecting surfaces can be omitted. A significant advantage
of the invention idea follows from this designing- and
manufacturing process, that is in installing reflector systems
in a light wall panel for the recovery of solar energy. Until
today, to my knowledge concentration systems on front walls have
not been utilized, because no industrialized process had been
found for the development and hanging of the reflectors. A
further advantage of the design for concentration systems
according to the invention lies in the adjusting capabilities,
whereby the light panels are especially suitable as sidingS and
whereby the wall cross section can temporarily serve as a heat
accumulator and heat-supplier for the inner space.
As is especially apparent in the example of a
"Trombe-wall", the ligh~ wall panel in accordance with the
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invention, can serve as an insulating system for an inner space
~in this case the space between the panel and a heat-storing
wall) with controlled opaqueness toward solar energy. The solar
energy is transmitted behind the panel via the reElectin~
surfaces, so that it receives heat from outer space, however, no
heat is given off to the same. The light wall panels can thus
represent a type of energy trap.
Especially in the case of the Trombe-wall, the ability
of the panels to function as a visual barrier must be
emphasised. To achieve good energy absorption on the wall
behind the panel, which is designed as a collector, the same
must be painted black. However, it is desirable for esthetic
reasons regarding a building front to achieve a bright and
friendly front and to hide the black wall surface. This occurs
with a panel of the invention via the reflector system. The
reflector also allows a colouring of the wall, which is achieved
by means of a transparent color lining.
The improved heat protection by ~he light wall panels
is effected through the reflector profile strips, by which
either several insulated hollow spaces are formed, or a
heat-insulation is placed in the panel-cross section by means of
foamed insertions.
Specific embodiments of the invention are explained in
connection with the accompanying diagramma-tic drawings, wherein:
FIG. 1 is a longitudinal cross-section through a plate
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which is a first embodiment showing a lay-out of reElector
profile strips in the hollow chambers formed therein;
FIG. 2 is a similar section through a second embodiment
including a concentration systern on the ray-penetrating side of
the plate as well as a dif~user system on the inner side of the
plate space and central hanging of the profile strips, allowing
penetration o rays through the plate.
FIG. 3 is a similar section through a third embodiment
having reflector profile strips with integrated collector part
and showing hanging of the reflectors on the panel wall surface
via adhesive;
FIG. 4 shows a light wall panel which is a fourth
embodimerlt with integrated collector parts on the inner side of
the panel space, in front of a collector/accumulator on the
outer wall;
FIG. 5 illustrates a light wall panel as a flat
collector cover wi~h a design of reflector proEile strips
providing ~ concentration systemO
FIG. 5.1 is a section similar to Fig. 5 but with
insulation provided between the shading-zone of the collector
cover and the absorbing plate;
FIG. 6 illustrates the use o~ light wall panels as
roofing over a collector/accu~ulator cover with parabola-like
re~lecting surfaces over the ray-penetrating cross-section and
several layers on the inner side of the space, which allows rays
to penetrate through the panel;
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FIG. 7 is a functional diagram of the dependence of the
concentration factor of the plates upon the angle of incidence
of the pentrating rays;
FIG~ 8 illustrates a concentration system with a
reflecting surface, consisting of several parabola-like portions
with offset focal points as well as variously tilted parabola
axes, so as to achieve several staqgered peak values for the
density of penetrating rays within the cross-sectional
concentration;
FIG. 9 is a functional diagram similar to Fig. 7 of the
concentration device according to Fig. 8; and
FIG. 10 is a functional diagram as in Fig. 9, showinq
the seasonal dependence of the density for pentrating rays.
