Insulating Heat Riser

I am pretty new to rocket mass heater and heating and am looking for ways to increase efficiency while cutting costs.

Has anyone experimented with using kittylitter, bentonite clay, to insulate the heat riser in the drum?

Also I was wondering about water storage of heat to improve efficiency, anyone out there done anything like that?



Thank You in advance

Harry A. Bott wrote: I am pretty new to rocket mass heater and heating and am looking for ways to increase efficiency while cutting costs.

Has anyone experimented with using kittylitter, bentonite clay, to insulate the heat riser in the drum?

Also I was wondering about water storage of heat to improve efficiency, anyone out there done anything like that? Thank You in advance

Harry : welcome to Permies.com, our sister site, Richsoil.com and the Rocket, Wood Stove and Cob Forum Threads ! with 29,000+

Fellow members world wide you can come here 24 / 7 and find someone who wants to talk about what you want to talk about ! No Trolling and

only one rule 'be nice' !

Unfortunately, bentonite clay has such high expansion/contraction rates during Your rockets Heating cooling cycle it will simply fall apart !

Durring the installation of any system that requires pumping water from one location to another it is possible to create a closed system, all
steam boilers are closed systems, when water flashes to steam it expands 1 cu. Foot becomes 1760 cu, Foot explosively !

Think Boston Marathon Bombing with more fatalities (Family) and more full body full thickness burns ! Here at Permies. we refer to this as
Squish Boom !

This is where I strongly recommend going to Rocketstoves.com to download your PDF copy of ''Rocket Mass Heaters", Truly
this is "The Book'', and will save you time money and materials, and will make sure that when you come back here we are all calling Your
Rockets parts by the same name ( You are doing fine so-far), and understand the orientation of the parts discussed, and their size, shapes
and ratios

Get 'The Book', read ''The Book'' and come back often ! If there is a Rocket Mass Heater in your future we will help you 'find it' Big AL

I wasn't thinking about using a pressure vessel to store heat as I am very familiar with the explosive potential of steam.

My idea was to use a layer of two of cob to insulate the heat exchanger tubes and act as a heat sink of sorts, then a waterproof membrane barrier then water. The temperature of the water will be considerably lower than boiling point, and would allow a much denser mass of storage.

Anyone done anything like this?

Harry A. Bott wrote:
I wasn't thinking about using a pressure vessel to store heat as I am very familiar with the explosive potential of steam.

My idea was to use a layer of two of cob to insulate the heat exchanger tubes and act as a heat sink of sorts, then a waterproof membrane barrier then water. The temperature of the water will be considerably lower than boiling point, and would allow a much denser mass of storage.

Anyone done anything like this?

Yes, it's been done.

Consensus among the people who have built dozens of stoves/heaters seems to be this:

Safely heating water with a rocket stove/RMH is hard.
It's worth doing if you really want the hot water.
It's NOT worth doing for the sake of a better storage mass.


The reason it's not worth doing just for the sake of mass is, none of us are so short on cubic inches and so long on money that we'll benefit by ignoring the free, unlimited, non-toxic/non-melting/non-corrosive/non-corrodable, phase-stable, perfectly adequate mass that's under our feet in favor of a mass that's dangerous and ornery and requires comparatively expensive equipment to corral.

The mass under our feet, of course, being clay or stone, and the ornery mass being water.

But I'll see if I can find the thread I'm thinking of about heating water.
Edit: Here we go, try this one: http://donkey32.proboards.com/thread/1096/hot-water

Harry Bott : Yes, I am sure that several variations on this have been tried, Here the problem is the expansion of the water vessel, while cracks in cob
are easy to fix the uneven expansion causes potential breach of the gas tight integrity of the Horizontal pipes in the thermal mass. Any crack is magnified
by the sideways loading of water contained in a non insulating container.

Generally we can't use metals to rigid-ize the vessel, and low expansion plastics are insulating .

While we sometimes run into this problem with the Monolithic construction of multiple layering of dense stone and Cob like making lasagna, it is a lot less
common ANDThere are no side loading.

It is possible ! am missing your meaning can you do a sketch ?

Clay is everywhere, and local clay is almost certainly to be better than bentonite! Your local Excavation Contractor is certainly knowledgable about soil/clay
conditions within 100 miles of his base. Local Highway departments are also great connections, as they know were hillsides slide down to the road blocking
culverts after rains _ You cant beat free clay. Big AL

Harry Bott : While this build is for the purpose of using hot water it is of the open type that greatly reduces the Boom-Squish danger!

link below :

https://permies.com/t/39243/rocket-stoves/Rocket-Mass-Heater-Workshop-emphasis

It maybe a little frustrating to you when everyone you talk to wants to cover the baby-steps with every post - please consider that ALL our answers need to
be very clear (especially repeating warnings) to other, future fellow members who will one day tread this path ! For the Good of the Crafts Big AL


Another useful link :

https://permies.com/t/34193/tnk/permies-works-links-threads

A.L.

Harry Bott : Call this a late late note : Check out the link below for the free stuff being given away to fellow members - right now !

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

Think like Fire, flow like gas, don't be the Marshmallow ! Big AL

I have experimented with building a firebrick burn chamber and insulated it with this clay based non clumping cat litter and perlite. I have not heat tested it yet, since I am still working on sandblasting and cutting the the barrel. I will post pictures for you. It turned out really well, I filled a 5 gallon bucket 1/4 full with cat litter and then added two electric kettles worth of boiling water(I'm not sure the exact water capacity of this kettle) boiling water helps to break down the clay as well you should mix the hell out of the cat litter and water. The longer you leave the cat litter and water, the better it gets, you can speed up the process by using a type of drill attached mixer. I then filled the bucket up to half with perlite and mixed it up well. You then want to make a mold around the chamber out of wood, and make sure it is really reinforced. I covered the inside of mine with masking tape to make it easy to remove after it is fairly dry. Pack the insulation with a piece of 2x2 or something so it it really tight. The end result of my insulation was very good and there were only a few tiny little cracks that are not all the way through, but nothing to worry about. It is still structurally very tough and should hold up fine.

p.s. do not use clumping or scented cat litter.

This is the litter I used


This is my cat litter mold and cat litter perlite mix.



I used the cheapest materials to build this including the smaller 1" thick firebrick, because I will be using this outside on a patio or in a greenhouse. Also this was my first RMH and did not want to make expensive mistakes.

The main benefit of using cat litter is that your RMH will be FRESH FOR LIFE! says so on the bag.

P.s. This core is very light weight I built it on a galvanized steel tray about 1/4" thick steel, I believe it was an old rabbit cage base. I can lift this core myself if I wanted to, but two people could move it with ease. Also this is a 4" sq. system so I am curious if it is going to work.