<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head><body ><div>Hi Crispin se this idea for street vendors I have made this to be use with TLUD stoves</div><div><br></div><div>Best regard</div><div><br></div><div>Gus</div><div><br></div><div><br></div><div><div style="font-size:9px;color:#575757">Enviado desde mi Samsung Mobile de Claro</div></div><br><br><div>-------- Mensaje original --------</div><div>De: Crispin Pemberton-Pigott <crispinpigott@outlook.com> </div><div>Fecha:26/07/2014 03:15 AM (GMT-06:00) </div><div>A: stoves@lists.bioenergylists.org </div><div>Asunto: Re: [Stoves] TLUD-Oven! </div><div><br></div>
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Dear Marc</div>
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Thanks for sharing the comprehensive report and providing many relevant numbers. The duration of the burn certainly seems adequate for most baking. </div>
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Your comment on heat loss is very relevant. I caution that you cannot tell how much heat is being lost without gas measurements. You might do something that results in a lower exit temperature but an increase in CO (chemical loss) or higher dilution by excess
air (mechanical loss). You have reached the point where further development needs a combustion analyser. </div>
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If you research the Siegert Formula you will find the appropriate tool for the next stage of development of the burner and oven structure. You need three fuel-specific constants, the temperature, the CO and either the O2 or CO2 concentrations in the exit gases
to make the calculation (which gives the total heat loss). </div>
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Controlling the primary air flow will control the oven temperature. Adjusting the secondary air flow will optimise the combustion and simultaneously limit heat losses by minimising excess air. </div>
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Bread baking is slightly endothermic. You must also heat the mass of wheat to 94 degrees minimum (in the centre) and evaporate some of the moisture. It takes about 3 kw for 1 hour to bake 16 loaves of 800 g each. That is the performance of a well insulated
electric oven. That provides a comparison of what energy is need for the actual baking. </div>
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There is a rule-of-thumb for gas ovens (which you have) which is something like 1/3 the electrical efficiency. Maybe Andrew Heggie remembers it. It means it is possible to bake 16 x 800 g loaves with 9 kWh of heat. 12.8/9= 1.5 kg of product per kilowatt-hour. </div>
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<span style="font-size: initial; text-align: initial; line-height: initial;">If the fuel was 15 MJ/kg it would take 2.5 kg to bake the 16 loaves (including preheating) at 180 C.
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As you limit the losses, the smaller reactor might turn out to be adequate for your needs.
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The above baking information and numbers are based in a real 220 v, 3 kW electric oven and a modelling spreadsheet predicting the time needed to bring the dough above 93 degrees at which point it becomes bread. </div>
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The model predicted 53 minutes and the oven took 55 so the process are reasonably well understood. Bakeries normally test the centre of the loaf ensuring it is 94 C or a little higher. </div>
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Regards </div>
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Crispin </div>
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<div><b>From: </b>Marquitusus</div>
<div><b>Sent: </b>Saturday, July 26, 2014 02:46</div>
<div><b>To: </b>stoves@lists.bioenergylists.org</div>
<div><b>Reply To: </b>Discussion of biomass cooking stoves</div>
<div><b>Subject: </b>[Stoves] TLUD-Oven!</div>
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<div dir="ltr">Hi,<br>
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I'm very glad to send to inform about my last work, the TLUD-OVEN. I wanted to put together the wonderful light thermal mass ovens from
<a href="http://www.rechoroket.com/Links_to_albums.html" target="_blank">Recho Rocket</a> with the very clean
<a href="http://www.drtlud.com/" target="_blank">TLUD technology</a>, and that's it!
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The results are very promising: no smoke at all, no soot, very fast heating and very comfortable cooking, as you can leave the fire unattended for about 2h30min, and concentrate on cooking!<br>
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I think it can be a really interesting device that can allow very clean and efficient baking.<br>
I send the link to the stoves bioenergylists where I posted the file with the details:
<a href="http://stoves.bioenergylists.org/content/tlud-bread-oven" target="_blank">
http://stoves.bioenergylists.org/content/tlud-bread-oven</a><br>
I also attach the temperature profile graph and the full pdf paper with all the details.<br>
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Just comment what you think!<br>
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Marc<br>
<a target="_blank"></a><a href="www.cuinessolars.jimdo.com" target="_blank">www.cuinessolars.jimdo.com</a><br>
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