The bigger a dome gets, the better it's energy efficiency.
Thank you for viewing my entry. I will post Instructables for all of the different aspects of the project as we complete them.
When I am asked about building an aquaponics center that has an area of almost 8,000 square feet, I always have the same answer. With domes, bigger is better. There are several reasons.
In "Critical Path," under Geodesic Dome efficiency, Buckminster Fuller says:
"Every time the linear dimension of a symmetrical structure is doubled (ie. 1 -> 2) the surface area of the enclosure increases at a two to the second-power rate (i.e., 2^2). Wherefore, every time a geodesic dome's diameter is doubled, it has eight times as many contained molecules of atmosphere but only four times as much enclosing shell--ergo, each progressive doubling of dome diameters halves the amount of enclosing surface through which each molecule of interior atmosphere may either gain or lose energy as heat."
With a 100' diameter dome, we will have almost 8,000 square feet to set up our aquaponics system. However, if we halve the diameter, knocking it down to a more realistically imaginable 50', we quarter the floor space, now not quite hitting 2,000 square feet.
Couple that with it being twice as hard to heat and cool, and you may begin to see the picture.
The prize money rounded to $100 (with tax:)
1760 6ft. 2x6's - $2800
616 Hubs - $25,000 *note* I edited this up from $5,000 as I got the quote back after contest closed
8,000 sq ft. ETFE exterior grade - $8,000
8,000 sq. ft. ETFE interior grade - $4,800
1.5' Concrete Stemwall - $1800
Concrete for Papercrete - $2700
Papercrete mixer - $200
The aquaponics setup is going to fall outside of the bounds of this prize money, it will be used on the structure. Fortunately for me, between the many team members we have a lot of easily useable parts. We also have earth moving equipment, irrigation supplies, an already running irrigation system, tools, etc. The aquaponics will begin in one area, near the pond, and expand out as we get more materials.
When we finish filling the bottom, we will build floors along the north wall, and continue expanding upward.
This dome will have two exterior types, papercrete, and ETFE.
Papercrete is an excellent insulator, cheap, light, and made largely from waste paper. The local Post Office will allow me to take theirs, which amounts to a couple of dumpsters full per week.
ETFE is the top of the plastics pyramid, and only this year has the price come down to make it realistic for use by you and me. The Eden Project in England has six massive domes all covered in ETFE. It allows them to have a tropical rainforest, arid desert, and temperate forest, all in different domes. ETFE is supposed to last at least 25 years, 8 times longer than conventional greenhouse plastic. When it wears out, it's 100% recyclable.
If this were to be something besides a greenhouse, we would use papercrete for the entire thing and it would cost significantly less.
And that is really the point of this whole project. Many families and extended families around the world would like to have super strong, energy efficient housing and food production facilities, but it's not going to happen in square buildings, or small domes. By building one this large for less than $25,000, even with expensive materials, I am showing the makers of the world that it's time to move up into the next era of buildings, and leave our boxes behind.