I thought some of the RMS enthusiasts here might benefit from excerpts from an old report I have, written by Professor Richard Hill of the University of Maine. I'm studying RMH stoves in general and water heating with them in particular because I want to make underfloor heating with pex tubing. I like the approach of really trying to understand the general principles and then employing those principles in cheap, custom designs. I'm aware of the flash steam / explosion issue with RMS water heating and Richard Hill's design seems interesting considering a balance between trying to heat water efficiently and not blow yourself up. Richard Hill's design is quite efficient but I don't like using electrical fans and I like using common materials like 55 gallon drums. But his "turbulator" design seems interesting for transferring heat to the water. Thoughts? (If anyone wants more pages of the report, I could email them to you. I was only able to upload 3 pages on this post)
Either a tall, insulated heat riser below the heat-collector, or an insulated chimney above it, could make it run without fans.
If the thing is to be manually re-fueled during operation (not just batch-burned until the smoke above the fuel is cooled and flushed out), then I'd want the air feed up above the fuel feed rather than in from the side.
In general, I'm more into keep-it-simple heaters; water is temptingly efficient but introduces problems too.
(Steam explosions / overcooling the fire / evaporation robbing heat / leakage that can cause rot and mold / crud buildup in open systems that can lead to blocked flow and both explosions and maintenance problems)
But there is a LOT of interest in heating water safely with efficient wood heat. I'd like to see more of this - maybe it's possible to re-type or scan the report like they do for books with Project Gutenberg?
Yeah, it would be nice to do a full scan PDF and park it somewhere for all to reference. Lots of good discussion. Hill did a lot of trial and error to arrive at really efficient burning.
One key principle I glean here relevant to water heating is that the interface between water and hot exhaust gas should be large. So Hill has the hot gas flowing through 7 smaller tubes instead of one big tube. He gets the hot gasses swirling also with his turbulator design. AND, the turbulators are removable for easy cleaning. Prolly not much cleaning though because of the super hi temp burn.
Dave, I know Dr. Hill's name. this is right in my wheelhouse! Good on ya for finding this report! If you get a chance, could you email me the report? Thanks Bruva! I originally started lurking on this forum so I could build an RMHwater heater to run my radiant floor system in my home.
Thanks again, C.Ray
Oh shoot, was that my out loud voice?!? O.o
Thanks for listening to my hair-brained ideas, now have a blast picking them apart! I have a habbit of over thinking EVERYTHING I do! C.Ray
I had guessed that something along the lines of rocket stoves and rocket mass heaters might have been in the works for perhaps hundreds or thousands if years, though it seems likely the knowledge was lost over the ages.
Of course, like many others here, as Erica suggests, I too am interested in rocket stove or RMH water heaters. I'm leaning in the direction of single-purpose designs, opposed to multi-purpose contraptions, for example a stove that might do heating, cooking and hot water all-in-one, that might introduce too much complexity.
If you are able, could you also email me copy of that report?
Location: Kansas City, MO
posted 5 years ago
Sorry guys, I do not have a personal scanner at the moment. Will stop by Fedex Kinkos when I get a chance and scan to a PDF so I can email to folks.
It's fun to be me, and still legal in 9 states! Wanna see my tiny ad?
Rocket Oven – is it Right for You? Here’s What You Need to Know