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Post by peterberg on Jan 10, 2019 1:12:26 GMT -8
I find out how to calculate ISA, so for a 20cm batchbox the ISA max is 10,6m² (if I'm right and if the informations I found here are still good. For a 8"system, 50.24x2.285=114.8sq'masonry) and I'm around 6m² of ISA with my actual plan. That information isn't exactly current, to say the least. Please have a look at batchrocket.eu/fr/construction#bellsizing. Bell systems built like that are on the conservative side but will run much more reliable in most circumstances. So I still have some energy supply to heat my water, what do you think about that? am I right? A 20 cm batchrocket system coupled to a 6 m² ISA do has some slack, yes, about 30%. But there aren't any firm figures for what you want so you need to try it out yourself. I am very curious how this'll turn out. When built nicely and working properly it would be a contender for to publish as an example application on the batchrocket website. Provided you are willing to grant permission to do so, of course.
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Post by ribeira on Jan 10, 2019 4:09:37 GMT -8
Thank's I missed that. Are you talking about the design of my bench, is it correct? Ok, I'll try it and for sure it will be a pleasure to share with the community the results still few questions remains (of course ) - If I well understood I don't need an ashtray between the main bell and the bench...right? - how thick must be the top of the bench to don't burn my bum or the wool mattress I plan to put on it -Is there any interest to slow the gaz by segmenting the bench in 3 with two high divider? maybe it will be worst and my worry is that the heat won't be uniform on all the bench...? what do you think about that?
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Post by ribeira on Jan 10, 2019 23:24:28 GMT -8
peter: I just read this sentence from you in another thread talking about box size:
I don't really understand cause in this kind of design the space a the right of the port is way bigger than the left:
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Post by peterberg on Jan 11, 2019 1:47:47 GMT -8
Are you talking about the design of my bench, is it correct? I was talking about the sizing method, but your bench seems to be right. I didn't calculate it though. - If I well understood I don't need an ashtray between the main bell and the bench...right? No, the main bell and bench are their own ashtrap, just because of their size. - how thick must be the top of the bench to don't burn my bum or the wool mattress I plan to put on it This is guesswork, sleeping on it is quite different to sitting on it during the day not to mention heat input isn't a fixed value. For sitting, 10 cm of concrete slabs would be nice. Sleeping on it... make it 20 cm. Just my 5 cents. -Is there any interest to slow the gaz by segmenting the bench in 3 with two high divider? The gases in the hollow bench are slow already because of the space. A devider will force the gases to stream at a pre-determined pattern, posing friction again. Some people build columns inside, free from other walls, to support the seat. This'll add some mass and ISA with minimal friction. maybe it will be worst and my worry is that the heat won't be uniform on all the bench...? what do you think about that? Whatever you do, temps closest to the main bell will be higher. But after a few hours all the heat will be distributed more evenly, although temps will remain (slightly) higher closest to the source.
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Post by peterberg on Jan 11, 2019 1:58:39 GMT -8
I don't really understand cause in this kind of design the space a the right of the port is way bigger than the left: I was talking about a straight batch box there, not a sidewinder. Sidewinders are different, some people omitted the narrow piece of wall between port and rear wall. Results were not as good as compared to the current recommended shape. If I remember correctly even Adiel in Israel, the guy who built the first one, made the same mistake at first and found out it yielded high CO levels that way. It's all a matter of (again) gas stream patterns and how to build it in such a way results are good and reproduceable.
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Post by ribeira on Jan 11, 2019 2:02:15 GMT -8
thank's a lot for all those precisions
the concrete slab for the bench top hasn't to be in refractory concrete I guess, can you confirm, no problem to put rebar in it neither?
In this configuration I won't be able to do a by pass, it won't be a problem when the bench will be cold?
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Post by peterberg on Jan 11, 2019 3:18:49 GMT -8
the concrete slab for the bench top hasn't to be in refractory concrete I guess, can you confirm, no problem to put rebar in it neither? I am unsure what is available in France, I used sidewalk pavers, 60x40x6 cm, normal concrete without rebar. Applied in two layers in such a way the seams are overlapping. Much better for keeping gas tight, the first layer with superwool in the horizontal seams, second with clay/sand mix. In this configuration I won't be able to do a by pass, it won't be a problem when the bench will be cold? This is very much depending on the quality of the chimney and your build. Provided it's built correctly and to the right ISA, there's won't be a problem. Starting up a wet heater is problematic but once it's dry it comes to life. In order to deal with this kind of difficulties it's best to heat up the chimney first so an inspection hatch would be nice. Such a hatch could be a small door, more expensive but worthwhile.
