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Collaborative effort on integrated Rocket Mass Heater/ Wood Gasifier/ oven/ Stirling Engine.  RSS feed

 
Wyatt Brush
Posts: 56
Location: Meade County, South Dakota
greening the desert hugelkultur trees
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There is a fine line between being genius, and being crazy. I will let you all decide which side of the line I am on with this idea.
Okay, here is the deal, I am good at coming up with concepts, but how good the concepts are, can be quite variable. I only have a cursory knowledge of these different component technologies, so I am hoping for some experienced help putting this idea together, hopefully for the benefit of many. This design is intended for placement in a full height basement, but could be adapted to other areas too.
What I want to do is build a rocket heater, using the J tube design. Then, instead of leaving the heat riser exposed, and putting mass around the exhaust tubes, I want to do it the other way around. I want to put mass around the heat riser, and put heat dissipating fins on the exhaust tube. In the mass, I want an oven above the heat riser, the hot end of a Stirling Engine on one side, and the hot end of a wood gasifier on the other side of the heat riser. This will give the Integrated System a bit of hight, and a relatively small, rectangular footprint. It would look rather like a large (steampunkish) fireplace, but could actually be more centrally located in the room, and not necessarily relegated to a wall, like a normal fireplace. The exhaust tube will exit out the bottom center of the back of the mass. Then an elbow will take the exhaust tube straight up to the ceiling, and then another elbow will take it through the outside wall of the building, slightly angling the tube down on the way. The heat dissipating fins will be on the straight runs of the tube. What would really be great, is if there could be a greenhouse on the other side of the wall, for the exhaust to vent into, but that would be optional.
I am thinking that it might be possible to actually use insulating layers of mass, to divide the overall mass into zones. Then with internal, moveable plates that are insulating on one half, and heat conducting on the other half, we could somewhat control how much heat is going into each zone. That way we could channel most of the heat produced by the Rocket Heater to any one of the Integrated System's various functions.
Last, but certainly not least, is the air intake tube. Instead of having the feed tube of the Rocket Heater open to the room, so that room air is being used for the combustion, it just makes sense to use a tube to bring in outside air. I saw a video on YouTube where a guy used such a tube. However, the intake tube on our Integrated System will be insulated up to the feed tube, to keep it from cooling off the room air. But, before the intake tube gets to the feed tube, it will make a slight detour, and totally enclose the cooling fins of the Stirling Engine! I think that this will accomplish two important functions. First, it will preheat the air with waste heat from the Engine, so that the air has less of a chilling effect on the rocket flame. And second, it will greatly increase the heat differential between the hot and cold ends of the Stirling Engine, which should translate into substantially more mechanical movement.
I am guessing that the wood gasses would give off some heat into the room, at the time they are being collected from the Wood Gasifier.
I figure, that if we can put this all together so that it works well, it will be exactly what many people that are, or want to be, off the grid, need. In essence, what this system will do, is use one of the most efficient combustion units known, to produce heat that can be used to gasify wood, and/or produce mechanical power for various applications, and then heat your house with the waste heat! Sure, it will only be enjoyable to run in the cold weather, but think of all the use it would get then!
I will try to do up some sketches soon, of how I envision this thing looking.
 
Xisca Nicolas
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Posts: 1318
Location: La Palma (Canary island) Zone 11
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This will not be the type of answer you want!
I can just say that the rocket makes more draft when the heat goes off at the top of the oil drum, because the less hot heat goes down.
So if you have a mass there...
I have read before that this is not a good idea.

I am "crazy" too, just because I imagine designs on topics I do not master....
This can lead to genius ideas, sometimes, because a beginner is not limited by knowledge.
A child is "ingenous", the genius of inocence!

So my crazy imagination is to make something tall (I have height, 2 floors) by making a
TLUD
+ a kiln for the gases to go through it
+ the rocket system of flues going out in a bench

I wander about draft.
Does the TLUD provides the necessary draft?
Or just a rocket can produce enough draft for the bench?

Wyatt your idea and mine might have a draft problem, because of an undue mix of techniques.
Dunno what is your goal...
My goal is to:
- heat,
- have an oven,
- and create biochar
- and use the batch feed of the TLUD
 
Wyatt Brush
Posts: 56
Location: Meade County, South Dakota
greening the desert hugelkultur trees
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This will not be the type of answer you want!
I can just say that the rocket makes more draft when the heat goes off at the top of the oil drum, because the less hot heat goes down.
So if you have a mass there...
I have read before that this is not a good idea.

