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Post by scottiniowa on Nov 9, 2017 13:38:21 GMT -8
I know the post from Peter goes way back to 2013, with all the excellent dimensions...have any of these been updated (changed)
And on the heat riser dimensions? if your riser is square out of fire brick, is an 8" square or a 7" square considered the same as a 8" and 7" riser diam.?
I have 2 8" systems that work well, but the J style of RMH, not batch box. I could handle (heat storage wise) more wood- for longer and perhaps hotter burn.
Last question, my heat riser for the 8" systems is not this long, do to ceiling height, but I guess I could change and do a split barrel.. i.e. instead of riser of 57" (1440MM) I have about 40-43" (1080-1090mm) or single barrel.
I do have excellent mass for heat storage, Long bench as well as 8'x20'cinder block wall behind the stove that vent runs along.
thanks.
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Post by pinhead on Nov 13, 2017 12:00:25 GMT -8
The dimensions are standardized and need no revision.
When comparing a square to a round riser, the square dimensions should be the diameter of the riser, i.e. 6-inch diameter is equivalent of 6x6 square.
You can shorten the riser slightly while sacrificing some emissions during the peak of the burn.
If you an 8-inch J-tube is sufficient, a 6-inch batch box will likely be sufficient as well; the BB produces much more heat than the J-tube of the same riser diameter.
Regardless of size, however, the BB generally runs through a full load in about 45 minutes while consuming much more fuel in that time than the typical J - hence the higher heat output.
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Post by esbjornaneer on Nov 15, 2017 9:38:40 GMT -8
The dimensions are standardized and need no revision. Sorry pinhead, I asked at an earlier point if there was any need to update the spreadsheet (or at least talk about) the floor channel versus the p-channel. If the floor channel is considered the better of the two I think it would be good to mention it in the first post. Just my opinion but it was not taken up at that point. I'll rest my case if you think I am mistaken.  |
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Post by pinhead on Nov 15, 2017 11:00:39 GMT -8
The dimensions are standardized and need no revision. Sorry pinhead, I asked at an earlier point if there was any need to update the spreadsheet (or at least talk about) the floor channel versus the p-channel. If the floor channel is considered the better of the two I think it would be good to mention it in the first post. Just my opinion but it was not taken up at that point. I'll rest my case if you think I am mistaken. The floor channel doesn't modify the overall dimensions of the standard batch box. I still haven't seen an equation to calculate the dimensions of the floor channel with relation to the batch box dimensions so I can't add it to the spreadsheet. |
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Post by giogee on Nov 16, 2017 14:06:42 GMT -8
 Guys can some 1 point out what is the base referring to on the above pic I have read the entire thread and there is mention of it but I'm more of a visual person. "The base has a fixed relationship to the diameter of the riser. So it isn't the physical base of the firebox or whatever." for my 150 Diameter the table shows the base as 108mm goo.gl/images/gJdDfX |
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Post by pinhead on Nov 16, 2017 15:51:09 GMT -8
Guys can some 1 point out what is the base referring to on the above pic I have read the entire thread and there is mention of it but I'm more of a visual person. "The base has a fixed relationship to the diameter of the riser. So it isn't the physical base of the firebox or whatever." for my 150 Diameter the table shows the base as 108mm goo.gl/images/gJdDfXYou can ignore the "base" figure; it is simply a mathematical constant to calculate the measurements in relation to the diameter of the heat riser. It's not representative of any particular physical component or figure. |
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Post by pianomark on Nov 16, 2017 18:40:59 GMT -8
"You can ignore the "base" figure; it is simply a mathematical constant....." Pinhead, I think you have confirmed what I have always suspected--the "base" figure is a mathematically unnecessary extra step in each of the calculations. Why couldn't all the dimensions (except port depth, obviously) be derived directly from the riser diameter? Expressed as a single multiplier for each dimension. Am I missing something? In any case, all the calculations have been done on the spreadsheet, so maybe it's a moot point. Never mind Mark |