Fiqure 1 shows the cross section through a first
embodiment which is a double-flange plate 10 with spaced
light-transmitting wall surfaces 11 and 12 and flanqe surfaces
13. In the resulting hollow ch3mbers 14 rel~ctor profile strips
15 are positioned, each providing at its underside and
uppersides respective liqht impervious reflecting elements 19
and 19', the underside element 19 of the strip facing the
upperside element lg' of the immediately adjacent strip, so that
each pair of elements form a light ener~y concentration
cross-section space in which the li~ht energy rays are
concentrated bounded by respective in~oing and outgoing
cross-sections in which the light rays enter the hollow chamber
and exists from the chamber at the respective light transmitting
walls 12 and are directed by means of reflection from the
reflector profile
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strips or directly through the flange plate 13, and the rear
wall surface 11 (located towards the inner space) onto an
absorbing outer wall 16, changed to heat by the absorption and
stored in the material of the outer wall. The rear of inner
space wall 11 is lined with a heat reflecting foil 17 in the
areas thereof covered by the reflector profile strips 15, so
that the energy incident thereon is also reflected back towards
the wall 16.
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The following functional advantages of the light wall
panels, according to the invention are explained, in connection
with th;s embodirnent as follows:
Based on the concentration factor of the reflector
sys~em constituted by the strips 15 only approximately 1/3 of
~he inner space wall ll allows light to penetrate, and
approximately 2/3 is designed as a heat reflector, while the
wall 12, located towards the outer space, absorbs the radiated
energy over its entire area. The panel thus serves primarily as
an insulation for the radiant heat radiated from the outer wall
accumulator 16, but also exhibits a specific opaqueness for
light rays incident thereon, so that the solar energy obtained
from the outside is transmitted behind the panel and can be
stored there. The insulating capability of the panel-cross
sec~ion is significantly improved by the reflector profile s~rip
and flange structures, whereby additional hollow spaces are
producedO It is especially advantageous to design the reflector
profile strips so that they reflect on bo~h sides in order to
increase the heat-flow-through resistance. More specifically
each strip comprises a parabolic arched, diagonally arranged
reflec~ing surface 19, by which a solid mechanical reinforcement
of the double-flange-plate 10 occurs. The strips also
include ~e additional reflecting surface 19'. Additional
rigidity can be provided by means of s~ructure foam in the
profile chamber 13 be~ween the surfaces 15 and 19'.
(
The absorbing surface 16 is not visible from the outer
space because of the visual barrier of the reflector profile
strips 15. The entire front of the panel appears to be
reflecting, but without a glaring e~fect.
It will be seen that each strip lS comprises a
reflecting upper side provided by the surface 19' and a
reflecting lower sids provided by the surface 19, with each
upper side of an element facing the lower side of the first
neighbouring element and the lower side of the same element
facing the upper side of the second neighbouring elemsnt, except
of course at the two ends of the panel. A specific shape for
the reflecting sides is illustrated consisting of the parabolic
surface 19 and a sloping flat surface portion followed by a
concave curved surface portion for ~he surface 19'.
In ~igure 2 a triple layer light wall panel 20 is
shown, whereby re1ector/diffuser profile strips 27 are hung on
a central panel member 23, which allows rays to penetrate
between inner and outer layers 23 and 24. This type of lay-out
and hanging method has the advantage that in this manner no
thermal bridge exists between the outer and inner layers 24 and
25. The inner
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layer 23 is provided with hangers 26 on which the reflector
strips 27 are hung.
The reflector profile strips are designed with two
protrusions on either side of the central member 23 to form a
concentration system 21 and a diffuser system 22. ~ach diffuser
strip 27 is designed in such way, that the rays falling on to
the diffuser system are diffused in -to the inner space. When
utilizing the light wall panel as a window, this enables a
uniform and glare free light-penetration. When using it as a
collector cover, for example for a Trombé-Wall, a uniform energy
distribution onto the collec-tor surface of the Trombé Wall is
achieved throughout the diffuser system, so that a heat
accumula~ion in the area of concentrated energy irradiation is
avoided. The radiation is incident on the reflecting surface
28, which is concave with a center 29, passes through the cross
sectional concentration area 30 and is reflected onto the
diffuser 27. At the same time, the diffuser 27 represents a
heat reflec~or for the layer 25, which allows rays to penetrate
and be converted to thermal energy by the collector surface
behind. A further advantage of the diffuser system lies in the
conditions for penetrating rays. At the layer 25 a certain
reflecting loss occurs by rays which are reflected back onto the
diffuser 27. Due to ~he conical shape of the space between
layer 25 and diffuser 27 the reflecting portion is subject to
multiple reflection as illustrated at 31, so that reflecting
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loss is minimised. This also makes it possible to design the
absorbing surface as a light collector when using the panels,
which also means designing the panels as non-absorbent, due to
the fact that the reflected rays are returned back to the
collector via the diffuser. Because the emission coefficient is
equal to the absorption coefficient, with the help of a diffuser
which is designed accordingly, the emission of a collector
surface can be reduced through decreasing of the absorption
capability at equal or higher tota] absorption coefficients.
