Lightweight solar heater employing tubes and channels

DETAILED DESCRIPTION In the drawings, the solar collector 10 includes a box-like frame including longitudinal and horizontal side walls 11, upright transverse end walls 12, and upright transverse stiffeners 13.
The latter extend between the side walls at longitudinally spaced locations.
The collector includes a multiplicity of elongated tubes 14 to pass fluid and receive heat for conduction to the fluid (such as water, for example).
The tubes may advantageously be tilted at acute shallow angles .
alpha.
from horizontal, in order to induce endwise and upward flow of fluid in the tubes in the directions of arrows 15; further, the tubes may be parallel and transversely spaced, as shown.
Typically, the tubes may consist of metal or plastic.
A first header pipe 16 is located at the left ends of the tube in FIG.
1 and in communication with the tubes as via entrance of the tube left ends into the header pipe.
A second header pipe 17 is located at the right ends of the tubes in FIG.
1, and is in communication with the tubes as via entrance of the tube right ends into the second header pipe.
Fluid such as water supplied from a source 18 typically enters the header 16 at its lower end 16a, flows into the tubes and rightwardly and upwardly to header 17, and flows upwardly and outwardly from the header upper exit end 17a.
Such flow is aided and typically occurs naturally by convection due to solar heating of the fluid in the tubes.
Header pipe ends 16b and 17b may be plugged.
In accordance with an important aspect of the invention, channel shaped heat transfer members 20 are provided, the members having flanges 20a and webs 20b interconnecting the flanges.
The webs are generally co-planar and face toward the sun for receiving impingement of solar radiation indicated by arrows 21 in FIG.
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Further, the members 20 are typically metallic so as to be heat conducting, aluminum being a typical metal; accordingly, heat is quickly transferred or flows via the webs 20b to the flanges 20a for transfer by conduction to the tubes 14