Abstract: An insulated log building structure comprising two parallel, vertically extending log walls having an insulative layer of foam plastic disposed therebetween. Each of the walls are formed of horizontally extending logs mounted vertically upon one another in a tongue and groove relationship. A layer of fiberglass insulation may be disposed between the tongues and grooves of contacting logs to insulatively seal the joints. Vertically extending tie rods within vertically aligned apertures of the logs making up the walls hold the two log walls in parallel alignment.

Abstract: Solar heat tracking and collecting apparatus including a frame, means for rotating the frame in altitude and azimuth, a solar heat concentrator mounted on the frame and a solar energy sensing means disposed on the frame and operable to control the frame rotation means. The solar heat concentrator includes a substantially rectangular, flat collector plate and two pair of oppositely disposed light reflective side walls bounding the collector plate, the side walls in a converging relationship to one another. The device may also contain a triphase solar mode sensor which is operable during the full sun phase to enable and disable the solar energy sensing means from automatically controlling the frame rotation. When the sky is overcast the solar energy sensing means become inoperable and the mode sensor then operates a timer which enables the obscured sun to be accurately tracked within very close tolerances.