free html hit counter Peak Oil Debunked: 291. NATURAL AIR-CONDITIONING

Friday, April 21, 2006

291. NATURAL AIR-CONDITIONING

By accident, my apartment has this strange natural air-conditioning. I noticed it when I first moved here. Every summer when it gets hot, I just open the front and back windows, and an incredible draft blows through. The blow rate is roughly equivalent to the medium setting on my 45 watt fan.

It blows constantly, always in the same direction, and I wondered about it for quite a while. The explanation seems to be this: Out back there's a black asphalt parking lot, which is usually about half full. The air rises off the asphalt, creating a convection current which draws in cool air from the shaded courtyard at the front of the building.

I spoke to some people, and apparently this technique has a long history. The romans used it, and it's a classic motif of middle-eastern architecture -- often enhanced by adding shade, trees and water in the courtyard, and tall convection chimneys.

These ideas are catching on in the architectural community. One example is the Eastgate Center in Harare, Zimbabwe:
Eastgate Center

From an article on the Eastgate design concept called Learning from Termites:
Mick Pearce's Eastgate, a mixed-use office and retailing high-rise built in Harare, Zimbabwe, in 1995, is particularly innovative in the way it responds to issues of sustainability. It is a biomorphic project modeled on a bioclimatic control of a typical termite mound that is to be found in the savannah of the countryside.

[...]

...ventilation running costs for Eastgate are a tenth of those for a comparable air-conditioned building. It uses 35 percent less energy than the average consumption of six other conventional buildings in Harare, and the client has saved $3.5 million on a $36 million building due to the fact that no air-conditioning plant had to be imported.
Another example is Portcullis House in London, an office complex for members of Parliament. It uses no chillers and consumes less than 30% of the energy of a conventionally designed building. Note the convection chimneys:
Portcullis House

Another low-tech scheme:
A plan to use cold water from deep in Lake Ontario as a natural coolant in downtown Toronto, Ontario buildings is a step nearer to reality. The Toronto District Heating Corp., the nonprofit utility behind the plan, has received a large equity investment by Canada’s fourth largest pension fund.

A new corporation, called Enwave, will be formed, to be held jointly by the City of Toronto and a subsidiary of the $36-billion Ontario Municipal Employees Retirement System (OMERS).

The investment by OMERS clears one of the biggest hurdles facing the project, which already has environmental approval from the provincial government.

The $120 million project will draw frigid water from more than 60 metres deep down in Lake Ontario, where it maintains a constant five degrees Celsius year-round. The water will be used to chill the water that presently cools downtown buildings, drastically reducing the amount of electricity needed.

A 2.6 km intake pipeline will be constructed, at an estimated cost of up to $45 million, to draw water from the lake, as well as a distribution pipe in the city's downtown core.

The plan could reduce carbon dioxide emissions by 40,000 tonnes annually and should be in use by 2010.Source
A pdf from the IEA on this topic: Avoiding the need for Active Cooling - The systems/whole building approach
-- by JD

8 Comments:

At Friday, April 21, 2006 at 12:37:00 PM PDT, Blogger HedgeFund said...

The use of cold water (sea or lake) via a *closed-loop* system to meet heating & cooling needs has been in use at Cornell (Lake Cayuga very quickly gets some 370+ feet deep) and on the Big Island. Honolulu is spending some $100 million on building a similar project.

Homeowners can do the same thing with a properly installed heat pump system -- preferably with vertically installed piping. As energy prices rise, these *simple*, but capital intensive solutions become very economical.

Until recently, these types of projects had such a long payback that they made little economic sense. Why build a house with an expensive heat pump system if you're just going to sell the home in 5 years? I guess these *green* energy solutions are the silver lining in the cloud of higher energy prices.

 
At Friday, April 21, 2006 at 3:56:00 PM PDT, Blogger diemos said...

Back when I was living in Ithaca the greens were still fighting against this, arguing that it would kill off the fish.

Do you know how the politics finally got resolved?

 
At Friday, April 21, 2006 at 4:03:00 PM PDT, Blogger Override367 said...

I think it's ironic how much the organized environmental movement has hurt the environment (anti-nuclear lobies anyone? because we all know coal is *sooo* much better for the environment than nuclear)

 
At Saturday, April 22, 2006 at 1:08:00 AM PDT, Blogger Chris Vernon said...

I've had a meeting in Portcullis House in the middle of last summer - 25C outside and the room was comfortably cool.

I don't think anyone doubts that it is possible to run society far more efficiently than we do now. The problem is that we certainly don't have the economy or energy to replace the nation’s buildings with efficient ones. So as nice an example this is, don't let it kid you that 15 years from now when the UK has decommissioned much of it's nuclear fleet, decommissioned a third of the coal plant and run out of North Sea gas we'll still have comfortable offices.

 
At Saturday, April 22, 2006 at 5:34:00 PM PDT, Blogger nick said...

For clarification, currently ground source heat pumps currently only need between 3-5 years to make the money back from the original investment. Not too bad even if you're selling in 5 years I guess.

 
At Saturday, April 22, 2006 at 6:57:00 PM PDT, Blogger allen said...

Livescience has an article about a zero heating-bill house built about 25 years ago. Nothing startling or leading edge about the place, just a house with a couple of additional design goals.

Read about it.

 
At Tuesday, April 25, 2006 at 9:19:00 AM PDT, Blogger nordicnomad said...

A couple of other examples of simple technologies we have abandoned in favor of a brute-force approach to indoor climate control:

If you look at older victorian houses with their high ceilings they often included small windows above interior doors that could be opened to allow a draft like that described in the original post.

Where I live (5000ft elev. in Southern Utah) older houses usually had a shady porch on the north side for sitting during the hot summer, and nearly all houses up until the 60s or 70s had awnings over the windows. One can be quite comfortable here with just the aid of awnings and curtains to reduce daytime heating and a fan to pull in our cool, dry nightime air.

Instead 95% of the houses built are standard plans with a minimum roof overhang and no awnings and many people are even putting in central air conditioning instead of using the more efficient evaporative (or "swamp") coolers that were standard on houses built in the '70s - '90s.

 
At Friday, August 18, 2006 at 6:39:00 AM PDT, Blogger kwalliander said...

It would be even more efficient to have air pipes in stead of water pipes running over the bottom of Lake Ontario. In that way the coolant (air) could be pulled up by convection towers (which requires only sun heat to work)in stead of energy consuming water pumps.

 

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