As you all recall, Belonio and I, using the same reactor and the same burner,<br> report a difference in boiling times.<br>I was bringing a liter of water to a boil in about half the time that Belonio was reporting.<br>I assumed this was because of the dome.<br>
But this assumption now appears to be completely wrong.<br><br>The dome does not reduce in any way the amount of time it takes to bring a liter of water to a boil.<br>In an experiment this morning, I took the dome off the burner<br>
and put the pan of water at exactly the same height as if the dome were in place.<br>I did a second experiment with the dome in place.<br>The boiling times were exactly the same with or without the dome.<br>I apologize to you all in leading you to think that thermal radiation was making a big difference.<br>
<br>So now the only thing that remains to account for the difference<br> in boiling times between Belonio and me is the burner housing that I put around the burner.<br>The burner housing feeds secondary to the burner holes.<br>
What you see here:<br><a href="http://www.youtube.com/watch?v=nZDt8DfgSls">http://www.youtube.com/watch?v=nZDt8DfgSls</a><br> appears to be just as efficient as what you see here:<br><a href="http://www.youtube.com/watch?v=yO3jcbQj-GI">http://www.youtube.com/watch?v=yO3jcbQj-GI</a><br>
<br>Here is a picture of the burner with burner housing:<br><a href="http://dl.dropbox.com/u/22013094/150%20Gasifier/Boiling/IMG_1024a.JPG">http://dl.dropbox.com/u/22013094/150%20Gasifier/Boiling/IMG_1024a.JPG</a><br>The two parts are welded together.<br>
<br>Also I did another test in which I boiled water without the dome -<br> but this time at about one inch lower than the dome pan height.<br>This put the pan one inch closer to the flames.<br>Again there was no difference at all in boiling times.<br>
<br>Also I took several temperature readings:<br><ol><li>with the probe as close as possible to the blue flames: 646 C (probe turned red)<br></li><li>with the dome in place and at the top of the dome: 463 C</li><li>with the dome removed but with the probe at the same height as if the dome were there: 532 C (probe turned red)<br>
</li><li>with the dome and with a pan of water above it: 390 C (probe situated in between the two)</li></ol><p>Thanks.</p><p>Paul<br></p><br><br><div class="gmail_quote">On Thu, Mar 15, 2012 at 9:26 AM, Tom Miles <span dir="ltr"><<a href="mailto:tmiles@trmiles.com">tmiles@trmiles.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Alex, Paul,<br>
<br>
One option is to use a suction pyrometer in which you pull the hot gas past<br>
the thermocouple in a tube. The tube limits the radiation so you get a<br>
better picture of the true temperature. Temperatures can be about 90C (200F)<br>
higher in the suction pyrometer than in a boiler or free air. A simple<br>
version can be made with compressed air venture drawing air through a pipe<br>
with a thermocouple inside it.<br>
<span class="HOEnZb"><font color="#888888"><br>
Tom<br>
</font></span><div class="im HOEnZb"><br>
-----Original Message-----<br>
From: <a href="mailto:stoves-bounces@lists.bioenergylists.org">stoves-bounces@lists.bioenergylists.org</a><br>
[mailto:<a href="mailto:stoves-bounces@lists.bioenergylists.org">stoves-bounces@lists.bioenergylists.org</a>] On Behalf Of Alex English<br>
Sent: Wednesday, March 14, 2012 6:18 PM<br>
To: Discussion of biomass cooking stoves<br>
Subject: Re: [Stoves] radiant heat capture, total heat measurement<br>
<br>
</div><div class="HOEnZb"><div class="h5">Paul,<br>
So this makes sense. The screen radiates away heat leaving a cooler gas<br>
beyond.<br>
If your thermocouple were smaller or shielded the difference would likely be<br>
even greater because the thermocouple looses more heat from radiation when<br>
it is hotter.<br>
<br>
Or are there other reasons, too?<br>
Alex<br>
<br>
<br>
<br>
On 14/03/2012 7:36 PM, Paul Olivier wrote:<br>
> There are problems with what I have written below.<br>
> Let me again.<br>
><br>
> Without the dome, the probe encounters hot gases and registers a<br>
> temperature of 563 C.<br>
> It turns red hot and starts emitting thermal radiation.<br>
><br>
> With the dome, the probe encounter hot gases as well as thermal radiation.<br>
> But it only registers a temperature of 500 C.<br>
> It does not turn red hot.<br>
> Therefore the probe does not absorb thermal radiation from the dome<br>
> very well.<br>
><br>
> Thanks.<br>
> Paul<br>
><br>
<br>
<br>
_______________________________________________<br>
Stoves mailing list<br>
<br>
to Send a Message to the list, use the email address<br>
<a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a><br>
<br>
to UNSUBSCRIBE or Change your List Settings use the web page<br>
<a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists%0A.org" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists<br>
.org</a><br>
<br>
for more Biomass Cooking Stoves, News and Information see our web site:<br>
<a href="http://www.bioenergylists.org/" target="_blank">http://www.bioenergylists.org/</a><br>
<br>
<br>
<br>
_______________________________________________<br>
Stoves mailing list<br>
<br>
to Send a Message to the list, use the email address<br>
<a href="mailto:stoves@lists.bioenergylists.org">stoves@lists.bioenergylists.org</a><br>
<br>
to UNSUBSCRIBE or Change your List Settings use the web page<br>
<a href="http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org" target="_blank">http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org</a><br>
<br>
for more Biomass Cooking Stoves, News and Information see our web site:<br>
<a href="http://www.bioenergylists.org/" target="_blank">http://www.bioenergylists.org/</a><br>
<br>
</div></div></blockquote></div><br><br clear="all"><br>-- <br>Paul A. Olivier PhD<br>27C Pham Hong Thai Street<br>Dalat<br>Vietnam<br><br>Louisiana telephone: 1-337-447-4124 (rings Vietnam)<br>Mobile: 090-694-1573 (in Vietnam)<br>
Skype address: Xpolivier<br><a href="http://www.esrla.com/" target="_blank">http://www.esrla.com/</a><br>