Solar water heaters use the sun to heat water. Typically these systems are mounted on the roofs of homes and utilize a pump and large storage tank in the basement of the house to hold the hot water. A mini solar water heater can be built using the same principles, though designed to be relatively compact and portable. A small portable solar water heater would be very useful for camping and similar recreation activities where hot water is very useful, but not abundant.
Things You'll Need
- Copper tubing (1/2 inch in diameter)
- 2 ft x 2 ft sheet of plywood
- 2 U-fastener
- Screw driver
- 2 hinges
- 2x4, 1- 2ft long and 2- 18 inches long
- Black paint (high temperature spray paint)
- Small water tank (2-3 gallons)
- Flexible heavy-walled plastic tubing
- Tubing clamps
Bend the copper tubing in a S shape up the sheet of plywood. The end of the tubing should start at the bottom corner of the board and the tubing should run across the board horizontally before curving up to make another horizontal row. There should be very little space between each row. The end of the tub should end at the opposite corner as the starting end.
Secure the tubing to the board at the start and end using the U-fasteners, screws and screw driver.
Attach the hinges at the top corners of the panel using the screws. The fulcrum of the hinge should be along the top edge of the panel.
Attach one of the two 18 inch 2x4s to each hinge. These will form legs for the panel to stand on and will collapse for easy transport.
Screw the 2 foot 2x4 to the bottom back-edge of the panel, creating a platform for the panel to rest on.
Paint the entire panel black. High temperature spray paint works well.
Connect one piece of flexible tubing to the circulation input and output of the water tank.
Place tubing clamps over the connections and secure the clamps in place.
Paint the tank and connections black.
Using the system
Connect the circulation output tube of the water tank to the input on the solar panel. The input is the copper tube at the bottom corner of the solar panel.
Fill the circulation line with water. There must not be any air bubbles for the water to efficiently circulate via convention currents around the system.
Connect the input tube of the water tank to the output on the solar panel. The output of the solar panel is the copper tube on the top corner.
Hang the tube from a secure support above the panel.
Fill the water tank with water.
Place the solar panel in a sunny area.
Wait for the water to warm up. The sun will warm the water in the copper tubing on the solar panel, then travel up to the water tank, where it will warm the storage water. The colder water will flow back to the solar panel and get reheated.
Tips & Warnings
- The water can get very hot and should not be used directly on the skin without first testing the temperature. A larger water tank can be used, though it will take longer to heat the increased mass of water.
- Photo Credit solar-cell image by carsten jacobs from Fotolia.com
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