[Stoves] Ph.D. Thesis on TLUD Stoves.
Paul Olivier
paul.olivier at esrla.com
Sun Jun 30 19:54:48 CDT 2013
Varun,
You say that with the Oorja, 70% of the total energy is delivered in
flaming mode and 30% in char mode. But would this not apply to all TLUDs?
In my case, if I leave the fan on after the flaming mode is finished, a
char mode begins. As the char is combusted, the temperature within the unit
climbs incredibly (dangerously) high.
This leads me to ask: why consume the char? Why not stop the process when
the flaming mode comes to an end? There is an inefficiency that kicks in
when char is consumed, since this takes place at a considerable distance
from the pot.
Thanks.
Paul Olivier
On Sun, Jun 30, 2013 at 8:28 AM, Varun ShivaKumar
<varun at cgpl.iisc.ernet.in>wrote:
> Dear Paul,
>
> Oorja is exactly TLUD. 70% of the total energy is delivered in flaming
> mode which involves migratory pyrolysis front (or flame front as discussed
> in chapter 5). Only 30% energy in the left over char is delivered in the
> char mode in the manner described by you. You are correct in saying that it
> is not TLUD in this char mode (in fact it is co-current in char mode as
> opposed to counter-current in flaming mode) . But in flaming mode it is
> exactly TLUD. I kindly request you to take this into account when you
> discuss this at Aprovecho.
>
> Varun
> ------------------------------
> *From:* Stoves [stoves-bounces at lists.bioenergylists.org] on behalf of
> rongretlarson at comcast.net [rongretlarson at comcast.net]
> *Sent:* Sunday, June 30, 2013 3:17 AM
> *To:* Discussion of biomass cooking stoves; Paal Wendelbo
>
> *Subject:* Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>
> Paal and list.
>
> The thesis was inspired by the Oorja, and helped to improve it, but
> the thesis itself is much more general. The word "Oorja" rarely appears.
>
> Does anyone know if there have been any Oorja test results reported by
> any of the major stove testing labs (Aprovecho, EPA, etc)?
>
>
> Ron
>
> ------------------------------
> *From: *"Paal Wendelbo" <paaw at online.no>
> *To: *"Discussion of biomass cooking stoves" <
> stoves at lists.bioenergylists.org>
> *Sent: *Saturday, June 29, 2013 1:18:21 PM
> *Subject: *Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>
> Ron and Paul O
>
> Into the advertising leaflet of the Oorja stove is written “at end of
> flame very little aches is left” and I have tested the stove and can
> confirm it is right. I could see sparks up in the air above stove. The grid
> of cast iron 10 mm thick was white yellow about 900-1000˚C and quite
> dangerous to handle to take out some few char left.
>
> With regards Paal W
>
> *From:* rongretlarson at comcast.net
> *Sent:* Thursday, June 27, 2013 10:51 PM
> *To:* Discussion of biomass cooking stoves<stoves at lists.bioenergylists.org>
> *Subject:* Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>
> Paul etal:
>
> I should have added there are some good discussions of the same
> stove/cylinder (glass) with numerous types of fuels. And he shows they
> obey the same laws - can predict performance (front velocity, power level
> (?) - given the superficial velocty.)
>
> Ron
>
> ------------------------------
> *From: *rongretlarson at comcast.net
> *To: *"Paul Anderson" <psanders at ilstu.edu>
> *Cc: *"Discussion of biomass cooking stoves" <
> stoves at lists.bioenergylists.org>
> *Sent: *Thursday, June 27, 2013 2:44:07 PM
> *Subject: *Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>
> Paul:
>
> I know very little on the Oorja stove. But the thesis is mostly
> (entirely?) on a packed bed, top lit. It is on the migratory pyrolytic
> front (MPF) - so should be applicable to all TLUDs. I would like to hear
> from any/all on whether I am getting the right reading about NOT consuming
> the char.
>
> Ron
>
> ------------------------------
> *From: *"Paul Anderson" <psanders at ilstu.edu>
> *To: *"Discussion of biomass cooking stoves" <
> stoves at lists.bioenergylists.org>
> *Cc: *rongretlarson at comcast.net
> *Sent: *Thursday, June 27, 2013 2:12:57 PM
> *Subject: *Re: [Stoves] Ph.D. Thesis on TLUD Stoves.
>
> Ron,
>
> I am in Uganda now and have not had a chance to see the thesis. Thank
> you for the comments.
>
> About #3, the Oorja stove is rather heavy for turning over, has a smallish
> fuel chamber meaning not much char and only short TLUD burns, and has a
> loose cast iron cup in the bottom that would fall out if the unit is tipped
> over to remove the char. It is designed to NOT be tipped over for saving
> char.
>
> It is intentionally designed to have continuous burning with the fire in
> the bottom consuming char. And when doing that, the Oorja is NOT
> operating in the TLUD mode which is specifically characterized by the
> migratory pyrolytic front (MPF), but the Oorja is not with MPF after the
> rather small initial load of fuel has been pyrolyzed.
>
> Therefore, the Oorja (and most others with forced air FA) essentially is
> NOT a TLUD because it is operated without the MPF except for the initial
> batch of fuel.
>
> I will be addressing this topic more at the Stove Camp at Aprovecho on 22
> - 26 July.
>
> Paul
>
> Paul S. Anderson, PhD aka "Dr TLUD"
> Email: psanders at ilstu.edu Skype: paultlud Phone: +1-309-452-7072
> Website: www.drtlud.com
>
> On 6/27/2013 2:43 PM, rongretlarson at comcast.net wrote:
>
> Julien and list
>
> 1. Thanks very much for providing this cite. I have read most and find
> it to be a well done thesis. I wish we had more like it.
>
> 2. The concepts of char and TLUDs are in here thoroughly. But nothing on
> the idea of a stove designed to make char. All char is presumed and
> desired to be consumed.
>
> 3. My conclusion (would like to hear more) is that a good case is made
> (not intentionally) for NOT consuming the produced char in a TLUD (this
> one fan-powered and widely sold in India as the "Oorja" (started by BP)).
> Very little gain in overall efficiency as the char is consumed.
>
> 4. A major advance was his study of the importance of ash in this "char"
> period as a poor radiator - thereby responsible for (undesired) high char
> temperatures.
>
> 5. Most everything shown as a function of superficial velocity (Vs) -
> with 16-17 cm/sec shown as key dividing point in stove behavior.. Above
> which velocity one swtches from char production to char consumption. I
> have not seen this before.
>
> For his highly automated fan system, measuring Vs was apparently not
> so difficult. Anyone able to give a way to get an easy estimate of Vs,
> when there is only natural draft?
>
> 6. Quite a bit on the importance of low emissions of CO.
>
> 7. Good information on both the experimental and computational side of
> top-lit (packed bed) stoves. Not much here for rocket stoves.
>
> Have I got #3 right?
>
> Ron
>
>
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--
Paul A. Olivier PhD
26/5 Phu Dong Thien Vuong
Dalat
Vietnam
Louisiana telephone: 1-337-447-4124 (rings Vietnam)
Mobile: 090-694-1573 (in Vietnam)
Skype address: Xpolivier
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