“Ecovillage Greenhouse Redesign Beta” or “Feeding the 5000… eventually”


Homestead 1In my previous article, I had discussed the Tir Tairngire Ecovillage project as the grand scope of things. I had decided to rush parts of it, simply because it was already after midnight and I knew I’d have to re-address certain facets of the whole thing, which I’ve been doing for nearly a decade and a half. I had real problems with the 45d angle that has been forever evident in the location of my site, and it would really be hellishly inconvenient to rotate lots, adjust roads, or search for another site when I already OWN this one. It’s just not practical. That said, I’ve decided to reassess one of my biggest concerns: The 1/2 Acre (~0.2 ha) Homestead Greenhouse. I also was faced with the challenge of angling the buildings to make best use of the lower angle of the winter sun in the northern hemisphere.

Those little pyramids on stilts are great and all, since the focus of my research for next year when I build my own greenhouse Homestead 4units attached to my garage to prove the technology, and then apply that research to the purpose-built greenhouse to see if there is any advantage. I really think that, for this environment, I can do better. That said, I think I just did. 😀

lot redesign 3What was really worrying me is that we need to build a sufficiently large greenhouse (as part of this particular version of the modular design units) to not only grow all the food for the household that they could ever want but enough variety to keep them from revolting. The last thing I want is a group of peasant farmers to lay siege to my castle (Wait… I get a CASTLE?!) with pitchforks and torches. As cool as that would be, I can’t imagine it ending well for anyone, much less their benevolent dicta… er… community leader. We also need excess to sell/barter for local goods, materials, labour and so on. Those 4 little greenhouses would do the trick, but I figured a re-design would settle some things. They were also in the wrong place.

Greenhouse 1For contrast, the smaller buildings are 15′ by 15′ (~5m square), with a 10′ (~3.5m) stemwall and a 8′ (~2.5m) tall peak on the pyramid. The building is also dug down 4′ (~1.5m) to help sequester more of the natural earth heat into the building and get away from ground-frost leeching away the warmth from the plants.

This new, larger building is 31′ (~10m) wide (as opposed to ~3m) and is 70′ (~21m) long. It is also a full 6′ (~2m) into the soil, with retaining walls, ditches and sumps keeping the water table down, though it’s pretty low as it is already. The angle on the left-hand side (in this case South-East. The footprint, by extension, is 31′ (~10m) by 70′ (~21m), which ends up being almost 2200 square feet (200 square meters). Not only that, but this greenhouse is 16′ (~5.5m) from the bottom right hand corner to the top of the wall (you can see the horizontal line delineating the straight wall to the curve). The curve, itself, raises an additional 10′ (~3m), making a total of 26′ (~8m) of building, and 20′ (~6m) above ground. This building is huge, and the angle of the slanted glazing is perpendicular to the noon-time sun in the pits of winter, so we should get some really good solar gains. The best part is, due to the temperature differentials and shape of the dome, we will get some natural convection currents to circulate air around the whole building and equalize the temperature across the whole building. When we get involved in building scaffolds, loose grills (think of the mesh decks on submarines. It will be a strong-enough platform and let light through, to boot!

lot redesign 1You can see this larger greenhouse here, poking through the trees, amid a massive redesign of the lot to make better use of the sun. I’m not AS worried about heating the homes, since woodstoves and fireplaces can make due (especially when we get involved in coppicing trees for firewood). My concern was getting as much natural light into the greenhouse as possible, which is why I switched them around, and may even build the workshop ONTO the cottage, which will both eliminate two cold walls and make it easier to work in the winter, thereby avoid having to leave to travel from one building to another. That remains to be seen. Furthermore, this new layout actually FREES a great deal of space on the site to allow for a 60′ (~20m) swath of free space (seen below) for private/resident use. Gardens, trees, a playground, a koi pond, anything. Exciting!

lot redesign 2My new layout has the HUGE greenhouse, has everything going for it, and though it could be a monster to build, and pricey to erect/install, we are looking for a sense of real permanence here. We need structures that will LAST, so we may actually go with aluminum or steel structures, heavy acrylic, glass or plastic panels and metal forms/frames. Once we build two or four of these units commercially, we can then worry about building them with timber-frame construction or something more sustainable.

We need to start from a place of stability and build a proverbial sky-scraper upon that solid foundation. Designs like this may be the key.

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4 thoughts on ““Ecovillage Greenhouse Redesign Beta” or “Feeding the 5000… eventually”

  1. I may have missed it…what about a cooling mechanism (door plus windows and maybe a fan for airflow) for the summer months?
    Too much heat in the summer can kill faster than a frost.
    Or maybe have a dedicated greenhouse for tomatoes(op) and cukes
    A couple separate ones for zuchinni and winter squash(they must be separated in order to harvest seeds)
    Having one that is suitable(year round) for bee keeping would be great too.
    I am finding, even though I have lots of bee attracting plants, that I am needing to pollinate plants myself because there just aren’t enough pollinating insects to do the job!! 😦
    (I could have had an amazing crop of winter squash this year had I realized that was the problem eariler 😦 )

    Like

    • One of the advantages of those big ol’ convection currents is that you can have tackle-operated (rope and pullies) hatches in several places, or a lever and some mechanical advantage to open different ones. Hell, for the energy required, some batteries and small motors could activate at the flick of a switch to open a whole series of hatches, latches and openings to allow proper ventilation.

      Be a relatively easy task, too, for a secondary curtain that can apply some shade and act as a light diffuser on the south-east facing sloped wall. Like a canopy, but this one is translucent, rather than transparent (parents, you can see RIGHT THROUGH ‘EM). This will act to dispurse the light a little better and shelter some of the light intensity from heating the space up.

      Having vents, and having lots of them, isn’t as important as vent placement. You need to have them in locations that will allow these passive convection currents work for you. Having some at ground-level and some at the top of the roof will create a wind-tunnel-effect and suck all the heat out. If we had little electric servos running on solar batteries, we could even have active thermometers that activate a circuit and open those hatches to cool off, closing them to stop the cooling process. That much is simple electronics.

      Incidentally, ANTS are better polinators than bees, but you get the side-effect of honey. Why not put a couple of beehives inside the greenhouse? It wouldn’t be a problem to separate some plants in separate transparently sealed rooms, but combining ants and bees would be a fantastic solution, I think.

      The real goal here is to eliminate as many manhours as possible, and the best part of hiring bugs is that they work for free!

      Liked by 1 person

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