According to the invention, this ~akes the light wall panel also
suitable as a collec-tor cover for flat collectors which tend to
be reflective.
The development of ~he diffuser system also allows a
multiple glass enclosure of the inner-space-side, without the
occurrence of a loss by absorption of energy following
reflection. Furthermore, it is possible to install a heat
reflector 32 on the inner-space-side of the layer 2S. Such heat
reflectors are produced for example by metallic vaporization on
to a suppor~ing substrate and generally possess a reflecting
capability for visible rays. As to mul-tiple reflection by the
diffuser 27, the reflected portion of the rays is led back, so
that in spite of the reflecting effect a loss by absorption is
avoided. The diffuser system therefor permits a high level of
effectiveness regarding energy recovery and thermal energy
storage, the embodiment of ~igure 2, as mentioned above~
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being especially suitable as a front element for a Trombé-wall.
In the embodiment of Figure 3 an energy receiver 34 is
integrated into the reflecting system on the ray-penetrating
side, which receives a constant density of energy absorption,
essentially independent from the seasonal variation in the angle
of eievation of the sun.
The receiver 34 is penetrated by rays on one side
received from a reflector surface consisting of two surface
portions 36 and 37. The surface portion 36 extends from an end
point 38 to an end point 39 and is calcula~ed from the maximum
irradiation angle B max., this angle being that of the radiation
which is just tangential to the outer cross section of the pipe
constituting the receiver 340 The end poin~ 39 results from the
incidence on the surface 36 of a shading line 40 which is
tangential to the absorbing pipe 34 at the maximum irradiation
angle B max. The reflecting surface 37 extends from the end
point 39 to the absorbing pipe 34 as an involute of the
absorbing pipe~
The absorber pipe 34 is installed in such a manner3
that the reflection 41 of a beam 42 forms a tangent on the
absorber pipe at a minimum irradiation angle B min. taken rom
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the end point 43 on the reverse side 44 of the deflecting
surface 45. The tangent ray 41 is calculated from the angle
~1 ~ a2 of the radiation to the radius 46 o~ the deflection
surface 45. In case of ano~her receiver-form for the surface
45, e.g. a level surface, a corresponding construction is
utilized, whereby the reflections hit the outer end point of the
receiving surface at a maximum and respectively a minimum
irradiation angle~
The receiver in this embodiment is an absorber pipe
through which a heat ~ransfer medium may flow; that is used for
example to heat utility wa~er. AlternatiYely the receiver may
consist of photo cells 52, which, as shown in the upper
representation 47, are placed in a glass tube through which the
fluid may flow.
In this embodiment an additional alternatiYe for the
mounting of the reflector profile strips 33 is shown. They are
adhesively secured ~o the outer and inner wall panels 50 and 51
with insulating strips 48 and 49 respectively which have
adhesive on both sides~ The insulating strips are produced of
foamed material, so that firstly they have the capability to
prevent a thermal flow from the inner to the ou~er spaee, and
secondly they possess a sufficient inner expension capability to
absorb different temperature expansions of the materials of the
panels.
Fig. 4 shows a further embodiment of the inven~ion
utilizing two differently working collector types~ In
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this embodiment the radiation is incident or is reElected from a
single parabolic arched concentration reflector 55 into the
cross-sectional space 56, is reflected ~rorn a radial deflecting
surface 57 on to the inner-space side, and either guided
directly or via reflection at a diEfuser 61 through an opening
59 onto the collector s-torage surface 62, or through an opening
60 into a collector 63.
