
by Susan DeFreitas | EarthTechling.com

In cities throughout India, street vending is a way of life. Christopher Gregory of Bent Harbor, Michigan, has a vision to reduce the carbon footprint of India’s streetfood carts using locally-available, sustainable materials: the Solar Thattugada.
This concept design is similar to the carts currently used throughout India, with the addition of low-tech solar hot water system. Composed of a copper water coil, rubber gasket, coated aluminum liner, fiberglass insulation, and an ABS plastic shell–protected by glass and supported by a layer of corrugated sheet metal–this system uses solar energy to heat water.
To produce hot water, the vendor simply pumps in cold water and adjusts the solar thermal system, via four attached cords, to pick up the best angle of the sun. After the water has been heated, it is delivered to a stovetop set-up via black plastic tubing, where it can be used to keep hot foods hot, via a double broiler, or directly for hot beverages, such as tea.
Gregory developed the Solar Thattugada concept in conjunction with a class of MBA students, and refined this design after a research trip to India.
http://www.earthtechling.com/2011/07/solar-powered-tea-street-cart-anyone/