Flex furnace and flue gas scrubber

[narottama]

A dear friend of mine shared an oven design with me I'm not all that familiar with and there's not much information about it to be found: the flex oven (Flex-oven, flexoven?) is what he called it, though the website and video call it "Flex furnace and flue gas scrubber" and "Rocket Stove with Smoke Washer". He learned about this stove from Steen Møller, a natural builder from Denmark, who will teaching a workshop in New York demonstrating how to build flex ovens November 11-13th this year. 

There is a website with more information about this design and a short youtube video I'll add. I was hoping the community here could provide more information about this design, and illuminate me on the history of this oven's development and compare it to other forms of wood heat that may do similar things. 

Flex Oven website: iaudvikling.com/ia-udvikling.html

Translated information from the website:

Flex furnace and flue gas scrubber We have developed a flue gas scrubber to condense the smoke and purifies it for all the particles and has an efficiency of 120%, like the large district heating plants. We combine the production of hot water on the stove. There is something special in the transfer from the oven to a radiator plate. The oven a surface temperature of about 200-250 degrees and heating plate, which transfers the heat away, has a surface temperature of 20 to 60 degrees. In the spaces we can put something called thermoelectric cells. The moment the heat on one side and cooled on the other side, then they make electricity.



That is, we suddenly get a free power source. It does not have a particularly high efficiency - it utilizes the heat by 5-8%. but that does not matter, for we turn up out of the oven anyway. If we fire with about 10 kg of wood, then we will get 40kW heat Committee, we say that it is 5% then it 2 kw electricity we get out of it. It beats fine for when we make small houses with led lighting and ipad and similar low power consuming electronics.



We have a stable power supply every time we fire up, and in the summer we are equipped with solar panels. With tomorrow's highly insulated straw elements we will be able to heat their homes of 50m2 with 2 m3 of wood per year. The house is off the grid - self-sufficient in electricity, heat and purified water from the roofs on the house and greenhouse. Future house should not just be built inexpensively, but we also think that it should be made ​​without waste in the construction process and low resource input and it must also be able to get costs and daily operations to a minimum and the house of the future must balance itself.

Drivhuset which handle wastewater to supply vegetables mm and gødningsaltene from røgvaskeren deliver nutrients to a garden of about 100-150 m2.

If anyone has any information or experience with this design please let me know. Thanks!

[Deleted]

An efficiency of 120% is impossible.
Such a claim tells something about the claimer, but nothing positive.
It also tells nothing positive about people who take something like this serious,
nor about people spreading it.

[peterberg]

A Flexovn is the Danish interpretation of a Ianto Evans rocket mass heater. Ianto came to Danmark in 2001 to conduct a workshop at Friland and the guys over there adapted the design. The barrel went out and the whole of the heater was built out of brick. In essence, it's a J-tube with a glass door in the front and the air inlet at the top of the firebox. I'll second Karl in his opinion that a claim of 120% efficiency has to be considered a fairy tale. As far as I know nobody put this type of heater really to the test so whether combustion is complete remains to be seen.