You may be right, I don't know. I did read somewhere, somebody with a lot of experience, I think that it was one of the Wisners, said that you can put cob on the Heat Riser as well as on the exhaust tube, you just won't get the 'quick heat' from the Heat Riser. I wonder if anybody has tried it my way yet. I was thinking that the heat would be going off at the top of the Heat Riser, just into the different mass zones, not into the air. I was also thinking that maybe the mass around the Heat Riser would help the Heat Riser to stay warm longer, thus helping the start of a new burn to be cleaner.
What does TLUD stand for?
Thank you for your input!
 
Xisca Nicolas
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Posts: 1318
Location: La Palma (Canary island) Zone 11
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I have mainly read that it is unwise to cover more than 2/3rd of the drum,
(Edit: in the last Wisner's ebook I have)
and this is not only about radiant heat,
this is to have a better draft.

Air conducts quicker, so the mass does not cool the rising air that fast if there is a thermal mass.
Draft is a main key I think!
The necessity of draft is the cause of loss of heat in all "normal" stoves.
Keeping heat and keeping the necessary draft is what is looked for...

TLUD stands for Top Lift Up Draft.
This is a gasifier that leaves you with biochar after burning.
It is lit on top of the batch of fuel, usually agricultural leftovers, wood only if chipped or small.
It really burns easily and without tending it after ignition.

...and I do not know what sort of drafts gives this, because it is mainly used for cooking in the tropics.
I opened a special topic for this specific question of draft.

As you also have vertical room, this solution can also be investigated in your case...
 
Wyatt Brush
Posts: 56
Location: Meade County, South Dakota
greening the desert hugelkultur trees
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Draft is certainly important! Another consideration is reverse draft. We certainly do not want the flame rocketing up the air intake tube! Since you seem to only have an educated opinion, and not experience, and I have even less, I guess that I will have to try making working miniature models, to test things myself, unless other people show up here that have some experience. I was kind of hoping that more people would have dropped by by now, but I guess that it is still early.
As for doing a TLUD, that sounds like a good idea for some people, no doubt. But what I am needing is mainly to heat a house. I want to make the heat do some work before it heats the house, whether it is baking bread, making mechanical power, making wood gas, or making bio char. I figure that there has to be quite a few people that could use such a combination, so I don't want to give up the overall idea. There is more than one way to skin a cat, so the actual shape of this contraption might change a lot before it actually gets built for the first time.
 
allen lumley
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Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
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Wyatt : You are in luck follow the link bellow to a great set of starter plans this is one of your membership has its privileges ! Do it now !

http://www.richsoil.com/email.jsp

This set of plans are nearly perfect for a newby to get a chance to see that we really know what we are talking about !

The rocket mass heater RMH, does not scale down well at all, many potential Rocketeers have broken their hearts attempting to make a First RMH
rocket mass heater smaller than 6'' and failed, A working Vertical feed J-Bend 4'' system can support a Thermal Mass just about big enough for a
love seat.

Consider the sq. area of a 6'' system is 27 sq. inches, the sq. area of a 3'' system would be 7 sq. inches, Though 1/2 the diameter the flow area is
1/4, And it gets worse due to a condition called Laminar flow ( It should be called NO FLOW) The flow of both fluids and gases are slowed by contact
with the circumferential surface, so that proportionally slows the flow down even more !

Have you been to Rocketsstoves.com to Download your PDF Copy of "rocket mass heaters'', this is an excellent place to start, and the
very 1st book that you kinda ought have !

For the Good of the Crafts ! Big AL
 
Wyatt Brush
Posts: 56
Location: Meade County, South Dakota
greening the desert hugelkultur trees
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I got the free rocket mass heater plans, and I have read them. I looked up the book that you mention, but it costs $18. Money is a bit tight for me right now. Maybe I will have the money to get it some other time.
I was really hoping that I would be chosen for one of the free 'Wood Gasifier Builder's Bible' books, but I wasn't. I was also hoping that there would be some discussion of what model of wood gasifier and Stirling engine would be best, and where to get the plans for each. And I was hoping for discussion on what would be the best materials to build the mass out of, but I guess that would be in that book. But, none of that really matters, if the flame cannot be made to go the proper direction. I think that I will try a miniature model of a Rocket Heater anyway. The main reason is that my gut is saying that it should work, so I have to prove it to myself that it won't. But if my gut is right, I will try to post a YouTube video of it for you, okay?

Thank you for your input!
 
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