Abstract: A variable frequency screening device consisting of a pair of spaced elongated side members, a flexible screen surface supported between the side members, a frame member supported between the side members and beneath a flexible screen surface, at least one striking frame shaft rotatably mounted between the elongated side members and beneath the flexible screening material, a striking frame mounted to the striking frame shaft, a second striking frame mounted to the striking frame shaft, and a motor to rotate the striking frame shaft which, in turn, causes the first and second striking frames to alternately strike the underside of the flexible screen material. The apparatus is equipped to permit the striking frames located on additional striking frame shafts to strike the screening material at independently selected amplitudes and frequencies.

Abstract: An apparatus which is in one embodiment structurally integrated with a building and has a solar collector plate with a front side and back side. The collector is mounted a spaced distance from an insulated building interior wall to form a preheating channel with one of its sides. Roof mounted solar admitting panels are mounted spaced from the other side of the collector to form a second or primary heating channel. A collection chamber is in circulating air communication with both channels and allows air to pass from the preheating channel to the primary heating channel. During heating air passes through preheating channels and primary heating channels and flows to a storage unit carried beneath the structure or cycled to the building structure. A valve to the ambient environment allows air to flow into the storage unit. When the storage unit is cooled by introduction of circulating air through a valve joining the apparatus with the building environment.