NEW! Crowdfunding campaign ARETHA Project

ARETHA is a new method to produce hot water from the sun, using low cost materials and without any particular expertise. Anybody can build an ARETHA solar panel of any size.
Traditional photovoltaic or thermal solar panels are too expensive for most people in developing countries, especially in small and isolated villages, because of material import and production high costs. On the contrary, ARETHA panel can be made from local material: wood, wool, car radiators, transparent plastic panels.
The ARETHA concept consists in producing hot air which heats water through an high efficiency thermal exchanger, built for a different purpose: the car radiator. Every car has to dissipate the heat produced by the engine. This function is performed by the radiator which promotes the thermal exchange between the water circulating into the engine and the external air.
In the ARETHA case the radiator works in the opposite way: it transfers heat from the hot air to the cool water of a closed circuit. Hot water is then stored into a thermal insulated tank, close to the panel.
ARETHA can be made with low cost and easy-to-find materials:
  • any insulation material as fiberglass, rock wool, sheep wool;
  • transparent materials as polycarbonate;
  • a car radiator for every 8-10 square meters (sqm), recovered from a car-wrecker.
A detailed description of ARETHA is in the section "Operating principles".
A 10 sqm prototype of ARETHA solar panel has been built in Milan (Italy) by a team of retired technicians who shares the love for DIY, solar energy and technology for social purposes. The project has been funded and encouraged by two no-profit associations: CISE2007 and GREEM.