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Post by independentenergy on Mar 7, 2024 9:43:18 GMT -8
in my little build i have a problem of high temperature at the chimney (160/200 degrees), Isa too small I think... I insulated the riser with superwool and on both sides there is space for the insulation, but if not if I put the insulation the gases would also heat the part where the insulation is now and perhaps they would lower the chimney outlet temperature a little, but I'm not sure if the riser heats up quickly enough at start-up, furthermore I have the configuration with the exit door in the upper position.
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Post by peterberg on Mar 11, 2024 6:42:34 GMT -8
Some hardwood was still lying around beside the heater, waiting for a test. After splitting one piece and measuring the split face, it read 12.5% moist. OK then, it's ready for running a hardwood test! Officially, the heater should be on operating temperature first, so I did half a load of softwood. This was measured, more because it did grow to a habit to do that on every occasion. The resulting diagram looked nice but not overly so, fire development might be too quick. .gif) After an hour the glow bed was far down enough to scoop it all out and build a new fire in the hot firebox. .jpg) This went very well, looked really nice. But... at about 42 minutes into the burn the software crashed once again. The data couldn't be recovered, by the time all was up and running again the burn was already in its tailout. .gif) A very nice tailout, though. Now that I had a glowing bed of coals and some pieces of hardwood left, what to do with it? I decided to do a refill test, so after an hour or so it was down enough. I shove the coals to the back and added the pieces against it, not directly on top. It catched fire within a minute and produced one of the most beautiful fires I've seen so far in this development model. .jpg) In order to prevent losing all the data again, I took some snapshots of the laptop screen, here's one. .jpg) The complete run was as good as I'd hoped for, averages O² 13.64%, eff. 84.01%, CO 543.6 ppm, Tr 156.67 ºC. The only proviso according to the EU rules: it didn't last long enough, as 40 minutes is the minimum. Bigger logs and some more could be the remedy to that. .gif) During the week following this event, I felt the urge for a final test run using my regular fuel, softwood scraps from pallets. One full load, reasonably tight stacked, lit on top, wind force 2 Bft. It went very well, CO bump at the beginning is there because of a cold start. But for the rest of it: an example of what a well-behaving stove should do. Here's the load: .jpg) And here's the resulting diagram: .gif) Averages for this burn: O² 12.1%, eff. 88.57%, CO 434.2 ppm, Tr 177.1 ºC. Mark that the CO is below 500 ppm for the duration of 40 minutes. Very good for a burn of just 60 minutes! I'd think this is a good moment to call the development over and done, as far as I am concerned. The Loam Freemanship in the north of the Netherlands wants to build an upscaled one as a test bed, a 200 mm or 8" system, built as a sidewinder. For me, that would mean making a drawing and go up north if and when it is completed. I am very curious what the results would be! Making drawings is what I planned to do next anyway, in order to publish them here (and there). |
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dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
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Post by dvawolk on Apr 9, 2024 12:57:26 GMT -8
Hi, Peter, this all is again great thread about an interesting development. Construction (brickwork and metalwork) looks really easy compared to previous batch RMHs! I went through the whole thread and tried to condense data (dimensions and all) - can you please check if this sketch looks correct? Dimensions are written in B value derivates. I do have some questions: 1.) Would a bell system (of accepted ISA dimensions in previous batch rockets) need any bypass or not? Is the insulation added inside needed or can it be a regular firebrick or insulated firebrick? Did you use insulation in your case just to get close to chimney diameter in an easy way? 2.) Are those added 3cm of additional height of insulation above the port the same even if the system size changes? Or should it be linearly enlarged/reduced? 3.) The "X" dimension in the sketch below - this goes to standard 50mm port depth dimension? 4.) The "Y" dimension in the sketch below - is this fixed 40mm for other system sizes, too? Or should it be linearly enlarged/reduced? 5.) Since the exit port is towards front, does that mean that there is no extra space in height needed from the top of the burner to the bell ceiling? If this is so, that gives 6.) Can the exit port be on the side/back of Shorty's heat riser? 7.) Reliability-vise and usage-vise if you would compare Shorty to original Batchbox (p-channel and floor channel) and DSR3, any specific thoughts? Regards, Klemen  |
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Post by peterberg on Apr 12, 2024 8:35:29 GMT -8
