Solar Heat Collecting Units

1. Field of the Invention

The present invention relates generally to solar heat collection and more particularly relates to a heat collecting plate as well as an assemblage of the collecting plates adapted to be used in a solar collector to trap and absorb solar radiation.

2. Description of the Prior Art

The tremendous energy output of the sun has been recognized for years and numerous attempts have been made at harnessing this energy so that it can be converted into a useful state. For example, the sun's energy has been successfully converted into electrical energy with solar batteries and similarly, the sun's energy has been converted into heating systems by so-called solar stoves, furnaces and the like. The solar furnace apparatuses, however, have been typified by extremely large collectors covering large portions of the roof structure of a building to be heated with the apparatus and it has been necessary that these collectors be oriented at a particular angle relative to horizontal (usually between 45.degree. and 60.degree.) to be generally in a perpendicular relationship with the solar radiation received at the location of the collector.

With the exception of the solar furnace apparatus disclosed in, U.S. Pat. Nos. 3,987,786, 3,946,721, 3,946,720, 3,946,944 and 3,894,685, the prior art solar furnace systems have required unusually large collectors to capture enough solar radiation to adequately heat a building structure even on a temporary basis. The combination of the extremely large size of the collector with the fact that the collectors had to be mounted at the preselected angle relative to horizontal to adequately collect solar radiation posed numerous practical problems. The most logical place to install a large collector was in the roof of the building structure but due to the necessary angle required of the collector, the angle of the roof normally adversely affected the aesthetic appearance of the building structure. Accordingly, it has long been recognized that a solar collector which could be oriented at any angle relative to horizontal, even purely horizontal or vertical, would resolve many structural as well as aesthetic problems which have plagued those trying to utilize solar radiation on a practical and efficient basis for energy purposes.

The present invention has for its primary object the provision of a new and improved solar heat collecting plate which will enable solar collectors to be oriented at any angle relative to horizontal and improve the solar heat collecting ability of the solar collector.

It is another object of the present invention to provide a new and improved solar heat collecting plate which can be used in a solar collector to not only optimize the collection and absorption of solar radiation but also minimize the construction costs of the solar collector.

It is another object of the present invention to provide a solar heat collecting plate which is adapted to trap solar radiation and minimize radiative losses which have previously inhibited the efficiency of solar collectors.

It is still another object of the present invention to provide a new and improved solar heat collecting plate which is adapted to cooperate with other identical plates in trapping and absorbing solar radiation in a solar collector wherefrom it can be readily transferred to a storage location in an efficient manner.

It is still a further object of the present invention to provide a solar heat collecting plate adapted for use in a solar collector to not only efficiently collect direct solar radiation but also collect indirect or diffuse radiation whereby the solar collector can be oriented in any direction as well as at any angle relative to horizontal and still collect useful solar radiation.

The foregoing and other objects of the present invention are obtained with a solar heat collecting plate or unit which is adapted to be mounted upon a support surface in a solar collector so that an inner plate portion of the plate extends away from the support surface and has an outer plate portion forming an obtuse angle with the outer edge of the inner plate portion. As will be more fully appreciated with the more detailed description later, a plurality of the collection plates mounted in spaced relationship cooperate in efficiently trapping and absorbing solar radiation so as to minimize radiative losses.

One surface of the outer plate portion of each collecting unit is reflective to solar radiation while the other surface of the outer plate portion and both surfaces of the inner plate portion as well as the support surface are absorptive of solar radiation so that radiation is reflected into an area defined by absorptive surfaces which cooperate with each other in absorbing direct radiation as well as reflected radiation. Since even black surfaces reflect a certain percent of the visible light spectrum, it is important that the collecting plates define a trap-like arrangement so that even the radiation reflected by the black surfaces will be reflected toward another black surface whereby the radiation will be substantially completely absorbed.

Since substantially all of the solar radiation received by a solar collector incorporating the collecting plates of the present invention is absorbed by the collecting plates, the double and triple pane glass previously found necessary in prior art solar collectors to prevent the solar radiation from escaping the solar collector is no longer needed. Rather, a single pane of glass can be used.

Due to the angular relationship of the outer plate portion of the collecting plate to the inner plate portion, the solar collector in which the plates are mounted can be oriented at any angle relative to horizontal and still efficiently collect solar radiation. In other words, by properly selecting the angle which the outer portion makes with the inner portion, it is possible to orient the flat front glass pane of the solar collector at any angle relative to horizontal. This makes it possible for the solar collector to be built into a vertical wall, placed on a flat roof or in any other portion of a building structure to minimize the adverse affects of the solar collector on the aesthetics of the building structure.

