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Benen Huntley
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Location: South Australia
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I think I understand. Thank you so much! Back to sketch up to redo the design 😊
 
Benen Huntley
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Location: South Australia
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Peter, in your specifications the pchannel must be 54x16mm, however, in your sketchup of the sidewinder it is 26x56mm. Is this not so important to get correct?
 
Peter van den Berg
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Benen Huntley wrote:Peter, in your specifications the pchannel must be 54x16mm, however, in your sketchup of the sidewinder it is 26x56mm. Is this not so important to get correct?

Both sidewinders on the batchrocket site doesn't have a p-channel, but a floor channel instead. The p-channel is an overhead device, the floor channel is incorporated in the floor of the firebox. Both secundary air channels work in different ways, that's why they aren't the same. It's perfectly possible to have a p-channel in the sidewinder by the way, although I'd regard the floor channel as the better one.

In short, it is equally important to get correct, but you'd better not to mix up two different concepts.
 
Benen Huntley
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Ah right. I assumed they were the same just in a different location. So I will keep it as is in the sketch and

I feel like I am getting much closer and I can't thank you enough for your willingness to help!

Before I go further. I'd like to clarify that a 150mm system is indeed the suitable size for the space in the sketchup file? It's a kitchen, living and dining. Larger than I'd like but it's what we have 😊
 
Peter van den Berg
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Benen Huntley wrote:Before I go further. I'd like to clarify that a 150mm system is indeed the suitable size for the space in the sketchup file? It's a kitchen, living and dining. Larger than I'd like but it's what we have 😊

Impossible to say, very dependant on what low winter temperatures are at your place, orientation to the sun and wind chill, to name a few aspects. To get a rough idea, revert to the calculator of Yasin Gach. See http://batchrocket.eu/en/building#size
 
Benen Huntley
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Hmm. Looks like the 8" is the more suitable option for the volume of the house. Particularly since you mentioned that it is always better to size up rather than down. I believe I can fit it into the space and gain most of the extra ISA by extending the height.

Back to sketchup
 
Peter van den Berg
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Benen, you've drawn the heater as a single bell with the exhaust pipe sticking out the side. This isn't really necessary, another way to do it is to build a brick upstream channel inside the bell and create a top vented heater. This results in more mass and a bigger bell externally. There's a catch here: the exhaust opening in the upstream channel need to be very wide, up to 200% of system size if that would fit. Such an internal chimney opens up the possibility of a bypass, which would start a cold and wet heater much, much easier.

Did you read the thread at Donkey's, about a bell inside a bell? See http://donkey32.proboards.com/thread/2260/bell-inside
 
Benen Huntley
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Hi Peter,

I don't quite understand unfortunately. I did read the article but it read as though it has not been tested a great deal or at all?
 
Peter van den Berg
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The thread I mentioned was quite separate from what I said about the internal upstream channel in the bell. The "bell inside a bell" is a new untested idea as yet but a tantalizing possibility, that's all. As far as I know of the first one is built or being built this week.

The internal upstream channel and the bypass valve in there is built dozens of times and it works for sure.
 
Benen Huntley
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Ah right. What do you suggest I alter with my current design then? Build mass around the exhaust?
 
Peter van den Berg
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Hmm... I wasn't clear enough, apparently. What I like to call an upstream channel is a brick chimney inside, in a corner of the bell. Two of the sides of that internal chimney would be formed by the walls of the bell. At floor level, still inside the bell, there's a wide and spaciously opening where the gases will be able to stream up.
This way, the exhaust opening is on top instead of low at the side of the bell. And you could build the heater wider at the place where the metal chimney pipe would go.

As an added bonus there could be also a bypass halfway up this internal chimney thing, to allow gases to stream in the chimney at a higher level. Thus making the heater much easier to start when cold.

is this clear now?
 
Glenn Herbert
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Another term for the concept is a "plunger tube", more often referring to a metal exhaust duct going from near the floor of a bell straight up and out of the top. It does the same thing, allowing only the coolest gases at the bottom of the bell to exit, while not occupying any space around the outside of the bell.
 
Benen Huntley
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Location: South Australia
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Ah man, I have had absolutely zero time to sit at the computer the last couple of weeks to play around. We have been renovating like crazy in the living area plus working two jobs! I will try to find some time this week!
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