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Post by Jura on Oct 28, 2019 13:26:06 GMT -8
.... Would love to see any pics you have of those stoves. Current state of affairs in the vortex cook stove world :-) :  |
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cork
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Post by cork on Oct 30, 2019 6:26:10 GMT -8
Thanks Trev for your explanation, however my recollection of your flue system is single wall and then twin wall.This would have a small mass and a large surface area making it a very poor "thermal flywheel". Your cowl seems relatively heavy and uninsulated so may be there is some condensation going on with it evaporating as it runs down using up a lot of energy this could cycle downwards.Also with the stronger draw the draft regulator could be open more often.
Watching a video of a build by Patamos he said his bypass is only just over half system size to prevent a runaway fire in the event of forgetting to close it. This seems sensible to me but I do not want to deviate to much from your design. Hoping I am not testing your patience. James.
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Post by Vortex on Oct 31, 2019 2:40:01 GMT -8
The lower inner chimney that is hidden inside the stove is made of 5mm thick steel wrapped in 1" ceramic blanket and high temp aluminium tape. The bypass enters through the top part and does a 90 degree turn, so the hot exhaust gases are being blasted against the inside of it. On top of that there is a heavy castiron collar with built in damper that transitions to the 1mm stainless pipe. I'm guessing it's mainly the 5mm internal chimney that is storing some of that initial blast of heat and re-radiating it back into surrounding materials and exhaust gases. I could well be wrong though. Unfortunately it's impossible to get at the internal chimney without taking the outer chimney off so I cant see a way to monitor the temp of it while it's running. This is the best picture I can find of it before it got wrapped in the blanket and foil:  .... Would love to see any pics you have of those stoves. Current state of affairs in the vortex cook stove world :-) Thanks for the picture Rafał, You've made good progress, not far to go now. |
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cork
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Post by cork on Oct 31, 2019 11:37:17 GMT -8
As you have expansion gaps on the top plate, are the steel side panels installed not quite into the inner radius of the angle irons?
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Post by Vortex on Oct 31, 2019 14:17:10 GMT -8
If you mean on these upright internal corners. I made the sheet steel panels so each would overlap the next going around clockwise. I left a couple of millimeters off each one for expansion.  |
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cork
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Post by cork on Nov 1, 2019 10:48:54 GMT -8
Yes that answers my query thanks very much. As regards monitoring flue temperature I was thinking of using a magnetic thermometer, even tough the probe ones are more accurate I read somewhere that they should be located at least 18 inches away from the stove. This would be to hard to read unless it had a remote reading dial/screen which for me looks to expensive. I hope a magnetic one will be good enough when I get used of operating the stove.
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Post by Vortex on Nov 1, 2019 11:44:43 GMT -8
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Post by Jura on Nov 3, 2019 23:58:29 GMT -8
I have been loaned a Testo 330 2LL but don't have the software to plot the graphs, if anyone can help me out with that I'd be grateful. Does your Testo offer functionality to write down the results in a form of an excel table? Do You know what kind of soft Peter uses? |
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Post by Vortex on Nov 4, 2019 2:23:08 GMT -8
I looked online and found Testo make a program called Easyheat, but it's 100 Euro for the full version that makes the graphs and I've only got a loan of the machine. I've never used one before so don't know much about them. It does write a log of results in real time with a new line about once a second, didn't notice an option to save it as a .xls file. I'll have another look.
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Post by Jura on Nov 4, 2019 3:31:38 GMT -8
I just had a few min to google the issue in the morning and ended up with the "comsoft-basic-5" as a software from Testo official website. Priced approx. 17€ www.testo.com/pl-PL/comsoft-basic-5/p/0572-0580. The results were PM'ed to you  and off to my Humanure Hacienda I went |
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Post by Vortex on Nov 7, 2019 5:57:36 GMT -8
This is the first proper run with the testo. I've set the graph up the same way Peter does so there's something to compare to. The CO spikes were me experimenting to see what effect the various air controls have at different stages. It really doesn't like air through the ash-trap except during the coaling phase. The temperature spike near the start is the warm up then bypass closing.  |
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Post by Jura on Nov 8, 2019 0:39:42 GMT -8
What caused the triple peaks at the end ? As to the air through the ashtray - I'm worrying now :-( about the previous vortex firebox I'm building, as all secondary gets into it through ash tray  |
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Post by Vortex on Nov 8, 2019 5:30:38 GMT -8
The triple peaks at the end of the first graph were me experimenting closing and opening the tertiary air through the ashbox. It seems to lower the CO during the coaling phase, but raises it dramatically when there's flame in the afterburner. Secondary air on both my stoves has been around the edges of the firebox door. I made an ashbox air control on the new stove because it burned best when the ashbox door was cracked open slightly, and it's great for burning up the embers fast. I've noticed since moving the afterburner shelf back from 3" to 3-3/4", and changing to the lower resistance cowl, that the stove seems to burn better without the tertiary air through the ashbox, whereas before it would pulse without it and the afterburner glass would get dirty. This morning the testo had lost all the graph settings I put in it yesterday, so I had to stop it to re-set them all and so it missed the start of the burn. The %O2 is also set to 0-100 instead of 0-20 so the green line is at the bottom. %η was running at around 103 so is just off the top of the graph. Today's run was without any air through the ashbox until the start of the coaling phase when I opened it at 9:36. At 10:02 I tried completely closing the firebox door, but that sent the CO up so I reopened it onto the 2nd catch at 10:07.  |
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Post by Jura on Nov 8, 2019 10:37:12 GMT -8
Sorry for the setting loss.
I wonder what conditions caused to CO to drop below 300 ppm's.
Seems your overall efficiency is above 100 ;-) (obviously out of range )
Other issue that wonders me is how disparate are your O2 and CO curves...
AFAIR there shall be clear relation between them. But I might be wrong with this.
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Post by Vortex on Nov 8, 2019 11:29:53 GMT -8
I have the settings back as they were now, hopefully they'll still be there in the morning...
The testo manual says: "η - Efficiency without consideration of the heat value range" It unfortunately doesn't elaborate on exactly what that means, but if it's relative to temperature it may explain my 103% efficiency ;-)
I wondered that about the O2 & CO curves, but looking at Peters DSR2 graphs the corresponding curves are only evident in about 2/3 of the graphs, so may show up yet.
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and off to my Humanure Hacienda I went 