Venetian blind for solar heating

In a venetian blind for use in a room adjacent the pane of a window disposed to receive solar radiation and spaced therefrom:

• a head rail attached to the frame of said window;
• a tilt rod pivotably attached within said head rail;
• a series of arcuate slats suspended vertically from said tilt rod and means flexibly interconnecting said slats in horizontally-oriented and vertically spaced relation;
• a bottom rail flexibly interconnected with said series of slats;
• means to pivot said tilt rod whereby said series of interconnected slats is reversibly tilted to present said arcuate slats at certain extreme positions with either concave or convex faces of said slats facing said window and substantially parallel thereto, and at intermediate positions;
• means to raise, lower and reversibly fix said bottom rail and portions of said slats whereby said venetian blind is adjusted to expose without obstruction portions of said window;
• the improvement therein being:
• a highly heat-absorptive surface on the concave face of said arcuate slats, each of said slats when pivoted in said extreme position to expose said concave face to said window having the lower portion of said concave face overlapping and concealed by the upper portion of the adjacent slat as viewed from said window so that said incoming solar radiation is substantially absorbed and partly reflected upon impinging said absorptive surface, a portion of said reflected radiation secondarily reflecting from said adjacent overlapped slat and entering said room,
• and an open generally upward extending passage between each of said slats and the upper portion of the slat next lower;
• air passage means at said head rail connecting between said room and said window;
• whereby solar radiation impinging on said absorptive surface heats said surface and heat transfers to air passing upwardly by natural convection through said passages between said slats and through said passage means at said head rail.