In the winter the energy distribution that occurs over
the openings 59 ano 6C, at the corresponding lo~ irradiation
angle ~ means that the outer wall collector 62 is in use, as
well as the collector 63, while toward the summer7 with
increased irradiation angle the portion incident on the outer
~all collector 62 decreases, and the larger portion of the
energy is guided onto the collector 63. This difference in
radiation distribution in accordance with the irradiation angle
~ is represented in the example by means of the rays 64, 65.
With this collector design also, an automatic effect is
achieved, which allows an almost constant energy-density in
collector 63 throughout the year, and a continuously decreasing
energy density in the case of increasing irradiation angle on
the outer wall. The collector 63 is designed as a concentrating
collector with a round absorbing pipe 65.
This type of embo~iment having two collector types
functioning in dependency to each other brings special
thermo-dynamic ~dvantages as ~ell as production-technical
advantages.
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Thus, the penetrating collector system 63 is installed
on the warm inner-space side of the panel. The irradiation of
energy into the collector 63 occurs from below so that the heat
losses of the absorber are accumulated in the collector and
cannot escape. This leads to a stabilization of the surrounding
temperature for the absorber 65, whereby the heat loss can be
reduced.
A concentration reflector 66 at the rear side of the
collector 65 at the same time serves as a heat reflector for the
outer wall absorbing surface 62. ~urthermore, due to the
concentration reflector 66, convective flow in the inner space
67 between panel and outer wall absorbing surface 62 is
prevented.
The location of the penetrating collector 63 on the
inner space side, among other things, represents a significant
simplification in regard to manufac-turing specifications. The
light wall panel along with the reflector profile strips 68 and
the sheets 69 and 70 can be manufactured with a lock on the
reverse side of the insulating glass enclosing elements. Now on
the reverse side, the absorbers 65 are positioned and reflector
strips 66 are glued on, whereby the gluing locations 71 and 72
of the reflector profile strips coincide. Due to the foamed
adhesive strips 73 and 74, the thermal energy, which is absorbed
by ~he sheet 70 in the ray-penetrating area 59, 60 is insulated
from the stripsO
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The location of the collectors 63 on the reverse side
of the panel, has a special advantage even with respect to front
wall moun~ing. Thus, the panel can be installed by a supporting
cross bar system without it being penetrated by the absorbing
pipe. The absorbers 6S can be connected to vertical forward and
return pipes in a grate shape, without causing contact with a
supporting carrying crossbar system. This also is a
simplification of an insulation thermal problern~
The term "light wall panel" does not necessarily refer
to a vertical layout. The panels can, for example, be installed
sloped as a roofing for a greenhouse or as coverage for flat
collectors, as mentioned before.
Fig. 5 shows an embodiment of the light wall panels
according to the inven~ion operable as a collector cover. The
reflector profile strips 80 are again designed as a
concentration system
aS a supplement to the inYention there is now described ~ new
design of the reflector system behind cross sectional
concentration area 81. The reflector element 82 is elongated
beyond the end point 83 by an integral portion 84. This section
84 extends to the end point 85 which is located on a curve 86
around the ocal point 87 of the element 82. However the
section 84 at i~s maximum extends to an end point 88, which is
positioned at the intersection of two curves 86~ 89 around the
side wall end point 83, 87 in the said
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cross sectional concentration area 81. The end point 85 forms
the outer extremity for a curved deflecting surface 90, through
which the radiation is directed onto the absorbing surface 91.
The elongation portion 8~ enables the positioning of
the openings cross section 93 through the rear panel at a
speciflc distance from cross sectional concentration 81, so that
firstly a heat heat reflection is avoided in the irradiation
funnel and secondly, due to the curved deflecting surface 90, a
cage is formed over the irradiation opening 93, whereby ~7arm air
can accumulate without 10wing directly into the irradiation
funnel 94 and becoming cool on the outer sheet 95.
