The Ecco Stove masonry heater story began in Finland after my co-director and I had been building Finnish polished soapstone appliances manufactured by a company named Nunnaunni.
The concept
“Nunnaunni with their competitor Tulikivi shared opposite sides of a mountain in Finland producing high quality soapstone, polished masonry heaters from the raw material they excavated from their respective sides of the mountain. As we had, as individuals, been building these appliances in England for the English market place and we were extremely happy with the style of heat these appliances produced. The principal being to charge the appliance with heat quickly and the mass masonry on the appliance then to retain the heat charge and release it slowly over a long period of time.”
The manufacturing process
“Having observed the manufacturing process; the disadvantage of cost; pure mass (very large appliance which could rarely be fitted into a conventional home without a specific area of the home being built or changed to accommodate it) sheer weight; time taken to construct the appliance along with its eventual cost for that construction we felt that there may be a more cost effective way of producing such an appliance with a smaller overall size that would fit comfortably into most homes without changes, yet produce the same heating benefits.
Due to our manufacturing Eldfast ceramic chimney linings we had contacts within the ceramics industry who we asked whether there could be a product of far denser nature and better heat absorption, reflection and emission than the typical clay, brick, concrete or soapstone that masonry heaters were and are still constructed from.
As the Finnish manufacturing process for soapstone slow heat release appliances produced a bi-product of soapstone dust (a mountain of that waste product could be seen at the production site). We did consider and check whether it could be moulded into a design and produce a product from it that could do the job we wanted and hoped for.
The answer quickly back that no, it wouldn’t be able to take the intensity of heat; continuous burning and heat release properties that we wanted to build into an appliance. We also wanted a much smaller appliance, which would do the same job, but an appliance, which could be burned continuously (which the existing slow heat release appliances could not).”
Silicon Carbide
“After some research and testing we considered silicon carbide to be what would seem an ideal material to produce our smaller, denser, higher temperature mass appliance from.
It was desperately important that we shrink the size of the appliance and the weight of the appliance to make it more acceptable within the home, but retain those features of high heat absorption, very high combustion temperatures and slow heat release (with a bright flame at all times if preferred).
After carrying out some trials and tests we produced the prototype Ecco Stove E850 in January 2008, which after rigorous testing in our own facility went for European testing at Gastec in Cheltenham, England. We had to test to 15250 standards for slow heat release appliances to be on par with any other tested masonry heater on the market place including the soapstone variations produced in Finland.
It was also one of our aims that our new stove should also be able to run as an ordinary room heater (conventional style of wood burning stove) as current masonry heater style of appliance including the soap stone appliances could only be fired once in a high fire period otherwise the internal structure of the appliance could be damaged. This meant that the appliances currently on the market place were black and uninteresting after the fuel had been burned, although producing a high standard of heat.
We wanted to produce an appliance that, after the initial heat charge fire would look bright and appealing all day long, as an ordinary wood-burning stove might, but when the fire went out would conserve the heat and yet release heat slowly after combustion has ended.
As a result, we also tested to EU 13240 standard for room heaters and wood burning stoves.
For America and Canada we have achieved safety standards testing; exemption from EPA requirements; Colorado and Washington States efficiency testing for masonry heaters.
We passed both style of tests at 85.3% efficiency rating (EU) and tested as a room heater/wood burning stove and slow heat release/masonry heater and is to the best of our knowledge the only appliance in the world which satisfies both of these standards.”
What did we choose to call our new invention?
“The concept and technology in the use of Silicon Carbide in a wood or liquefied fuelled heating appliance is both patent applied for and unique to Landy Vent UK Ltd.
“The ideas came thick and fast but the conclusion came in unison very quickly, the Ecco Stove had to be it. How else could we term an appliance that burns so efficiently, so completely, so evenly, so thoroughly and uses so much less fuel to do a similar job to any automatically fed heating system, but will continue to work and heat in a power failure.”
Had we achieved what we set out to do?
“The stove we have produced would burn under its flash fire conditions to charge heat into the appliance at some 900-1000°C. We had created an appliance that would absorb heat readily but as we found to our amazement our mineral mix of Silicon Carbide being a very “greedy” material holds that heat for a long period of time (25% of heat stored after 12 hours after the fire has gone out – Model E678).
Now we have produced an appliance that burns so efficiently the particulate emissions are extremely low. The UK requires 6 grams per hour maximum. On our initial testing, we burned at 2.1 grams per hour. America at the time of testing required 8 grammes /hour with us burning at 2.1g/hour. Success! We have achieved more than we had hoped to achieve.”
Confirmation of performance
“In our prototype testing we found that our new appliance would heat a whole house evenly. Sat 8’ in front of the Ecco Stove® you will be no warmer than 1 or 2° than if you were one or two rooms further away from the appliance, subject to the dynamics of the house it is heating and provided internal doors are left open.
To our utter surprise, Silicon Carbide in our new appliance had done something quite unexpected. We needed to quantify how this heat was being released into the whole house air envelope. We approached Business Link in the UK who acquired funding for Birmingham University to make a study of the appliances’ performance and quantify how it releases its heat so evenly through the whole house.
When I first met Professor Raya Al-Dadah and Saad Mahmood in their Mechanical Engineering Office at Birmingham University, I was asked what we needed to quantify with our new heating appliance. Of course, they were told how the appliance was constructed and what materials were used.
In answer to their question I quite simply said I needed them to quantify how sat 8’ in front of the Ecco Stove you would feel no hotter than 1 or 2°c than if you were one or two rooms further away. The answer came back that of course that is impossible!
Ultimately, following lengthy discussions with the University they came to look at the appliance operating and were quite surprised to see it achieving exactly what we said it did, even to the extent of that they queried where had we built heating elements into the wall of the house to back up the heat as physically it could not do what they witnessed it doing.”
The Birmingham University report is published on our website which quantifies how silicon carbide does work to produce the heat that heats the house evenly. Typically, one degree will be lost per room every room away from the appliance.
“The conclusion was reached that Silicon Carbide produces very low frequency, shallow, flat heat waves that rather than losing heat into a surface the heat moves around that surface to travel through air rather than lose energy into objects.Steel or metal produces very much higher frequency heat waves which will heat a surface near to it quickly but that energy will die quickly and not travel as far.”
Final Design of the Ecco Stove
Heating the house for 12 hours after combustion
We started marketing around January 2010 whereupon the very first model Ecco Stove E850 went onto the market place with new models following to suit smaller sized houses with lower heating demands and to date a fourth model the E730 has since been produced with an oval design. Because the components are cast in silicon carbide we can add many air and gas flow channels into those components for re-burning gases within airways, (it’s a castable product so we can cast what features we need). Primary air is fed in simply through the ash pit, secondary air and gasification air (tertiary air) is fed into the Ecco Stove from both the back and the front.”
The appliance had been balanced at test with the air setting fixed so that all the stove operator had to do is flash fire the stove into high combustion to reach a temperature of 150 – 200°C on the outer surface – by opening the ash pit (bearing in mind a metal stove would reach some 500-600°C on the outer surface on full burn). Close the ash pit and walk away from the Ecco Stove – it will then produce heat over the next 12 hours to heat the whole house envelope”
David Ashmore
Managing Director and Inventor of the Ecco Stove