SOLAR ENERGY COLLECTOR AND A PANEL FOR USE WITH SUCH A COLLECTOR

Abstract: A solar energy collector having as its basic compo­ nent, a moulded multi-pocketed collector panel, the pockets of which are modified polyhedral or tetrahedral shapes, to increase exposed surface and heat transfer areas. This panel, having various polyhedral pockets in combination with glazing and a back cover, providing an overall, struc­ turally sound collector which may have degrees of curva­ ture ranging from flat to compound to spherical. A through-­ window ventilation receptacle may be used to support the collector, and may also serve as a plenum, if desired, to facilitate intake and distribution of room air.

Description: SOLAR ENERGY COLLECTOR This invention relates to solar energy collectors. The basic constituents of any solar energy collector include a collector element, glazing and an enclosure frame (preferably insulated), to support the glazing and the collector element. The ability of a solar collector to collect solar energy is a function of the collector element surface area and the orientation of the collector surfaces relative to the incident angles of the sun. The ability of a solar collector to transfer the collected energy to the desired media (air, liquid, etc.) is a function of the collector element surface area and the distance the media travels over the collector element. Heat losses are a function of the type and number of glazing utilized and the insulation capacity of the frame enclosure. Cost effectiveness of the collector is a function of the effective use of low cost materials and designs which lend themselves to automated mass production. Numerous solar collector designs have evolved over the years However, none of these designs have attempted to optimize all of the above mentioned parameters in a single solar energy collector concept, Accordingly, it is a general object of this invention to optimize all of the above mentioned parameters in a single solar energy collector. A solar energy collector in accordance with the invention comprises a thin-walled energy collector panel having a number of pockets formed therein, projecting 'rearwardly' from an exposed 'front' surface, each of the pockets having an open top in the sad exposed surface and a closed base, a glazing being sealingly attached to and enclosing the front of the panel and a back cover being sealingly attached to and enclosing the back of the panel, circulation means being provided for circulation of air along a flow path from an inlet across the said unexposed surface, to and across the said exposed surface, to an outlet. The collector panel, besides serving as an efficient solar collector, also serves as the basic structural member of the collector providing inherent structural integrity, the frame for single or multiple glazing and a portion of the integral ductwork for the transfer media. The energy collector panel preferably comprises a plurality of collector pockets in the form of convex, tapered, truncated, three dimensional polyhedra. Such pockets of three dimensional polyhedra provide numerous exposed surfaces which are oriented at various angles relative to the path and azimuth of the sun as it sweeps its arc across the sky. Thus, there are always some surfaces favourably inclined relative to the rays of the sun. The relative positioning of the pockets is such that, as one internal surface of a polyhedra begins to become shaded, a neighbouring surface begins to receive sunlight. Wit such a structure, positioning of the collector relative to the sun is not critical. It is also contemplated that each pocket may be in the form of a cone or truncated cone. The solar energy collector panel may be made from any of the mouldable materials including, but not limited to, plastics, metals, wood products, and composites. The pockets of the panel may be identical in size and shape or may be any combination of various sizes and/or shapes of polyhedra. By incorporating regularly or irregularly placed polyhedral pockets of various sizes and/or shapes into the collector, different degrees of curvature may be accomplished. This curvature may range from flat to compound to spherical, and the geometry necessary to produce the desired curvature can be determined analytically. This collector structure provides increased compressive strengths and increased flexure stiffness. The bases of the polyhedral pockets of greatest depth are preferably joined to a (preferably insulated) back cover to produce a sandwich structure in which the pocketed collector panel serves as an integral core, as well as a partial face sheet. By design, the collector panel also serves as the collector closure (sides, top, bottom) and as a frame for the glazing The sides and top of the collector panel also are designed to present themselves to the sun's rays, thus acting as an uninsulated, unglazed collector member. The sides, top and glazing framework are an integral part of the