pocket rocket & alternative fuel

Oh my, take a look at hardworkinghippy's pocket rocket in action in this thread about preserving peaches: https://permies.com/bb/index.php?topic=1991.

Amazing photo and explanation of heating water while cooking tomatoes while using dried corn cobs as fuel. 

Just in case some of you don't make it over to the cooking and food preservation forum! 

hardworkinghippy, any chance of a closer pic?

Paul, do you mean of the stove itself ?





I can take more pics - just tell me what you need.

The new pics are good ... but ... I would like to get a really good look at it!

HardworkingHippy,

Nice closeups, good enough for me to ask some questions:

-looks like a bucket with a fuel feed tube welded to the side: does the feed tube have an air way underneath the fuel shelf (or is the fuel shelf at the very bottom of the hole you cut in the side) -Lorenz stoves use the "under the fuel shelf air way";

-looks like you put another tube in side the bucket, maybe a 7" tube, and then filled the space between the bucket and the 7" tube with an insulater: is this correct ? if not what makes the heat riser? what is the insulator fill?

thanks for sharing this stove by the way!

So ..... this looks like an L-tube design.  Maybe this is a bucket ....  and a hole near the bottom and .... insulated with something? 

You'll laugh it's so simple !

This old galvanised bucket already had a hole in it at just the right place so we made the hole bigger to fit the elbow. It's not welded just bashed in to fit well. The elbow is surrounded by wood ash.

This is a biscuit tin lid used as a shelf, cut and folded to fit and just pushed in. I'm careful to keep the underside clear for the entry of air. We remove the tin lid for scraping out the ashes from the bottom of the stove.

Firebricks are placed in a "u" shape to direct the flames and heat towards the cauldron.

In this photo the flames are a bit too high but you can see them licking the cauldron, when they are less fierce they go under the cauldron.


I realise that this little stove won't last long but it only took half an hour to make it and the we've got a lot of waste materials like this lying around our farm. We've got loads of wood but I like the corn husks because they're clean, dry and light to carry !

We installed the cauldron when we built the house, it is the back boiler for a closed thermosyphon system which heats a serpentine inside the water tank behind the fireplace. The system can be either heated by wood or by solar in the summer but our panels are really old and we've taken them off to repair them and put them in a barn for washing fleeces and dying goats' wool. I'll replace them with new vacuum panels next spring.

I've taken off the tank's insulation (mostly sheep and goat wool) to show some of the intriguing plumbing.  The system also heats two radiators in the rooms upstairs.


Ps. For the new extension we're building I'd like to build a really good rocket mass stove to heat water and cook on too - I found this forum while I was looking for ideas.  P

You sure have a nice touch with the pictures.  Thanks for posting them.

So you are cooking on top of the heat riser with a flat pan, and sending the flames back to a second pot (cauldron) behind that? 
It sounds almost like you've re-invented the LoReNa Stove or "the Good Stove" from India. 

Nice use of available materials; ash as insulation is very smart.

-Erica Wisner
http://www.ErnieAndErica.info

I see this is an L-tube.  Have you tried J-tube?

So you are doing the home-made hot water thing, eh?  Have you been reading the stuff about legionnaire's disease?

No worries about exploding hot water tanks?

No Paul we haven't made a J tube stove yet but at the moment we're rushing to get the roof on to the extension before the end of October when the weather changes. We're gathering materials to do some experiments and reading up a lot on dimensions and designs ready for building the stove in the extension.



The building highly insulated 30cms of stone, 2Ocms brick with a straw bale interior. Do you think a rocket mass will be capable of heating the downstairs room plus the the two rooms upstairs ? I could also put a smaller stove under the stairs on the first floor if I need to as it's right next to the chimney but I suppose we need to live through a winter before we'll know for sure.

Re legionnaire's disease, I've read up what I can and we're trying to do all the right things. It's only this summer when we've had no solar panels that the water hasn't been hot all the time. (over 60° anyway) Once the new panels are up it should always be OK. 

Exploding tanks do frighten me and we've had a few rumblings when we had to rush to run some water off  but the system has been in use now for ten years and we've had no problems. On the same circuit there are now two radiators in bedrooms upstairs to dissipate the excess heat. I've never felt the need to add another one.

The extension will have a separate water system which I haven't finished designing yet but I'll bear health and security in mind. Thanks for mentioning it, it's so important when you're DIYing.     

hardworkinghippy wrote:
No Paul we haven't made a J tube stove yet but at the moment we're rushing to get the roof on to the extension before the end of October when the weather changes. We're gathering materials to do some experiments and reading up a lot on dimensions and designs ready for building the stove in the extension.



The building highly insulated 30cms of stone, 2Ocms brick with a straw bale interior. Do you think a rocket mass will be capable of heating the downstairs room plus the the two rooms upstairs ? I could also put a smaller stove under the stairs on the first floor if I need to as it's right next to the chimney but I suppose we need to live through a winter before we'll know for sure.

...Erica pipes up:...

You don't mention the size of the extension, but it sounds well insulated.  Thermal mass on the outside won't affect the interior temperatures as much, except to establish a consistent baseline.  A mass heater will make up for that somewhat, giving you controllable, stable indoor temperatures.

I can vouch for an 8" rocket mass heater in a converted garage.  It was a good-sized beastie, maybe 30 feet of heat-exchange pipe, and it heated the garage space, an office loft above, and made an appreciable difference to an upstairs bedroom that shared one wall with the office (BR was in the main house, not the garage). 
Pictures at: http://picasaweb.google.com/eritter/RocketStoveDecember2007#
and there's a report from its owner (Andy) at http://www.ernieanderica.info/rocketstoves_ownerreports

There's also some info on things that can go wrong.  Good cleanout placement is key, as is choosing the right size (and sticking to it) and building the chimney and feed tube to suit the situation.  You can wrap the barrel in cob or tile for looks, but insulating it is not recommended.

Give us a yawp if you want to bring us in on the project. 
Good luck (and good weather) for roofing!

Yours,
Erica Wisner

Erica, thanks for that !

I've already seen your Picassa photos - you're in my "favourites".

I've been researching this for about 18 months. A Russian stove was my first thought for heating but I've now found out a lot more about mass rocket stoves and I think we'll be building one for this winter. 

The extension is 13x5m² with two bedrooms 5x5m² with 2 metre high ceilings - I've calculated that it's over 8000 cubic feet. 

The stove will go here :



(There's 2 feet of empty bottles for insulation under the kitchen floor.)

I'm still doing drawings and looking at other people's stoves for ideas for the finished "look" but if I post up the design I'd be delighted if you could have a look at it and spot potential problems.

I'll start a new thread for that but it won't be for a while.

Irene