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Claims  |
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What is claimed and desired to be protected by United States Letters Patent
is:
1. In a collection system for solar energy, having a trough-like reflective
collector, means passing along the focal area thereof for conducting fluid
to be heated, means for circulating and extracting energy from the fluid
heated, and means for orienting the reflective collector, the improvement
comprising:
the reflective collector having a parabolic cross-section;
the means for conducting fluid including: a first tube system having a
portion thereof passing along the focal line of the reflective collector;
and
a second tube system, having a portion thereof passing outside the focus of
the reflective collector in parallel-spaced relation with said first tube
system portion said second tube system portion being in the incoming beam
of solar energy and arranged in front of said first tube portion.
2. In a collection system as recited in claim 1, a glass-like panel, and a
frame with ends affixing the glass-like panel over the reflective
collector and forming an air-tight greenhouse effect heater chamber around
said portions of the first and second tube systems.
3. In a collection system as recited in claim 2, the reflective collector
including a form, and an aluminum foil surface cemented over the form.
4. In a collection system as recited in claim 3, the form being of
fibreglass.
5. In a collection system as recited in claim 3, the frame including a
preheat compartment behind the reflective collector, the first and second
tube systems having respective coils therein.
6. In a collection system as recited in claim 5, said means for circulating
including means for passing said fluid in sequence through said preheat
compartment, then through said second tube system portion, then through
said first tube system portion for thereby heating said fluid.
7. In a collection system as recited in claim 3, and additionally a
plurality of reflective collectors juxtaposed as a unit to the first said
reflective collector, each reflective collector having a said means for
conducting fluid.
8. In a collection system as recited in claim 1, said portion of the second
tube system comprising a plurality of tubular members sectionally in
arcuate array about said portion of the first tube system. |
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Claims |
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Description |
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This invention relates generally to energy utilization and specifically to
solar energy collection and distribution.
In the prior art various systems having the general purpose of this
invention have been described, including the reflector system described in
U.S. Pat. No. 497,079 granted May 9, 1893, to M. L. Severy, which, like
the others, fails to provide the combined features of the present
invention.
A primary object of the invention is to provide an improved system for
collecting and distributing heat from the sun, yielding greater efficiency
at less cost than previously known systems.
Other objects of the invention are to provide a system of the type
described which is inherently tolerant of misalignment relative to the
sun, which is particularly adaptable for massing in one unit to multiply
the amount of area exposed for energy collection, which uses not only
direct radiative heating, but also greenhouse effect heating, which
reduces re-radiation, and which provides either single or plural fluid
systems, as desired.
Still further objects of the invention are to provide a system as described
which is exceptionally light in weight so that loadings on supporting
structures such as roofs are kept low, which is easy to maintain and
repair, and which is economical to obtain and to use.
In brief summary given for cursive description purposes only, the invention
includes an elongate reflective collector with means for conducting fluid
through the focus for heating, means adjacently outside the focus for
conducting fluid for heating, and means for retaining heat around the
fluid conducting means.
The above and other objects and advantages of the invention will become
more readily apparent on examination of the following description,
including the drawings, in which:
FIG. 1 is an isometric view of a first embodiment of the invention in
operation;
FIG. 2 is a sectional detail adapted from 2--2, FIG. 1;
FIG. 3 is an isometric view of a detail of the first embodiment of the
invention with a portion removed to show interior arrangements;
FIG. 4 is a hydraulic circuit diagram; and
FIG. 5 is an isometric view of a second embodiment of the invention.
In the Figures, like reference numerals designate like parts.
FIG. 1 illustrates the collector invention 10 in operation in an exposed
location L such as a rooftop. A horizontally extended reflector 12 having
a parabolic cross-section 14 is provided as a feature of this invention
for optical efficiency in radiation collecting and focussing. This may
advantageously be of molded fibreglass with a reflective surface of
cemented-on aluminum foil 12a. The reflector collects radiation R from the
sun and focuses the radiation collected onto a tubular conduit array 16
comprising a first tube system 18 having a tube extending parallel with
the reflector in the focal line and a second, folded, tube system 20
extending parallel with the first by outside the focus of the reflector,
and generally forming a hemispherical group of tubes in section. Fluid in
the conduit array 16 is heated directly by the radiation and also by
greenhouse effect heating of the air surrounding it, contained by
transparent front panel 22 which preferably is of light weight plastic
material having the general transmissive characteristics of window glass.
