We're about 30 miles west of Portland and looking to add a rocket mass heater to our shop before next fall/winter. Because of the size of the space we're heating, a batch box seems more practical than the traditional J-tube. I don't feel as confident with the batch box systems, and we definitely need the final product to be functional.
We're on a 93 acre homestead where we're currently establishing a food forest with the aim of donating our surplus to those in need. We also want to hold permaculture related workshops on the property as we get it established.
My hope would be to hold a batch box RMHworkshop on our property. You would provide the experience and we would provide the materials. You could charge whatever you feel is appropriate for the workshop to compensate you for your time.
At this point, mostly just putting out feelers to see what possibilities exist. If any of this sounds interesting to you, let me know.
I just added your post to the rocket mass heater forum. You will get more views from rocket scientist's that way.
Also you might consider joining and making a post over at Donkey pro boards, those guys seem to only build batch's. Here is a link donkey32.proboards.com
Thanks for the resources, guys. Peter's site is actually what overwhelmed me to begin with. 😂
When I was put in charge of heating the space, my initial plan was the simple J-tube/steel barrel/cob design that I'm familiar with. I started doubting whether that would be sufficient for heating the space (it's 40x100'... but I don't remember if that's the internal dimensions, or if that includes the greenhouse on the south side, and the covered parking on the north side.) Found batch boxes when I started researching that particular problem. Our space is quite a bit larger than the other examples of large spaces I saw people trying to heat.
My biggest concern is missing some functional element necessary for the size and type of space I'm trying to heat. I don't have masonry/metal fabrication experience (I got the good growing genes, not the building things genes), and I'm trying to utilize on site resources as much as possible (namely rock and clay). I want to limit new/purchased materials as much as possible (especially since the landowner is footing the bill for any upgrades, and I'm not sure how much, if anything, they've budgeted for the heater at this point.)
I love the casserole lid door design for it's simplicity (and the ability to view the fire.) I like Ken's cyclone design, but I do want to minimize the use of brick where possible in favor of resources we already have (Seriously, we have a lot of rock. The back corner of the property was part of a now-abandoned quarry.) I'd also like to have a nice big heated bench, but I'm not sure about getting the right balance between fast heat and long-lasting heat in the space I'm working with... I think I remember Ken saying the cyclone was comfortable to touch, so it seems like at a certain point you'd have a level of mass that would require an impractical amount of wood to heat. I'd also like to have exposed barrel for heating a kettle, etc., but don't know how that aligns with the other design goals. And one of the big ones is figuring out if there's a practical way to insulate the heater from the cement slab with materials we have already. And protecting the existing structure from damage (my previous experience was working with cob inside of cob, so you really couldn't burn the place down even with as bad design.)
So, yeah. The project has gotten a bit more complicated than is originally envisioned. 😂