Peter is so great! He has quietly invested a lot of time and intelligence in rocket mass heaters.
One part of his background that you didn't mention was that he trained for several years in building masonry heaters, however he did not pursue it as a career.
He brings a lot of useful thoughts from that tradition, for example using internal surface area to calculate heat-exchange capacity, or the correct allowance of extra space to avoid restrictions at turns and gaps.
I suspect some of his inspiration for how to improve the fireboxes and fire-layout comes from there too. Coincidentally, all our innovators in 2014 had sailing, surfing, or boat-building experience; these are also disciplines that can bring useful insights into fluid dynamics and how to affect them with 3-D shapes.
I would go so far as to say Peter has a genius for offering little incentives to the fire to help it burn brighter and cleaner.
Of course, it helps that he is working to the data - repeatedly testing with sensitive equipment to verify his predictions. I know what that equipment costs, and I want it, hopefully this year. I don't know how many unsuccessful experiments are behind his remarkably successful ones, but the process must take a great deal of his spare time.
It was a pleasure to talk with him in person about the dynamics of the flames, the exhaust gases, materials and their limits, and obstacles such as chimney stalls which must be overcome for a successful working heater. And I enjoyed watching his quietly precise masonry technique. He used clay and sand as most of us do when building prototypes, but he included details like wiping down the faces as he worked, and installing the second skin that protects the firebox and helps to store heat.
I am grateful that he continues to offer his insights on these forums.
Peter v.d.Berg or any other who may be able to answer this question..... In your video links in this thread, there is the use of a clear panel through which the fire can be seen. Is that tempered glass? As an alternative, is there a synthetic (plexiglass-like) substitute that one can use given the heat involved? OK, that's two questions....Thanks.
“The most important decision we make is whether we believe we live in a friendly or hostile universe.”― Albert Einstein
I have somebody on twitter who like to measure the rocket mass heaters or your new design the batch rocket, this guy has a very expensive UFP fine particle meter,
and is a professional one used on universities.
We will do measurement for free, this way we have a little rapport of the rocket because I do not yet find one on the internet.