In the previous post, we talked about how we could reduce cost if we reduced weight. Weight is tied to work which is tied to energy which is tied to the economic cost of procuring, distributing and using that energy. When we look at any item we use every day, such as a light bulb or a mirror and ask if that same functionality is provided by nature at no cost, the answer is, yes, some of the time.
Light is provided for free by the sun, moon and stars. Even in the middle of the night, there is often some light, enough to see one’s way around. Therefore if we wish to minimize the weight of items we use to reduce cost, we need to find a way to make better use of this natural light.
In a temperate three season climate (summer, spring/fall, winter) housing is often built for the most extreme temperatures and conditions encountered. That is, a house needs to retain a livable environment whether it is -40C or +34C outside. In addition, it needs to be rain, snow and wind proof. The net result of these parameters is that the roof is solid and fixed, the windows comprise a minimum of the wall space and the walls themselves are also fixed and relatively thick to contain the insulation, the exterior cladding (brick or siding) and the interior wall (often drywall).
But what would happen if we could shed these extra layers when the weather turned warmer, throw off the solid roof, and allow a little light and a nice breeze to come through. In Canadian winters we dress warmer by putting on a coat, hat and gloves or mittens, and then shedding these layers as it gets warmer. What would happen if we could do this with a house? The answer that appears from this question (apart from the details) is that we could do the same thing with our living accommodations. That is, we could have a thick (~3″) outer layer for in the winter, a middle thinner layer (perhaps 0.5″ or less) for the spring and fall, and then just a mesh layer (to keep out the bugs) with a clear plastic top to keep out the rain as the inner layer.
The importance of this approach is that the layers that are needed could be used as the climate determines. The closer one gets to the equator, the less cold it gets in the winter, so at a certain point only the spring/fall and summer layers would be needed. If all three layers are integrated, then a single design could be manufactured and used as needed.
Thus we could move a solid, fixed house (below),
to something that is yurt like, but more aesthetically appealing and high tech. The picture that comes to mind is that first, the horizontal profile would be circular, as a circle provides the maximum area with the minimum amount of circumference and therefore material. The amount of material is tied to weight, weight is tied to work, work to energy and energy to cost, therefore to reduce or minimize cost we want to make use of the shape which provides that, which is a circle.
By the same token, the vertical profile would also be a circle. This is different than a yurt, as a yurt typically has a horizontal wall. The end result is that we have half of a geodesic dome. This is fortunate, as when we start working with materials we realize that it is easier to find and work with shorter pieces (such as would be required in a geodesic dome). With that we get something like the following1, below (a 3D model of a C60 molecule cut in half, horizontally).
Notice that the bars are all roughly the same length and that the joints could also all be identical (the position of the mounts for the bars could be adjusted to accommodate different sized domes). This is what we want to make better use of materials. It is easier to find shorter lengths than longer.
Finally, if we were to make use of designs already existing in nature, one other picture that comes to mind is that of a tree. The outside shape is what we are after. Thus, if we could throw a tarp over a tree, lower the trunk to the ground so the height was just what we needed, and then remove the tree part, we would pretty much have an optimized shape.
Therefore, instead of lowering a standard maple (which has the dimensions we would be after), we could simply raise the “floor” by building a platform underneath it. The interesting thing about a tree is that the main sunlight capturing leaves are towards the outside. The further we go towards the inside of the leaf canopy the more sparse the leaves become. Thus, if we could figure out a way to live in between the existing branches and leaves while removing a minimum of the leaves and branches on this inside, we wouldn’t even have to build the structure, only the extra canopy we would need, being the delicate human beings we are.
In summary, this discussion is not designed to provide a clear cut answer. However, it has provided us with a few more parameters, different from those typically used. The first was that a circular profile (both horizontally and vertically) results in the least amount of material used with the maximum amount of interior space (this also results in the strongest structure). Second, a geodesic design means that the struts or bars could all be the same length and shorter than otherwise in a typical structure with a straight horizontal and vertical profile. And third, although some creativity might need to be used to imagine a tree as a “home”, the outside shape of many deciduous trees in temperate climates is already tried and tested. All we want to do is take the innermost part of that shape and design (already pre-filtering the sunlight, with greater light available in the winter months!) and construct a livable space. Talk about being ecologically friendly!
So, what are your thoughts? Does this discussion make sense? Do you see how we can make use of designs already tested in nature to minimize the materials we need, reduce cost and be more ecologically friendly, all at the same time? Perhaps there is a reason for this connection. Not sure. At any rate, if you would like to comment, please feel free to do so. Email me at cbos [at] tnoep [dot] ca, and I will post the best comments here. Thanks for reading.
After writing the above, I thought that a number of these ideas meshed quite well (no pun intended). Janine Benyus, in her book Biomimicry mentioned that nature does not use distinct joints. Rather a more gradual transition is preferred. This results in lighter and strong joints.
When we remove corners a number of possibilities opens up. It would be easier for the surface of a geodesic dome to be covered naturally with vegetation without any corners showing. What came to mind was a double layer to the dome with a mesh in between that would support the growth of something like moss. On the outside could be a growing vine, like a grape vine, that was prolific, and would automatically take a hold of the existing structure and fill in the gaps. Having a spongy moss like layer about six inches thick surrounded by grape vine like plant growth would provide insulation from the sun during the hot summer months and potentially more light to the interior in the winter months, depending on how the inner layer was formed. In addition if an edible vine was used (like grapes), the external layer of the dome could actually produce something edible! Again, this follows nature lead, as often the same structures are used for two or three purposes.