[Stoves] Water heating fuel efficiency formula

[Lanny Henson]

Jock,

 >Jock said "I find that a flat bottom container set inside a closed kettle 
(domed container such as a modified Weber grill), boils water beautifully. 
The benefit is that ALL surfaces of the pot and the top surface of the water 
are exposed to temperatures above 350 degrees F. "

This is what I do with my School Lunch Cooker which uses an exhausted pot 
shell that totally encloses the pot. The exhaust stack provides some draft, 
but extra draft is not necessary for my design. The main purpose is to 
exhaust the fumes up out of the cooking space. Cook space air pollution can 
be a problem outside as well as inside.
Lanny