TLUD fired outdoor boiler

Inspired by Martijn Macaopino's indoor TLUD build I have started building a boiler.
The design takes advantage of the heat exchanging central chimney that gas fired water heaters use.

Here are some photos of what I have so far:

This looks promising.  Despite being actively involved in making biochar for years, I can't really say that I have effectively managed to use the heat for a very useful purpose.  I experiment with cooking small vegetables, but I am intrigued by the possibilities that some of you have developed.  Thanks for posting.  As H. Ross Perot would say, show me what you got-I'm all ears!

John S
PDX OR

Ive cast a heat riser from perlite and calcium aluminate cement.
Despite motor oil and and plastic, it does not want to release.
Its probably to dense anyway, with too much cement too little perlite,  too thick altogether.

With a lot of finangling I able to remove massive heat riser from the boiler.
I may try a refractory heat riser again in the future,but its one innovative to far right now.
I will replace it with a steel can, or perhsps a stainless steel bain marie with the bottom cut out.
Mean while I have a prop for a B.C. comic and I've added legs to the boiler.

I edited the above post,having posted the wrong photo before.
The goofy  joke might make more sense now!

Im talking to the driveonwood.com crew to see if I can stack another function on top of making char and space heating.

Speaking of stacking functions, I think this boiler might have as much or more life as a still than as a hydronic heater.
Not that these things are mutaually exclusive.

I really do want to send the water into the house as steam and condense it there.
After it flows through a series of old water heater tanks, a sump pump in the final tank would refill the boiler.
A heater core in my furnaces return air plenum will distribute the heat via thermosiphoning.
I think it should work, but the boiler itsef isnt built yet,  so one mad scheme at a time..

I remember the B.C. comic guy rolling a wheel.

There will be a lot of innovations based on ideas that people get from looking at your experiments.  Most people don't have the entire group of skills or tools
necessary to even try them.  Cool stuff.
John S
PDX OR

I just fired this thing for the first time!
Here's my report:

1.It needs insulation.
The door and sides get too hot to touch, water sprayed on them hisses and steams off.

2. It leaks!
Not water, smoke.
Mostly that was when I turned on the air pump.
It came out where the upper and lower halves came together.
I think I'll put some mud/clay slip in a squirt bottle and use it to fill in some gaps.

3. It doesn't need forced draft.
The  mattress pump wasn't needed, it actually seemed to create smoke.
I might try it again with a lamp dimmer for a speed control.

4. The reservoir/heat exchanger is huuuge.
As in wide.
As in, there is a lot of volume not in contact with the center chimney.
It was shaky with 3 gallons in it, filled up entirely, it  would be dangerously top heavy.
Next time I will choose a narrower water heater tank, if I can find one, but it may not be enough and I'm neck deep in this build.

So,what to do?
Narrow the diameter of the water tank?
Concrete would be strait forward, but it would also make the boiler top heavy.
Insulation would be great, but can it be waterproof and resist boiling temperatures?
I could cast styrocrete inside the tank, around a sheet metal cylinder, and fill any gaps with silicon.
Seems fussy, but doable.

A water tight metal tube would be better, allowing me to set the bottom in water stop cement and fill the space between the tank wall and tube with almost any insulation.
This seems better.

Hey, I'm about ready to insulate my beast and I was considering some options.

Sawdust, perlite or Styrofoam mixed with cement,mud or cat litter.
I'll add some scrap Fiberglass or Rockwool fibers to alleviate cracking.

Another way to go would be loose perlite or rockwool fiber,sand or just dirt.

I'm leaning towards perlite and cat litter as a good compromise between cheap, easy and gas tight.

Sodium bentonite (cat litter)melts at 1200 degrees Celsius which is probably good enough as long as I keep it away from  direct contact with flames.


Any ideas or opinions on these or other options?

I'm moving my chickens back into the greenhouse.
To do that I have to/get to sort out my tlud boiler and my refrigerator grow beds.

The chickens always get sorted, they demand attention, but I actually would like to use the greenhouse, grow beds and tlud boiler before I die,so I am simplifying the designs.

I want to plumb directly from the boiler to  a insulated  water heater  tanks, in  such a way as to induce thermosiphoning.
I need advice on how best to connect and   arrange the tanks.
Will heat  equalize between the two tanks without putting the insulated tank higher than the boiler tank?

This boiler tank  has two bungs plumbed in 3/4" NPT.
Both are rather low in the tank.
Since hot water should come from near the top of the tank, I was planning on using 3/4" iron pipe to plumb an "L" inside the tank from one of the bungs to within inches of the top of the tank.
I could actually plumb it parallel to and almost directly against the internal flue, but I'm not clear that that is preferable.

I  will eventually need some sort of sight glass or something to check water levels, ideas welcome.

I love what you're working on William.  As I said, I haven't managed to make much use of the heat from my biochar yet, but I'd like to figure it out.   I wish I had an answer, but it's kind of like asking a little leaguer to hit a major league fastball.  There are a lot of other people on here with some of these skills. I hope they see it and answer.

John S
PDX OR