Eco-innovators from all over the world have been rising to the GE Ecomagination Challenge, which this year seeks to power the homes of the future. Among them is Debesh Raj Bhattarai, General Secretary for the Society of Nepalese Architects, who hails from Baneswor, Kathmandu.
Bhattarai’s entry in the competition is a simple passive solar hot water system based around a commodity that can be found cheaply almost anywhere–a basic plastic barrel–used in conjunction with an innovative HDPE solar heat absorber.
This heat absorber is, essentially, a large coil of black plastic tubing, connected on both ends to the plastic barrel, which is set at an elevation above it. As water is heated within the coil during the heat of the day, it rises, forcing cooler water from the other end of the tube to refill it.
According to Bhattarai, this entire do-it-yourself solar hot water system can be constructed for around $70, putting it within the reach of many around the world currently doing without hot water at home.