Alternatively, the front panel may be of ordinary window glass if desired.
Further, double pane insulating glass may be used, if desired.
The front panel is held in place and the air around the tubular array is
confined hermetically by a box-like frame 24 which preferably is molded of
fibreglass, with insulation within, but which may be of light weight metal
having an insulative covering on the inner face, or which may be of
weather-resistant insulative fibreboard, or other suitable material. The
ends 26, of the frame have reflective sheet 28 such as aluminum foil
applied to the inner faces in heater chamber 30 defined by the ends, the
reflector and the front panel. The frame has a back 32, top 34 and bottom
36, and has pivot supports in altitude 38 and azimuth 40 to permit
continuous orientation toward the sun in any conventional manner, as for
example by selsyn motors 42, 44 controlled by a selsyn programmer, not
shown, or by any other usual heliostat mechanism.
Fluid in the tubular array, which may be water, ethylene glycol, freon, or
other conventional liquid or gas used for the purpose of heat transfer,
passes, after heating, through conventional means such as insulated
flexible tubing 46, urged by any conventional means for pumping 48, and
then through a conventional heat exchanger coil 50 in the space to be
heated, and back into the tubular array in the heater exchanger for
re-heating.
FIG. 2, a section of the first tube system 18 portion and the second tube
system 20 portion is at the focal line F of the reflector. The peripheral
rays a and a' of the full beam on-axis heat tube system 18 and any
portions of the beam such as b which pass by or reflect from the tube
system 18 heat the tube system 20 surrounding, outside the focus, that
portion of the tube system 18 lying along the focal line. This makes the
system efficient when illuminated off-axis, when overfilled by scattering
of sunlight, and when the reflector contour is less accurate than would
otherwise be required.
FIG. 3, a detail view of the frame with the rear end removed to show
associated parts, indicates the relation of the transparent front panel
22, the tubular array 16, with the proximate portions of the tube systems
18 and 20, the reflector 12, the heater chamber 30, and rearward of the
reflector the preheat compartment 52. In the preheat compartment the tubes
of the first and second tube systems leading from the pump are folded into
respective proximate heat exchanger coil sections 18' and 20', insulated
from the outside and warmed by heat transfer from the heater chamber.
Fluid warmed here is then passed into the focal area, heated further,
circulated out by the pumping means for heat exchange in whatever space is
to be warmed, and returned for re-heating.
FIG. 4 indicates a system not specifically claimed as a part of the
invention, but exemplifying a conventional means for carrying out a
provision of the invention, providing either for the separate fluid
systems 18', 20' to be maintained apart outside the collector unit 12, 18,
20, or to be used serially through sequential flow in valves V.sub.1
through V.sub.6 which are conventionally employed to isolate system 50 and
produce return flow through system 20' in the preheat compartment, then
through system 18' in the preheat compartment, then through system 20 in
the heater chamber and finally through system 18 in the heater chamber,
following which the fluid passes through pump P.sub.1 and heat exchanger
50 and back through system 20'. Valves of the following types may be used:
V.sub.1, V.sub.2, V.sub.3, V.sub.4 and V.sub.6 are two-way valves; valve
V.sub.5 is a dual two-way valve.
FIG. 5 shows an embodiment 500 of the invention in which a number of
reflector units 512 are juxtaposed in parallel in a large-area
arrangement, each with an associated tubular conduit array 516. A single
transparent front panel 522 may advantageously be employed. Fluid
circuits, drive, and other details may be as described earlier. The
lightweight, economical, shallow-depth design of the invention makes
possible large-area collection without employing large-area optical
precision, each element being independent, and the reflectivity of each
being easily renewed if for any reason tarnished, by application of an
additional layer of aluminum foil. It is evident that several layers of
foil may be superimposed as for example using epoxy cement before any need
to be removed, since distortion or moving the focal line outward does not
cause loss of radiation, the spill-over from tube system 518 being caught
by the shielding tube system 520; this same advantage is available with
all embodiments, as is the smoothing over of small irregularities in the
mold by application of the foil.
It will be apparent that the collector apparatus described herein can be
employed for air conditioning purposes using the thermal or servel system.
Obviously many modifications and variations of the present invention are
possible in light of the above teachings. It is, therefore, to be
understood that within the scope of the appended claims the invention may
be practiced otherwise than as specifically described.
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