gusmus Wallace

Ahh. But what I don't want, or should I say, the missus doesn't want. Is a batch anything. She wants a nice little fire where she can watch the flames dancing and casting patterns on the ceiling. If I wanted a batch whatever I would have built one. I now have this and without sounding blasé about temperature gradients, insulation characteristics, and exchange surfaces, etc, etc, etc,,,, it works, it works for me, it heats the house, it uses little fuel, it makes little or no smoke from the chimney, and it's mine. I don't really want to rock your boat Satamax, but if I'd wanted perfection then I'd have bought a good pellet burner and had a hell of a lot less fun. As it is, I enjoy my little experiment whilst reaping the benefit of a cozy cave to live in for little cost. I've achieved what I was looking for. Tell me. What is it that you are trying to achieve?

Satamax. The stove has been running for about 6 years now without any problems until early this year when the firebricks in the burn tunnel started to crack and partially collapse. When I rebuilt the tunnel I decided to try and design a new front end which was a little bit more than the usual hole in the wall. Now if you look at the original drawing you will see that the steel insert only goes half way down the burn tunnel, this caused a bit of spalling in the last 10 centimetres of the tube so I decided to reduce the amount of steel insert to just over a quarter of the burn tunnel an expect to maybe have to replace or repair after about 5 years if at all since the main burn takes place much further inside the tunnel which is completely built of firebrick as is the vertical burn tube inside the barrel. Everything on the combustion side of the stove is insulated with expanded clay marbles mixed with heavy duty fire cement. I have no doubts at all about anything collapsing and since firing up the new front end I would reccomend people to at least try it since it gives an alternative to the "All or Nothing" approach. Where I live I don't want the mass to be running until maybe mid november until the end of march but it is nice to have the fire lit in the evenings from october and then again in april/mid may. With the new front end I can bypass the mass and use the stove as an ordinary but highly efficient wood burner in the cool to cold evenings without having the mass blasting out heat during the relatively warm daytime hours. When the daytime tempreature drops I simply switch over to the mass which sits at between 26 and 36ºC depending on the burn times but I have had it as high as 50ºC which was extremely uncomfortable to say the least. The mass (1 Cubic Metre) is built of ceramic coated tubing encased in high density concrete and took about 18 hours of continuous burning to reach 50ºC yet only 4-5 hours to reach 45ºC but once there held that temperature for quite a few days. I tend to take it up to about 28ºC and it'll hold that temperature indefinitely with a 3-4 hour burn each evening. That's enough to heat 115 Square metres of house quite comfortably at an average of 19ºC. In the main room where the Stove is situated (40 SQ Metres) the temperature is a steady 24ºC. If anyone is interested I'll post the front end dimensions and a drawing. The Mass and combustion side are the same as posted on the other link.
PS. No. it has never stalled although I notice now that when I bypass the mass, the chimney or exhaust is now much hotter since there is no mass to leech out the heat from the gasses. If you think about it. One cubic metre of concrete takes some heating so every last calorie is being soaked up until the mass becomes saturated and that I imagine is why the exhaust temperature is so low..

Satamax Antone wrote:So Gusmus, , you seemed to get cranky with me. No need to be.

I have questions tho.

Are the feed tube, burn tunnel and heat riser insulated?

How long have you been running it?

Do you have temperature data for the core? Like burn tunnel and heat riser temps? Anything under 900 celcius in the heat riser i consider not rockety enough.

You don't seem to be close to anybody i know with a Testo 330 II. That would be intresting to see if you can reach better numbers than Peter or Matthew, and make the stove last.

Bye.

Max.

PS: another question, what is your width to height ratio of the burn tunnel?

As I stated in reply to your earlier post. "All of the details are on the original thread". Nothing has changed except the front end which doesn't even get hot enough to burn your hand when placed on top.
As for your temperatures of 900C well, on a six inch system. I call "Bullshit" and on an eight inch system I'll call almost unless we all live in a perfect world of laminar perfection. 6" 600C, 8" 800C. Of course you have to take into account that internet never forgets and I quote.

"Thanks a lot guys.
Well, the next question which comes to my mind, do we realy need the hotest flame to burn everything. If we have a bit more air intake, than the ideal adibatic combustion, the gasses in the burn chamber and heat riser will somehow cool down. The thing would be to find the good compromise between proper burning through the burning lengh, and not too hot as not to melt things Since i'm a keen user of metal." You said it Satamax. Not me.

It's not quite cold enough to run it yet but I wanted to try it out before I put a new porch roof on and had to change the chimney run. It works great. no smoke, no blow back, and it rockets like a rocket. It also rockets with wood, pellets, and compressed logs in both front and back combustion chambers. My missus loves it because she can see the fire and burny bits. More homely I think.

Well I don't like to say "I told you so" ,,,,but "I told you so", It does damned well work and IT IS A ROCKET MASS HEATER.

Janet. Do you have your wood burning on top of a grate? If not, try one. Just enough to lift the wood and charcoal above floor level and allow the air to circulate underneath and create a hotter burn. I also sometimes open the front of the tunnel a tiny bit to allow a bit of air to have an unrestricted flow directly to the burn tunnel although this means that you have to compensate by closing down the feed tube by approximately the same amount otherwise it will allow the wood to start burning up the tube.

Expanded clay works and is very cheap. Building suppliers and garden centres sell it.

Well you see "Satamax", I always find it helps to read all of the post before commenting. That way you don't miss out on the important bits like the instructions.
If you click the link to the original post " https://permies.com/t/40044/rocket-stoves/Stephenson-proud " you will see that it is a rocket. This is simply a new front end which allows a bit more variety of usage and also lets you see the fire which although doesn't really matter in terms of performance, you must admit an open fire gives a little more homely feel. I've run this up twice now and it seems to work fine with both pellets and waste wood. I've yet to try the open hearth at the front but I dragged some pellets forward during the last test and it seemed to work fine with the door both open and closed which surprised me as I was expecting to see some smoke out of the top feed tube with the door open. Here's hoping.

Photos