Thermal rating and design of woodstoves: A new approach

The paper is divided into two parts. In the first part, the results of tests on 13 stoves currently being marketed in India, compared with two traditional stoves, are presented. The bulk of the tests (about 140) pertain to variation of efficiency against fuel burning rate. Also, a few tests on the variation of chimney heights (18 tests) and damper position (20 tests) were conducted. The levels of efficiency were quite low on account of improper dimensioning of the stoves. Except for two stoves, all recorded consistently low efficiency figures. In the second part of the paper, the results of tests on combustion chambers of different sizes, ranging from a diameter of 180 mm to 500 mm, are presented in the form of design equations. The optimum length to diameter ratio is about 0.35, and optimum height of the ash chamber is 0.2 times the height of combustion chamber. A new approach to the sizing of combustion chambers is presented.