Aim: To build a solar batch water heater using some old materials and some new. The idea behind this heater is to use as many old materials as possible, keeping them out of landfills and to use new materials as efficiently as possible. For this reason the box has been designed to use exactly two sheets of plywood without any waste. This also gives the box a trapezoid shape, making it stronger and angling the sides to reflect light onto the bottom of the tank. This was a lucky accidental feature;-)
I think this is a very simple design most people are capable of making with fairly basic tools, cheaply and without advanced carpentry skills. it is a effective heater - I have seen the water on top reach 150F on a hot spring day.
I have built a few of these and am still working on improving the design. I will log in and update this as I have more pictures and info. If these are not completely clear directions, well, this is my first instructable, so it will only get better.
Step 1: Materials Needed
Double glazed patio sliding glass door, 3' wide ideal. Should measure about 36” x 79”
Old water heater tank. I have only used 40 gal gas heaters so far, but I see no reason why larger tanks and electric tanks should not work, fine.
½ inch sheet of plywood
5/8 inch sheet of plywood
2 sheets of 1 inch foam insulation with reflective foil surface
Rustoleum or equivalent flat black metal paint, 1 pint
Stain or exterior primer and paint, 1 quart of each
¾ inch steel plugs for extra tank holes, maybe.
2 cut off pieces of 2 x 8, 16” long
One tube of latex or other caulking
Box of 1 5/8” drywall screws
10 3" wood screws for tank supports
16" long 1/2" copper pipe with cap and
2" long 3/4" threaded steel pipe
JBWeld for above
Teflon pipe tape