[Stoves] TLUD-Oven!

[Mike Mahowald]

Looks like a great oven we built a few of them in Haiti. But we decided
there was plenty of heat left over after boiling water making rice and
beans while also cooking sausage or tomato sause all with one TLUD.
Here is a picture of us cooking and baking bread last weekend.

On Sunday, July 27, 2014, Marquitusus <marquitusus at hotmail.com> wrote:

> Hi James,
>
> Right, my oven followed the rechorocket one as close as I could. They are
> Jon and Flip, my mentors since now!
>
> You are right about door heigh to dome heigh, that, as far as I know, it
> should be about 0,6. BUT this only applies when you want the gases coming
> out of the oven through the door. On my case, as the gases are escaping
> through the top hole, I can make the dome lower, which is a good idea for
> efficiency, as you normally bake in the low part of the oven, and, on the
> other hand, you have the dome walls closer to the food, giving it more heat.
>
> Also, as you say, if you want the gases coming out through the door, is
> better to put the fire entrance near the door and then force the gases to
> travel to the back, to the top and finally to the door again to exit. This
> is a very interesting model of heating. In my case, I put the fire entrance
> hole in the center of the base, as I have a little diffusor (a round granit
> stone piece) that spreads the flames and gases all around the dome walls,
> and logically in this case you have to put the exit hole also in the
> center, to encourage the flue gases to "lick" the walls before going out.
> Anyway, the model of gases circulation you purpose is very interesting and
> I think it can work very well. Sure I would built one of these if I had
> time! and enough space in my house!
>
> In your Truck Oven, I wonder if you are thinking about putting a rocket
> stove or a TLUD in your firebox? Or will you leave it just empty to make a
> simple fire?
>
> Marc
>
>
>
> ------------------------------
> Date: Sat, 26 Jul 2014 11:52:09 -0700
> From: james at hensel.com <javascript:_e(%7B%7D,'cvml','james at hensel.com');>
> To: stoves at lists.bioenergylists.org
> <javascript:_e(%7B%7D,'cvml','stoves at lists.bioenergylists.org');>
> Subject: [Stoves] TLUD-Oven!
>
> Marc,
>
> I watched a TLUD oven work at stove camp on Thursday with the gas exit at
> the top of the dome.  I believe this oven was built by the rechoroket folks
> although I was a bit confused about that.  It looked very similar to yours.
>  In my mind a small dome with a hole at the top with a door almost the same
> height as the dome.
>
> My experience is with black hearth ovens, both Kiko Denzer's *Earth
> Ovens * http://www.amazon.com/Build-Your-Own-Earth-Oven/dp/096798467X and
> Alan Scott's brick ovens http://ovencrafters.net/ as well as a brick oven
> yahoo group https://groups.yahoo.com/neo/groups/brick-oven/info
>
> In the case of black ovens like mine, the dome of the oven is appreciably
> higher than the door lintel.  In the case of both of my ovens, the door is
> about 10" high and the interior dome height is 16".  This ratio of door
> height to dome height was also talked about in *The Bread Ovens of Quebec* [out
> of print but I have a photocopy here somewhere]. This ratio optimizes the
> draw for the fire without excessive cooling in the oven.  I don't think
> there is any empirical data on this rather I think it was learned through
> trial and error.
>
> A "white oven" is one where the fire box is separate from the oven itself
> unlike a black oven where the fire is built on the oven hearth. I think
> there are two styles of white ovens. In one style, the flue gases travel in
> flues immediately adjacent to the oven but not in the oven itself and in
> the second, the flue gases travel through the oven.
>
> Your TLUD oven has the flue gases traveling through the oven. If I were to
> apply what I know and see from my black ovens to your white oven, I would
> make the oven shape much like a black oven paying more attention to ratio
> of the dome height to the door height.  I would not put the flue exit at
> the top of the dome.  Rather I would make the flue gases exit the door and
> then add a chimney in front of the door - just like my black ovens.
>
> I believe this circuitous route of the flue gases would improve the
> heating efficiency of the oven, but that is just an educated guess.
>
> While I am at it, there are other changes I would make to the TLUD Oven.
>  I would not connect the TLUD at center of the bottom of the oven.  Rather,
> I would attach the TLUD near the doort of the oven and force the flue gases
> to travel under the hearth (think of it as a large deflector plate) all the
> way to the back wall  of the oven and then have the gases exit upward at
> the back of the oven hearth and back out the front door.  You could play
> around with the thickness of the hearth as a way to adjust the relative
> heat of the hearth. You may want the hearth thicker at the front where the
> flue gases first contact the underside of the hearth and then thinner
> toward the back as the gases cool a bit.  Alternatively, you may want a
> true deflector plate below the hearth so the heat is more diffuse when it
> hits the underside of the hearth.  Here is a picture of the general idea.
> http://brickovendiaries.wordpress.com/2011/04/01/initial-white-oven-design-for-mobile-truck/
>  This is not a TLUD of course, but the rest is similar.
>
> Hope this helps,
>
> Jim Hensel
> Portland, Oregon
>
>
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