The idea of thermal storage is not a bad one at all. It has been used very effectivly in europe with their masonry heaters for a long time. And properly designed i see no reson a rmh could not do a good job heating a house safely if it was designed right. That being said much of the designs i see from wheaton and his buddies are unsafe without question.
Why dont we all want rocket mass heaters?
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The mass in a large house is certainly a factor. Even my partially insulated 3 story double home holds a certain amount of latent heat within the walls,floors,furnishings,large aquariums ect. Temps fall very slowly in a no heat situation,so much so that i sometime run one load of wood a day in winter 12 hr heat,12 hr no heat. Start at 10Pm,Stove out by 10 to 12 noon next day ,house stays warm enough on sunny winter days so can go until 10PM again before firing up the stove. Not more than about an 5-8 degree swing in temps in 24 hr period.
maple1
Minister of Fire
Yes, it is. It is likely even more noticeable going the other way - in how long it takes to recover, after everything has cooled off. Takes quite a while to warm up a house and everything in it - all that 'stuff' needs to soak up the heat again.
What im contemplating is using my regular EPA stove i have now, but building same mass around it ,like about a ton or 2 of mountain stone as fireplace type structure around the stove(but leaving sufficient air space around the stove) to absorb some of the excess heat at startup and give some back after the wood has burned to coals. Im wondering if this is worth the effort. Sort of the Mass part, of the equation but not the rocket part. Im also doing this because i like the look of a large fireplace.
Works out well because the big harman makes TOO much heat and actually overheats the finished first floor a bit but im not spending time there overnight.
I am guessing this style of heater is going to be more for the folks that don't utilize insurance, need any permits, and would rather DIY stuff inexpensively rather than pay high dollar for factory made products. And it seems they can be made to look very nice, I like the granite top used in the one video, just the barrel that sticks out a bit. But stoves used to be made out of barrels... something nicer of course is possible. Of course beauty is in the eye of the beholder, as even on these forums folks argue about stove looks and how but ugly this or that one is.
Have you looked into the folks that are experimenting with these? I don't think home resale value is a big item for them. Paul Wheaton and his associates seem to be more of the homesteader types. I mean they use outhouses... resale value I am sure isn't weighing in. It's a different culture. Even still it's probably no harder to remove (maybe much easier) than my gigantic brick fireplace. Just that a wasteful gigantic brick fireplace is more acceptable to the masses. But yes as an answer to why they won't appeal to the general wood burning population I am sure many would be concerned of resale value.
You can't just make a blanket assumption that it's overrated or not...Thermal mass/storage is one characteristic that may or may not be useful depending on the circumstance. A well insulated home with conventional furnace works fine with little thermal mass, the controls regulate the temperature to keep it relatively even. Something like a passive solar home with thermal mass utilizes the suns heat to warm the thermal mass which is needed to store the thermal energy for the night when there is no sun. Some woodstoves even regulate just fine like a BK with thermostat control. A RMH pretty much requires a large thermal mass by what I've read, as it uses the method of extremely fast & hot fire to fully utilize all the combustibles in the wood, as opposed to say a CAT stove that burns low and smolders but uses a combustor to extract the heat from the fuel. This rapid release of heat benefits from thermal mass to smooth out the release of heat into the home. At least that is the basic theory.
I may have missed it since I haven't read all the pages or done a lot of research on these, but how does one clean the flu? Some of these designs like the main one talked about earlier using the horizontal flue with a U bend and double layer all sealed in the thermal mass? Maybe it does indeed burn so clean it's not an issue but what about getting the fire established and all the smoke and soot initially? Or does the intense fire self clean all that back out every time??
I was wondering about that. I guess there is a way to calculate the heat storage capacity of a given weight of material to find out. LIke is said i love the look of a fireplace but not the efficiency of it. This way i get the look and the long burns and also dont suffer from insert heat trap.
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