Passive cooling. The sun shades keep the sun from penetrating into the house now that it is moving lower in the sky. In the winter it will keep the earthship toasty but now, in August, with outside temps of 90 degrees we can do without the heat. The shades hang on cuphooks and will be taken down as soon as it starts getting chilly.

Sun shades and zuchinni.

Very Cool Solar

A thirteen-year-old used Fibonacci sequence to optimize a solar array. Very cool.