Hi Brad, You want insulation (light and heat resistant materials) to be around the fire to get it to burn as hot as possible (for the cleanest burn) then once it leaves the combustion zone (exiting the heat riser) you then switch to thinking about heat extraction with a possible barrel for quick extraction and heavy and dense materials for a bench or bell.
brad weirich wrote:Not sure,,,,,,but here goes.
Using aircrete in rocket stove bench in place of cob???
Not as heavy
I am guessing that you may have seen some of the videos by Darwin of the honey do carpenter. He had done some pretty interesting things with air Crete, but he is an intuitive designer and does not have a technical background.
Darwin believes that you can use air Crete in a thermal mass which is not a good material to use principally for the reason Paul indicated. His belief comes from (I believe) his experiments on the forge he built, because it got so hot and held the heat so long. This is because it is an insulator. If you heat an insulator really really hot then it will stay really really hot for a really really long time. This has NO bearing on its ability to store relatively low temperature heat and gradually release it into a room. Darwin did not measure the huge amount of heat that went into heating up the forge and then compare it to the relatively small amount of heat released very slowly by his insulating material.
I do not intend this in any way as a dig at Darwin. He had created some really unique projects and I encourage him to continue. He will eventually figure out things like this with additional testing. I think that some of the air Crete mixes that he had created may eventually revolutionize sections of rocket ovens, stoves, and mass heaters. Time will tell.