In many countrys the Finnish fireplaces, develloped by Heikki Hyytiainen during the 70ties, are well known.
It is from his work, and my own former work, as a advisor for the Danish Goverment in quistions of efficient combustion, that i have carried on develloping these stoves, during the last 17 years.
Today theese stoves are develloped to never the less than extreme performance.
Clean combustion: 0,13% CO at 7,5% CO2 (means no visibel smoke from the chimney).
More than 87% (European standard) of the calories in the wood, becomes very nice and long lasting heat in the house. (This is about 10% more, than the ordinary Finnish Fireplaces, or Canadian Masonry Heaters.)
10% of the calories is used to perform the nessesary draft in the chimney.
That means, that allmost every calori in the wood, is made usefull. Furthermore, this happens without any kind of use of electric equipment at all.
As long as you have firewood in the shelter, you have a nice warm house.
Outputvariaty: 0 to 8 kw without any loss of efficiency.
Variaty of temperature in the house: + - 2 degree C. during more than
24 ours after a short fire.
(Not mutch caretaking)
Creative adabtability to any home.
Great beuty (a matter of taste of course)
Tested and documented by the The Danish Institut of Tecnology
Besides the doors and dampers, that are factorymade from castiron in Denmark and Finland (Morsoe and UPO), everything is handmade stone by stone.
Inside we use the best fireproof and chockresistent bricks we can find at any time. The mortar here, is the same material crushed and mixed with natriumsilica.
Outside we use ordinary bricks and claymortar (clay, sand and water).
The claymortar have the ability, that cementmortor dosnt, to stretch and bend and this way obtain the forces that occur during the heating up and cooling down cyklus. Furthermore, claymortar can be reused again and again. You never know, if the mortar you are using have been part of a house centuries ago. Fore the same reason, you can allways, and very easely, repair any small cracs that might occure. We dont se mutch of them, but it happends, and is no problem at all.
We consider, that the lifetime of ours stoves very often will be mutch longer, than the lifetime of the house that they serve.
Efficient combustion of wood needs 3 things:
High temperature (above 900 C.)
Good turbulens (mixture of gasses and oxygen)
Time – (to finish the combustion before taking away the produced heat).
We call it “The 3 T´s” just to remember.
If one T is missing, your fire will make smoke.
To obtain the 3 T´s as fast as possibel in a lot of relatively
cold bunch of stones, i develloped a new “device” called “the centrifugal
In this “device”, the burning gasses are forced into a cirkular movement, and will this way be surrunded by new burning gasses. This way it is eaisy to kepp up high temperatures in the burningzone. Furthermore – the heaviest gasses, that are the most difficult to mix with oxygen, will be forced by the the centrifugal forces, to stay in this chamber and in the cirkular movement, untill they are mixed with oxygen, can burne, and that way become lighther, get into the mittel of the cirkel, and get out of the chamber to the downdraft channals.
You dont se this “device” in the stoves. It just looks like an ordinary bakeowen with a hole in the mittel of eatch side, but you se it clearly in the amount of carbondioxyd in the smoke.
The ordinary “hill” in the beginning of sutch messurings, is extremely short and low.
All the bricks in sutch a stove, obviusly gives the possibility to store a lot of heat.
The bricks at the outside of the stove however, allso determine how fast you can get the heat out of the stove to heat the house.
If the way from the core to the surface of the stove is to long or to difficult (many layers), you will get the heat out slower (less heat pr. our).
Some masonry heater builders thinks, that “ the bigger the better”. That is the biggest mistake you can make. I have seen to many gigantic stoves, that just could´nt heat up an ordinary house.
If you goes from just one layer of bricks between the smokechannals and the livingroom, to two layers, the output will fall drasticly to less than a thirdpart of just one layer. So take care about this, wheater you want to build a stove, ore buy one.
A masonry heater should allways be builded according to the actual house
and the surroundings, where it shall function for many years. No one will
ever move it, would they ?`
How to increase the output
The temperature of the surface, and the size of the surface, is the main factors to ajust the amount of heat you can get from a masonry heater.
My partner and i wanted to se, how simpel we could build a stove, without
selling out of the main qualitys (clean burning, high efficiency and a
heating period of 24 ours pr. fire.
At the same time we wanted to make the period of a fire longer. Many of our custumors wanted more than just 1-2 ours of firing pr. day, that was the nessesary in the stoves we had builded untill then.
So one day we made “Gymse”.
A cute little stove, whitch showed surprising opportunities.
The burning chamber is smaller, so the fire can burne efficient for a longer period, without an unacceptabel rise in the temperature of exhoust.
Even if the stove itself is smaller, the possibility of getting a high output is very mutch there. In fact, this stove can produce twice as mutch heat pr. our, than the ordinary stoves. To do this, it needs a long (or wide) hot beanch.
This way the stove can be placed up to 4 meters away from the chimney !
Most surprising, this stove can be fired with open door, or without
the door at all. Off course without any smoke in the livingroom.
The efficiency is still reasonable good, allthough it is better with the door closed.
Hot beanches has been very popular. This combined with the possibility
of an open, but efficient, fireplace, has made this litle stove very popular,
even if we still dont have official testresults, as we do with the big
All the stoves meantioned here, can be made to supply your hot-water-store. Combined to a solarheating system, hot water is just there at all time (allmost).
Here at the little island Drejoe, we are right now building up an education – and develloping center for mainly masonry heaters.
This year 2009, we offer courses of 8 days in masonry heater building.
I have been teatching in sutch courses for many years, but i have allways missed better circumstances to do this. (Several different stoves in function, laboratory equipment, possibility for the participants to build without consideration for the poor owner of the result, and so on).
If you schould be interested, please mail me at firstname.lastname@example.org as
soon as possibel.
More information at my homepage: www stenovne.dk (The English version have not been updated for a longer period, sorry, i hope to do something about it soon.)
(Thats why i put this on).
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