Sidney Beauchamp

Hey Thomas, Good to hear from you.

I got the burn chamber and riser basic designs from Peter Berg. I have an idea for a secondary burn chamber that uses a vortex to reduce the amount of ashes going to the rest of the system. So, I plan to build prototypes with relatively thin steel. The first being a replica of peter berg's batch system. Then I'll build prototypes and I'll have a known good system to compare it with.

For my final build for the home I want to get a vacuum formed Riser sleeve for the riser

and I want to build the burn chamber with fire brick and insulation brick as a base. As for the heat exchanger to water, I'm looking at high efficiency wood boilers for ideas. There are a few designs that might work. My sister is a mechanical engineer, and I'll ask her to check them for flaws. but basically the most efficient way is multiple small tubes. like in Peter'g webpage. The thing that I need to consider is what happens when there is a power outage. There must be fail safes in the system and I think I can use wax thermostats to generate circulation by convection to keep the water from boiling.

Will I'll be prototyping, I want to try to make carbon foam from bread in a manner that is usefully for a racket mass heater. If I succeed in my prototypes, I'll try it in my shop. I have an automotive repair shop that I want to install one in. This one will be my test bed for different ideas.

Right now I'm looking for building materials. I'm in my slow season right now so I don't have any money to spare, so I'm hunting old food stoves, chimneys etc. Even old oil furnaces if I can find one. Their combustion chamber is usually vacuum formed ceramic fiber. I am also getting dimensions for cutting my sheet metal so I have the least amount of joints as possible.

I've also looked into moving heated air to areas of the house that are isolated by running the furnace air intake around the "barrel" so it sucks the heated air and blow it around the house.

As I ponder a solution for the house I want to get the mass heater done in the shop for next winter. The problem at the shop is space. At the moment there are very little space not used. I need to re arrange what can be moved around to accommodate the masse heater and not have it impede the work space. The rocket stove is not to much of an issue, but there is no room for a bench.

Sid

Thomas Tipton wrote:Sid,
I just wanted to get back with you about an idea I had.  Unfortunately, the batch box I was looking at is way to big for my space, and I'm getting too old to want to be crouching down on the floor to load the burn chamber.  I think I'm going to compromise and go for a J-tunnel since it would be easier to feed,  but I still want an 8 inch diameter profile to heat the size of cob bench I'd like and that's what puts the top of the barrel uncomfortably close to my basement ceiling. (wood)

There are many different solutions possible for that problem. I'll get back to that in a bit...

Thomas Tipton wrote:

I have yet to see anyone attempt a single burn chamber/tunnel, dual riser configuration.  what do you think?

Could dual risers, either both in one barrel, or one in each of two barrels serve the needs of one larger burn chamber?

Theoretically it is possible, but it would be technically challenging and prone to malfunction specially in a single barrel. Even in a 2 barrel configuration, any small change can and will trigger an unbalanced flow. The complexity of fluid dynamics requires fine calculations and flow control provisions. Without the proper math, you would need a lot of trial an error testing and you can't assume it is good simply because you had a few good runs.

Remember that fluids always takes the path of least resistance this means that the slightest difference in one of the paths then to favor one over the other.

It is best to stay within the KISS principle. In the link I posted in my thread (http://batchrocket.eu/en/) there are designs that would make the burn chamber more accessible. Instead of using a barrel, you can use a masonry bell. You can insulate the top of the barrel since your not going to be cooking. You can install a simple heat shield/deflector made of cheap sheet metal. You can use convection to control the ceiling's exposure to heat.  

Check out this thread too for more info: https://permies.com/t/41635/Top-Questions-Rocket-Mass-Heaters

Check out this Peter Van De Berg's masonry build with an insulated top  

Sid

Peter van den Berg wrote:Neither of those. Measurements has been done in the vertical stove pipe that comes out of the heater, between 1 yard and 2 yards away from the heater's exhaust opening.

After the bench if there was one right ?

