• 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:
  • Carla Burke
  • Nancy Reading
  • John F Dean
  • Jay Angler
  • paul wheaton
  • r ranson
stewards:
  • Pearl Sutton
  • Leigh Tate
  • Liv Smith
master gardeners:
  • Christopher Weeks
  • Timothy Norton
gardeners:
  • Jeremy VanGelder
  • Matt McSpadden
  • thomas rubino
  • Likes 7
  • Mark post as helpful
  • send pies
    Number of slices to send:
    Optional 'thank-you' note:
  • Quote
  • Report post to moderator


Listen Online
Download

Get all of the Podcasts in convenient, giant zip files
Subscribe on iTunes

Summary

part 2 of a 2 part podcast

Paul and others continue to discuss improvements to the rocket mass heater in the library, and rocket heaters in general.

Paul comments that a pebble style mass as previously in the library can be moved and rebuilt someplace else, which you can't do with cob.  However there's a trade-off that initially the rocket heats the mass more slowly.

Peter is invited to comment on the rebuild.  He re-iterates the point that bypasses and such are prone to human error.  

He has the following comments:

* 4" flue is only a quarter the area of 8", so it's too small.  6" could even give problems.

* A given size batch box is about twice the power of a J tube, but you do need a bigger/better heat extraction to use the heat efficiently.  Peter has a build with a tall stratification chamber, about 6ft high and maybe 2ft x 2ft footprint.

* He suggests making the connection from the rocket heater to the stratification chamber larger.  There's no need for restriction at that point and a wider connection will speed up heat transfer to the chamber.  He also points out that without a single flue (as with a mass) more fly ash might gather in the stratification chamber.

Paul feels not enough has yet been done to improve efficiency when the stove is not burning which is what they are experimenting with on this build.  For example, the smaller exhaust should conduct less cold air in from the outside when not burning, and kissing the barrel mitigates the possible draw issues with the smaller exhaust.

The last part of the podcast has some questions and answers from the live session.

Paul finishes up by stating his position that anyone starting out in rocket heaters should start with a J tube as it's a simpler build.  Batch boxes are harder to build if you don't already have the skills, so it's easier to get it wrong. Peter agrees that the batch box is more complex to build but the payoff is bigger as well.  Paul reasons that as the batch box burns more wood, faster it is better suited to places like a workshop or cabin where you want heat fast.

Relevant Threads

Rocket Mass Heater forum

pebble style rocket mass heater in the library

Support the Empire

Help support the empire and get all of the podcasts in a bundle here in the digital market at permies.

To support production of these podcasts, make a donation here at Paul's Patreon page.



This podcast was made possible thanks to:

Dr. Hugh Gill Kultur
Kyle Neath
Bill Crim
anonymous
Chris Sugg
Kerry JustTooLazy
Jocelyn Campbell
Bill Erickson
Sasquatch
G Cooper
Dominic Crolius
Penny McLoughlin
Mehron Kugler
Pasquale DeAngelis
havokeachday
Julia Winter, world's slowest mosaic artist
Greg Martin
Mark
Sean Benedict
Rita Bliden
Dana Martin
Candace Dahlk
Keith Kuhnsman
Leanne
Eric Tolbert
Nick DePuy
Nathan Hale
Opalyn Rose
Polly Jayne Smyth
Todd Gerardot
Katie Young
Ivar Vasara
Brent Lawson
Weston prestage
Candice Crawford
Chris Holtslag
Song Zheng
 
I have a knack for fixing things like this ... um ... sorry ... here is a concilitory tiny ad:
Contribute to BEL fund and stay in the Red Cabin for free!
https://permies.com/t/268918/Contribute-BEL-fund-stay-Red
reply
    Bookmark Topic Watch Topic
  • New Topic