Build It Solar has a great DIY article about an easy solar hot water heater (a thermosyphon system) made by a resident of Costa Rica named Peter. Peter wanted to build a simple, rugged, inexpensive system to provide hot water for showers:
Like most houses in Costa Rica, our casita in Monteverde had no hot water. Our two showers were fitted with electric shower heads. At best, these take a little of the chill off the water. Sometimes it is difficult to know if they are even working, yet they use a great deal of electricity to do even that modest job. Further, having electrical wires attached to the shower head does not inspire confidence. Solar hot water seemed to present a great opportunity to generate more and hotter water at minimal cost, while being safer and more ecologically sound. Since solar is not commonly used locally, I also wanted to build something that could serve as a model for others, using readily available, inexpensive parts and simple construction.
Peter writes that because he lives in a remote community, the design needed to use readily available materials, few tools and his limited plumbing skills. His collector panels use galvanized steel roofing and chlorinated polyvinyl chloride (CPVC) pipe. The unit is located on a south-facing, 10° pitched roof (his latitude is fortunately also 10°) and painted with black roofing paint. The thermal rating for CPVC is close to the operating temperature for thermosyphon heaters, so Peter modified his design to provide extra ventilation and prevent overheating.
About 300 USD in all new materials were used. The result?
It was a smashing success from the beginning.
We love it. For more photos and information, see: A Simple DIY Thermosyphon Solar Hot Water Heater for the Tropics.