Peter van den Berg wrote:
Chimney (pipe) diameter need to be the same or at least very close to the riser diameter.
Peter van den Berg wrote:In case you want to use an intermediate figure and are wary about using the spreadsheet I can do the calculations for you.
Peter van den Berg wrote:In case you want to implement the heater as a true cube, the ISA should be divided by 5. For determinating ISA all the surfaces count except the floor. In practise, the heater would be higher than wide and deep because of the required minimum riser length. Don't worry about the walls of the firebox and riser, those should be insulated with superwool anyway. Don't forget the distance between riser top and bell ceiling (known as the top gap) should be equal to the riser's diameter at the very least
17.5 cm (7") ISA 7.2 m² (77.5 sq ft)
thomas rubino wrote:Hi Lucas; Big Welcome to Permies! And a big Welcome to the wonderful world of rocket science!
thomas rubino wrote:Pay no attention to that unless you are a math wizz! I sure didn't. It has no effect on your bell size or box dimensions.
thomas rubino wrote:An 8" batch is a beast , very big.
thomas rubino wrote:Air channels)...So Peters comment referred to not using a P channel AND a secondary air tube on the same stove.
thomas rubino wrote:So a batch can have a separate secondary air inlet OR the primary air inlet can be enlarged to feed both secondary and primary air needs. This is accomplished by shortening the secondary and placing a "blocking plate" to direct air to the lowest point in the batch.
Peter van den Berg wrote:Hi Lukas,
Thomas answered your questions already, bar the one about the calculated base number. That base number is used for to scale the combustion core and its parts without steps as in the provided table.
Peter van den Berg wrote:...the chimney diameter..
Peter van den Berg wrote:..above information and more is already on the website
17.5 cm (7") ISA 7.2 m² (77.5 sq ft)
This secondary air supply duct is an alternative to the p-channel, not to be used in the same heater.