Rocket stoves

[MIGNAL]

Given their great efficiency and the ever rising cost of energy, why aren't we seeing these things in domestic installations? I know that some of them can look a bit 'home made' but surely there are home friendly versions. Do they require constant attention/feeding?

 

[bugbear]

Given their great efficiency and the ever rising cost of energy, why aren't we seeing these things in domestic installations? I know that some of them can look a bit 'home made' but surely there are home friendly versions. Do they require constant attention/feeding?

I would assume that a well designed gas or oil boiler already achieves comparable efficiency. It appears that rocket stoves are specific to wood as a fuel.

BugBear

 

[MIGNAL]

Yes I know but many people use a relatively inefficient wood burning stove. Why aren't they using the more efficient rocket stove?

 

[condeesteso]

I was looking at these a while ago - rather impressive. I recall one guy made one with a very extended flue which ran horizontally along an internal wall then up and out, so heat exchange was greater into the room. I have only seen them run wood, but cannot see why solid fuels wouldn't work though the combustion chamber might need beefing a bit.
One issue seems to be hopper-feed (lack of on most) so regular refuelling maybe, but again I imagine this could be designed around. It did seem to me that these were shop-made devices - no company seems to have commercialised the idea into an aesthetically pleasing product.
Someone sent me a link a few days ago... a variation on the theme as it was a horizontal rocket stove, with a tree fed into one end (on rollers for convenience).I better try and find the link!

here we are:

http://i81597.wix.com/sprucestove

 

[Hivenhoe]

Sod's law, just arranged to buy a Franco belge insert stove!
When I worked for British Steel in the late 70's,we we're helping a local "inventor" with a hopper feed for solid fuel. Supplied him with quite a bit of stainless steel sheet, unfortunately I moved on before completion, not sure if my successor followed up and he's since died but is daughter how was involved still lives in the same area iirc, may try to contact? Anyway wood pellet systems use hoppers, would wood chip be any use as vast amounts of this are dumped to rot down by councils edge trimming teams around here?

 

[Graham Orm]

I did a thread on these last winter when I built mine. i was searching for it when I came up with this one. Mine achieves 450deg at the top and radiates masses of heat. I have some fins to add this year when I get round to it. Consumes very little wood and virtually zero emissions. No smoke whatsoever as it gets re-burnt in the rocket. This is one of the videos of the development of mine. It's progressed now from this stage. I'll do some pics or a vid when I have a minute. http://www.youtube.com/watch?v=OI_n6Nr_LsU

 

[houtslager]

just a quickie, I 've built 2 and have one in my conservatory, built into a seating bench - works great, veryt little smoke, in fact last section of the chimney is a temporary bit of 3m drainpipe [ red plastic] it doesn't even get warm, though the local sweep nearly had a heart attack LOL

K

 

[bugbear]

I did some reading, and found this;

http://solarcooking.wikia.com/wiki/Rocket_Stove

Now, they're basically a fairly nerdy bunch, much given to research, science and technology,
albeit carefully tailored to use in developing countries.
The whole page is quite helpful, but I was particular struck by this:

Rocket Stoves operates roughly twice as efficiently, and substantially more cleanly, than the open fire cooking methods still used in many areas of the world.

Only twice as efficient as an open fire ain't magic (although very helpful if your alternative is an open fire...)

BugBear

 

[MIGNAL]

So what's the point of a rocket stove, over the more usual woodburning stove? Why on earth would anyone go to the trouble of making one when all they really need to make is a square box? Which leads me right back to the original question: why aren't they being sold at fireplace outlets?
The more usual woodburning stoves average around 75% efficiency, give or take. I've seen sites that strongly dispute the given figures and state that their efficiency are much lower than claimed. IF rocket stoves burn very clean (i.e. little smoke) it would seem to imply that they are relatively efficient, in that the waste products of combustion are being burnt. But who knows? and is there a scienticific standard test for such things.
It's also true that some Gas fires are pretty inefficient - 60% or even less and that's using the manufacturers own figures.

 

[bugbear]

So what's the point of a rocket stove, over the more usual woodburning stove?

The page I linked to lists a number of advantages, carefully put in context.

My conclusion is that they're "interesting" but not a panacea.

BugBear

 

[Graham Orm]

So what's the point of a rocket stove, over the more usual woodburning stove? Why on earth would anyone go to the trouble of making one when all they really need to make is a square box? Which leads me right back to the original question: why aren't they being sold at fireplace outlets?
The more usual woodburning stoves average around 75% efficiency, give or take. I've seen sites that strongly dispute the given figures and state that their efficiency are much lower than claimed. IF rocket stoves burn very clean (i.e. little smoke) it would seem to imply that they are relatively efficient, in that the waste products of combustion are being burnt. But who knows? and is there a scienticific standard test for such things.
It's also true that some Gas fires are pretty inefficient - 60% or even less and that's using the manufacturers own figures.

I can only quote from personal experience. The top of my stove reaches well over 400 degrees (measured with a laser thermometer) This is the temperature of an electric cooker ring. It uses very little wood to achieve this, it creates hardly any ash and the outlet of the exhaust shows zero smoke. You wouldn't know it was lit to look at the vent outlet.