-A 20mm insulation air gap that should increase fuel efficiency while at the same time radiating some heat off the middle cylinder to the outer cylinder. The outer cylinder should be safe to touch while the stove is in operation. The theory is using a 3 cylinder stove creates a sweet spot for metal lifespan, fuel efficiency and safety. Need to compare water boiling times and outer metal surface temperatures with and without the middle cylinder
-The handles are double so 1.5mm goes to 3mm which is hopefully thick and robust enough. The double welded tabs should provide strong attachment of the handle to the outer cylinder - maybe orientate North-South so they don't act as hinges when the stove is tipped over!
-An independent pot stand that is suspended above a 1.25kg Milo tin riser and 'Permastove'. The legs are made from bamboo (any variety) and the metal cross should be able to support flat-based pans as well as round-based pans/woks. If the fuel runs out, the 'Permastove' can be easily removed and replaced with another 'Permastove' (with fuel) without any need for moving the pan/pot/wok during cooking.
-The lid tabs could be screwed into the outer cylinder with 3.2mm x 20mm galv screws which would help anchor the cylinders, increase pressure in the secondary air gap by reducing air leakage at the top
-For USB fan control I found this: https://www.coolerguys.com/products/coolerguys-manual-speed-controller-for-usb-fans It means now you can adjust the (5V USB centrifugal computer) fan speed which will adjust the flame size for better cooking control - just like a deluxe gas stove ring!
-2 spare grates per stove. The inner cylinder will eventually wear out from exposure to fire and need replacement at some stage but probably not before the grate will burn out in the middle. Replacing the grate will extend the life of the inner cylinder. For convenience the central grate should be able to be snipped out with good tin snips and replaced with a spare one that can be screwed in with 3.2mm x 20mm galv screws (can be purchased from Bunnings).
-The power bank could be the 'Zendure X6' or 'Ultron'
-The power bank could be powered from a 60W Megasolar PV panel which has USB C PD output, DC and USB A
-Why not a TLUD dehydrator? There's always the ol' solar bed frame...
-Why not a solar oven when the sun's shining and a TLUD when the sun's not shining?
Where's the CAD for 'The Permastove V3'?
I'm still saving up dollar to prototype 'The Permastove V3'. Information will be provided during the prototyping stage as there may need to be final adjustments to the CAD - which might be posted if I think the stove is worth mass producing!
The 'Permastove V4' is a '3 in 1' stove for
2) backup stove for the household (if you already have a stove connected to the grid)
(3)primary stove for the household (if you're off grid)
-lightweight: made from 0.55 304 stainless steel - very durable too
-multi-fuel: can use plant waste (biomass) from the environment while trekking or use fuel pellets if you're alpining eg. sawdust, rice husk, coffee bean pulp etc The base/grate has many small air holes so all types of fuel won't fall through
-light ecological footprint (offsetting Carbon released by unsustainable sources and technologies eg. fossil fuel based transportation, energy production, agriculture et al like deforestation/land clearing...)
*fuel efficient with clean emissions (smokeless) via passive/non-pressurised micro-gasification (uses primary and secondary air supply)
*produces biochar (as a by-product of pyrolysis via water boiling/cooking). This can be left in the environment and will lock up Carbon for hundreds to thousands of years (eg.35,000+ years) reducing the impact of climate change/chaos
*no non-recyclable fuel (gas) canisters to deal with (that usually get turfed into the environment)
-no moving parts eg.no fan or any electronics
-fits in all sizes of billies eg.1.4 litre, 2 litre, 3 litre to reduce volume in bag
-replaceable inner cylinder
-creates local 'Green collar' jobs along the supply chains eg. fabrication, biochar collection and application
Quoted AUD$513 at 'Laser 3D' for cutting. Just need to fabricate. Prototyping will be done over the next few months. The stove will hopefully be available for sale in 2020!
Note that the 3D model is for illustrative purposes only. Unfortunately, a software bug prevented lining up the base perfectly central with the inner cylinder - it's not a design fault :)
The 'Permastove' is more complicated to build compared with the 'Carbon' V3 (See the Flat-Tiki 'Carbon' page). There are more parts and more things need to be done to the metal. I've been told that the double fold on the 'Carbon' V3 is tricky but doable for a skilled press brake operator. The 'Permastove' however requires rolling, bending (with the exception of V4) and welding in addition to laser cutting (which is a skill in itself). I'm thinking that 500W fiber optic laser cutters could be purchased in a given region (maybe with Nori tokens) and located at a centralised workshop for both the kilns and stoves. The 'Permastove' could be distributed as a flatpacked kit to local workshops that can do rolling, bending (with the exception of V4) and welding. These workshops could then act as stove and fuel distrubution hubs. For stoves, I prefer this model over a centralised workshop that does everything but only creates distant jobs through the biochar related supply chains but in some cases centralisation may be the only option. It makes more sense to do the cutting and folding of the 'Carbon' V3 at a centralised workshop then distribute it from there. For both stoves and kilns it depends on local preferences too eg. What's the most appropriate way of doing business? Where is the unemployment? What transportation links are available? Most importantly, where is the market?