Anyone have a rocket mass heater?

[hammercore]

I was on youtube the other day and came across videos of rocket heaters. They look pretty simple to build and cheap, just time consuming and labor intemsive. I did a little research and they're supposed to be really efficient

 

[ts39136]

I have been researching these also. They have the small ones, but the bigger ones I"m interested in. My friend makes them out of propane tanks and uses sand to retain the heat. The idea is to burn the wood hot and fast, reflect enough heat to keep the coals and incomming air hot, and keep it hot for good secondary burn. You must size it for your application to get the best efficiency.

Because we use pine almost exclusively, the thermal mass stoves seem to be the best option for me. Optimum burn with lasting heat.

My plan for this winter, is to add some thermal mass to my woodstove in the form of concrete blocks. I'm also going to add some baffles. Let me know how it works out for you.

Are you thinking of building one for use inside the house? I haven't got that gutsy yet.

 

[betterbuilt]

I have a friend with one and he only goes through about 2 face cords a year. He only makes a fire in the morning and one in the evening and the mass does the rest. They are nice if you have the right place to put one. They work better if they are in the center of the house.

The thing I like is it doesn't make any smoke. It burns so hot there isn't any of the creosote or smoke. When the exhaust comes out of the house its about 100-200 degrees and no smoke.

 

[cnice_37]

That is some interesting stuff right there. Has me thinking, although kind of difficult to implement in an existing home. Not sure homeowner's insurance would like it much.

I have so many bricks/ patio blocks in the yard that this could be a sweet outdoor exercise for a prototype.

 

[hammercore]

Let me know how it works out for you.
Are you thinking of building one for use inside the house? I haven't got that gutsy yet.

i just found out about these a couple days ago so i'm still kinda thinking if i would really want to do it. And no i wouldn't be putting it in the house, we're getting a fireplace insert this fall. I was thinking of building one for the garage. You may have noticed a lot of people make a heated bench as the thermal mass, but i was thinking of having my exhaust zig zag up a wall so then it wouldn't take up as much room as a bench would

 

[ericjeeper]

Sand is a piss poor thermal mass storage media.
Think of standing on the scorching hot sand at the beach.Now wiggle your feet maybe two inches down in,now the sand is much much cooler.
Crushed limestone, commonly known as ag lime will work much better.

 

[trailmaker]

I've done a little research on these. It's a very cool concept, kind of like a poor mans masonry heater. All of the designs I've seen have an open feed chute which would make me a bit nervous. I would definitely be standing by during the entire burn cycle.

 

[betterbuilt]

I've done a little research on these. It's a very cool concept, kind of like a poor mans masonry heater. All of the designs I've seen have an open feed chute which would make me a bit nervous. I would definitely be standing by during the entire burn cycle.

Most of the people that have them have stone or dirt floors. Once they get going they have quite a suction to them. There is a danish design that has a door and its even like a normal wood stove.

I think the main principle is that you have got to have a lot of mass to store the heat or its no better than a wood stove.

My friends is quite nice, but it took him about a year to build and its still not done. There is a lot of math to them and I would build one without a few books or even taking a class on them. I know they give classes around here once a year.

 

[SpiralAcacia]

This is the book
http://www.amazon.com/Rocket-Mass-Heaters-Superefficient-Woodstoves/dp/0966373839
I have it. Interesting. I'm thinking of building one to replace the iron box.
It's either that or a traditional masonry heater.
(My wife) Haven't made my mind up yet.
If you consider it as an option, get that book to know more.
Paper is 22$, PDF version 13$ to download at www.rocketstoves.com .

SA