Columbia Uni. proposes skyscraper farming in cities.

[CJvR]

Economy would sink this in a hurry. It will be cheaper to use ecological transport, even horse and cart I suspect, than to use huge costly buildings on the most expensive land in the world to grow vegetables. In theory these vertical greenhouses will work fine but in practice?

[Molyneux]

Economy would sink this in a hurry. It will be cheaper to use ecological transport, even horse and cart I suspect, than to use huge costly buildings on the most expensive land in the world to grow vegetables. In theory these vertical greenhouses will work fine but in practice?

Well, that rather depends on if we stop propping up the farmers these would be competing against, doesn't it?

If we got rid of the subsidies to farms, I think it's a fair bet that these farms would be at least as inexpensive as standard farming.

[Darth Wong]

Farm subsidies: Never have so many given so much to so few.

With apologies to Winston Churchill.

[Turin]

Ideas in sustainable architecture are beginning to gain a lot of ground here in the US, among architects at least. At my fairly large firm, many of us are in the process of becoming certified "green designers" and an increasing number of our projects are incorporating major sustainable design elements. While my firm doesn't do skycraper work (mostly doing healthcare/pharma work), it is something of a personal interest of mine.

The skyscraper has a somewhat counter-intuitive inherent sustainability as a building form -- the vertical farm is really just an extension of this idea. It maximizes useable space with a minimum amount of ground-impact. It has a potential economy of scale with respect to water and energy use.

Questions were raised as to available energy on a vertical farm. The biggest energy cost for a skyscraper is in cooling. Even during the colder months, most skyscrapers require a considerable amount of cooling with only minimal heating in inhabited spaces performed by local "reheat coils." A vertical farm can maximize the energy received from sunlight by having a narrow profile (N-S) which allows the sun's rays to reach as far back as possible.

Broomstick mentioned the heat problem that might arise. First, the narrow profile I've mentioned above can improve cross-ventilation in the building. Second, a "thick wall" system can be used to create vertical airflow (this can be done in a way to prevent fire chimneys), again tapping into that same source of solar/thermal energy that ordinarily is considered waste to drive convection currents in the building.

In the US, naturally ventilating skyscrapers like this has been frowned upon for a combination of factors: 1) cheap energy, 2) large summer-to-winter and day-to-night climate swings, and 3) mushy-assed American office workers who got used to having the temperature constantly and rigidly 68F year-round due to factor #1. The nice thing about the vertical farm application is that you're going to be a lot more tolerant of "uncomfortable" temperatures and higher temperatures can potentially help you improve yields anyway.

Several others have mentioned waste disposal. Obviously a vertical farm is an excellent resource for this, but I would also like to point people in the direction of something called a Greenhouse Ecosystem or Living Machine (I think the latter is a trademark). A good-sized living machine on top of a skycraper can easily handle the typical wastewater produced by a building of this size. There have been a number of very successful projects in this vein -- the trick is finding clients who actually want to take on this scale of project for their building!

[Ted C]

* Year round crop production in a controlled environment

* All produce would be organic as there would be no exposure to wild parasites and bugs

* Elimination of environmentally damaging agricultural runoff

* Food being produced locally to where it is consumed.

Well, that's absurdly optimistic. No bugs or parasites? He's dreaming. We can't keep rats and roaches out of urban buildings, so there's no reason to think we can keep out other pests. They'd probably be easier to control, but they wouldn't be absent.

Unless they put extensive filtration and collection systems on the building's sewer output, there will still be "runoff" from the plant beds. Any fertilizers or other agri-chemicals used have to go somewhere.

Producing food locally is nice, but if this giant greenhouse system costs signficantly more to operate than your typical rural farm (which wouldn't surprise me considering the cost of contructing the building alone), it's not going to bring down food costs, meaning it will fail miserably.

[Molyneux]

* Year round crop production in a controlled environment

* All produce would be organic as there would be no exposure to wild parasites and bugs

* Elimination of environmentally damaging agricultural runoff

* Food being produced locally to where it is consumed.

Well, that's absurdly optimistic. No bugs or parasites? He's dreaming. We can't keep rats and roaches out of urban buildings, so there's no reason to think we can keep out other pests. They'd probably be easier to control, but they wouldn't be absent.

Unless they put extensive filtration and collection systems on the building's sewer output, there will still be "runoff" from the plant beds. Any fertilizers or other agri-chemicals used have to go somewhere.

Producing food locally is nice, but if this giant greenhouse system costs signficantly more to operate than your typical rural farm (which wouldn't surprise me considering the cost of contructing the building alone), it's not going to bring down food costs, meaning it will fail miserably.

Again: we currently subsidize farms HEAVILY because, especially including the costs of transporting food, farming is a high-cost, low-profit business.