That's pretty clear - I had no desire to offend. The digester is a small part of the device - and one of the least expensive sub-systems. As I have described the machine, it would be too small to handle that much poo in any case - this one is for people and dog doo.
For your application - and you did a very cool thing and I appreciate that - but for your application, a ground tank digester (No water machine, no steam engine, no condensing boiler, no VAWT, no bio-reactor, no battery) with the most basic benefaction, you're looking at maybe 500 to 1000 in parts to produce gas depending on size - Indian models are pretty good, no compressors, gas is stored in a float-top-tank and scrubbed by activated carbon/water only. That's all. Labor intensive up front to be sure - but this isn't to heat stock water (which, I like your judicious observation) - it's for providing gas to your house, and maybe your neighbors... your shop? (lots of sheep?)
The 10K that I quote is inclusive of ALL a household's energy and water - not just gas. It is a total-utility-replacement - that is the cost that must be factored. I've seen some guys spend more than 10K just on power poles for electrical lines to their place, and then they "get to" pay the electrical bill - and still have to pay to fill a propane tank, as they throw their methane (poo) away in a septic, and don't recover any of the flue gas into diesel for their
tractor... Small to mid-scale operations can realistically recover the cost of this system in a single year (for new construction) and five years at most for retro-fits. The 10K is for my sized operation - 3-4 humans, and maybe 20 different animals - and is up-front cost amortized over a 20-50 year service life (indefinite with good maintenance). It intends to completely replace all energy costs.
I am interested to know how the sheep fare though - a bit off topic, but I don't care!
Do sheep ruin the ground, or is that a myth spread by llama farmers? I heard once that they yank
roots of plants, and will denude a field. That doesn't seem like it can be true. Can they forage in a hard-scrabble cedar and pine forest?
Does the wool market sustain the current work, or is it necessary to spin it before it's worth enough? Is long fiber a decently paying crop? How do you put it out there? Big qty, or small scale?
Are old sheep good for meat? Dog food? Stew?
I had thought to keep two of them with my llamas, goats, and ducks. I know that's really different than the standard "mono-herd" (flock) But I have seen that llamas, goats, and ducks get along (and maybe a mini hereford) but I don't know about the sheep.
My operation is small-scale diverse production - you think sheep would fit the equation? I've gone back and forth a lot with that.
Anyways, please forgive if I've given offence! I don't mean to discount your work - not in the least! It's been by simple observation and investigation that I've conceived of this in any case - just like you!
Aside from all of this - the machine won't work for someone who leaves the front door open - to heat the neighborhood so to speak. It requires conservation like you! It just takes it to the next level, and makes it all free (after materials costs) and closed-circuit.
Your work + mine = permie-free!!
I really appreciate your feedback, I may incorporate your details into the final draft of the paper when I publish.