07 March, 2009

Heat accumulator: Increase the performance of the wood stove (Russian Stove or Masonry Heater)

In this post we will see how to get more performance from a wood stove smoke passing through a vertical loop firebricks and do not involve maintenance.

I spoke of the "Russian stove" , which is simply a low heat oven or built with bricksrefractory and gives a great performance and comfort for heating. 

However I made ​​the mistake of assuming that the narrow passage I left still allow the passage of smoke (considering 4 meters in fire that made ​​shooting), but the smoke is cooled much and slowed both passing the shot was almost zero,introducing a lot of smoke in the room every time the door would have and it was very difficult to remove.
So since I had to disassemble the entire block bricks, took the opportunity to completely change the design because putting cast iron stove out from the wall it was a botched it had more disadvantages than advantages; this time the put-in wall, and on it, the heat accumulator block smoke, leaning against the wall by an arch .
I've always liked the brush fires; when I was little I was soup on the couch in front of the fire in my parents' house; careful with the crackle of firewood and comforting warmth, causes drowsiness;-).
I learned from the mistakes of the previous experiment, with the new design and I hope to have more advantages:
  • Avoiding the maintenance, with a simple circuit favoring vertical soot fall within the same range.
  • Better take advantage of the space and the brick is flush with the wall, plus it is prettier.
  • Increase the shot, making a larger even than the smoke outlet of the stove step, which prevents the smoke comes out of the great door of the stove I have chosen.
  • By using more bricks to the accumulator increases the stored heat and hours of comfort.
The only downside is that its performance is reduced by 10% (not recessed stove so easily and quickly releases the heat), heat up more slowly home. Still, a daily charge burning temperature sufficient to maintain at 18 ° C with 7th outside.

The nice thing is big refractory bricks which are highly resistant to shock, so I could disarm them,removing the refractory mortar with a pickaxe or hammer. It took me six hours to clean every drop and a Chinese work.

After placing the stove in place and discussing how to support the brick arch, I saw that I couldput bricks in the space between the concrete wall and the stove, so I have decided to support the weight distributed between the bricks and wall, to minimize the cut to be made ​​in the wall.

To the right I have chosen to put two vertical bricks instead of lying, and I think it will be well placed enough to support the weight and stress.

More mass must be put on top of the curve to be doing. It is better and stronger if purchased or prepared bricks wider on one side than the other, but it takes more money or work.

To hold the bricks as you would have used by placing pieces of brick. It would have been much better if he had made ​​a wooden template which then could remove, but I hoped to do guesswork and has been my right hand a little fall lr. so there is a lag of one centimeter. Although it has not been so bad for the first time I do one.

Attention: In my case this solution is suitable for the wall on which rest the 250 kg.Brick is solid concrete and stone. If you want to do the same and the wall is brick,build good columns on both sides with refractory bricks lying, supporting the arch in them.

The part of the center, with the mouth of the chimney is the most difficult, leave the hole but putting bricks wide as possible for resistance to the whole arc. Then the weight of the bricks will go around the center, so I'm not worried that the area can support less weight.

A note: It would have been stronger still mixing short and long bricks to prevent the continuation of the line of cement in the binding of both rows, as has been weaker for that part.

Do not forget to place fiberglass or rock wool (an insulating support that high temperatures) in the gaps left between the flue outlet of the stove and bricks.

We hope one day it has begun to harden the dough and we can lay bricks until a flat base, with bricks cut in half to reduce the use of mortar as possible.

We're raising the tower, laying bricks in the path of smoke, forcing him to go out and toward the center, so that the entire block into contact with the heat of the smoke, yes, always keeping the minimum smoke evacuation step.

I have been very conscious step to do so sufficiently to favor the natural fall of excess sootinto the mouth vent the stove itself. This way I avoid having to put records accessible for cleaning.Although there is also the possibility of getting dirty enough to stop smoke freely, I think it will take several years and can always drop the last row of bricks for cleaning.

The width of the passage for the smoke I have left is greater than before; but does not have to be excessive, the bricks must go coil supported at least two centimeters; heat may crack but between the weight of the other and mortar will not fall.

You have to leave a little space between the wall and the bricks that allow them to cool and heat the room, an inch is enough. I have not stopped and the heat is not released from the bricks so easily, making it less efficient.
Furthermore, in the mortar spare not used; it is important that there are no gaps where the smoke escape. You can always pick up the remains after the palette. It is also important not to leave any meeting without mortar and use a rubber mallet to set them right.

Finally arriving at the fire escape, I closed with big old bricks, using fiberglass to seal the gapsbetween the pipe and the bricks.
In this post I have not repeated some of the advice given or information on the Russian stove, I invite you to also read the above for more information.

Between the stove and the arch is a hole through which emits a lot of heat and partially shut, putting a grill with holes for the top. Keep in mind that the metal expands more than the mortar or refractory brick, so that should not be put between the stove and bricks.

Try to remove all that is between the stove and let the bricks to dilate freely.

And in this video you can see how it works; shoots much better and use is practically the same. I do not he could have ended at a better time: is back to snow in my area.
I hope that it do not give me any more problems for many years.

Ya just need to finish placing firebricks around beautify and clean them. Probably take the heat of this stove and to heat the water, but that later ...

What has been good to me, and how proud one is left watching your project and illusion performed, priceless!

Greetings to all and see you soon! Suggestions and comments are allowed, do not be shy!

Related links:
Russian stove in Bioclimatic Architecture blog (very good page on sustainable architecture)
Manual for the manufacture of a Russian stove - ( source )
"As a Russian stove is manufactured" on Forosolar of SolarWeb.net
Stoves high performance or "Kachelofen" in the German wikipedia ( translated into Spanish )
Masonry Heater in North America