courtesy of www.jc-solarhomes.com/gallery.htm,
Here is a nice little solar greenhouse in Saranac NY about 40 miles south of the Canadian border. The five 4X8 one-inch thermo pane panels face south. They are tilted at an angle of 60 degrees to optimize heat collection during the coldest months of the year. The stone floor of this greenhouse is about four feet below the outside knee-wall. The back-wall was built out of cobble stones mortared into position to provide a heat sink. Rising hot air at the apex of the solar greenhouse pushes top flaps open to heat the interior living space of the house. Lower flaps open into the greenhouse to allow cold air return.. Shortly after the sun sets the flaps close to prevent living space heat from being lost into the cooling night-time greenhouse. Besides providing additional heat to the house the greenhouse provides an excellent plant nursery.