Dear Stovers Thanks Alex for the latest report. So: here is at least on empirical number from Alex's combustion analyser that confirms the output from a reasonably correct application of the Siegert formula. Well done, Siegert.
The SeTAR test protocol makes this calculation in real time (actually every 10 seconds) making it possible to chart the thermal efficiency during the burn. If you are developing a stove the usefulness is obvious: you can change the stove while it is burning (like lowering the pot a little) and see the effect it has on the efficiency. The normal result is a pretty jumpy line because of the 'snapshot' nature of the readings. What we found useful is to plot the sum of the performance to that point by which I mean a mass-compensated sum of the efficiency numbers. By the end of the test it shows the average efficiency for the whole burn of all the fuel. This is useful from the point of view that one can compare space heating stoves over a period of a whole burn, not just when things are going well. The end result is meaningful, in the sense that it predicts fuel savings relative to a baseline even if the stoves, fuels, power, burn time and refuelling method are different in each case. At an absolute minimum you need the O2 level, the temperature where no more heating is taking place (such as the bottom edge of a pot, the CO and the fuel type to apply the Siegert formula to get a % thermal efficiency. If you want to do the running average calculation the stove has to be on a scale because you need to weight the efficiency numbers with the mass of fuel burned during each interval. Regards Crispin _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://www.bioenergylists.org/
