The present invention has for an object an absorbent panel for solar energy and the sloping roof composed of such panels.

At present, the panels used on roofs to collect solar energy with a view toward heating are generally comprised of a background that is black and absorbs heat, an intermediate compartment and an insulating and protective window or glass fixed to the edges and projecting from the background. The tubes in which the liquid to be heated circulates are disposed in the intermediate compartment.

Such panels are subjected to severe thermal stresses and require various maintenance. Moreover, over a long period of time, they do not ensure complete watertightness of ⁺he roof and, from an esthetic standpoint, they are noticeably different from a roof of conventional tiles, creating reflections and undesirable vibrations.and are difficult to emplace and replace. Moreover, for large surfaces, the cost of known panels is high.

The panel according to the invention is characterized by the fact that it comprises a metallic or non-metallic tile preferably blackened having preferably at least one raised heat-collecting portion, in which may be provided a throat, forming the seat for a metallic tube traversed by the liquid to be heated, a transparent cap being adapted to be provided as a cover, to insulate and protect the raised portion of the tile and of the tube, the tile being adapted to present on its exposed face one or more protuberances corresponding to a like number of lower cavities interconnected by conduits permitting the circulation of air contained therein so as to transport the heat toward the raised portion of said collector.

• Figures 1, la and 2 of the accompanying drawings show by way of example a first form of execution in metal of a panel according to the invention.
• Figure 3, 3a show a second form of execution.

Figure 1 shows a transverse section of the panel: the tile 2 provides throat 3 in the zone of the raised heat-collecting portion 4.

In throat 3 is inserted tube 5 retained by clip spring 6. Transparent cap 7 encloses from above the elevated portion and overlies at one end the following cap not shown. The next tile 8 is shown in broken .line. At 9,. there is shown a pyramidal protuberance while at 10 are shown air conduits.

Figure 2 shows the same panel in perspective. The numbering of the same parts is identical to that of the preceding figure. There is shown at 11 the lateral edge overlain in its turn by the next tile not shown.

Figure 3 shows a second form of execution of the invention, without throat 3 and without tube 5 but with raised portion 4 and transparent cap 7. The protuberances 9 are preferably of pyramidal form, spherical caps (Fig. 3a) or partially truncated conical (Fig..3b). The hot air below protuberances 9 is carried by conduits not shown to raised heat-collecting portion 4 and thence to an air-liquid heat pump.

The portion of the panel referred to as a tile is compara, ble to a conventional ceramic tile while having protuberances 9 which project upwardly, of various forms but preferably pyramidal, truncated conical or cupola shaped, serving to collect solar energy while always presenting at least one of their faces oriented in the optimum position relative to the sunrays and serving as a support for personnel who must walk on the roof as well as to retain snow.

The recesses below the protuberances are connected with each other and with the recess beneath the raised portion by means of conduits in which air circulates thus transporting the heat absorbed in the region of the protuberances toward the raised portion 4 and the tube 5.

The conduits create on their upper surface reliefs which serve to prevent the longitudinal displacement of the transparent cap.

The tile is disposed on a thermally-insulating panel which is secured to a flat surface resting on the structure carrying the roof. The tile is nailed to this surface through eyelet holes which permit expansion and removal of the tile. It is possible in this way to cover a sloping roof with an esthetic effect comparable to that of an ordinary roof covered with traditional tiles. In the throat, which because of the superposition of the edges of the tile is continuous from the summit to the base of the incline, is secured the tube which is covered by the transparent cap.

The tube and the transparent cap are retained in position by an annular clip'6 comprising a spring which permits the emplacement or removal of the tube 5 and of the cap 7 by simple manual pressure or traction.

At the upper and lower ends of the incline, the tubes 5 are connected to a collector tube which thus integrates all the roof covering in the usual heating equipment for solar energy.

To improve heat absorption and to reduce production costs, it is foreseen that the tile according to the present invention will be made of glass, ceramic, asbestos-cement agglomerate, synthetic material.

Also the number of throats can be increased especially in the case of a panel with a large surface.

To avoid reflections, the external surface of the transparent cap, which can be of a synthetic material, is roughened and/ or irregular while the outer surface of the protuberances may be so configured as to reflect the sunrays toward the tube.

Modifications are foreseen as follows:

• a) Protuberances 9 may be formed truncated conically or as spherical caps or in such a way as to present portions of their external surface perpendicular to the sunrays and to serve as supports for maintenance or in such a manner as to reflect, sunrays toward tube 5.
• b) The tile has two or more throats for tubes for fluid to be heated, with corresponding transparent caps 7.
• c) Along its edges the tile has channels and flanges 8, 11 which permit removing it by displacing it lengthwise of the plane of the slope without having to move the adjacent tiles.
• d) The tile is applied to a panel of insulating material and is nailed on the surface of the roof lining by means of nails which pass through suitable eyeholes in the tile and the insulating panel.
• e) Throat 3 of raised portion 4 is upwardly open so that the tube 5 disposed in the throat is seated and retained in the throat while being visible from above, said tube being blackened, fins or protuberances of the panel serving to retain the tube 5.
• f) Throat 3 is downwardly open such that the tile is applied onto the tube 5 and the latter is invisible from above.
• g) The tile has cavities disposed in its surface turned toward the sun and having concave, spherically capped, pyramidal or truncated conical shape.
• h) Each tube 5 is fixed in its throat 3 by a cement or substance having good thermal conductivity.
• i) The panel is partially or completely composed of several materials disposed in layers, the external layer being transparent.
• k) Elemental panels are interconnected and disposed as conventional tiles with the same esthetic effect so that the throats for the tubes will be continuous from the bottom to the summit of the incline thereby to permit insertion of tubes interconnected endwise in conventional collector tubes and to integrate all the surface of the roof into the solar energy collecting equipment.
• 1) Panels which are associated and form the covering are slightly elevated above the support surface, each elemental panel having toward its base projecting portions which serve to space the panels from the support and which serve to facilitate heat exchange between the tile and the fluid circulating beneath it.
• m) In the space between the assembly of panels and the support surface circulates air whose heat is recuperated as by an ordinary air-liquid heat pump.
• n) That several panels are interconnected in such a way as to form a unit facilitating emplacement of the assembly.
• o) That the transverse section of the tube 5 (Figs. 1 and la) instead of being circular can be polygonal, square, rectangular, trapezoidal, semicircular or triangular, each having its blackened base disposed upwardly so as to receive solar radiation on a large surface. This section of the tube 5 being anything desired, even having the cross section of a mushroom with a large head exposed to solar radiation.
• p) That the pyramidal, truncated conical, spherical cap- shaped or other shaped protuberances 9 may be eliminated.