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Post by fasardi on May 6, 2020 8:14:33 GMT -8
My system is a DSR-II open, is still drying out, buy I´m starting slow with some wood and seems to work very well. Only problem so far is than sometimes a little smoke comes out, aparently it depends on how the wood is stacked. Your fuel need to be at a minimum of 5 cm inside the firebox, shorter is better. And there need to be a space above the fuel, 5 cm at least again. Well, the firebox is extended, and I only loaded the back half, and just to the port's height. Maybe it is still drying, maybe I haven't got enough draft. Will see after a few more fires. I won't use the glass in that case. Thanks for all your help!
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Post by fasardi on May 8, 2020 3:40:43 GMT -8
Update: After a few more fires, with soft wood and the firebox half full, I am happy to say than the DSR-II is working very well and starting to heat the house. Very important in this days, temperatures are going lower day by day here in the Patagonia Argentina. So I think than the problem was just the moisture.
I want to thank the community, and specially Peter Van Der Berg, for sharing your knowledge and patience. Keep up the good work!
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Post by fasardi on May 29, 2020 4:08:38 GMT -8
Another update, with questions this time: After almost a month using diary the stove, i'm happy with the results, but maybe i could be happier. There are no issues firing the stove, but I really never see flames going up the riser too much. The "rocket sound" is strong, and flames go into the riser, but really don't see them going up. The stove is only bricks (I wanted really lots of inertia) and really heavy, about 1.5 Tons in a rough calculation. The issue I see is than the bricks don't seem to get really hot. It's a single skin bell, with some regular red bricks (23x11.5x10 cm) lower than the core exhaust and some big red bricks (28x14x12cm) in the top part. The top part, specially near the core exhaust, gets hot but i can touch it without burning (sorry, currently i haven't got anything to measure temperature) and the bottom part of the bell it's only a little warm. It's a 150mm open DSR-II system, the core is made with split fire bricks and hollow bricks as isulation. The bell ISA is 4.7m2. I haven't made a door yet, I'm using a metal sheet and the air inlet is in the top of the firebox, about 40x217mm. Thinking about it, this are my hypothesis: 1) The bell is too heavy for a 150mm system 2) The hollow bricks don't isulate enogh in the riser. 3) The opening in the door is too little and in not well located.
Any suggestions?
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Post by peterberg on May 30, 2020 2:34:42 GMT -8
The "rocket sound" is strong, and flames go into the riser, but really don't see them going up. As I see it, it seems to be perfect. The whole design is geared towards clean burning with minimal chance to get a fuel overload. When the flames are going into the top box all the way to the end port there's a fat chance combustion won't be complete resulting in smoke out the chimney stack. Namely the stumbling block is the detail that keep the flames mostly inside that short riser. Without knowing anything, I would say: the sound is excellent, while that's going on there shouldn't be any visible smoke outside apart from water vapor. There's a counter-intuitive tendency with this design: the stronger the draft the less flames will come out of the riser. It's a pity you don't have any numbers, chimney temperature and surface temperature of the bell are good tell-tale figures. The bell isn't too heavy, mine is 2 tons and I would preferred it up to 2.5 metric tons. All the heat that's accumulated will come out, quaranteed, the heavier the bell the more heat can be stored. The speed of heat dissipation is slower while employing a larger mass, that's all. 1) The bell isn't too heavy for a 150 mm system. To understand this, think about this example: in order to get enough heat out of a small system this should be very hot. A small stove of say, 0.5 m² external surface need to be at least 200 ºC on average. A much larger heater of 4 times the external surface need to be only 50 ºC on average in order to deliver the same energy. Whatever you do, that heat will come out irrespective of the wall thickness. 2) Can't say anything about the insulation properties of hollow bricks you have been using. But then, the heater runs well, don't smoke, what do you want more? 3) The opening in the make-shift door is about half the total csa of a 150 mm circular riser. That should be enough but it isn't well placed, it should be left and right according to my findings. So the metal sheet should be like a vertical strip in the middle of the opening. Have you tried to run it completely open? Also, is it completely closed (and no fire or glowing embers to be seen or feel) through the night?
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Post by fasardi on May 30, 2020 11:13:02 GMT -8
Thanks Peterberg, as always. I'm a lot less worried now, I was expecting lots of fire in the riser. In a few days I will try a new door with your findings. I have tried running it with the door open with the same results, and the smoke seems always clean. The chimney, at the end of the bell, it's hot but not so much, I can touch it for half a second... When the endless quarantine in Argentina comes to an end, a friend will visit me with a laser thermometer and we will check real temperatures.
