Appropriate Technology: Solar Water in Poor Cairo Neighborhoods
Posted on September 7, 2009 Comments (8)
Solar CITIES’ hot water systems are constructed from recycled materials and are uniquely tailored to the parts of a city where water and electricity availability are often sporadic. “The problem with professional solar hot water systems is that they’re made for cities with continuous water,” Culhane said. By contrast, Solar CITIES’s water heaters use a city’s water when it’s available but draw from a backup storage tank when it’s not.
The setup consists of an insulated rectangular box covered in clear glass or plastic on one side. Inside the box are copper tubes wrapped in sheets of aluminum, which are painted black. Sunlight striking the darkened aluminum is converted to heat, which is then used to warm water flowing through the pipes. The glass sheet on top of the box prevents the heat from being carried away by wind.
Solar CITIES also installs biogas reactors, which are based on designs Culhane saw while working in India. The reactors use microbes harvested from animal guts to break down food wastes into flammable gas that can be used for cooking and heating. If necessary, the reactors can draw hot water from the solar water heaters to maintain the warm temperatures the bacteria need to survive.
By attaching a simple plastic tube to the reactors, gas can be piped down several stories for residents to use. “In 24 hours, you’ve got 2 hours of cooking gas from yesterday’s cooking garbage,” Culhane said. The biogas reactors provide a more reliable supply of cooking gas than most residents currently have.
Awesome, I love to see people using engineering to make life better for those that can truly use help.