Solar Panel With Plastic Bottles – A Pensioner’s Revolutionary Invention

by Paul Ciocoiu · August 14, 2015

Solar panels are starting to become an ever visible presence around us amid growing concerns for the environment and the personal goal of saving money by using ingenious solutions that positively impact on the natural environment. Several years ago, an invention of a Brazilian pensioner, Jose Alano, would hit the headlines around the world: the former mechanic built a plastic water bottle based water heater. Since then, thousands of people in southern Brazil have benefited from Alano’s invention, saving money while reducing waste, thanks to the involvement of governmental bodies and NGOs. In some towns, local councilors decided to implement the invention to save money in producing thermal energy.

He says the idea struck him after he piled plastic bottles, cartons and other recyclable waste at home and when he realized he had a problem: a room full of rubbish. Using his basic knowledge on solar water heating systems, he and his wife built an alternative version using 100 plastic bottles and 100 milk cartons. His invention soon drew the attention and awards from environmental publications and associations. Even though he patented his invention, he made it available to use as a not for profit design, hence the quick spread of such alternative solar panels across Brazil.

But how does his invention work? In brief, the plastic bottle solar water heater is based on the thermosyphon technology which is used in many solar water heaters. It is a gravitational heating system which makes use of the circulation of water based on density; hot water which is less dense moves upwards while the cold water which is denser moves down. Alano estimates that to heat water for a shower of one person, a one square meter panel would be enough.

More precisely, Alamo used a water tank which supplies cold water to the plastic bottle panel. The sun heats the water which then goes up and is collected by the pips which go to the bathroom. The cartons and the PVC pipes are all painted in black matt paint to attract heat. The panels must be placed at least 30 cm below the tank and be sited on a south facing wall or roof, as seen in the sketch below. Alamo recommends plastic bottles are replaced every five years because they become opaque in time.