I just dropped the price of
the permaculture playing cards
for a wee bit.

 

 

uses include:
- infecting brains with permaculture
- convincing folks that you are not crazy
- gift giving obligations
- stocking stuffer
- gambling distraction
- an hour or two of reading
- find the needle
- find the 26 hidden names

clickity-click-click

  • Post Reply Bookmark Topic Watch Topic
  • New Topic

RMH design questions  RSS feed

 
Posts: 38
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I am facinated by the RMH technology.

The likelihood of one going into the main living area of my home is NIL, but the basement is a good option for a MH of some sort.

Also, I have a garage that is not insulated ATM but will be if I get off my lazy arse and clean it out and put heat into it.

my question though, and I have read many threads but seem to have overlooked this:  How far above the burn chamber, or barrel, or other fixed point on the RMH does the exhaust have to be, or NOT be above?

in my situation, I would need to vent at least 7 feet above the floor to get it above grade on the outside of my house.

could I use an insulated pipe of say 3" to increase the verticle speed, thus getting me the ability to increase the height?

I live in Central Sask, where -40 is not unheard of at all, and we average -25C for 8-10 weeks during the winter.

 
gardener
Posts: 2326
Location: Upstate NY, zone 5
82
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Brad: For almost every situation, you need a vertical chimney ending above the top of your roof to get the best draft and avoid smoke puffing back into your house. This is the same no matter what kind of heater you have, unless it is fan-forced (and dependent on an uninterrupted electricity source).
 
Posts: 12
3
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I think people often overlook how much heat will be lost if the heater is NOT where the heat is ultimately wanted. 'Put it in my basement' sounds good, how are you going to get the heat from there to the living space? That's a whole can of worms right there. Even if you did solve that problem efficiently, there will be an awful lot of heat still down in the basement that you will never be able to get to your living space. The transfer of heat from the firebox is not the primary way of getting heat from a RMH (indeed that is why we insulate it as much as we can) but notwithstanding, it WILL and does get hot/warm. That will be lost in the basement, whether it is a batch heater or j tube etc. (if it is in the basement you'd be mad to go j tube anyway, but that is not the main point here)

For the amount of work/effort needed to figure out a way to transfer the heat from the basement to the living space, I personally think putting that work into figuring out how to strengthen the above floors so you can have the RMH in the living space would be more useful.
 
gardener
Posts: 2444
Location: Southern alps, on the French side of the french /italian border 5000ft high Southern alpine climate.
63
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
http://batchrocket.eu/en/applications#redbell


Why not doing a batch?
 
Brad Hengen
Posts: 38
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
thanks for the replys.

main floor is NOT an option.  There is no way I would be able to support 2tonne up there, ergo the basement idea

I have rethunk my exit, and I now see I need to vent above the roofline as per solid fuel requirement.

having heat in the basement is not a problem, as it is cold, and any cheap/easy form of heat would be very welcome.
 
Glenn Herbert
gardener
Posts: 2326
Location: Upstate NY, zone 5
82
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
If structural load is your main issue, and the basement below where you would want the RMH is not finished living space, it is totally possible to build piers or other foundation to support the heater on the main floor. This obviously adds to the work and expense, but the typical RMH load is spread out enough that there is not a major point load like you would have with a traditional masonry heater. In fact, for some RMH installations, it is possible to spread the load over existing floor joists with no or minimal reinforcement. In your case, you would want a larger system which would likely require dedicated support.

The heating effectiveness of a system in the living area, and ease of tending it, will quickly repay the effort of building supports.

Another possibility is what I am planning for my best friend's house. It has a tiny 200-year-old core with no space for firebox or barrel clearances, but a large 1950s fireplace/chimney mass near the center, and a basement below. I am going to build a batch box combustion core to minimize tending, and a two-story masonry bell which will bring the hot zone up into the center of the living area adjacent to the existing chimney mass. This only requires a new spread footing on the basement floor and a hole cut & framed in the main wood floor.
 
No matter how many women are assigned to the project, a pregnancy takes nine months. Much longer than this tiny ad:
Shippable core kits will be available January 1, 2018!
https://permies.com/t/72909/Shippable-core-kits-January
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!