how did they air condition the world trade center?

Answer 1

The same way they air condition modern skyscrapers.

At first you could put the AC unit on the top or under a grate beneath ground level, but pumping the air to all those floors takes too much power so when you get over 20 stories you need to have multiple AC zones. Then the building designer takes an entire floor and devotes it to utilities including AC and heating units. They do this at the rate of about once every 25 floors. The key idea is that you can only lift water so far; the pumps can't push hard enough against the force of gravity so you need a holding tank on a high floor and then you pump water from that floor. When you do this you need a large space on the floors so you might as well do the same thing when designing the AC unit. In fact engineers treat air handling units as if they are pushing around water and use the same math to calculate the flow and volume needed, just like they do for water.

This picture from Wikipedia: http://en.wikipedia.org/wiki/Image:World_Trade_Center_Building_Design_with_Floor_and_Elevator_Arrangment.svg
Article: http://en.wikipedia.org/wiki/World_Trade_Center
Shows the Technical Services floors, which held the AC units; you can look at a picture of the twin towers and notice that an off color band encircles each tower at the same height; this is because they didn't have windows on that floor. The World Trade Center used two technical floors in the middle, one near the top and one near the bottom; for an average of 1 per 27.5 floors.

If you look at the picture you will see the open office area in yellow, and the service core in blue. The ducts ran between floors in the service core and overhead across the yellow area. This way the entire building could be served. It was divided into 4 zones with each system independent of the other three. Usually the space behind and around the elevators is also used to run wires, pipes and air ducts between each floor.

The most common method used to actually cool the air is to use large water chilling towers where the water flows down the side of a tower letting it relase its heat. Then the water is chilled by refrigration units and incomming warm air is run over it. This cools the air which is then circulated through the tower zones.

The building was designed by Skidmore, Owings and Merrill: http://en.wikipedia.org/wiki/Skidmore%2C_Owings_and_Merrill

Answer 2

the use of HVAC, using the flow of air and recycle thru the use of water, to circulate around the building and returned it to recycle again, the use fire or smoke damper can hold the flow of suffocation.

Answer 3

I think it was potable water.....