Toni's Permaculture Project Profile: 2010

Date: November 2010

Location: Corga de Peirera

Aim: Use as an efficient thermal mass heater to warm cold cellar\basement room directly below main living area

References: We used designs and advise from the book Rocket Mass Heaters by Janto Evans and Leslie Jackson http://www.rocketstoves.com/

Benefits and reasons for choice of stove:

Able to be built with few materials, cheap\free and readily available
Fast to assemble (a few days)
Best fuel efficiency, small twigs\sticks which are in abundance on this particular farm as the neighbouring fields are used for pine\eucalyptus plantations and are felled often. Both woods are fast and hot burners
Only needs to be actually burning for a short time and heats thermal mass via flew quickly
No\little heat is lost and all is used for thermal heat
Multi-purpose, able to cook\heat water on top of stove
Easy to control from main living space upstairs, can fill feed tube with say, eucy branches about an inch width and put on lid, sticks will burn and gravity feed, so you could possibly leave it for 45min-1hr before having to re-fill. If the thermal mass\bench is cold, it would take several hours to heat, at 1 inch per hour. The more often you light it the better, for the mass we used, it would still be warm for a few days
Seating created, makes room more hospitable
Easy to maintain, using inspection tubes at various points
Know success rate and desire to try it out!

Disadvantages:

Must maintain fire while burning, but can be loaded up and left

Problems Encountered:

Costs and locating parts, ie; fire bricks, elbow and T-junctions
Not all heat is used, smoke comes out warm, not enough time or space to run flew back and forth under the bench, but in future bench could be extended along back wall to utilize the heat
Spring line-water flows under house through that room, stove now in the way and water will build up behind. Not too much of a problem luckily, seeps down below and runs out holes on other side of room under flooring.
Should have left a gap all the way around the barrel foundation and the heat riser as only just had correct surface area to release the hot gas out into the flew, luckily!

under the floor boards, placing the granite

laying out the firebricks to align
granite and ash hole

Benji cuts the lid off our
55gallon drum

cob under the granite as a base

Benji mixing cob

Nigel angle-grinds the
granite for the ash hole

getting measurements and levels

fire-brick foundation is laid
and cobbed in

fire-brick base, feed tube, tunnel and
heat riser

Andy cuts the wire mesh to hold in
the Lekar around the heat riser

Filling the gap between the mesh and the heat
riser with Leka, small balls of clay, and then
cob to keep them in. This will act as insulation
for the hot gas rising from inside