Peter van den Berg wrote:I am sorry, but that won't do the trick. A cyclone after the riser could be done, but it'll cost a lot of energy. Which need to be compensated by a strong draft, either from a very hot chimney or a chimney ventilator.

Thank you for the feedback.

Peter van den Berg wrote:Sid, could you please start a separate item about your plans and proceeds? As it is now, you are going off-topic in this thread.

All ready in the plans. I only have this rough idea at the moment. Nothing else to elaborate on until I understand your batch rocket in more details. There is a lot to learn and I am very grateful for your patience.

Sid

Peter van den Berg wrote:
Testing has been done with a Testo 330/2 gas analiser and a computer to log the numbers every ten seconds.

Ouch. These testers are not cheap.

Peter van den Berg wrote:Temperature, oxygen and carbonmonoxide are measured directly and can be compared with other gas analisers.

Where the measurements done at the exit of the chimney or at the top of the riser ?

Peter van den Berg wrote:All the rest is calculated  using those three, so is the efficiency. As Jura Rafal mentions, the formula to calculate that are slightly different from country to country depending on what the rules say for that specific country. So difference between mine and say, Matt Walker's analizer's efficiency is about 8%. Regrettably, making efficiency numbers a very unreliable number to go for.

I see. It does give an idea of the efficiency, just not reliable.

I have a theory that by adding a secondary vortex combustion chamber between the riser and the port, it would greatly minimize the amount of ashes that get sucked up the riser. Basically the same technology used in Dyson vacuums. It is used successfully in the Cyclone steam generators.

I'm planning to build a prototype out of sheet metal and tweak it before making one out of refractory material.

I have access to a lot of fuel that generates troublesome ashes like leaves, sawdust, coffee grinds and contaminated paper and cardboard ( a single drop of oil on them is considered contaminated and is sent to the landfill ) this generates unburnt ashes. By keeping them in the vortex they should burn completely and settle at the bottom center of the chamber.

Sid

Hi Peter,

I've read you article and I find it very informative. I've also read many of you posts here and all of this has inspired me to tryout some ideas.

In your http://batchrocket.eu/en/designs page you show results of measurements that demonstrates the performance of the design. I'd like to learn more about the instruments used and guidelines to run those tests so I can see the performance and share my findings.

Thank you for all your efforts.

Sidney

Thank you Daniel for that clarification. It confirms my thoughts. The gap calculations are most important to maximize the heat transfer to a surface like a cook-top without negatively affecting the flow of the gases.

And I totally agree with the learning part. With everything going on in the world and the greed that keeps crushing the masses, I decided to be less dependent on the market and more self sufficient so I've been learning a lot lately.

I have a few idea's of my own, but I want to get a better understanding of the basics first.

Thomas,

For the length wise cuts for the riser, check in the applications section and the water boiler. That is how they build the riser.

Thomas,

Peter van den Berg is the one that seems to have gotten the most efficient burns of this type of batch burn fire boxes. I think that he came up with the idea.

For very detailed information and some options check out this site: http://batchrocket.eu/en/

BTW, these old fireplaces should have a fair amount of firebrick in them. If you are condemning the fire place you could re-use those.

Sid

Thomas Tipton wrote:You may well be right about cutting the insulating refractory bricks length wise.

Here's something regarding vortex induction you might be interested in.

https://www.youtube.com/watch?v=iTlOZdpMd6I&list=PLb2E9ll1ekcJcUuJqfkoykF5Q2R3Enuue

Yep, I saw that, this is the video that triggered the question if anyone here and tried this. I Tried to find the link to some instruction for the length wise cuts for the riser. I can't remember where I saw this. When I find it I'll post it

Sid.

Thomas, you can save on material building this octagonal stack if you cut them length wise. These soft brick are expensive. They insulate so well the building it like in the video is a little bit of an overkill. You could also add a layer of much less expensive material on the outside like an perlite mix with fire concrete or the likes.