Solar energy is a powerful force that people are beginning to consider using for everything from powering cars to heating water. If your property has full sun exposure during the day, solar heaters can handle all or some of your water heating needs. Glass bottles are best to use for a solar water heater, as the hot water could cause plastic bottles to leach chemicals. While not all plastic contains chemicals, glass bottles are generally safer.
Wash and dry the glass bottles completely. Any size of glass bottles will work.
Paint the bottles with a spray-on primer in the darkest colour you can get, for maximal heat absorbency. Allow the bottles to dry completely.
Drill a hole into the bottom of the bottles, 1 inch in diameter.
Paint the bottles with flat black spray paint. Allow the bottles to dry completely.
Thread the hose through the bottles, stacking the bottles neck to end. Use epoxy to hold the bottles together. Make columns of bottles with four to six bottles in each column. Cut the hose about 2 inches below the bottom bottle and about 2 inches above the top bottle.
Paint the plywood black and allow it to dry. Place the first column of bottles on the plywood. Hammer nails into either side of the neck to keep the first bottle in place. Repeat this for each bottle in the column. Place the next column of bottles beside the first and repeat.
Paint the PVC and T-joints black and set aside to dry.
Insert a T-joint into each of the cut ends of the hose that enters and exits the bottles.
Measure and cut the PVC pipe to connect the T-joints. Apply glue to the joints and allow it to dry.
Run PVC pipe to the storage tank that will hold the water. Water will rise as it heats, creating a thermosiphon to slowly draw water up. Hot water exiting the top of the columns of bottles should enter the top of the tank, and colder water that goes to the bottom of the columns of bottles should exit the bottom of the tank. Repeat this process as often as you wish to make enough hot water for your needs.
You could also pipe water directly to wherever you want it.