And for the last week, I've been sitting several hours a day in a deer stand, experiencing below freezing Minnesota weather and being very disatisfied with a propane fired IR heater. I can tell it's producing some CO from the way I feel, plus it's either too hot (or turned off) in an 8' X 6' space with a 7' ceiling. There is about 2' of space under the floor...
I'm thinking abour using that space, combining a TLUD with some leftover masonry building materials on hand to make a variation on the "ondol".
That is, the center of the floor of the stand would be ceramic tile over a thermal mass of heated masonry, with a TLUD stove feeding its exhaust into this from below and me with nice warm feet and butt situated above. Ideally, this could be fired once a day in the morning, perhaps again in early afternoon. Heat doesn't need to be stored and released all night long, but would need to begin to be released into the space rather sooner after lighting than is usual for mass heaters.
I've found various resources linked on Permies in the rocket mass heater and wood heating forums regarding planning firebox & chimney size/draft requirements, fuel heat content- and I learned just enough about thermodynamics in school to be dangerous.
I need to identify materials with quick enough response to get some heat out of the floor within an hour or so of lighting the stove- Not waiting half a day for the mass to conduct heat into the space as is common for a home heating "rocket mass heater" setup.
Starting to dig out some answers, from Permies and elsewhere-
A handbook of refractory properties, I have included a table of conductivitie for refractory brick materials. No idea how much these cost, probably way too much if bought new. But that magnesite-Carbon brick is interesting...
First ideas for some cheap, relatively high conductive thermal mass?
I have a fair ammount of natural stone tile scraps and leftover tile from doing my girlfriend's basement floors and bathroom walls, these look like good candidates- Tiles I used were marble and granite. Both are among the highest conductivity of natural materials, yet not too shabby in specific heat.
Whoa, emmisivity coefficient of white marble is listed as .95!
That tile should be able to conduct AND radiate heat pretty fast.
This is great Bert, and I am only about halfway through reading your thread on the classiccampstoves forum (which is a real treasure trove in itself that I had never been to). I did not realize there was such a following around those little stainless TLUDs, but count me as part of that cult. Mine is finally giving up the ghost after years of use, I wonder if there is any difference between the different brand names slapped on each one? Looks like the Lixada one you got was a bit different, any recommendations?
I love the quest to stop sooting up the pots and to fully burn the CO, especially for any type of confined space usage. The quarter inch of soot buildup on my pot that they were teasing me about over in the tin can post was almost entirely from using one of these TLUDs. Since the soot reaccumulates so quickly, I gave up on ever cleaning it and just carry around a large plastic container for the stove and sooty pans and kindling and whatnot (it is actually a kitty litter container with a flappy door cut into it).
I am curious about any further progress on the ondol. The idea seems perfect for the space you describe and I imagine the cold weather is setting back in right about now. I don't know if this is a dumb idea or not, but rather than finding one happy medium material that balances insulative and emissive properties, how about a composite of two where you vary the proportions? I am thinking something along the lines of a highly insulative brick or porous stone for the bulk of it, and then some intentional thermal bridging of angle iron that also provides the structure... Hmm maybe tile on top of the angle iron to prevent burns and insulate a bit more... Hmm... I'm not sure.
Thanks for posting the scientific papers and other pdfs from your research, I have a lot of reading to do.
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