Hot Water heating it is one of the most cost-effective uses of solar energy. If you are ingenious like Ma Yanjun, of Qiqiao village, Shaanxi province, you can make it yourself and its completely free. "I invented this for my mother. I wanted her to shower comfortably."
66 beer bottles are connected to each other so that water flows through them; it looks like thin plastic tubing is going in and out of each bottle . Sunlight heats the water as it passes slowly through the bottles before flowing into the bathroom as hot water. Ma says it provides enough hot water for all three members of his family to have a shower every day, although we doubt it will push the volume for any jazzy shower heads. ::Annanova