TheNaib writes -
This project will create a DIY solar hot water heater for less than five dollars (if you have access to a garbage dump). It will allow you to see the principles of solar water heating in action, and is highly customizable.
Its a great way to learn about using the renewable energy of the sun to produce useful effects, in this case hot water. You can use these instructions to build a device that will actually heat enough water to use in the home, but it would require modifications.
This device is more useful for camping or as a science experiment and teaching tool. A word of caution it is possible to create very hot water with this technique and you should be careful not to burn yourself. You can find this and more great DIY projects relating to renewable energy, solar cooking, and sustainable design at The Sietch
By using the sun instead of fossil fuels to heat your water you will be preventing dangerous greenhouse gasses from being released into the atmosphere, helping to prevent global warming.
HOW TO – Make a solar thermal water heater for less than five dollars – Link.
Beer bottle solar-powered water heater – Link.
DIY Solar heater – Link.
HOW TO – Make a homemade solar water heater – Link.