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Post by ribeira on Jan 11, 2019 5:09:46 GMT -8
I will do the concrete pieces myself, it will be cheaper than buy it, as this is a bit large I wanted to know if I reinforce them with rebar would cause problem because of steel dilatation into concrete... I will se by myself so...
ok perfect, I already planed to make a hatch at the aplomb of the chimney!
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Post by ribeira on Jan 16, 2019 2:09:01 GMT -8
Hi I just realize that by doing a lateral door I increase the width by a brick thickness do i have to correct this.
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wooda
New Member
Posts: 2
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Post by wooda on Jan 16, 2019 6:09:51 GMT -8
You cannot embed from dropbox. upload to Imgur and copy the URL from there.
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Post by peterberg on Jan 16, 2019 6:45:32 GMT -8
I just realize that by doing a lateral door I increase the width by a brick thickness do i have to correct this. Sorry, I've seen that detail but forgot to comment on it. This lateral door thing has been built in limited numbers, in essence it's an untested system. The reason to want it like this is to have a better view of the fire. In my opinion it is such a diversion from the tried and tested design there could be any kind of problems with it. Aerodynamics are different, air inlet is in a different location. The only aspect which is correct is the port, riser and placement and layout of the secondary air provision. In other words, it isn't very realistic to take a design, stick some nice looking details to it, leave other features out and expect it to work the same way as the original one. My advice: don't do it this way, it isn't very handy to place the fuel parallel to the door. The properties of the design are such that the fuel could be stacked against the left and right wall, right to a level about 5 cm from the ceiling. At right angles with the door without any criss-crossing. Following your idea that would be very difficult, the alternative is to load it with smaller batches. Loading a second batch on top of a glowing coal bed isn't a sinecure parallel to the door, in contrast with the way it could be done at right angles and against the left and right wall. Are all these uncertainties and handling difficulties worth the supposedly better view? I don't think so, the chance that the glass window will get black almost every run is a negative aspect. My design is done in such a way the staining of the glass is minimal or even totally absent like in my own heater. My advice: don't deviate from the design, you will be rewarded for it by an impeccable running heater.
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Post by ribeira on Jan 16, 2019 10:36:33 GMT -8
Ok Peter, I totally understand your arguments and I can see kindness in your advice, having a better view is not the only reason that make me choose this design, I collect a door with the frame from an insert, so if I do the regular design I'll have to buy a glass and the metal to make the door...and it would be a big save of time (and also a bit of money) using the door I already have I intend to put the air inlet at the same place that in your design, I just didn't represent it on my plan, I understand the "flow thing" I've seen this kind of design here and here , that's why I wanted to do it this way...
I realize that I don't know exactly how a fire must be start in a batchbox is there a special way to do it?
So if I do this modification the difference with the regular design will be lesser right? I think I'm up to try to experiment
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Post by peterberg on Jan 16, 2019 12:16:39 GMT -8
I've seen this kind of design here and here , that's why I wanted to do it this way... I know of the first one but haven't heard of that since it was built. I don't know about the second one but in there are more changes. One of those, the off-center port won't work the same way as the example design so it's something else again. Have you seen or heard about those after running for a couple of seasons? I realize that I don't know exactly how a fire must be start in a batchbox is there a special way to do it? Yes, there is. The best and easiest way to do it is loading the firebox before being lit. biggest pieces at the bottom and higher up smaller pieces. The fire is lit on top and the door can be closed. Loading a stove that isn't lit is the biggest handling advantage, at the same time pollution will be absolutely minimal. It's not my invention, it's called upside-down firing. I think I'm up to try to experiment Please do what you like, but the same larger door could be used another way. I urge you to consider a proven approach which is the shortest way to a working heater. If you like to experiment I won't be able to advise you anymore.
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Post by ribeira on Jan 17, 2019 0:20:48 GMT -8
Have you seen or heard about those after running for a couple of seasons? Yes I know what you mean, I was wondering the same thing. ho yeah I know it buy the name of top-down
I will consider it Peter! thank you
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Post by ribeira on Jan 22, 2019 2:17:34 GMT -8
hi
I read on batchrocket.eu (but I can't find back where on the site) that the diameter of the chimney after the bench can be smaller than the diameter of the heat riser, in what proportion please, I'm very interested about this point cause I'm obliged to pass the chimney between two wood beam, and the farest the chimney is from them, the better it is.
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