Thanks for your response! 120 sqft (actually a small fraction less) is apparently exempt from universal code requirements. My county is not zoned but I would rather build small now, avoiding any Imperial entanglements, and add on later as needed.
thomas rubino wrote:Hi John;
10x12' sure seems small to me but its your tiny house.
Yes I do. An older version.
Most important) Do you have a copy of the RMH builders guide yet? Readily available on Amazon.
I have ... It does help. Fun fact: The front elevation I sketched up bears a small resemblance to the letters in the name "Jill". :) (J tube on the left.)
To start a drawing might help clarify things some.
I'll use the standard 1:2:4 ratio, or as close as I can get it, and follow the generic plans I have as closely as I can.
Ok) 6" feed tube? Did you mean 5.5 x 5.5 by how deep ?
That's good to know.
burn tunnels are generally only 10-12" long.
36" overall from floor to the top of the cook top. This is to locate the cooking surface at standard kitchen height. I'm thinking a riser of rock wool lined firebrick. I may start out with just the firebrick and add the rock wool liner as soon as I can. Ceramic blanket is new to me. I'll have to compare costs.
A 36" riser made with what material ? Ceramic blanket ? Insulated fire brick ? Heavy firebrick?
Steam table pans have a lip so they can hang inside a standard sized opening. This firm rectangular rim should snug up nicely to the firebrick below once inverted and clay-sand mortar should make a good seal between the sides of the pan extending below the red brick structural top. I wonder if nesting two pans together to increase the overall thickness would be advantageous. I'm not wedded to the steam table pans, but it seems like they would serve well as a smallish rectangular channel between the riser and the diversion tube -- like one independent section of a barrel from riser to barrel edge. The 6" depth and 12" width should allow for good flow across the inner surface of the pan, and the outer surface should get plenty hot enough to set cooking pots and skillets on to be heated for cooking. In my mind it should function very similarly to the top of a barrel, just smaller and more rectangular.
What is your plan for the transition area ? Below your cook top ?
I know that's the standard design. I just don't know how I could have the overall width of the stove be basically the width of the tube plus outer structure only, and still be able to have the exit below the entry tube. Since the hot gasses mix and stratify in the chamber rather chaotically, I don't think it would cause any problems to set the exit tube right on top of the entry tube at the bottom of the structure. Maybe extending the entry tube along the bottom of the chamber a foot or two would be enough to avoid any potential problems with the gasses entering and exiting too quickly without filling the entire chamber for effective mass heating.
The exit to your stratification chamber should be at the lowest point.
You've hit on one of my most serious concerns with this design. My hope was that using a 6" system, making the riser as tall as possible within the overall height dimension, and giving plenty of clearance between the end of the riser and the inverted bottom of the pan would be sufficient to keep from overheating the cook top while still achieving rocket stove temps for complete combustion. Perhaps a removable cover made of thicker, more massive material would keep the pan from burning up when not having heat pulled out for cooking. I've seen barrel stoves with cob covered plates sitting on top of the barrel to avoid overheating the top. I would also need to experiment to see if there would be an effective range of temperatures across the cook top for cooking. You can't be a very good cook if the only setting on your stove is 'incinerate'. I've considered using trivets of various thicknesses to control the amount of heat being transferred to the cooking vessel.
Your cook surface is going to be glowing hot at times, my 8" J tube can hit 1100F at the barrel top....
Yes I have. It's a great design. Much to emulate there. Unfortunately, I don't really have room for a glass range top, and also it appears to take up a minimum of (I'm guessing) 16-20 sqft of floor space for just the stove and wall clearance. I don't know if I can afford to use that much space all in a chunk in the middle of the house. I've also considered a design like the tiny stove with the gothic arch masonary bell on the top, but I don't know how I would cook on it. I'd rather have a design I can cook on during the cold part of the year and extend the thermal mass along the periphery of the floor plan to take up as little of the most valuable estate as possible.
Finally, have you seem Matt Walkers tiny house cook stove ? Here is a link to it https://permies.com/t/71700/Tiny-House-Cook-Stove-Heater
That's great. Would you expand on your specific concerns with the SS pan? According to the info I found, 18/8 stainless has quite a high temperature tolerance.
Jason Broom wrote:I know you were expecting challenges to this design, but aside from the long-term viability of the stainless steel steam tray pan, it looks like you're going "by the book".
Since there will be a 6-8 inch space between the back of the strat chamber and the glazed and insulated south wall I'm not anticipating any issues. I want the back of the strat chamber to pull double duty as a Trombe half-wall.
Long and (relatively) narrow masonry heaters have been built for many years, and a properly constructed rocket mass heater is simply a masonry heater made from less expensive, locally sourced products.
I think your plan will work well, provided you insulate the wall very well from the stove, and the stove from the wall, lest you wind up attempting to heat the entire outdoors.
john Harper wrote:I'd like to hear a little more about your idea to add a cooking plate to the masonry rocket heater. Where do you envision it being located?
I've also been investigating masonry stoves (non-rocket type) but I'm a bit hesitant because rocket stoves with their high combustion temps seem safer to live with. Some masonry stove designs without a riser worry me when I think that they could be giving off CO2 and CO in the living space. In videos when they take them apart the inside bricks are always black from soot which tells me the temps aren't very high and there are a lot of products of incomplete combustion being produced.
I guess another option would be to create a largish stratification chamber beneath the floor to absorb and slowly release heat and to mitigate a possible overheating situation. In a 10 x 12 foot house a 30" x 72" chamber beneath the floor doesn't seem that hard to incorporate into the design. Especially with a tamped earth floor like I plan to have. I may lose some heat to the ground, but a layer of insulating dry sand around the chamber should cut down on that.
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