[Stoves] Flue Gas Analysers

[Tami Bond]

Hi Stovers

> Could we have some comments about how and if flue gas analysers could be used
> for stove testing equipment
>   
I do have some comments on this.

First, the instruments at Madur look better than the ones we were 
investigating a few years ago. Flue gas analyzers were of course the 
first thing we considered when spec'ing the Aprovecho lab. Major 
disadvantages included: (1) No real-time output (thus, no way to average 
fluctuating combustion) and (2) CO2 inferred from oxygen measurement. 
The Madur instruments-- and probably others by now-- do not have these 
limitations.

With regard to (2), the advent of small, cheap infrared (IR) devices for 
measuring CO2 directly has been much cheered by me. It's a fantastic 
development that's only become public in the last ~4 years. For many 
stoves, one really cannot infer CO2 from O2. One needs an infrared 
analyzer. That's because the dilution above a traditional stove results 
in O2 very near ambient O2, the difference is small, and the uncertainty 
is high. This may not be true if you are measuring just atop a good 
gasifier.

Always be sure to check the detection ranges before buying, to make sure 
they meet your needs. Most exhaust gas instruments are made for vehicles 
or stationary boilers. They may not be optimized for stove measurements. 
If an instrument reads 0-10% CO2, it may not have very good resolution 
around the 1% CO2 in the diluted air above a stove.

Hope that helps.

Tami


*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
Assistant Professor                       
Arthur & Virginia Naumann Endowed Faculty Scholar
Dept. of Civil & Environmental Engineering
University of Illinois, Urbana-Champaign
Newmark Civil Engineering Laboratory, MC-250   
205 N. Mathews Ave., Urbana, IL 61801   USA