The inner sheet 92 is provided with a heat reflecting
lining 96 in the shaded zone. From the relationship of the
irradiation opening to the shade-zone, which results from the
concentration factor, it can be observed that the panel allows a
very good effectiveness level for energy recovery since the
larger portion of the absorbing surface is covered by a heat
reflector. In the structure of Fig. 5.1 the absorbing surface
is designed to be as big as the cross sectional concentration.
This corresponds with the design of conventional concentration
collectors. However, it appears to be more advantageous to
design the absorber surface to be as big as the panel itself,
and to position the same at a distance from the absorber
surface. Due to this the non-absorbed portion of radiation is
reflected onto the heat reflector 96 and again directed back
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onto the absorber surface. Furthermore, due to the energy
distribution a localized overheating of the absorber below the
panel is prevented in the irradiation area and thus also the
heat radiation of the absorber, this energy diffusion being
improved by a diffuser as mentioned previously. I the
collector is being operated with extremely high temperature, it
is economical to direct the radiation energy via additional
deflecting surfaces below ~he shade zone 92 onto an absorber;
the deflecting suraces are either part of the reflector profile
strips 80 or are fastened on the inner space side~
Fig. 6 shows another embodiment o the light wall
panels o~ the invention as a collector cover installed in a
sloped fashion. Here again a concentration syste~
i5 utilized. With the
structure of Figure 5 a diffuser 101 is used behind cross
sectional concentration area 100, which is designed in such a
way, tha~ each ray 102 reflected from the surface 101, is
reflected back ~o i~ at least onceO This requirement is
fulfilled when the difuser 101 forms a parabola with ~he focal
point F in the end point o the oppositely located side wall
surface 103. Between collector cover and absorber surface 104
several oils lOS and 106 are placed as a heat protection
measureO The radiation portion indicated by rays 107 and 108
reflected by ~hese foils is re1ec~ed back either on ~he
diffuser or on the reflec~ing under-side 10~ of the collector
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cover to the diffuser. Here the absorber is a collector-storage
of a ceiling construction 110, above which the light wall panel
is positioned as roofing, and can be compared in function with
the siding panels of Pigs. 1-4, in reference to its capability
of guiding the solar energy which falls at a low irradiation
angle to the absorber surface in the winter, and in the summer
at a larger angle, and to shade the absorber surface~ and thus
keep it cool. This capability is shown in the dia8ram of Fig~ 7.
The irradiation data shown corresponds to the solar
azimuth angle at the 50~h degree of latitude at 12:00 o'clock
mid~day. The curve 111 represents the ma~hematical
concentration factor in coordina~ion with the irradiation
angle. The deviation of the curve in the area 112 is caused by
a continuously increasing radiation portion which is reflected
from the side wall sectio~ 113 between the end poin~s 114 and
llS out of the irradiation opening. Due to the elongated side
wall part 113 an especially high concentration factor is reached
during the coldest time of the year at a low irradiation angle.
The radia~ion reflected out of the irradiation opening falls in
a very low angle onto the outer sheet 116. Wikh this low
radiation angle the reflection portion is very high, so that a
reflection back to the concentration funnel occurs and
concentration factor according to curve portions 117 and 118 of
the diagram in Fig~ 7 develops.
Fig. 8 shows a further development of a concentration
s.Ystem
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whereby a special low radiation angle of the outer cover sheet
is to be reached during the Eading out of the individual surface
sections, to achieve a high reflecting effect if possible,
following a reflection on the cover sheet. The design of the
reflector profile strips, according to this invention, follo~s
from the Eact that the outer cover sheet of the light wall panel
is utilized as a reflector in order to achieve an increase of
the total receiving angle of the light wall panel, which is
larger than the receiving angle of the reflector system itself.
This problem is solved hy the fact that -the elongated
side wall section 120 is designed to be arched parabolic, and
that the focus point F2 is located behind the opposite side
wall surface 121. The focal point is positioned in an optimu~
fashion on a circular section around the focal point F3 of the
first side wall section 122. The radius r of the circular arc
123 corresponds to the width of cross sectional concentration
area 124, so that via the oppositely located side wall panel 121
a shifting of the actual focal point F2 to the end point of
the parabolic side wall surface 122 occurs. The arching of the
side wall surface develops fro~ center points of circular paths
via F2 and F2l.
