As I’ve probably mentioned before, our house is old and drafty. We are constantly trying to find new ways to keep it warm in winter. To that end, I’ve been looking through some designs for DIY solar heating units, like this one made with old soda cans, and this one made with pennies. Certainly both of those have their uses, but neither completely fit what I wanted to do, so I came up with an alternative that I think combines the recycling of the first nicely with the portability of the second.
Materials You will need 6 clear plastic bottles with the labels removed and the bottle lids, 1 spool of 18-24 gauge copper wire, wire cutters, black poster board, scissors, black paint, a paint brush, clear packing tape, 6 half inch PVC elbow connectors, a few ounces of black modeling clay, 1 foot of half inch rubber tubing, and a knife.
Core Lay each bottle on its side and cut an opening on the bottom side of each bottle with the knife. Paint the side facing you completely black. Stand the bottles up and allow to dry. Cut the poster board into six ½” x 6” strips. Cut 30 six inch pieces of copper wire, and six 7 inch strips of wire. Tape 6 strips of wire to each strip of poster board, using one 7 inch strip in the center of each piece of board, with an inch protruding off one side. At the opposite end of the board, attach a gumball-sized bit of clay. Use the extended wire as a handle to lower one strip into each bottle and stick into place with the clay.
Assembly Tear off 2-3 eight inch strips of packing tape and lay them next to each other vertically, sticky side up. Lay three bottles, black side down, onto the tape to form a stack. Repeat with the bottles facing the other way. Turn each stack over, so that the bottle bottoms touch and the taped sides are now facing up. Use horizontal strips to connect the two stacks. This will be the back of the unit. Attach an elbow connector to each bottle’s mouth opening, using modeling clay to hold it in place. The elbows’ other openings should be pointing toward the rear of the unit. Cut 2 inches of rubber tubing and insert into each elbow. Use the modeling clay to stick the lids to the bottom bottles, open side down, to create feet and hold the unit upright.
Use Place the unit into any window that gets direct sunlight. The tubing can be directed through blinds, or curtains can be arranged around the unit so that the back is clear.