collector panel and can be fabricated in a single operation thus lending to low cost, automated, mass production. Additionally, the design and placement of the core polyhedra is such that they provide, in combination with the back member, a natural path (ductwork) for the transfer medium (air). Thus, little or no additional ductwork is required. The design of the collector is such that the flow path of the media starts at the top of the collector (between the unexposed surface of the collector and the back cover) and proceeds to and through holes in the bottom of the collector element. The- medium then flows upward between the glazing and the front exposed face of the collector. Since the medium flows over both the unexposed surface and exposed surface of the pocketed collector panel, the effective heat transfer area is greater than that of a flat panel. As such, the design provides excellent heat transfer to the medium and minimizes the need for insulation. Venting of the heated medium to the room or area to be heated may be accomplished by a simple external vent housing which must include inlet and outlet ports (with or without directable louvres) attached to the holes in the back cover of the collector and a circulation device (such as a fan or pump). Any material or design can be used for the vent so long as it is compatible with the inlet/outlet ports in the collector. Since the collector panel and attached back cover provides a high degree of structural efficiency, the collector is self-supporting and may be used as a mounting unit for through-window, through-wall and the like installation. In one preferred embodiment of the invention, each solar energy collector pocket is a minor variation of a tetrahedron, more preferably a truncated tetrahedron. It is a documented fact that a tetrahedron has the highest surface area to volume ratio of any known regular three dimensional shape. The pocketed collector panel increases the surface area presented to the sun by a factor of at least 2.5 over a flat plate panel, thusproviding a highly efficient, exposed shape for solar energy collection. The invention will now be further described by way of example with reference to the accompanying drawings, in which Figure 1 is a rear isometric view of the collector with the back cover partially cut away to show the unexposed surface of the pocketed panel, Figure 2 is a front view of the device of Figure 1 with the glazing partially cut away to show the exposed surface of the pocketed collector panel, Figure 3 is a sectional view along the lines 3-3 of Figure 1, Figure 4 is a section on the line 4-4 of Figure 2, Figure 5 is a partial sectional view along the lines 5-5 of Figure 3, and Figure 6 is an enlarged, fragmentary view of the exposed surface of the collector panel, showing several of the pockets. Figures 1 and 2 of the drawings depict the overall structure of the energy collector. The side of the solar collector that is exposed to the sun is shown in Figure 2. Referring to Figure 2, the basic collector panel 10 includes a plurality of moulded, plastic, truncated tetrahedral pockets 20 interspersed with smaller pockets 20! of the same general structure. As may be seen iii fiigure 6, each of these pockets 20 and 20' are generally tetrahedral-shaped recesses. These modified tetrahedral pockets 20 and 20' include faces 22, quasi-faces (truncated edges of a tetrahedron) 24 and a base (truncated vertex of a tetrahedron) 26 opening toward the exposed surface 12, with the bottom side of each pocket protruding outwardly from the unexposed surface 14 of the panel 10. As may be seen from Figures 4 and 6, pocket 20' is smaller than pocket 20 in all dimensions. Although the structural strength of the panel is increased when more of the pockets are of the same depth (to provide an increased number of support points for back cover 34), the interspersing of pockets 20 and 20' has been found to provide adequate structural support while, at the same time, limiting the points of contact of the collector panel 10 and back cover 34 to decrease heat loss. Additionally, with pockets 21' of smaller depth, less of an obstruction to airflow is presented. Referring to Figures 2 and 4, a transparent or trunslucent glazing 30 is mounted in an integrally moulded inset step 16 of panel 10. Various spacers 18 are attached to the exposed surface 12 of panel 10 and engage the inside of glazing 30 for support, while allowing spacing of glazing 30 from exposed surface 12. Panel 10 also includes sides 11 and the flanges 13 assisting in the support and positioning of a back cover 34. Additionally, flanges 13 are extended further toward the rear as at 15 for mounting or spacing purposes with respect to the side of a building or the like. Referring to Figures 4 and 5, back cover 34 includes inlet ports 35 and outlet ports 38, as well as crossover holes 17 are located in the bas of the bottom row of small pockets 20' of the collector panel 10. Of course these