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Post by giogee on Nov 16, 2017 23:42:29 GMT -8
thank you for that it was driving me mad  |
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dvawolk
Full Member
DSR2 125mm open system (actual project)
Posts: 271
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Post by dvawolk on Nov 18, 2017 4:15:19 GMT -8
Here is a .xls file that can be used to calculate the desired floor channel or p-channel parts. All dimensions are in milimeters (1 inch=25,4mm). Also, for easier understanding, do read the info on the links among the "how to" explanation. They are linking to Peter's Batchrocket.eu website, directly to the relevant information. HOW TO USE THIS FILE:Columns show the relevant system size, from 100mm (4") to 250mm (10"). In lines from 15 to 18 there are calculated values of required CSAs of needed channels for P-channel (one part, read THIS) or floor channel (horizontal and vertical part, read THIS). If you decide to use P-channel, you should also have the width (without walls) the same as the width of the port (calculated in line 12). If you decide to use F(loor)-channel, you would need two different ducts - one vertical (square) and the other horizontal (usually rectangular). When searching for a vertical part, you need to get one that has as good measures as possible... As for horizontal part (as stated HERE) there is no need to get exact measures - it can have a much higher CSA (compared to calculated values). But do not pick a smaller one - it wouldn't deliver enough air to the port. Basically you insert the dimensions of channels that are available at your place to see if they are close to mathematically correct measures of CSA (in lines 15 to 18). Insert the dimensions only into green cells in the appropriate column (pick the column of the system size that you need calculation for - system size is the same as Heat riser diameter given in row 4). If you look at Column B, there are values already inserted: B21 shows the width of a vertical duct of F-channel (in mm) = 35 B22 shows the wall thickness of a vertical duct of F-channel (in mm) = 2,0 B23 calculates the CSA (in mm squared) = 1089 B24 calculates deviation from the mathematical value of CSA (calculated in B17) = 14% This one means that CSA for the given information of a duct (35mm and 2,0mm) is 14% larger as it should be. But this is close enough, because these ducts were used in Peter's heater and he did lots of testing with good results...Similar calculation is done for horizontal duct of F-channel in cells B26 to B30. For F-channel you need to insert only values in rows 21,22,26,27 and 28. Everything else is calculated on its own.
For P-channel you need to insert only values in rows 32,33 and 34. Everything else is calculated on its own.I did try to make it flawless, please, do check if the calculations are correct.Best Regards, Klemen
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Post by action0525 on Nov 25, 2017 9:37:50 GMT -8
I am finding it impossible to find a P channel for a 6" system which meets the I.D. dimensions that you specify. Can I go to a slightly larger P channel size which is commonly manufactured in the tubing industry? Or are the specified I.D. dimensions for the P channel critical for the optimum operation of the system?
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Post by peterberg on Nov 25, 2017 12:35:11 GMT -8
Yes, namely the width of the channel may be slightly larger without any repercussions. I assume you are somewhere in the USA, imperial standaard tubing is of course different from metric.
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Post by action0525 on Nov 25, 2017 13:48:51 GMT -8
Yes, I am in the US (Wisconsin).
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Post by Orange on Nov 30, 2017 3:28:11 GMT -8
when calculationg ISA, we use for uninsulated chimney 1/2 of the surface. How about 1/4 of surface if the system has a bypass, makes any sense?
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Post by peterberg on Nov 30, 2017 4:00:58 GMT -8
when calculationg ISA, we use for uninsulated chimney 1/2 of the surface. How about 1/4 of surface if the system has a bypass, makes any sense? The calculations I am recommending doesn't count the chimney stack in, at all. As far as I know, there isn't a way to calculate a bypass in and it depends highly where in the system the bypass is situated what you could add to the ISA. |
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Post by Orange on Nov 30, 2017 7:07:27 GMT -8
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