
This tech eliminates the need for water for air-conditioning of buildings - tkhdi
http://www.thebetterindia.com/56439/air-conditioner-water-conservation-green-india-building-systems-and-services/
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pcl
TLDR: the article discusses a geothermal heat sink, instead of the typical
evaporative heat sink.

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psheets
Click bait title

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zwily
Seriously... geothermal has been around for a long time.

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jbob2000
Am I missing something? I've never heard of using water for A/C, is using
freon and other refrigerants a western thing? Do refrigerants not work as well
in India?

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yardie
Yes, industrial chillers use water. Water is much more efficient at
evaporative cooling than just air so you can cool more refrigerant in a much
smaller space.

Most skyscrapers will keep the chiller on the roof or in the basement. And
that is enough to cool the entire building. The domestic air cooled condenser
in most homes and small offices just don't scale.

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jbob2000
Oh, cool! Thanks for the info. Is it a closed system? Does the water need to
be replenished?

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cdr
They are definitely not closed; poorly maintained, the water vapor they output
can spread pathogens for miles. Cooling towers were blamed for the recent
outbreak of Legionnaires' disease in New York City.

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yardie
I wouldn't doubt it. Even a small domestic AC can be mold city if not cleaned
regularly. It's a warm and moist environment just perfect for all types of
bugs.

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psheets
Not really anything new...

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CyberDildonics
Something I haven't yet understood is why is it not possible to pass air
underground to cool it and cycle it back into the building, giving air
conditioning with the day to day cost of running fans?

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jetengine
It exists, it's called a geothermal heat pump / ground-source heat pump.

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CyberDildonics
That typically refers to cycling water underground and using it to immerse one
side of a heat exchanger, does it not?

I am wondering why cycling air directly with no heat pump isn't used more
often.

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JshWright
Because air is not very good at moving heat, so it's more efficient to use
water or some sort of refrigerant.

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CyberDildonics
In the context of a heat pump yes, but what I'm saying is why not cycle the
air of a building underground directly? I would think lots of air would be
moved for very little energy and could be put through an underground radiator
with lots of surface area.

Even with a heat pump, air has to be passed over the evaporation coils anyway.

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JshWright
If you're trying to cool a building, the goal isn't moving air, it's moving
heat. Pushing air around is a convenient way of moving that heat around inside
a structure, but it's a lousy way of changing the total amount of heat inside
the structure.

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CyberDildonics
But again a heat pump is still running air over the evaporation coils so how
does that end up better than having a radiator underground?

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JshWright
The amount of surface area you would need to have underground to expose the
air to would be tremendous. The reason heat exchangers work is because they
substantially concentrate the heat (or the 'cold'), reducing the surface area
needed.