crossover holes 17 could be located elsewhere in the panel, such as through the faces or quasi-faces of the large or small pockets. Also referring to Figure 4, it may be seen that the back cover 34 is attachable to the bases of-the larger pockets 20, as at 32, to lend overall structural support and integrity to the collector. Additionally, the solar collector includes a means of circulation of the active medium (such as air). This embodiment of the invention discloses a ventilation receptacle 40 attached to the back cover 34 of the collector, and includes an exhaust fan 42, air intake ports 44, and tubing (such as that indicated at 46 in Figure 4) to connect the exhaust 42 or the intakes 44 to their respective outlet ports 38 and inlet ports 36. Of course, exhaust 42 and intakes 44 may be arranged in a different configuration and may include adjustable louvres in order to segregate and direct the air flow. The advantaye of a ventilation receptacle 40 is that the collector may be positioned on the outside of a building while having the collector receptacle 40 extend through a window opening or the like to the interior of the buIlding, thus providing a ventilation interconnection between the exterior and interior of the building as well as a means of support for the collector. As indicated by the airflow arrows (seen in Figures 1 and 5), air is sucked into intakes 44 and inlet ports 36 to flow downwardly between back cover 34 and the unexposed surface 14 of the collector panel 10. The smaller pockets 20' obviously enhance airflow across the unexposed surface 14 of panel 10. Near the bottom of panel 10, crossover holes 17 allow the air to circulate through panel 10 to the space between the exposed surface 12 of panel 10 and the glazing 30. As stated earlier, various spacers 18 aid the support and spacing of glazing 30 from exposed surface 12. Having circulated through crossover holes 17, the air then passes over the exposed surface 12 as it circulates to the outlet ports 38 and the exhaust fan 42. Of course, means of circulation other than a fan including naturally occurring thermal convection, could be utilized with the solar collector. In addition, a thermostat control could be incorporated into the device. The exposed surface 12 of panel 10 may be coated with a black matte finish to enhance absorption of the heat from the sun. In addition, the glazing- 30 may be tinted as deemed appropriate for use. Back cover 34 could be insulated, however, it is preferable that sides 11 have a black matte finish and are not insulated, thereby increasing the collection of incident solar energy.

Claims: CLAIMS: 1. A solar energy collector comprising a thin-walled energy collector panel having c number of pockets formed therein, projecting 'rearwardly' from an exposed 'front' surface, each of the pockets having an open top in the said exposed surface and a closed base, a glazing being sealingly attached to and enclosing the front of the panel and a back cover being sealingly attached to and enclosing the back of the panel, circulation means being provided for circulation of air along a flow path from an inlet, across the said unexposed surface, to and across the said exposed surface, to an outlet. 2. A collector as claimed in Claim 1, in which spacer means are provided for spacing the said glazing from the exposed surface to provide the flow path across the exposed surface. 3. A collector as claimed in Claim 1 or Claim 2 in which the pockets are generally cone-shaped. 4. A collector as claimed in either of Claims 1 and 2, in which the pockets are generally polyhedral-shaped. 5. A collector as claimed in either of Claims 1 and 2, in which the pockets are generally tetrahedral-shaped. 6. A collector as claimed in any preceding claim, in which the depths of some of the pockets are less than the depths of others of the pockets 7. A collector as claimed in any preceding claim, in -which the back cover is supported by the bases of at least some of the pockets to provide internal structural support 8. A collector as claimed in any preceding claim, in which at least some of the pockets are truncated to provide flat bases. 9. A collector as claimed in any preceding claim, in which the circulation means includes an ar pump. 10. A collector as claimed in any preceding claim, in which the circulation means includes an attached ventilation receptacle adapted to extend through a wall of a building to support the apparatus and to provide air circulation between the interior of the building and the collector panel. 11. A thin-walled energy collector panel for use with a collector as claimed in Claim 1, the panel having a number of pockets of cone, polyhedral or tetrahedral shape, and having an open top in the plane of the panel and a closed base, the bases of the pockets being spaced from the plane of the panel.

Inventors: FIGGE, IRVING E.
Applicants: FIGGE, IRVING E.
Application year: 1980
Main classification: F24J3
IPC codes: E04C2, F24J2