Gerry Parent

Tiffaney Dex wrote:Thanks everyone for the replies. Gerry, height is a problem and excavating isn't an option. So we can't add more mass, except for a thin, finish layer. But perhaps we could put something insulating in the finish and that would help it? If we put marble powder in the finish layer, do you think that might provide a little bit of insulation?  

Quite honestly, I had to look up what marble powder is:
"Marble powder is also known as limestone and calcium carbonate. In nature, marble powder is mainly found in old rocks and seashells."
Based on that description, I don't think a thin layer would do much for you.

Do you have a bypass installed?
If so, it could be opened up when the bench reaches your optimal butt warming temperature and closed when your ready to migrate off the bench.

Hi Tiffaney,

I looked into the builders guide, as I remembered this topic was covered there as well, but it seems you've pretty much covered their suggestions.

Not sure of what materials you made your bench out of but could you add more mass to the top of your bench? Something that would take longer to heat up in the short term but also prolong the heat storage capacity for the long term.
Or, instead of adding more mass, perhaps go the opposite route and incorporate some insulation like rock wool, perlite etc right into the mix?
Perhaps this would then make it too high to sit on unless you excavated down a bit before adding the mass/insulation?

Benjamin Dinkel wrote:The chimney is a regular pipe but coated in cob and with a traditional "hat".

Great job Benjamin!
The only thing that looks questionable is the "hat".
From the picture, it appears that it may cause too much dampening of the draft.
I guess time will tell when you light it up. An easy enough fix to enlarge the pillar openings if needed.
Also, wondering how close the hat is to the future roof. Hope your client is not insisting on a straw roof!
Could it extend through the roof instead?
Keep up the great work.

Peter van den Berg wrote:The numbers doesn't look like fixed figures, it could be that the figures are at least partly interchangable. Maybe, with an awful lot of turbulence induced both the other two T's, time and temperature, could be smaller.

Actually, I am convinced this could be the case, although I am unable to prove it.

I was under the impression that a person could cheat and use a fan and/or a heater to decrease the amount of time before a smokeless fire is achieved.
If so, wouldn't using such devices be able to prove that these numbers are not fixed but are interchangable as you mention?

Ahmet Oguz Akyuz wrote:Yes, I disconnected west panels one by one. Sorry for the typo.

The brand of the inverter is Lexron - it has a 6.2 kW rating and a MPPT voltage range of 90 - 500 Volt. I think my inverter was turned off when I arrived at the site from the on-off switch.

If the inverter was off, what does the monitoring of the incoming current from the array?
Also, I assume to get you by, you've disconnected the faulty string and are at least getting some solar input into the system with no other problems?

Do you know if these panels have micro-inverters? If so, perhaps the whole string went into rapid shutdown mode (from your stormy weather) and need some kind of resetting?

Ahmet Oguz Akyuz wrote:  
We do have a 6.8 kW inverter and 5kWh lithium battery

.....But 0 was coming from the west side. I then disconnected all the east panels one by one and individually measured their voltages. 0 on all of them.

Did you mean "I then disconnected all the WEST panels". (You said "east")
What may I ask is the brand name of your inverter? Some have a log function that could be accessed to narrow down the time and day the problem happened.

Rocky,   Unless you have some kind of wild card up your sleeve your not showing us that would warrant such a thing-a-ma-jiggie to be birthed into existence, I'm still scratching my head.
If a large firebox is what your after, why not just build a Batch Box from the get go? Establishing draft with a BB is no harder than with a J tube.

Rocky, A picture would be helpful as I can't even imagine what your talking about. :)

Rocky Massengale wrote:So Gerry,
From what i have seen is that the burn tunnel is supposed to be 1/2 the size of the riser as is the feed tube to be 1/2 size of burn tunnel 1:2:4 ratio is that not correct ? So lower the chimney pipe closer to floor level ]without restricting the flow, so that only the coolest air is sent up the chimney ?

That ratio will work however, a shorter burn tunnel makes it easier to collect ash and is a bit more forgiving for a shoulder season cold start.
1:1.5:4 has also been suggested later on in the development stages which I had good results from.
Originally, it was suggested to make the tunnel length "as short as possible".

Yes, sending the coolest of the gases up the chimney near floor level is what your after.

Glenn's statement is still spot on even after 11 years of innovations. In particular : "The proportions are not ironclad - minor differences can be tolerated..."

Edit: Revision 5 looks to me like a pretty good place to start. Feel free to start your own thread on the build and take lots of pictures to help document the build. It will help to keep them all organized for future reference and helps others on their journey. Good luck!

Rocky Massengale wrote:J tube Dims appear to be good ?

Just now looking at your core dimensions.

Top gap (space between top of heat riser and barrel) could be made more spacious as this is where ash tends to build up.
Instead of raising the barrel height, I'd just lower the heat riser height by at least 1.5" since its already slightly taller than needed.
3" has been found to be a minimum for top gap in a J tube, a bit more if you can manage it.

In regards to the height of your feed tube being 14" tall.
It is recommended not to have any wood sticking out of the feed tube (mostly for safety reasons) so if your wood is cut 16" long, you may consider a shorter fuel supply. You don't want to raise the height of the feed tube too much either as it can lead to it being a competing chimney and also make it that much harder to be able to reach in to scoop out ash.

Burn tunnel could be made shorter.
Closer to 24" is preferred. The heat riser doesn't  have to be in the center of the barrel so it can be moved a tad closer to feed tube.

Your update to the exhaust exit looks much better. Depending on your space and layout preferences, you could also have it exit straight out the top of the jut-out you've created eliminating the 90 degree pipe bend.