By attaching a grid-like pattern made of 66 beer bottles to his roof, Ma Yanjun, a farmer from China, created a solar-powered water heater for his family. He said that he invented the device so that his mother could shower more comfortably.
The mechanism is simple: Throughout the day, the sun heats the water inside the bottles, which are connected to each other. When a member of Ma Yanjun's family wants to take a hot shower, hot water slowly runs through the attached bottles into the shower piping. The three family members can each take a hot shower every day.
In Ma Yanjun's Qiqiao village, which is in the Shaanxi province, several of his neighbors have asked him to build them the solar-powered water heater, as well. (Sounds like they'll have a good time collecting their supplies.)
While innovative, Ma Yanjun's invention is not the first do-it-yourself success story for a solar-powered device. Other backyard enthusiasts have used other materials, such as soda cans and other metals, to create solar water heaters.
The Department of Energy also has a page on solar-powered water heaters for environmentally and economically minded people interested in learning more about this heating solution.
via: Scientific American blog
Read: Homemade Soda Can Solar furnace