I found this old article from back in 2007. What a great way to do a little double-time recycling. After guzzling a ton of tasty soda, you can now get even more out of your old plastic bottles by using them to heat your water! Temas says:
"The government of the southern Brazilian state of Paraná has been conducting an interesting experiment in environmental design utilizing waste materials.
Since August 2006 state agencies have sponsored projects to construct solar water heaters constructed from used PET bottles and “long life” (aseptic) milk packaging. So far some 3,000 such heaters have been constructed and put into operation in 254 Paraná municipalities, in the process diverting about 1.2 million PET bottles and aseptic milk cartons that otherwise might have gone into landfills. It takes 200 PET bottles and 200 aseptic milk cartons to construct the solar water heater array.
It’s estimated that if the heater is used to heat the water for two bathrooms, it can save as much as 120 kilowatts per month."
However, if you're not quite into the extreme DIY approach as our friends in Brazil have so brilliantly developed, check out our approach, developed and designed right here in the heartland of the USA at www.simpledrainback.com
Read more about the PET bottle solar hot water heater here: http://www.temasactuales.com/temasblog/environmental-protection/waste-recycling/a-solar-water-heater-made-of-pet-bottles/