This -type of design has two advantages. Firstly the
oppositely located side wall section 121 is shortened, whereby
the direct irradiation portion in the cross sectional
concentration area 124 is increased in irradi tion angles which
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are larger than the receiving angles of the concentration
system. Thus an energy absorption still takes place when the
reflected rays are already completely attenuated. Secondly as a
result Or the focal point construction, a conlcal concurrence of
the reflected rays takes place, whereby in exceed.ing the
receiving angle, the attenuated rays form a pointed angle toward
an outer cover sheet, which would run parallel to the reflected
ray 125. With -the pointed angle a high reflection portion of
the attenuated rays is achieved as desired.
In order to achieve an even more pointed angle to an
outer cover disc, and also to obtain a very flat design of the
side wall 127, the side wall 127 is extended with another
section 126~ which again is designed as a parabola with a focal
point Fl in the end point of the opposite side wall. Because
of the shifting of the focal point, a decrease in the size of
tlle parabola is achieved, whereby the parabola section 126
becomes increasingly flat as a result of the decrease in size.
Due to the flattened condition of the parabola an increase is
achieved in the opening width 128 of the cross section or the
penetrating light.
An additional development of the invention provides for
a type of lay-out, whereby the x-axes of the above-mentioned
parabolas are positioned in such a way, that depending on -the
irradiation angle ~, several peak values of the density of
incoming energy are reached. This is shown in the diagram of
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Fig. 9. Thus, the irradiation angle B = 0 is fixed parallel to
the collector axis 129 which runs vertically perpendicular to
the concentration cross section area 124. The diagram
represents the individual por-tions of the parabola sections
Pl, P2 and P3. One can see that due to the parabola
sections Pl and P2 a shading of the receiver cross section
occurs at a 10W irradiation angle. Otherwise a steep curve
increase and a very high concentration fac~or is already
achieved at low irradiation angle.
The curve sections 130 and 131 are shown in broken
lines, and indicates an additional energy recovery, which is
achieved after non-utilisation of the reflector surfaces due to
reflection on the outer irradiation opening cover. The diagram
clearly indicates that the total energy recovery possible can be
increased by using the reflection on the cover sheet.
While there is a continuous increase of the
concentration Eactor up to a maximum value comparable with curve
132 as a result of parabola section P3 at a side wall design
with one or more focal points but at equal sloping of the
X-axis, whereas a progression of the peak value is achieved due
to the different sloping of the X-axis. This can for example be
utilized for heating purposes, in connection with a flat roof
collector of the type shown in Fig. 7, to obtain the highest
concsntra~ion factor at the lowest sun-position during the
winter9 which factor then decreases in the summer at the higher
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irradiation angles, ;ncrease in amount of sunshine and less need
of heat.
The curve of Fig. 10 permits a recommendation to be
made, regarding the layout of the reflector system shown in Fig.
8 and 9, as flat roof collector covers for heating purposes.
The curve 133 represents the cosine at Q diversified irradiation
angle onto a horizontal surface. The curve 134 relates to the
recovery of incoming rays inside the collector. The collector
axis is sloped against the horizontal line in such a manner that
at the lowest irradiation angle the incoming energy radiation in
the collector is greater than the incoming energy radiation onto
the horizontal surface. The incoming energy radiation then
decreases ~ith increasing sun irradiation angle. The high
concentration factor makes a small light penetration surface and
a larger insulation surface of the panel feasible in the winter,
according to the requirements of the high temperature
difference, whereas as the reflectors are used for energy
radiation and thus the cooling of the building to which they are
applied during the SUDImer.
The wall panels which allow light to penetrate do not
necessarily have to be designed level, and especially the outer
panel wall can for example be designed arched or folded.
Preferred materials are glass or synthetics. The reflector
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7~l
profile strips can also be manufac-tured of glass or synthetics
and can be metal coated by vaporization or galvanizing. Both
processes for the production of a reflecting surface presen~ the
possibility of providing the reflector protile strips with a
certain amount of transparency.
. z ~
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