Mike Fullerton

Been on a bit of a Matt Mahaffey kick lately. A fascinating musical rabbit hole to fall down...

If anyone has any tips on how to shred Miscanthus faster, I'm all ears.

Interesting insights on the shredding. I had assumed that it would shred really easily due to the small diameter and the fact that it's a large grass rather than a tree branch. Less dense and presumably easier to shred than a branch of the same diameter? But I guess it depends on the cutting type. I can see how the kind with the gears could have trouble, since it's more of a crush than a slice.

From a quick search, most of the info out there about shredding miscanthus seems to be aimed at commercial operators and enormous industrial units. Maybe since it's so similar to bamboo, figuring out which home unit is best for that would lead to better results? Then again, a lot of that info is about shredding *green* bamboo, which is not really a great analogue.

Pretty cool concept!
The regenerative jacket-cooling/intake air pre-heating is very reminiscent of the sort of cooling loop you see in actual rocket engines. In fact, if the turbine you mentioned were used to spin a blower that forced more air into the system, you'd have the basic ingredients of the expander cycle - like some sort of wood-fueled steampunk RL10.

"It's 40 degrees and I feel like I'm dyin'..."

Duckweed seems like seriously awesome stuff, especially if you're going with ducks instead of chickens as your poultry of choice. You can also dig it straight into garden beds as a soil amendment or add it to compost piles.

Lemna Minor - Wikipedia
It grows extremely rapidly - they say it can double in mass in 24 hours. 73 tonnes/ha/year dry mass is cited in the article above in ideal conditions. There's even mention of a trial growing it in north carolina on diluted swine lagoon fluid at over 100 tonnes/ha/year which is downright astounding. As far as I know the best you can do on land is giant miscanthus at 40ish tonnes/ha/year, so duckweed is over twice as productive per unit area.

Duckweed Aquaculture Tutorial - Vegetronix
It's also quite high in protein. 20-40%, comparable to soy. Can apparently replace soy in duck diets, which I guess isn't surprising considering it's their biggest plant food source in the wild. You can dry it down and store it for winter feed too. Poopy duck water (which ducks produce in seemingly limitless abundance) would seem like an ideal medium on which to grow it too.

Jen Fulkerson wrote:Ok I admit it, I'm a crazy person.

You're not alone there! This lady here seems like an ultra-enthusiast about duckweed, complete with trips all over the world to study it and find unique strains. She's even got a post a bit down the page about feeding duckweed to black solider flies. Seems like a winning biomass combo - you'd have the ridiculous plant productivity of duckweed helping feed the ridiculous animal productivity of BSF and ducks will happily munch both of them like they're candy!

T Melville wrote:Just found this the other day. I don't think it's spread so much as it's grown into a full sized plant, but it was planted beside a railroad tie and now has two stems on the other side of it.

Good to know! I was worried it would be like raspberries, which I've seen shoot up new canes 15-20 feet from an established patch. Those railroad ties are usually pretty chunky aren't they? 6-7in deep? Seems a subsurface barrier would need to be deeper than that to be effective, but I guess if it spreads that slowly it's not exactly threatening to get out of control and take the whole place over or anything!

I looked a bit further into using it in strawbale construction, and I came across this article about it:
Miscanthus: the game-changer in building construction
It's written by a group that markets and promotes miscanthus in the UK, so they're tooting their own horn a bit here, but they seem quite chuffed about the compression strength and thermal/acoustic insulation properties. Seems like it would work pretty well, and since you can grow it yourself in quantity on marginal land it may turn out much cheaper than paying to truck in bales of grain straw.

Casie Becker wrote:That article is from 2015... how did I not hear of this before.  We don't have enough Styrofoam coming into the house to do a large scale test of this, but it's just screaming to be a kids science fair project.

I know, right? It's almost like a kind of permie alchemy. Transform styrofoam into farm-fresh eggs just by passing it through mealworms and then chickens! And both of those stages also output garden fertilizer in the form of two different kinds of poo!

The wikipedia page notes that no attempt at commercialization has been made, which is kind of a shame, since this would be a perfect add-on to any local recycling depot. Maybe not commercialzed as much as run the way a lot of municipal compost programs are. Around here everyone drops off their garden waste at the compost facility and you can get bags of free compost every spring if you want. I'd picture the same thing with styrofoam and mealworms to feed backyard chickens or farmed fish.

There's also a larger, similar species, "superworms" that can reportedly do the same thing.

The suggestions above for re-use (especially for insulation) are probably the best option, but there's one kinda weird use-case - albeit one more suited to a situation where you have a continuous flow of material to get rid of - feed it to mealworms.

They have a combination of gut bacteria and digestive enzymes that can break down, digest and metabolize polystyrene. Their droppings can be used as fertilizer, much like worm castings, and the mealworms themselves are technically edible. Myself I don't think I could get past the "eww" factor of that, but they make a nice high-protein feed for chickens, ducks or fish.

Direct injection of flue gasses into a greenhouse is an extremely dangerous idea and I would encourage you to fundamentally rethink it. Carbon monoxide is sketchy stuff and you don't want to mess around with it.

Some non-combustion methods of enhancing greenhouse CO2:

Alcohol fermentation
If you've got barley, make beer. If you have fruit trees, make cider or fruit wine. If you've got bee hives, make mead. The gas that bubbles out of it during fermentation is CO2. As a bonus, the "spent" material post fermentation can be used as animal fodder, which is what you're after in the first place. See here.

Compost
Aerobic compost gives off CO2 during the decomposition process. You need to be a bit wary here too, since CO2 isn't the only gas produced. Small amounts of CO, H2S and other sulphur compounds, and N2O can sometimes come off, and if you don't turn it enough and it goes anaerobic you might get CH4 too. But it's a whole lot safer than running a wood stove into the place. All of these other gasses are reduced the more you aerate the pile, so setting it up in one of those rotating drum composters and then turning it religiously would be the best bet. Gives off some heat too.

Animals
If you've got chickens/ducks/geese/goats etc, make them a little pen inside the greenhouse to sleep in at night. Instead of going to the gym in the winter, put a stationary bike in there and get on it and pedal. Bonus points if it's a bike like this. Double bonus points if it's also rigged up to spin the aforementioned compost tumbler.

Mushroom Cultivation
Fungal metabolism is more similar to animals than plants - they breath in O2 and exhale CO2. You might not get a huge quantity out of them, but every little bit helps.

These methods, even in combination may not generate enough for your needs, so some degree of air exchange with the outside will still be necessary. But you don't want to lose the heat by pumping in cold winter air, so you'll need to look into heat recovery ventilation.

Yes it does work for mushrooms!

Oyster mushrooms can benefit from the meat substitution trend
This is an article about growing oyster mushrooms as a protein source in vegetarian and vegan diets, and it mentions this company using a mixture of shredded miscanthus and straw as their substrate.

Safe and sound: Decentralisation with Miscanthus giganteus
This one is about the more large scale industrial uses for miscanthus as feedstock for decentralized generation of combined heat and power, pulp and paper applications, and bioplastics. But it also contains a mention of using it for mushroom cultivation. Oysters again, but they also mention growing shiitakes on it, which is rather intriguing.