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Post by sksshel on Aug 7, 2019 8:06:18 GMT -8
peterberg would it be acceptable if I extended the same dimensions of the riser area all the way to the top of the shoebox? The Sketchup shows it widening to the shoebox width once it's above the burn chamber. At this point I'm merely exploring my options for construction.
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Post by peterberg on Aug 7, 2019 9:50:48 GMT -8
As you may be aware: the DSR2 is tested in different configurations. One of them happens to be the one you describe and it didn't yield the same level of results. It tended to be prone to overfuelling in three consequetive burns.
Actually it's the same for most of my designs, I tried a multitude (although not all the possible) configurations and ended up with one and sometimes two that seemed to be the best. You could try the option you mention without any guarantee it would work as expected.
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Post by Orange on Aug 8, 2019 2:13:49 GMT -8
thanks Peter, I love the design  |
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Post by sksshel on Aug 8, 2019 10:41:27 GMT -8
As you may be aware: the DSR2 is tested in different configurations. One of them happens to be the one you describe and it didn't yield the same level of results. It tended to be prone to overfuelling in three consequetive burns. Actually it's the same for most of my designs, I tried a multitude (although not all the possible) configurations and ended up with one and sometimes two that seemed to be the best. You could try the option you mention without any guarantee it would work as expected. Thanks Peter, I'd rather stick to a proven design. I shouldn't have much issue with adjusting my existing heater to meet the specifications. |
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yasin
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Post by yasin on Aug 16, 2019 1:16:13 GMT -8
hello peterbergThank you very much for your kind words, the family is fine ! I had not realized until a few days ago what a breakthrough this no-door system was ! I was focused on system with air coming from under the stove through a pipe to match the new french regulations.. but a door without glass and without air intake is really so simple ! That is a perfect system to make a cheap heater ! I had been thinking for a while on how to make a half-refractory half-iron heater that would replace old cast-iron stoves. Now I think I have it. I'll have my testo repaired and I'll build a new prototype in the coming month. Here is the sketchup file of the prototype : www.dropbox.com/s/3z7jm3awdj96azs/2019-08-16_poele_pita_sketchupV8.skp?dl=0Approximate weigth with the plancha and evrything : ~200 to 250 kg. Kind regards, |
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Post by Karl L on Aug 16, 2019 5:36:49 GMT -8
If at all possible could you draw up a 6 inch core showing the closed system version? I have followed this tread closely but have gotten a bit confused about the side air intakes. I'd put it on the list but please don't hold your breath since it isn't top priority, maybe done in a fortnight? All ice, weather and health permitting. Hello Peter, Can you give a short verbal description of the how the closed system is different from the open system? (I understand how to construct the door, side air intakes and floor channel.) Are these the only other changes: 1. Remove the stumbling block? 2. Lower riser floor? Thanks |
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Post by peterberg on Aug 16, 2019 6:17:06 GMT -8
All would be clear when the drawing is ready. But that is some days or more away.
So the short verbal description would be something like this:
The firebox' floor is lower because the floor channel is on top of it, forming the lowest part of the firebox. Since the floor of the riser is at the same level it is lower by the same amount as the thickness of the floor channel.
Moreover, the horizontal feed part (of the floor channel) is twice the vertical stub but it isn't necessary to search for matching sizes. Just buy one size of square duct and use two of those for the feed part.
The stumbling block is still there, it helps to keep most of the flames at the rear of the top box.
There's a separation between the firebox and the air inlet part in order to lead the air to the sides properly.
I'd recommend to wait for the drawing. As the Chinese used to say: one picture is worth more than thousand words.
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Post by peterberg on Aug 16, 2019 6:23:49 GMT -8
I'll have my testo repaired and I'll build a new prototype in the coming month. I downloaded the drawing but some things are unclear. The riser stub opens to a wide space under the plancha and I see where the bypass is but the rest of the gas path escapes me. You know, the double shoebox sports an exit which is a little bit larger than the port. The overall effect is that the maximum speed in the port is limited, preventing the thing to go berserk. You'll need that Testo, that's clear. Good to hear the family is fine. |
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yasin
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Post by yasin on Aug 16, 2019 11:12:02 GMT -8
Thank you peterbergSorry, the first drawing was just a mockup. I amended the .skp file of my previous post with some more details to make it clearer. Basically the heat extracting part is a downdraft system. On the batchblock it worked remarkably well but it had 2 U-turns (one on top, one under the firebox). I hadn't thought at all about this effect of the exit port of the DSR ! I can't wait to have my testo ready to check if my modification still works ! Regards, |
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Deleted
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Post by Deleted on Aug 17, 2019 7:55:47 GMT -8
You know, the double shoebox sports an exit which is a little bit larger than the port. The overall effect is that the maximum speed in the port is limited, preventing the thing to go berserk. That would clearly violate the laws of physics. Fluid systems are limited by their smallest cross-section, not the larger ones. |
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Post by Karl L on Aug 17, 2019 11:48:33 GMT -8
You know, the double shoebox sports an exit which is a little bit larger than the port. The overall effect is that the maximum speed in the port is limited, preventing the thing to go berserk. That would clearly violate the laws of physics. Fluid systems are limited by their smallest cross-section, not the larger ones. The temperature of the gas will have an effect. If the gas is hotter then it will have a greater volume (at constant pressure), and so be restricted more by a given aperture. The temperature of the gas at the exit is likely to be higher than the temperature of the gas at the port, because of the secondary burning. So, the exit port could be the limiting cross section. |
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Post by Orange on Aug 17, 2019 11:54:23 GMT -8
I like that gasses on DSR2 exit on the front part of the stove where heat is really needed |
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Post by peterberg on Aug 17, 2019 12:33:39 GMT -8
The temperature of the gas will have an effect. If the gas is hotter then it will have a greater volume (at constant pressure), and so be restricted more by a given aperture. The temperature of the gas at the exit is likely to be higher than the temperature of the gas at the port, because of the secondary burning. So, the exit port could be the limiting cross section. That could well be the case, what I do is measuring a number of different configurations and try to find out what caused it afterwards. So my explanation could well be wrong while the result I measured was very real. I tried half a dozen different end port configurations and one which was slightly larger (5%) than the riser port had the effect of flattening the peak burn rate. Which largely solved the problem of overfuel situations. Maybe it would be better to refrain from explanations and leave that to theorists. |
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Post by pianomark on Aug 17, 2019 13:48:39 GMT -8
At the risk of adding further confusion....
I interpreted Peter's statement (" You know, the double shoebox sports an exit which is a little bit larger than the port.") to mean that the exit is ONLY a little bit larger than the port. And thus a second restriction. The exit is slightly smaller than the defining system CSA throughout, which includes the chimney, true? I hope I am correct in my understanding of this.
Perhaps a better way to word this would be "the DSR sports an exit somewhat smaller than system size CSA, which helps limit gas speed in the port". So this is happening not because the exit is larger than the port, but rather because the exit is smaller than the chimney.
Or, to state it another way, any restriction (smaller than system CSA throughout) beyond the riser port will limit the draw at the riser port, and therefore will limit gas flow through the port. No laws of physics need be violated.
Peter, thanks for all your great work. Here's wishing you good health and continuing research!
Mark
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Post by Karl L on Aug 17, 2019 14:10:09 GMT -8
Just to clarify: my post above was in support of Peter's explanation.
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