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How to fill once and burn for a whole day?

 
              
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Typical outdoor wood boilers allow filling once per day it will last for 24 hours.

For rocket stoves and rocket mass heaters, is there any way we can do this, without any feed mechanism?

(IMHO the key to slow and complete combustion is effective primary/secondary separation and controlled heat transfer from secondary to primary, but how to implement on rocket mass heaters?)
 
Rocket Scientist
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Hi Dog; Welcome to Permies!
I'm afraid that RMH's are not designed  to burn long term.
The principle is an ultra hot fire that heats a mass and then it goes out.
The fireboxes are to small for multiple hr burns.
 
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thomas rubino wrote:
The principle is an ultra hot fire that heats a mass and then it goes out.



Exactly, the idea that the fire needs to burn the whole day comes from cast iron stoves which function in a completely different way.
I don't have a rocket stove, but something like a finnish downdraft masonry stove and most of the heating season it needs to be fired for a 2-3 hours every day or two and the thermal energy accumulated by the brick mass keeps the house warm the rest of the time.
 
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Hi "Cow Dog",

Indeed, as both Thomas and Ansis state... the rocket mass heater and the masonry heater exist on two ends of a spectrum of heat retaining devices.  

The rocket mass heater is intriguing in how cleanly it is able to burn at a relatively low caloric output, the combination of quick and retained heat it provides, and for the simplicity and economy of its design.  

A masonry heater (like the Finnish Contraflow Ansis refers to) is characterized by a larger fire-viewing firebox where a significantly larger load of wood is incinerated into heat energy over a 2-3 hour timespan and stored in its mass.  The cleanliness of the burn has a lot to do with the size and intensity of the fire.

A batch box rocket mass heater exists somewhere in between these two.  As I see it, a batch box is basically a masonry heater with a smaller firebox whose firebox and propulsion design are inspired by original rocket mass heater designs.

When you start burning more fuel at once to store the heat over a longer period of time, the use of metal as a radiating surface becomes less useful because you can overheat the material, which results in either overheating the space or stressing the material.

Design and choices have a lot to do with the amount of heat that you need for the building, how responsive you want it to be, and how long you want to be firing each day.
 
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Hi Max....and big Welcome to Permies!
Its an honour to have your presence here.
I've enjoyed looking at all the beautiful stoves you've designed and built over the years and know it will be a valuable resource to share with others here.
 
Max Edleson
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Thank you for the kind words Gerry!  Our work at Firespeaking is evolving from design/build to being more active in education and distribution so I thought I would make an effort to be present in relevant forums such as this one.  We look forward to being a part of the conversation.
 
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