I rebuilded the firebox four times, and there is some critical things to consider. The airgap in the back of the burn chamber should be thin enough to shoot the air as a laminar flow along the back edge of the chamber for secondary burn of the gases up in the tube. (Thanks to both Alex Chernov and Ekonomka for learning more about that) Thats why it doesnt work as well having the exit at the front or middle position over the chamber. This setup showed in the movie works ok, but I think it will work better if I make the chamber deaper and have the wood laying dow keaping the airgap in the back clear through the whole burn. The burn dosent nead a lot of air to maintain combustion. Ratio 1/3 or 1/4  compared to firebox exit seams ok including gaps around door.

Cleaning it is also an issue. The best way seams to be knocking on the barrel now and then and vacuming at the flue exit. But probably once a year it is good to take out the rocks and clean it throughly. That means that constructing it with a removeable lid seams  necessary.

Compared to the rocket mass heater we here have a stove that dosent nead to be constructed permanently in a house. And it dosent nead a special foundation. It will work with a standard 4″ flue that they use here. It burns down the wood in one go with minimal maintainance of the fire. It burns almost as clean as the RMH? It gives a very hot cooking surface.Its total cost for a selfbuilder is about 20$!
On the down side it “only” retains heat for about 8 hours after the burn. Other negatives??

Some questions to be answered. Will it be sufficient to heat a livingroom space throught the winter in this climate? Will it give the fuel savings that we are hoping for?

I will have this construction tested through winter to heat a friends livingroom, and come back with some reports on its performance.

If you ever do this construction yourself, I would love to hear about your experience with it.

Solar collectors are almost unheard of, even thoe the climate is mild enough for large solar fractions to cover the heating bill. The picture shows an experimental unit made with only local supplies. We believe we can produse these localy at a resonable cost. As in any design or new construction there are compromises and these criterias are set to guide us in the development. It is possible to end up with a very good system that just a few can afford, we could still might have a great buisness, but then the environmental impact would be small. Our dream is to see these around everywhere around here, and therefore it is crusial that we devlop it under criterias guided by our local knowledge.

• Price equal to two year payback potential. ( 500 manat for a small system for domestic hotwater)
• Made of local available materials.
• Manifacture as much as we can of it in sothern Azerbaijan.
• A simple design
• A robust design
• An estetic design (in Azerbaijan people are in general more conserned with appearence than in feks. scandinavia)

This is not a complete list, some would might ask:

“Why isnt high efficency in that list?”

simply because it is not our main priority. Solar collector design can improove efficency by using more expensive materials. But with price beeing such a big deal we can rather increase the effect of a solar collector simply by adding square meeters. So spending a lot of money to increase efficency dosent make sence if  the cost for adding 10% area costs much less. Solar collectors have been developed before, so there is nothing new to it, the difficult thing is to make it cheap enough and simple enough so that it can be a “nobrainer” to implement it when you are planing to build your house. It is at that point our company have the desired effect. So our main challenge in this is not to make it work, but to balance our criterias and do our compromises well so we get a product that will be selling enough to make an impact.

“Why not import something from china or Iran?”

This has been concidered, and we might still do so. But at this point there seem to be enough good reasons to do avoid it:

• The pricetag is to high (1000 manat and up)
• They will not be easy to maintain and tend to be more sofisticated.
• It will generate less local jobs.
• It will not contribute less to local knowledge and knowhow.
• Importing stuff to Azerbaijan is in general not at all effortless.
• Most of them dosent look nice.