Dubai Tower generating 10x more energy than required to power it | Hacker News Reader

Dubai Tower generating 10x more energy than required to power it

designgeist.org

10 pointsthemichael11 comments

This is ridiculous.

The designer, David Fisher, makes more detailed claims here: http://www.dynamicarchitecture.net/dubai-project.htm

Judging by the drawings of his tower (http://www.dynamicarchitecture.net/schema/schema_big.htm), it's about 300 x 50 m. Ignoring the narrowing of the tower as it rises, roughly 20% of the area is devoted to wind turbines. That's around 15000 x 0.2 = 3000 m^2.

He claims that the average wind speed in Dubai is 16 km/h, or 4.4 m/s.

Assuming a Rayleigh distribution for the wind speed, the average power available as kinetic energy in the wind is (6/pi) * 0.5 * (density of air) * area * (average velocity)^3.

The density of air is 1.2 kg/m^3.

That's (6/3.14) * 0.5 * 1.2 * 3000 * (4.4^3) = 290 kW. If the wind turbines were 30% efficient, which would be pretty good for a vertical axis turbine stuck in a building, the yield would be 100 kW.

This ignores the narrowing of the building, the lack of wind near the ground, and obstruction from other buildings.

The building has around 50 m * 50 m * 60 floors = 150000 m^2 of floor space, so the areal power density is about 0.67 W/m^2.

To meet the claims of a 10x ratio between energy generated and used, the building can budget 67 mW/m^2. That might be enough to light a single LED in each room.

Oh, and the average temperature in Dubai is 27 C. I guess they can run the air conditioning when all the LEDs are off.

Excellent and humorous analysis. Thanks !

No, thank you, my good man.

As I've been thinking about it more, the most disturbing part of the tower design is not the low energy yield. It's far more alarming that this gets picked up as an exciting direction for development (judging by the discussion of the tower on TreeHugger, Inhabitat, and similar sites).

I desperately want us to figure out how to capture energy from renewable sources in an economically viable manner. If we don't do that, we are royally screwed. However, the central problem is not, for example, that we have no land for wind turbines or solar panels. The core problem is low power density. We need to be putting up the most efficient, cheapest turbines we can build in the windiest areas, not less efficient turbines in a not very windy area with the added costs of building integration.

It's not a good idea that won't quite work-- it's a terrible idea that's headed in the wrong direction. It's morons like David Fisher (the designer) who give conservatives a reason to say "Bah, that renewable energy stuff is a load of crap."

I agree. What we have with energy is a supply side problem. Yet all the thought energy of the public is directed toward the demand side (either reducing/conserving things, or changing the sourse). Yet if we were to solve the supply side in a sustainable manner, we would solve a whole lot of other things very very quickly.

Sourse? What the heck was I thinking ;)

I think "is expected to generate" is much more appropriate than "generating" since it doesn't exist yet. I would have been suitably more interested if it was real instead of a prediction.

"It will be continually in motion, changing shape and giving residents the ability to choose a new view at the touch of a button. The form of the building would constantly change as each floor rotates separately giving a new view of the building as it turns."

"Each floor, made up of 12 individual units, complete with plumbing, electric connections, air conditioning, etc., will be fabricated in a factory."

http://www.inhabitat.com/2008/06/09/rotating-wind-powered-to...

"In our buildings you can have breakfast facing sunrise, and dinner in front of a sunset over the ocean... without moving from your room."

http://youtube.com/watch?v=RzQazjw-4jI

Sooo... what happens when the residents on both sides want to have breakfast in front of the sunrise and dinner in front of the sunset? Maybe they need a social-voting aspect to the building...

Anyway, this is still ridiculously cool, whether or not it's practical. I want one.

This doesn't pass a minimal sniff test in terms of accuracy.

The solar energy impinging on the building will top out at 1kW/m^2, with an insanely optimistic 50% conversion rate, I can't imagine it generating more than 7500kW from solar.

That, by the way, isn't enough to run the hand dryers.

Don't worry about all that environmentally efficient stuff going on in the tower, most of the people who enter the building will drive there in $300,000 supercars that get 6 MPG.

There's the link with some actual info:

http://www.inhabitat.com/2008/06/09/rotating-wind-powered-to...

And how much extra did it cost to build the tower? This isn't free energy. It has a cost. Any serious analysis would consider how much energy we could get spending the same money on additional power plants.

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