• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education skip experiences global resources cider press projects digital market permies.com pie forums private forums all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Anne Miller
  • Leigh Tate
  • Pearl Sutton
  • r ranson
stewards:
  • Nicole Alderman
  • paul wheaton
  • Mike Haasl
master gardeners:
  • Carla Burke
  • John F Dean
  • Jay Angler
  • Beau Davidson
gardeners:
  • Jordan Holland
  • thomas rubino
  • Nancy Reading

thermal mass too slow

 
Posts: 32
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Stove is drafting great, however my thermal mass is not soaking up heat correctly.
1.) Its taking about 8 hrs to penerrate about 4in of cob and broken concrete mix.
2.) A thermometer read 148 degrees exit temperature yesterday,
My duct is 20 feet 10 from core to tee 3 feet accross and  and 10 feet going back toward the core.  I have an 8" system no smoke. 20 foot stack outside to compensate for my tall house. My mix was in most cases 2 clay and 1 sand to fill, and 1 to 1 everywhere else. Could it be too heavy with clay? For duct, i used sch 40 carbon for two feet, then 8 in stainless steel thin stove pipe, then spiral duct for the last 5 feet. Gave as much info as I can think, thanks.
 
gardener
Posts: 849
Location: +52° 1' 47.40", +4° 22' 57.80"
211
woodworking rocket stoves wood heat
  • Likes 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Philip, is your heater still wet? That could be the reason, damp clay will take forever to warm up. The cure is here: keep firing the thing, drying out completely will take the best part of a fortnight and in some cases even more. A related problem is condensation fluid in the bench in most cases, that'll stop also when the whole bench is bone dry.
 
Phillip Baldwin
Posts: 32
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
It could be, we have been burning it about a week, we have seen the last wet spot dry, but there could be moisture within the thermal mass. Is there an amount of hours that would satisfy you in terms of having been given enough time for it to be classified as a malfunction?
 
rocket scientist
Posts: 5350
Location: latitude 47 N.W. montana zone 6A
2242
cat pig rocket stoves
  • Likes 1
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
Hi Philip ; My mass took well over a month to dry out. Not seeing wet spots on the outside is not an indicator of how dry the inside is. The more cob you have versus rock the longer it will take to dry out. Your numbers and temperatures all sound good , I think you just need to burn burn burn , the mass will dry out and it will warm up, it just takes time.
 
pollinator
Posts: 293
Location: US, East Tennessee
34
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator
After completing the thermal mass bench fill, my stove had a whole summer in which to naturally air dry, in a 45% RH environment. By the time Fall arrived, all the brick mortar and cob (3.5:1, masons sand to fire-clay) appeared totally white in color and dry to the touch. Even so, it took several days of daily firing before the stove stopped making condensate, and then another full week of daily firing to be dry enough so that the mass (6 inches thick) would come up to temperature normally.

So keep the stove going and give it a few weeks of daily firing, of something like 2 hour sessions or longer. When it's fully dried, you'll notice a sizable performance increase in the amount of radiant heat from the mass.
 
Ruth Stout was famous for gardening naked. Just like this tiny ad:
An EPA Certified and Building Code/UL Compliant Rocket Stove!!!!!
EPA Certified and UL Compliant Rocket Heater
reply
    Bookmark Topic Watch Topic
  • New Topic