1.) Would a bell system (of accepted ISA dimensions in previous batch rockets) need any bypass or not? I've used accepted ISA dimensions for the barrels/bell, no bypass installed. But... there's a very good chimney behind it, so I am unable to confirm 'no bypass needed'. It would depend on the quality of the chimney, for now. Is the insulation added inside needed or can it be a regular firebrick or insulated firebrick? No added insulation required. That said, it'll take longer to heat up with more mass in the core but it will still work as intended. Did you use insulation in your case just to get close to chimney diameter in an easy way? Yes, that's the sole reason. 2.) Are those added 3cm of additional height of insulation above the port the same even if the system size changes? Or should it be linearly enlarged/reduced? It's only there to extend the depth of the port. Without it, it didn't work reliably. 3.) The "X" dimension in the sketch below - this goes to standard 50mm port depth dimension? The "X" dimension, the port depth, should be defined as twice the port width. Port width is 0.5xB (not 0.4xB as in your sketch) so the port's depth is 1xB. 4.) The "Y" dimension in the sketch below - is this fixed 40mm for other system sizes, too? Or should it be linearly enlarged/reduced? For this "Y" dimension I am leaning to equal the height of the exhaust opening. That's what it is in the development model. Always calculate the exhaust opening though: a slightly wider core won't hurt at all except for this opening. 5.) Since the exit port is towards front, does that mean that there is no extra space in height needed from the top of the burner to the bell ceiling? I'd think so, but this isn't tested as yet. It would take a completely different setup as compared to the pure bell system the development core is in at the moment. More experience is required on this aspect. 6.) Can the exit port be on the side/back of Shorty's heat riser? Not sure about this, it isn't possible to mimic this in the development setup, due to space constraints. Again, more experience required. Building and testing a scaled-up sidewinder version is in the pipeline though. 7.) Reliability-wise and usage-wise if you would compare Shorty to original Batchbox (p-channel and floor channel) and DSR3, any specific thoughts? The cold core tends to start up slow but it's reliable. No steel in the core itself, just in the front, which is good. No very specific parts like the afterburner in the DSR3, for instance, good again. To my knowledge, uptil now only one scaled-up version is built, a 180 mm system. This ran as a bare core without a chimney, once heated up. Build-up is very simple, just stick to the dimensions, more about this below. In your sketch there are some discrepancies: width of the port is 0.5xB. Internal height of the core is leaning to 5.5xB now. Just to make room for some space above the firebox' top, the exhaust opening and cap(?). The insulation at the back of the lower riser isn't there anymore, it's one wall from top to bottom. The higher part of the riser box is square, 2xB. I just checked one of the drawings, this is correct, so the lower part of the riser box is also a square, chimney diameter size. The port is surprisingly deep, twice the port's width is quite a lot. But results are best with this, so it's correct nevertheless. I've made a drawing of a possible brick layout so far, 150 mm system. Much of it uncut bricks, slightly off specs here and there, except the port and exhaust opening. Have a look. Click on the link, click on the title shorty150core.skp. It's in SU2017 format. |
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dvawolk
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DSR2 125mm open system (actual project)
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Post by dvawolk on Apr 22, 2024 8:39:15 GMT -8
Hello. Wow, port depth is really long, especially with larger systems.. Below is the sketch, all dimensions in one place. Based on your comments, peterberg , in the table below are gathered all the dimensions which are derived from base number B... ISA equal to Batchbox.. base number B = 72,34% of chimney diameter| A= 0.75 × B | C= 2 × B | D= 0.75 × B | E= 2 × B | F= 3 × B | | G= 2 × B | H= CHIMNEY DIAMETER | J= CHIMNEY DIAMETER | K= 2 × B | L= 1 × B | | M= 4 × B | N= 2.1 × B | O= 0.5 × B | P= 5.5 × B | R = 30mm |
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Post by peterberg on Apr 22, 2024 12:51:59 GMT -8
As far as I can see, all numbers are correct. Built like this, the core should be capable of running on its own.
Any takers?
I tried this with a 180 mm system and it took some persuasion but at the end the core burned clean, without a wiff of smoke. This was done in a small(ish) house, with the heater being in construction, with windows and doors open.
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Post by hunter on Apr 25, 2024 13:17:57 GMT -8
Thank you Peter for the design and testing, and dvawolk for the sketch!
This design could fit nicely to dry saunas. Possible issues if using fireglass as the roof of the riser?
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Post by peterberg on Apr 26, 2024 1:15:47 GMT -8
This design could fit nicely to dry saunas. Possible issues if using fireglass as the roof of the riser? Honestly, I don't know, no experience with glass in that location with this design. But I could guess, of course. Fireglass on top of a firebox: done and approved. Black glass from an induction cooker by Schott Ceran has been used on the only DSR1 cook stove that's ever been built. The flames behind the horizontal port were streaming directly under the glass and to my knowledge, it never cracked. So, would proper fireglass hold on a Shorty's riser box? Almost sure. There's a good chance the glass would turn opaque though. I would like to see pictures and/or a video! |
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Post by hunter on Apr 26, 2024 2:16:12 GMT -8
Thanks Peter!
