09 April 2009

Rocket stove mass heaters!

Another very inspiring idea I knew nothing about, until Keith blogged it that is! Rocket stoves with mass heating.

I'm seriously considering building one of these downstairs. We have a log burner upstairs, and we need to install some thermal mass around it to make it more efficient, but downstairs has no heating! On the one hand we could extend the log burner downstairs, but I think I'd rather build the rocket down there for my learning's benefit, try and make it so it effectively heats down and upstairs, then consider uninstalling the log burner and selling it to recover costs... permits will be an issue :(

Here's a great video Keith found:

Here's the book that the video refers to, but I'm gutted to find my local library doesn't have a copy :(

And here's a really good illustration of the functional design from Erica, along with many other photos she took during a build in the US. Thanks Erica!

Here's another photo documented installation with some adaptations by Michael Blaha.

I started a Wikipedia article to see where it might take me information wise. Also, an Appropedia page to document our progress and hopefully meet experienced people.


Frances Bell said...

Fascinating! Any blog whose entries for April are Rhubarb and Rocket mass heaters gets my vote and now I think I remember that you are the person who did the lovely flickr slide show - thanks for all of these. Your slideshow is one of my favourites on flickr and was part of the inspiration for me to do a flickr project work book. Mine was a craft project but I'll use it for a demo for student technology projects in September. Here it is http://www.flickr.com/photos/francesbell/sets/72157616064980620/

Rachel Simpson said...

Thanks for the videos of the rocket mass heaters!

I'm very curious- where are these houses located? Who owns them?

I'm working with a group of students to develop a living body of research(online) about tiny and low impact housing. We'd love to be able to chat with more of these people about their experiences.

Leigh Blackall said...

@Francis - cute little camera case.. I wonder which flickr slideshow of mine you're referring to? I see you work in a business school.. it might interest you that I work at a Polytechnic, helping the business school develop a course in sustainable business planning. Here's the progress notes so far.

@Rachel, I'm not sure where these people are? Best contact the person who made the video I think. If you click the video in my blog twice, it should open it in Youtube where you can get the details of the author. I'm guessing they're NW coast USA/CAN and I'm noticing the same people in most of the other vids on Youtube too. I'm in NZ so its a bit far for me to travel. Am hoping to find experienced builders and users here.. its always harder finding Kiwis online :(

My wife and I are planning a trip to Vancouver and Seattle in August.. maybe I should try and find out who these people in the video are as well..

Another group I watch are the people in Kansas who call their work Open Source Ecology. Very inspiring.

Anonymous said...

I love this idea, but is it safe to leave the stove burning for 8 hours while I'm at work?

Will it even burn that long?
With my cast iron woodburner I can load it up and let it burn all day without worrying. It will have enough coals to easily build up the fire. Can this stove do this?

Leigh Blackall said...

I dunno yet, I hope to build one in August or September, but I imagine that its more the case that the thermal mass is the thing that stays hot (hence the efficiency on fuel). So you crank it for an hour or so, then let it go out. The mass will stay hot for hours after, and because its hot, the draw is still in it, so a restart is relatively easy.

Kirsten said...

awesomely awesome, Leigh. A great resource. Our Rocket-Powered Shower http://www.milkwood.net/content/view/80/1/
is amongst good company! We'll let you know when the How-To video of the construction process goes up... Have fun with the Cobb Cottage Crew! xKirsten

Black Earth Bert said...

Black Earth Rocket Stove and Thermal Mass Heater

Well, I’ve built rocket type thermal mass stoves and heaters out of many different materials. Mostly what’s available from used fire brick to irrigation pipe, and channel iron. They all worked OK but none of them performed exceptionally as I had hoped. So I have developed the Black Earth all steel rocket stove designed specifically for thermal mass heating. This stove core is quick to set up and install and burns cleanly and very well.

Why this stove performs exceptionally and its design attributes:

· The inner parts of the stove are fabricated from 10 gauge steel
· All seams 100% welded
· The feed tube top is strengthened and famed with angle iron
· Large 588 cubic inch ash area with air tight cover
· The heat tube top is also strengthened with extra iron.
· The heat tube top is flared for better flow at the barrel head and better heat distribution
· Built in barrel supports, so the barrel is centered and at the correct elevation
· Barrel supports allow the owner to replace the barrel easily.
· Bottom barrel discharge to thermal mass pipes is a steel fabricated barrel to pipe connector for excellent flow of hot gasses.
· Bottom barrel discharge assembly has its own sealed clean out.

