How to Build a Solar Water Heater
Build a solar heater from recycled parts. The heat exchanger is the grill from the back of an old refrigerator. The greenhouse heating effect is made using an old door or set of windows attached to a frame of 2-by-4- boards and plywood. Water is stored in an old cooler. This solar heater is best suited for climates where it doesn't get cold enough for pipes to freeze.
Things You'll Need
- cooler enema tubing old windows or sliding door door hinges three 2-by-4 boards space blanket fiberglass insulation safety release valve JB Weld Epoxy duct tape black paint
Instructions
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1
Remove the heat exchanger from an old refrigerator that has had the CFC gas (freon) removed professionally. The heat exchanger is the grill on the back of the refrigerator. Do not damage the integrity of the pipes in this grill since they will carry hot water. Paint this heat exchanger black to absorb as much light energy as possible.
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2
Get an old sliding glass door (or window big enough to cover the heat exchanger) from a home renovation or recycling site. It is best to use a double-paned door but any door type will do. Nail a frame of 2-by-4 boards to a plywood board so that it matches the shape of the door and creates depth. Drill small double holes at four corners of the frame so that they are halfway between the insulation and the door. Make sure the hinge is on the door so that the door closes, using gravity as an aid.
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3
Get insulation. A friendly conversation will often allow free material for a project. Use this insulation to line the box created in Step 2. Cover the insulation with a space blanket that is held in place with duct tape.
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4
Secure rope to the heat exchanger through the holes in the frame of this newly made box without touching any surface when the box is closed. Plug the holes for the ropes so that air cannot pass.
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5
Attach enema tubes to the input and output of the heat exchanger by sliding them on to the piping. Connect the enema tubes to an insulated container for the hot water storage (perhaps a cooler from end-of-summer sales or the garage) by using JB Weld Epoxy. Make sure that a safety valve is attached to the system so that built-up pressure has a way to escape safely if the cooler lid is sealed tightly (with the sealant). Buy the valve new (not used) and attach it with the sealant.
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6
Attach two 2-by-4 boards that are 4 feet tall (depending on the desired angle) on either side of the top of the frame so that it is propped up and the face of the heater faces the sun.
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If desired, add a Fresnel lens from an old projector screen television to magnify any heat that goes into the box but beware of fire.
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Tips & Warnings
Do not use this device in climates where freezing will occur. A different type of system is required in these cases and is available in the first link at the end of this article. Since hot water is expected to rise and cold water is expected to fall due to relative density differences, make sure that hot water is expected to leave at the top of the heat exchanger and cold water is expected to leave the bottom of the water storage. The water storage tank should be stored higher than the heat exchanger for proper flow.
The water coming out of this heater can heat up quickly (in seconds) and scald. Be careful since any part of this device can become hot. Do not allow the safety release or any leaks that develop to emit hot water or steam on people, pets, or anywhere else it should not be allowed.
