Pocket Rocket woodfired shower

[caithnesscrofter]

Our shower is now provided with hot water heated from a pocket rocket stove. It's quite efficient and needs work yet, but, so far it consists of a "pocket rocket" made out of an old gas bottle and flue pipe and metal feed tube.



We can boil 40 litres of water in 20 minutes with only one piece of pallet wood sawn in half than split several times longwise into thinnish splinters. We use the 1.5 meter pallets. Fire is lit with two pieces of newspaper shoved down the vertical feed tube to the bottom of the stove and the wood is stood up in the feed tube on top of the burning newspaper. The forced air action pulls air down the feed tube and the flue pulls the gases out again producing an extremely hot and efficient burn. The wood being very long and stood vertical the stove feeds itself as the wood burns. After the newspaper burns away within 30 seconds, there is no smoke from the flue as it is such a clean burn. After 15 minutes the entire stove is glowing cherry red, quite remarkable considering the thickness of the steel of a gas bottle. And yes, it does sound like a rocket! Wood has to be really dry which is why we use pallet wood.

We considered installing a copper coil into the stove to heat the water via thermosiphon however, considering the price of copper coil, we wondered what happened if we submerged the entire stove into a basin of water.

My mate who is very handy with an angle grinder split a large oil barrel in half and installed an old tap at the bottom.



We sit the stove in the barrel and fill with water. Light the stove and 20 minutes later we have 40 liters of boiling water. We then of course have to empty the water into buckets and adjust the temperature for the shower. The shower consists of a shower head attached to a submersible pump powered by a small 7.2 ah battery charged from our small wind turbine.

Highly recommended for the off griders here. The price is right too. Cost £0 to build the water heating unit. Installed into a shower room with the flue exiting the roof or wall really heats the room up quick for your shower too.

[ENIGMA]

A brilliant concept to heat water by immersing the fire in the water instead of the conventional method.I am thinking of building similar but with a larger tank to heat water for a bath.I would like more information on building a rocket stove from a gas bottle.I couldn't find any information on the net.Have you got any closer photos of the top of the stove? How far does the feed pipe extend into the stove?Any other information on constructing the stove appreciated.
Thanks in anticipation.

[ina]

That's basically the Kelly Kettle system in larger, isn't it?

[caithnesscrofter]

Hi Enigma,

I have taken some closer photos for you. The gas bottle is I believe a propane bottle 19kg. size. Maybe even a size up. Canna mind now. The flue pipe is 6 inches wide and the feed tube is 5 and half inches wide. These can vary but, the flue must be larger than the feed tube for the obvious reasons. The feed tube on ours is 13 inches long and the flue is 53 inches long. We used a gas bottle because I've seen several pocket rockets in action built of grease barrels and various metal containers and they tend to burn through fast. The gas bottle does glow red and don't know how long even it will last taking heat at these high temps so often. You can build these any size but, the main things you need to keep the same are roughly the proportions of the length of the feed tube to the length of the flue, the flue needs to be larger in width than the feed tube and you'll need to play with how far the feed tube extends to the the bottom of the stove. There is about 6 inches between the bottom of the stove and the bottom of the feed tube in mine. When you are testing, if any smoke is coming up the feed tube you'll probably need to play with how far the feed tube is extended into the stove. If you get Iantos book Rocket Mass Heaters it gives more ideas for heating water with rocket stoves.

If you are wanting to submerge a larger stove into alot more water you'll either need to weight the stove down or weld it to the side of the water container to combat bouyancy. If I put much more than 40 litres water in the barrel I then need to weight the stove down.





Ina, the kelly kettle or storm kettle are only the same to this idea in that you are trying to heat a large amount of surface area of the water. Kelly kettles are fed from the bottom and depend on wind blowing into the fire hole to get a good burn going hence, why it's called a storm kettle. If you try lighting a kelly kettle in no wind you will not get a good burn going unless you blow a lot of air in there to get it going. The pocket rocket on the other hand produces a good burn purely because of the clever design, creating an action of forced air down the vertical feed tube. Kelly kettles are less efficient and also smoke. They require quite a bit of fuel just to boil a liter and half of water.

The efficiency and the clean hot burn of this thing is just remarkable. It is even possible to smelt aluminium with one. As an example, everyone knows what happens when an aluminium can gets thrown into a bonfire or campfire. You usually end up with a half burnt tin the next day. An aluminium can dropped into a pocket rocket disappears completely in 10 seconds. When you empty it after its cooled down you are left with a clump of melted aluminium the size of a 5p.

[ina]

Cheers for the explanations! Yeah, I can see the difference now... Although I did get a cuppa from a bit of newspaper with my kettle. You are right about the smoke, though - not to be used indoors!

[caithnesscrofter]

There is such a thing as a coffee rocket as well that burns wood inside with no flue and no smoke!

[snapdragon]

There is such a thing as a coffee rocket as well that burns wood inside with no flue and no smoke!

In that case I want/ errm ahem koff - NeeD one

[ENIGMA]

Thanks caithnesscrofter for your detailed reply.I have all the information to build this project now.I will post when I finally build it which wont be for sometime as I need to pick up the materials from my house in France.This will replace the electric immersion heater I have there.
Most of my other water will be heated by a homemade solar heating system,which I also have to build but have a plan.
Thanks again for giving me the idea and sharing your knowledge.

[stormpebbles]

please caithnesscrofter,
i spent weekend making a smaller version of your boiler (which refuses to light .. but have done some modifcations and NEXT TIME IT WILL GO.... hopefully lol )
ive spent hours searching for your "coffee rocket ' just wondering if u had a link ???

[Wombat]

I just made a rocket stove out of a 20litre container and some steel tube for use with our wok. It works pretty well once it gets going?

Nev

[theabsinthefairy]

That looks great - we are already looking at how we can adapt this to heat the water in our daughter's plastic pool for the summer, with the water pumping through the pool filter.

And yes - I know a pool is not necessarily green or eco - but it was one of her stipulations for moving to France, and she paid for it with saved money she earnt doing odd jobs (she was only 10), and we fill it from the well in the spring with all the snow melt water.

[stormpebbles]

hello ,

has anyone got a link to a "coffee rocket" ????

[caithnesscrofter]

coffee rocket is described in Ianto's book.... the book is highly recommended.. lots of ideas for different things.