Yes, I think most of the folks here considering glass are interested in the cooking stove application, but as one gets heaps of heat through a glass, I find it somewhat convenient option for dry sauna usage. Especially as there is no ”room” for any metal or barrels (outside stainless steel) as the air must be pristine in a sauna where you got all your skin pores wide open and the air temperature is many times higher than in a standard use. So material options are limited to raw wood(room round it), bricks, fireglass and vermiculite.
Just measured the old 7 meters high brick chimney and it is 12cm x 15cm square with an entrance at the floor level. The slab where to build the whole thing is roughly 100cm x 80cm and it would be a dry sauna stove and do not have to look fancy, just provide heat. What size of a system would you recommend?
This is the first batch box thread I have read, so are there any general tips not mentioned here that would benefit a man who has never built any of your designs Peter? Thank you!
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Post by peterberg on Apr 26, 2024 6:10:16 GMT -8
Just measured the old 7 meters high brick chimney and it is 12cm x 15cm square with an entrance at the floor level. The slab where to build the whole thing is roughly 100cm x 80cm and it would be a dry sauna stove and do not have to look fancy, just provide heat. What size of a system would you recommend? Assuming that old brick chimney is the same size over its entire length and using the old chimney sweep's formula: (2 x W x L) / (W + L) = equivalent diameter of circular chimney. In your case: 2 x 12 x 15 = 360 cm, devided by 12 + 15 = 27 cm = 13.333 cm diameter. All other dimensions are derived from that, even the bell's dimensions. This is the first batch box thread I have read, so are there any general tips not mentioned here that would benefit a man who has never built any of your designs Peter? Thank you! So you are a batchrocket novice then. Welcome to the club! Best to build a standard core using air entrained concrete in the backyard and fire that up. It won't hold for long, but enough to give you a pretty good idea what it should look like and how it performs. No door or secondary air supply, just the bare core. |
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Post by hunter on Apr 27, 2024 7:48:46 GMT -8
Just measured the old 7 meters high brick chimney and it is 12cm x 15cm square with an entrance at the floor level. The slab where to build the whole thing is roughly 100cm x 80cm and it would be a dry sauna stove and do not have to look fancy, just provide heat. What size of a system would you recommend? Assuming that old brick chimney is the same size over its entire length and using the old chimney sweep's formula: (2 x W x L) / (W + L) = equivalent diameter of circular chimney. In your case: 2 x 12 x 15 = 360 cm, devided by 12 + 15 = 27 cm = 13.333 cm diameter. All other dimensions are derived from that, even the bell's dimensions Thanks Peter! I did the calculations and drawings and the only thing I would like to adjust is the height of the firebox (+3cm) because of the dimensions of standard firebricks. Would a bigger firebox height/volume be much of an issue? I assumed the ports and riser are most significant. |
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Post by peterberg on Apr 27, 2024 8:33:38 GMT -8
I did the calculations and drawings and the only thing I would like to adjust is the height of the firebox (+3cm) because of the dimensions of standard firebricks. Would a bigger firebox height/volume be much of an issue? I assumed the ports and riser are most significant. A slightly higher firebox won't be much of an issue. But it would be better to do the calculations again with a base value that's increased by 10 mm. That way you'll get your 30 mm higher firebox but all the other dimensions are slightly increased as well. So there won't be a port that's too low, for instance. |
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dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 272
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Post by dvawolk on May 20, 2024 6:00:56 GMT -8
Hi, Peter. One potential option is appearing in near future - a customer wants a long bench and i cant get through regular batchbox... Using this heater the ceiling can be significantly lower and consequentially it spares me that extra ISA for the bench... It this will come true, that will be a 150mm system. Will post if anything comes to life.. Regards, Klemen |
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Post by peterberg on May 20, 2024 7:59:16 GMT -8
One potential option is appearing in near future - a customer wants a long bench and i cant get through regular batchbox... Using this heater the ceiling can be significantly lower and consequentially it spares me that extra ISA for the bench... It this will come true, that will be a 150mm system. Will post if anything comes to life.. Regards, Klemen Hi Klemen, That would be a real proof of the pudding... Remember, best to build each and every corner, channel or whatever about twice as wide as you think will be enough. This core is even more prone to friction as compared to all the other members of the same family. |
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Post by martyn on Sept 15, 2024 11:48:15 GMT -8
I have read through the thread, I think I can follow the construction details apart from a little confusion around the area where the rams horn is formed.
In Dvawoiks excellent drawings, it shows a system sized square surrounded by a 50mm step that is 30mm higher than the port.
In most of Peters pictures, they show this step goes all around the riser but in Dvawoiks drawing it only goes around three sides?
Could you please clarify this aspect?
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