[Stoves] Top lit updraft combustors

Andrew Heggie aj.heggie at gmail.com
Sat Dec 16 05:48:07 CST 2017


On 16 December 2017 at 00:08, Ronal W. Larson <rongretlarson at comcast.net> wrote:
> List, cc Andrew and Norbert
>
> 1.  Thanks to you both.  So we are all on the same page, the message the
> Andrew received at 15:36 PM was received at 9:38 AM Denver time.

My bit of the world gets to see the sun 5 hours before yours!


> [RWL3:  Norbert - my interest in this topic is from the perspective of
> char-making stoves (both cooking for this list and heating from yours).  In
> your world, would the practitioners accept the idea that your “kilogram of
> fuel” be modified by subtracting out the fuel that went into char?   (I’m
> simplifying here, because char has higher energy density).  I’d appreciate
> anything more you could add on “harmonizing” with char in mind.

Norbert mentioned one of his designs that was shut down after the
flaming finished and left char which he then collected in the ash
before his next burn. I just wonder how Norbert values this char? I
assume the reason he shuts down the masonry heater while there is
still char to burn is that it is cleaner in the flaming phase?
>
>
> Yes but of course we would be interested in figures for all
> cookstoves, not just TLUDs.
>
> What I want to know is how cheaply could acceptably accurate and
> precise (i.e. repeatable) protocol and equipment be made?
>
> [RWL4:   I think Andrew is (tn part) here raising the issue of what we call
> a WBT - water boiling test.  A certain load for the test.  Do you see
> anything wrong with a 5-liter standard cookpot of water, where you measure
> both temperature gain and evaporated loss?  (with arguments about how to
> handle char.)  Perhaps describing a little more on your thermal equivalent
> of a reproducible load (with char-making, if you can), valid anywhere on
> earth.

I was thinking more about the simple metric of PM per kg or MJ of fuel
burnt, rather than a full blown test to simulate cooking, bearing in
mind the current concerns.

The thing is I can see official miles per gallon figures for my car
and I can take various journeys from full tank to full tank and
compare them. I see the official figures are not much use to me, I
plainly drive differently from the computer software doing the
official test. Fuel economy is but one part of choosing a car. So I
can see a full cooking test being fraught with difficulties but
precision (repeatability) would be a core issue.

Norbert aims to run his heaters flat out, no turn down, I think this
is because he can get a cleaner more complete burn, if I am frying I
don't need turn down but I do for steaming or boiling+simmer
(acknowledging simmering only matches heat loss from the pot), given
that TLUD with controlled primary air is particularly clean and a
batch burn it would seem to lend itself to this sort of masonry
heater.

As I have said I have not been involved with testing other than my few
home comparisons. I did not think Dean Still or others at Aprovecho
claimed their WBT was the be all and end all of testing, it was
something they used and seemed to be picked up in the absence of other
protocols. Now we are seeing criticisms but unfortunately Dean and his
co workers have been so offensively criticised on here that they no
longer reply to give their views.
>
>  Do you think that your test approaches have helped or hurt your industry?
> (EPA and all the other tests.)  And users?
>
> I know from watching your video that the emphasis there was on carbon
> buildup on filter paper.  And “our” tests seem to have some of that.  I
> personally doubt  that individual “stove activists” on this list will want
> to get into the detail you showed on your video, but maybe you could say
> more - and about the other hard one: CO.

Yes a simple discussion of what and how things are measured would be good.




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