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Post by esbjornaneer on Nov 30, 2017 1:08:45 GMT -8
yasintoda's thread donkey32.proboards.com/thread/2099/125-mm-batch-heater-france where he introduced a design for a caravan rocket got me thinking last night... I have limited space but would like to put in a rocket heating two un-heated upstairs rooms, but both are small. yasintoda's thread got me thinking of the discussions back in 2013/14 about triple bells donkey32.proboards.com/search/results?captcha_id=captcha_search&what_exact_phrase=triple+bell&who_only_made_by=0&display_as=0&search=Search as can be read there the conclusion was that the total(?) ISA should be reduced by 15% for each additional bell, compared to the previous bell arrangement. Do I understand right that a double bell will hold the heat in the house longer than a single bell? If so then for each added bell there should be less need for mass. Is my logic right? For the flywheel effect the more mass the better, if the space is to be continually heated. But in an upstairs (or caravan) situation there is a maximum amount that is good to add. And what happens if there is a second skin to the bells? Will that retain the heat for longer with less mass addition? Your knowledge and thoughts are most welcome. But in Matt's spirit it will be great to specify if it is knowledge or thoughts. Thanks, Esbjorn
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Post by peterberg on Nov 30, 2017 2:13:47 GMT -8
Do I understand right that a double bell will hold the heat in the house longer than a single bell? If so then for each added bell there should be less need for mass. Is my logic right? More mass means longer heat retention, nothing or very little to do with the number of bells. It's possible to build a single bell sporting a very high-mass double skin, even with some insulation between the skins, which would be able to hold heat for 24 hours. A triple bell with single skin would be the lesser choice heat-retention-wise as there's less mass in there. The double or triple bell is better in extracting more heat in a smaller space. All knowledge through experimentation.
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Post by satamax on Nov 30, 2017 5:44:38 GMT -8
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Post by esbjornaneer on Dec 29, 2017 9:14:25 GMT -8
Belated thank you for the replies. When it comes to several bells, should they all be the same size? Or would there be any reason that any bell should have a larger ISA than the other(s)? Is there any reason that it would make any difference?
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Post by Orange on Dec 29, 2017 13:00:57 GMT -8
here's my logic which may be right or wrong in reality:
-more bells means more heat retention as the gasses just have to travel longer -single skin bell is better than double skin bell if they have the same thickness
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Post by esbjornaneer on Dec 30, 2017 6:51:22 GMT -8
Here is a picture of two setups of bells. One is a single bell (ISA 5.38m^2), the other is a 3-bell (ISA 3.91m^2). The foot print is the same. The height of the sealing in the room is the same, that is where the pipe ends in the picture, external chimney is the same. The internal chimney in the bells both reach equally low in the bottom bell. Is there any reason that one of the chimney stack would be more efficient (have more draw/work better) than the other? And how much of a difference would it be if so? The SketchUp is available here.
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serg247
Junior Member
The mountain can not be conquered, it can allow it to ascend...
Posts: 111
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Post by serg247 on Dec 30, 2017 9:07:36 GMT -8
Please SketchUp V8.
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Post by esbjornaneer on Dec 30, 2017 10:22:20 GMT -8
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Post by coastalrocketeer on Jan 10, 2018 6:48:07 GMT -8
Do I understand right that a double bell will hold the heat in the house longer than a single bell? If so then for each added bell there should be less need for mass. Is my logic right? More mass means longer heat retention, nothing or very little to do with the number of bells. It's possible to build a single bell sporting a very high-mass double skin, even with some insulation between the skins, which would be able to hold heat for 24 hours. A triple bell with single skin would be the lesser choice heat-retention-wise as there's less mass in there. The double or triple bell is better in extracting more heat in a smaller space. All knowledge through experimentation. More mass means longer heat retention IF the outer surface area and surface conductivity of the material to air is the same. Change either of those and the same mass will lose heat more or less quickly. Change them on the inside surfaces and it will gain heat more or less quickly. Increase external surface area of the same mass and increase heat loss. Thinner walls of the same thermal conductivity will get hotter on the outside sooner and shed more heat with less surface area. Conductive materials (copper wire, aluminum, other metals, conductive bricks, and others) can be strategically embedded in a mass skin to affect the speed, and location of heat transfer, as well as concentrating conduction of heat from one part of the interior of a mass to another part of the exterior. Ie: taking heat from the upper portion of a mass and giving it a path to spread downwards and heat lower sections of the outside of the mass more evenly while minimizing upset to interior thermal stratification. Oil in closed loop pipes could be used to transfer heat from inner layers of a mass to the outside. (These are my random ideas and may not be correct, I welcome comments, corrections, re-interpretation, input and inspiration from others)
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