Quote:
Originally Posted by briantech
I agree with you that as fossil fuels get more expensive, atlanta's suburban model of growth is going to come to an end very abruptly, and people will collapse back into the city centers to be closer to things.
How in the world you translate that to "we can only make it if we build short squat buildings" is beyond me.
What has more population density per square ft: 50 floors of condos or 15 floors of condos?
If we're talking about reducing energy consumption by getting people living closer in the cities, its kind of a no brainer that the taller you make the buildings, the more people will be able to live in them.
|
There seems a myth circulating around that the taller a city becomes, the more energy efficient it becomes and the less infrastructure it needs.
There is in fact a reverse bell curve for infrastructure needed: too low density and short (as with suburban sprawl) and your infrastructure becomes too spread out and unnecessary, too tall and the amount of infrastructure needed per square foot increases exponentially. Ever hear of the law of diminishing returns?
"The city is paying a lot, and sometimes it does impoverish itself -- which is apparent when you see the wastelands of parking that the skyscraper creates around itself. The taller the building goes, the more it needs to be supported underneath. If you don't have the support it starts to be parasitic on the surrounding area. If you do have the support, fine. But it's extraordinarily expensive, and the ridiculous thing is that there's no reason for this expense. Why pay for it? You're paying for it because it's a totem -- it's like Northwest Coast totem poles. It's a religious totem from the mind of Mies van der Rohe and Le Corbusier. We're worshipping and building these totems because they have become part of our culture."
"The disadvantage is that a skyscraper is like a tree with leaves -- what you see up top represents something even bigger down below. The skyscraper has to be fed. It exists as a concentration of nodes in the network -- the electricity, the sewage, the transport. So there's a concentration of nodes there, and when you concentrate nodes things become singular. Too many, and the thing becomes unmanageable. You have to invent more and more technical solutions in order to take care of this over-concentration of the network."
(
http://www.2blowhards.com/archives/000732.html)
In addition, the amount of energy expended for construction and operation of skyscrapers also increases as it gets taller.
"The skyscraper as a concept is a product of the industrialized age, made possible by cheap energy and raw materials. The amount of steel, concrete and glass needed to construct a skyscraper is vast, and these materials represent a great deal of embodied energy. Tall skyscrapers are very heavy, which means that they must be built on a sturdier foundation than would be required for shorter, lighter buildings. Building materials must also be lifted to the top of a skyscraper during construction, requiring more energy than would be necessary at lower heights. Furthermore, a skyscraper consumes a lot of electricity because potable and non-potable water must be pumped to the highest occupied floors, skyscrapers are usually designed to be mechanically ventilated, elevators are generally used instead of stairs, and natural lighting cannot be utilized in rooms far from the windows and the windowless spaces such as elevators, bathrooms and stairwells."
http://en.wikipedia.org/wiki/Skyscraper#Sustainability
The sweet spot, where infrastructure is the most efficient and the least energy is expended, is in the 4-7 story range, which is exactly why I'm advocating that.