Cooloing towers?

[John Connor]

Why do cooling towers look like this?

Why not just a flue-gas stack? http://en.wikipedia.org/wiki/Flue-gas_stack

 

[PottedMeat]

looks like:

cooling tower - exchanging large amounts of heat with water vapor -> short & wide
flue stack - dispersing combustion products over a wide area -> tall

 

[John Connor]

So do coal fired power plants use cooling towers?

 

[SecurityTheatre]

So do coal fired power plants use cooling towers?

Yes, many do.

Any plant that uses hot water as a medium will have some means of coolin and recirculating water. Coal plants might ALSO have a stack for dumping the crap that burned coal turns into and some use the same tower as a combined cooling tower and stack.

Some plants just dump hot waste water into a nearby Ocean, but you can't do that without heating up the area, unless you're in an area that can handle it (a natural lake biosphere certainly couldn't).

Some plants use dedicated ponds for this, rather than towers, but it's not very common, because you need pretty big artificial ponds and they aren't super awesome environmentally, as far as I am aware.

 

[Mark R]

Cooling towers need a large internal cross sectional area to ensure good cooling capacity. They also need large height for the same reason.

Early designs were cylindrical or rectangular. However, the characteristic hyperboloidal shape is now used as it provides the best balance between strength and material requirements.

 

[John Connor]

Cooling towers need a large internal cross sectional area to ensure good cooling capacity. They also need large height for the same reason.

I thought that. How do you know so much about cooling towers?

 

[Mark R]

I watched a show on discovery channel once.

 

[Brian Stirling]

I suspect the shape is also designed to make use of the heat as a means of pulling air up the stack in somewhat the way the coke bottle shaped glass of an oil lamp is used to pull more air into the burner area to increase oxygen flow to increase brightness. They are something like a kind of inverted velocity stack.


Brian

 

[ratjacket]

Not all cooling towers look like that

they are every where from cool stores, metal foundrys to large buildings for air conditioners

many styles and types

Evaporitive condensers are another form of a fancy cooling tower

cool the water and send to a heat exchanger or direct cooling

or cool a tubenest/bundle with water

water evaporates and removes heat

hot water is passed over a large surface (usualy via a medium) and is cooled with air flow

its takes as much energy to evaporate the water as it does to heat it to the point of evaporation

the down side is as you heat and evaporate the water the solids are left behind, which increase overtime leading to scaling on hot surafaces which inturns insulates the material you are trying to cool

to over come this you need to bleed water from the system and make it up with fresh water and/or apply anti scaling chemicals

another down side is warm water likes to grow bugs thats cause fouling and or disease

Not only can water corrode a system some of the bugs like to munch on your metals aswell