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Post by fasardi on Oct 1, 2020 4:56:27 GMT -8
Hi to all! Well, the heating season in the Patagonia is almost over, so building season (and rebuilding too) is coming! After my first winter with my 6" DSR-II i'm happy with the results, but i think there's room for improvement. First of all, I'll need a bigger system. Really a 10 incher, but i think the bell just won't fit. So I'm thinking about building a 8 inches system and burn 3 or 4 batches a day. Maybe it's a mistake, I guess I should try using 2 bells. Well the question here is this: Can I get away using a 6" chimey (it's all straight up, no elbows) for a 8" or 7" DSR-II system? I think it's very risky and probably won't work, but maybe someone tried it.
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Post by peterberg on Oct 1, 2020 6:15:50 GMT -8
Heating demand can be satisfied by fuel, so you need to ask yourself how much more than you have now. Having said that, a batchrocket system scales up very fast. For example: a 150 mm system's firebox is grosso modo 28 dm³ in volume. Less than half of that volume can be filled with fuel, due to the air gaps between the logs and the 5 cm space above the fuel. Fuel weight of 0.55 kg/dm³x 12 dm³ is 6.6 kg for a full load. A 200 mm version's firebox is 73 dm³, meaning it's 2.6 times as large in volume. Interestingly, due to the volume scaling up faster than the wall area of the same firebox, it could hold more than half of the space in fuel. So say, 38 dm³ x 0.55 kg/dm³ = 20.9 kg per full load. Compared to the 150 mm version it is able to hold just over three times as more, are you sure you need that much?
Given the chimney you have there is 150 mm in diameter, (preferably) stainless steel, straight up, smooth inside AND insulated, it could drive a 180 mm system, tops. Such a system's firebox volume is approx. 53 dm³, could hold half that volume in fuel, 26.5 x 0.55 kg/dm³ = 14.6 kg, already more than twice that of the 150 mm one.
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Post by fasardi on Oct 1, 2020 7:54:41 GMT -8
Given the chimney you have there is 150 mm in diameter, (preferably) stainless steel, straight up, smooth inside AND insulated, it could drive a 180 mm system, tops. Such a system's firebox volume is approx. 53 dm³, could hold half that volume in fuel, 26.5 x 0.55 kg/dm³ = 14.6 kg, already more than twice that of the 150 mm one. I guess I will go ahead and rebuild for a 180mm system, and get some metal in top of the bell to gain some quick heat. When the pandemic is over, we won't be that long inside, and some quick heat will be neccesary. As always, thanks for your help!
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fuego
New Member
Posts: 5
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Post by fuego on Jul 12, 2021 16:15:43 GMT -8
Heating demand can be satisfied by fuel, so you need to ask yourself how much more than you have now. Having said that, a batchrocket system scales up very fast. For example: a 150 mm system's firebox is grosso modo 28 dm³ in volume. Less than half of that volume can be filled with fuel, due to the air gaps between the logs and the 5 cm space above the fuel. Fuel weight of 0.55 kg/dm³x 12 dm³ is 6.6 kg for a full load. A 200 mm version's firebox is 73 dm³, meaning it's 2.6 times as large in volume. Interestingly, due to the volume scaling up faster than the wall area of the same firebox, it could hold more than half of the space in fuel. So say, 38 dm³ x 0.55 kg/dm³ = 20.9 kg per full load. Compared to the 150 mm version it is able to hold just over three times as more, are you sure you need that much? Given the chimney you have there is 150 mm in diameter, (preferably) stainless steel, straight up, smooth inside AND insulated, it could drive a 180 mm system, tops. Such a system's firebox volume is approx. 53 dm³, could hold half that volume in fuel, 26.5 x 0.55 kg/dm³ = 14.6 kg, already more than twice that of the 150 mm one. Greetings Peter, sorry for the intrusion, but it is good to know that a 150 mm chimney can drive a 180 system. Because in my house I have all 4" outlets already installed, but I could make a core with the measures of 5" to use the installed pipes and have more heating power. I would have to make the riser higher than what is indicated and a good hood with a 55 gallon drum?.
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Post by peterberg on Jul 13, 2021 0:09:30 GMT -8
Possibly the jump up from 4" to 5" is too large. The example you are quoting above is from 15 to 18 cm diameter, which is a jump up in cross section area of 143.5%. The jump you are planning is from 10 to 12.5 cm, which is 156%. You might, just might, get away with that provided the chimney is like you quoted above: straight up, smooth inside AND properly insulated. No other buildings or trees that are higher around PLUS sufficient height like 5 meters. If one or more of these requirements aren't met, spare yourself the trouble as the chances are not favourable.
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