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Enclosing exit pipe with cobb and related questions  RSS feed

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Newbie here.Considering  the concept of the rocket mass heater in the first floor (basement) of a raised ranch. Conceptually, I am think of making the thermal mass more of a wall than a bench. I would like to make the area as  conventional as possible as my wife likely won't like the earthy look.

[Question 1; Instead of the embedded pipes laying horizontal like on the bench, create the looped pipes in the cob vertical instead of horizontal  creating a thermal wall? Doable? Less efficient?

Question 2: Can the exit/exhaust pipe be enclosed and hidden within the "thermal wall"?  In my scenario to the top of the cob wall that would be almost to the ceiling of the basement room. My guess is that you lose a little of the radiating heat coming off the pipe.

Question 3: Related to question 2, do typical builds not embed the barrel in cob because you lose the heat radiating of the metal?  I worry about people getting burned on the barrel, especially if there's a bench.

Question 4: If I run the exhaust pipe up through the first floor and up the roof, what type of encasement would it need as it runs through the bedroom above and through the crawl space to the roof?

Too many questions at once, I know. Thanks for any help.

Posts: 217
Location: US, East Tennessee, north of Knoxville
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A thermal mass wall can be done, maybe even Russian stove style. Personally, I'd encase the cob inside a sturdy wall of brick. The brick will add thermal mass and cut down on the amount of cob production. Properly designed, the wall could even be built as a thermal bell (bell mass heater), thus leaving out the ducting pipe and cob altogether.

If you've never built a cob RMH before and don't have this book, it's highly recommended reading:


Also check out Peter van den Berg's site of batch-box rockets for additional ideas on metal barrel-less stove designs:

Shiny ad:
five days of natural building (wofati and cob) and rocket cooktop oct 8-12, 2018
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