the Jompy

David Osborne. The Jompy water heater.This was one of the entries into the Shell World Challenge last year.  It is very clever: a flat coil of hardened aluminum alloy, like a flat skillet, that sits between the fire and the cooking pot.  What looks like a handle is attached to water, cold or contaminated which circulates through the coil, is heated and comes out of the other end of the coil hot and boiled. 

Although in use in South Africa, Kenya and India, in theory it is the same as the hot water on demand burners which are slowly replacing the elephantine hot water tank that lurks in most basements.  The Jompy is much more minimal however, and consequently more adaptable to different conditions and uses. 
David Osborne, a plumber and gas fitter from Troon in Scotland was on his honeymoon in a water-challenged part of Africa and figured out this inexpensive way of boiling water with fire already doing some other task such as cooking food. 

The website, celsiussolar.com is a bit cumbersome, but all the information is there, plus various videos, including the World Challenge introduction. 

David Osborne. The Jompy in demonstration in Kenya by Celsius Solar's enthusiastic representative, Kalfan Okoth, just reminding everyone that this is a Scottish product.