This Black Earth Rocket Stove core has been designed for long life and ease of installation. It stands level on its own feet and makes placing fire brick easy.

The angle iron around the feed tube mouth keeps the refractory protected and locked in.

Ash clean outs have always been a problem with rocket stoves. The ash builds up and there is no place for it to go. The fire needs to be stopped and the ashes scooped out somehow. The Black Earth Rocket Stove can burn continuously and ashes removed as needed from the large ash clean-out.

The heat tube top is fabricated with extra plating and flared to provide better hot gas flow. This enhances radiant heat output and makes the barrel top a more predictable and efficient cooking surface.

The built in barrel supports let you set the barrel accurately and at the correct elevation. If the barrel is off center or the heat tube top is not at the correct distance internally from the barrel top, the performance of the stove is compromised. If the owner needs to replace the barrel simply remove the COB or refractory around the bottom of the barrel, remove the barrel and place a new barrel in place on the supports. Re-seal the new barrel bottom and you’re ready to start a fire.

The transition from the bottom of the barrel to the thermal mass tubes has always been a weak design arrangement. It’s hard to provide for even and efficient discharge to the thermal mass at this point. Shaping the refractory by hand and providing for a clean-out is difficult. The separate bottom barrel discharge assembly takes care of these issues and makes hot gas discharge to the thermal mass much more efficient. This assembly is also designed to easily attach to the barrel and can be removed and re-attached when a new barrel is needed. The discharge is fabricated for the attachment of standard 8 inch metal duct to the thermal mass.

Black Earth Bert said...

To see some photos go to (goggle)


Best Regards

Leigh Blackall said...

Great design Black Earth Bert! I've been wondering how long before a prefab would be on. I think you have really added features that were needed. Thanks for sharing. How much you planning to sell these for? I'm watching your blog for pictures and notes of installations.

Black Earth Bert said...

At this time I'm pricing the whole stove less barrel for $425. This would include the hot gas discharge box to the thermal mass, set up for an 8" stove pipe. If you built one out of fire brick you'd have half the money in bricks and it will never draw or burn as well as my steel assembly. With this assembly you can use any type of bricks as they would be protected from extreme temps by the steel. Purchaser would have to provide the bricks, vertical tube to insulate the hot gas tube inside the barrel and mortar. Purchaser would also need to build the thermal mass and the stove pipe placed in it. I am also amenable to barter to possibly lower the price.

Leigh Blackall said...

I think that's a good price BEB.. I'm not in that kind of money at the moment, or in a position to build anymore (we sold the house that is this blog) and now rent :( But I will watch out for your documentation on a full build and run, with a view to buying. Bricks, materials and time would easily equal the value of your assembly if you had the money.

Black Earth Bert said...

I have re-priced to $390 US. And I'm not too hot on aggressive marketing. It seems that as soon as I get one done someone else wants one made and/or installed. I weld/invent other things so there is a full day ahead of me 7 days a week. But it is all creatively enjoyable. I'm working on a biomass compactor that will turn paper, cardboard, grass, weeds, sawdust etc into a briquette form to be used for fuel. I hope to start up the prototype this spring. It's 10 degrees below Fahrenheit this AM here and I'm trying to get my shop comfortable (it's not insulated yet).


Infinite Possibilties said...

TERRIFIC Black Earth Bert! Thank you for developing a "Better" Rocket Mass Heater. I would like to contact you and cannot get through the email on your personal blog. Please contact me at ((( flyinpigtoo at aol.com ))). I look forward to getting in touch to see about hearing more about your devlopments with the greenhouse installation and to a future purchase for a home being built this year. AND more. I live in an area in rural Virginia where there are many folks who would appreciate knowing about your sustainable technological developments.


javieth said...

I love the big stove specially because i like to cook all kind of recipe, how ever i prefer to have a reasonable place. Actually i saw a beautiful stove in a house that was published in costa rica homes for sale it was big and beautiful, i think i will go there because it catched my attentio.