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Dear Julien</div>
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Taking only your last point, if the heat transfer efficiency is known, the heat gain known continuously and a known mass change, can be, particularly late in the burn, be translated into an understanding of what is burning. This would be very helpful for analysing
TLUD's. </div>
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More later of the signal delay and quantifying and correcting experimental and systematic errors...</div>
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Crispin </div>
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<div>Hi Crispin;<br>
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A water heat exchanger is a reasonably inexpensive option <br>
(<a href="http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/2015-June/010408.html" target="_blank">http://lists.bioenergylists.org/pipermail/stoves_lists.bioenergylists.org/2015-June/010408.html</a>)<br>
but I expect that there is a bit of a lag in responsiveness. I think it will be important to make sure that the mass of water is as small as possible so that the rig is responsive to changes in time and magnitude.
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I have been looking into heat flux sensors, such as the one sold by Huksflux<br>
<a href="http://www.huksefluxusa.com/HF01.php?pSection=heatFlux" target="_blank">http://www.huksefluxusa.com/HF01.php?pSection=heatFlux</a><br>
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That is a more expensive option at $5,600 CDN not including the data logger. If a heat flux sensor was used, it would have to be calibrated against heating water in various pot geometries.<br>
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<div>The above sensor has a maximum operating temperature of 800 °C, and a ND-TLUD running on a reactive bed of fuel could surpass that.<br>
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<div>Since in the course of pyrolyzing a batch of fuel, the power output of a ND-TLUD can decrease, characterizing the temporal profile of energy flux is more informative that water-boiling tests, because water-boiling is only an average. A change in energy
output from a ND-TLUD may affect the interpretation of its turn-down ratio.<br>
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<div>I suspect that the decreasing power output from a TLUD is caused by diversion of some pyrogas to secondary char as the height of the char bed increases. The power decrease is greatest when primary air is greatest, and the char bed is hottest. The power
decrease can be small to none if the TLUD is run at its lowest primary air setting.<br>
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Cheers,<br>
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Julien.<br clear="all">
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<div dir="ltr">Julien Winter<br>
Cobourg, ON, CANADA<br>
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