Another advantage of the use of the collecting plates of the present invention in a solar collector is that the collector can be made much smaller than a typical solar collector because of the higher efficiency in absorbing solar radiation. Also, because of the angular relationship of the outer plate portions with the general angular orientation of the solar collector, the collecting plates are effective in absorbing diffuse solar radiation so that the collector can be oriented to face in a direction other than south and still absorb solar radiation.

FIG. 1 is a fragmentary perspective view of a solar heat collecting plate of the present invention,

FIG. 2 is a fragmentary vertical section taken through a solar collector with a plurality of the collecting plates of FIG. 1 mounted therein,

FIG. 3 is a fragmentary vertical section taken through a solar collector utilizing a second embodiment of the collecting plate of the present invention, and

FIG. 4 is an end elevation of still another embodiment of the collecting plate of the present invention.

Referring first to FIG. 1, a collecting plate or unit 20 is shown to include a pair of parallel inner plate portions 22 connected along a common edge by a back plate 24 which is perpendicularly related to each of the inner plate portions. An outer plate portion 26 extends away from the outer edge of each inner plate portion 22. Each outer plate portion forms an obtuse angle with the inner plate portion and is in parallel relationship with the other outer plate portion of the collecting plate 20. The collecting plate 20 may be made from one sheet of material with the material bent to define the separate plate portions 22, 24 and 26. The plate portions could also be suitably connected as by welding, to define the collecting plate 20 as it is illustrated in FIG. 1. Each plate portion 22, 24 and 26 is rectangular in configuration and could be made of any length, but preferably is of a length to completely traverse the width of the solar collector 28 into which the collecting plate is to be positioned. The spacing between the pairs of inner plate portions 22 and outer plate portions 26 is preferably in the range of two to four inches, and the collectors are made of a heat absorptive material such as aluminum.

The aluminum or other material from which the collecting plate 20 is made is preferably black or at least coated with a black material with the exception of the lower surface 26a of the outer plate portions 26 as viewed in FIG. 1, which surface is either reflective or coated with a reflective material which will reflect solar radiation. The purpose for the reflective surface and the black surfaces will become more apparent after a description of the manner in which the collecting units are mounted in the collector.

Referring to FIG. 2 wherein a vertical section through a solar collector 28 utilizing the collecting units 20 of FIG. 1 is shown, it will be appreciated that the solar collector has a back or support panel 30 with a front surface thereof having a covering 32 of a black material which is absorptive of solar radiation. The collecting plates 20 are mounted upon the front surface of the back panel 30 so that each plate is equally spaced from an adjacent plate and at a spacing substantially the same as the spacing between the inner plate portions 22 of each collecting plate 20. The back plate portion 24 of each collecting plate is mounted in contiguous, parallel relationship with the front surface of the support panel 30 and is secured in position by fasteners such as screws or the like (not shown).

The solar collector 28 has side wall members 34, only one being seen extending forwardly from the peripheral edges of the support panel 30 and defining at their leading edge means (not shown) for retaining in hermetic sealed relationship a transparent glass pane or panel 36. The glass panel is spaced from the support panel so as to lie in closely spaced relationship with the outer free edge 26c of the outer plate portions 26. It will, therefore, be appreciated that each collecting plate singly and in combination with adjacent collecting plates defines a channel 38 therewithin or therebetween, respectively, which extend transversely of the solar collector. Air or another heat transfer medium, such as water or the like, can be passed transversely through the channels 38 to withdraw heat from the collector 28 and transfer the heat to a storage area (not shown) in a manner similarly to that described in the aforementioned application Ser. No. 445,473. While the solar collector illustrated in FIG. 2 is shown in a vertical orientation it is understood that this is only for descriptive purposes and that the collector could be oriented in any relationship relative to horizontal and still efficiently collect, trap and absorb solar radiation dependent upon the angular relationship of the outer plate portions to the angle of the sun.

Referring to the dotted line representation in FIG. 2 of a single solar ray R, it can be appreciated how the solar radiation is trapped and absorbed in and between the collecting plates 22 and 26. With the solar ray illustrated, it will be appreciated that the ray enters the solar collector through the glass panel 36 in the form of long wave radiation R1 and impinges upon the lower surface 26a of one of the outer plate portions 26. This surface forms a selected angle between 180.degree. and 270.degree. with the lower surface 22b of the inner plate portion 22 to which it is connected. The ray R of solar radiation is reflected from the lower surface 26a of the outer plate portion downwardly to the upper surface 26b of the next adjacent outer plate portion which forms an obtuse angle with the upper surface of its associated inner plate portion. As mentioned before, the upper surface 26b of the outer plate portion is black so as to absorb the radiation but, as is known in the art, even black surfaces reflect a certain percent of the visible light spectrum. The reflected ray R2 from the upper surface of the outer plate portion is directed toward the upper surface 22a of the associated inner plate portion 22 where more of the visible light spectrum is absorbed but again, a small portion of the ray received by the upper surface 22a of the inner plate portion 22 is reflected as R3 to the back plate portion 30 of the collecting plate, or in the illustrated instance of the black covering 32 on the support panel 30. The black covering on the support panel absorbs some of the solar radiation from the ray R3 it receives and reflects the remainder as R4 to the lower surface 22b of the adjacent overlying inner plate portion. By the time the solar radiation reaches the lower surface 22b of the next adjacent overlying inner plate portion 22 substantially all the energy in the ray has been absorbed and trapped within the collector plate 20.

Accordingly, by utilizing a plurality of the collecting plates 20 shown in FIG. 1 within a solar collector 28, an optimum amount of solar radiation can be trapped where it can be transferred in a known manner with a transfer medium, such as air, to a storage area by passing the transfer medium through the channels 38 defined in and between the collecting plates.

Referring to FIG. 3, a second embodiment of the collecting plate of the present invention is shown mounted within a solar collector 41. The collecting plate 42, illustrated in FIG. 3, consists of an inner plate portion 44 to which an outer plate portion 46 extends at an obtuse angle from one edge, and a back plate portion 48 protruding from an opposite edge of the inner plate portion at a perpendicular angle thereto. As in the first described embodiment, the collecting plate 42 is made of a black material or coated with a black material with the exception of the lower surface 46a of the outer plate portion 46 which forms an angle of between 180.degree. and 270.degree. with the lower surface 44a of the associated inner plate portion 44. The collecting plate 42 is mounted within the collector 41 by affixing in any suitable manner the back plate portion 48 to a black covering 52 on a back or support panel 54 of the solar collector. A plurality of the collecting plates 42 are mounted in overlying relationship, as illustrated in FIG. 3, so that they are equally spaced with the associated plate portions 44 and 46 being in parallel relationship. In the solar collector 41 illustrated in FIG. 3, instead of utilizng a glass panel at the front of the solar collector, a lens panel 58 is supported by sidewalls 60 of the collector, only one being seen so as to lie immediately adjacent to the outer edge of the outer plate portions 46. The lens panel 58 has a plurality of elongated transversely extending lenses 61 formed therein which are aligned with the space between the outer edges of adjacent outer plate portions. The lenses 61 are convex inwardly to focus solar radiation whereby it is desirably trapped by the collecting plates 42 and absorbed thereby in optimum fashion. As will be appreciated, the adjacent collecting plates define spaces 62 therebetween which are similar to the channels 38 in and between the collecting plates 20 illustrated in FIG. 2, so that the solar radiation is trapped in the same manner as described in connection with FIG. 2.

FIG. 4 illustrates still another embodiment of the present invention wherein the collecting plate 64 has a pair of inner plate portions 66 interconnected along one edge by a back plate portion 68 so that it can be mounted in a solar collector (not shown) similarly to the plate 20 shown in FIG. 1. A pair of outer plate portions 70 are connected to the outer edge 66a of the inner plate portions 66 by a conventional hinge 72, such as of the piano hinge-type, so that the outer plate portions 70 are freely pivotal about the outer edge 66a of the inner plate portions. To assist in uniform pivotal movement of the outer plate portions, as interconnecting rod 74 can be pivotally connected to the outer edges of the outer plate portions whereby upon vertical movement of the interconnecting rod the outer plate portions 70 are caused to pivot about their connection to the inner plate portions 66. The relative angle between the inner and outer plate portions is selected according to the angle of the sun, which changes with the seasons, and the spacial orientation and direction in which the solar collector is oriented. In other words, a solar collector which is not receiving direct solar radiation might have the outer plate portions 70 adjusted so as to optimally receive difuse radiation while the outer plate portions directly receiving solar radiation would be oriented so that the radiation is optimally trapped and absorbed by the collecting plates 64.

It will be readily apparant to those skilled in the art that the embodiment of the invention shown in FIG. 3 could have the outer plate portion 46 pivotally connected to the inner plate portion 44 in a manner similar to that illustrated in FIG. 4 for obtaining the same results obtained by the collecting unit shown in FIG. 4.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.