USING POOL WATER AS A HEAT SINK Instead of cooling tower

[navas72]

Hai,

is it possible to use pool water (10m X 10m X 1m) volume pumped & recirculated to a water falls.the idea is to use this pool water in water cooled chiller instead of cooling tower. The flow rate required for electrical is 45CMH & inlet/outlet Temperature is 34/39 Deg C. The heat rejected is 192755 Kcal/Hr. the pool water is available at 32 Degc.
please guide me how we do the calculation to check is it possible or not

 

[IRstuff]

How are you going to maintain the inlet temperature without some means of cooling the pool water? This doesn't seem to compute, but you should do the calculation on how the pool water will lose the heat it gains.

TTFN

FAQ731-376

 

[navas72]

Here the pool water is pumped & spread into a water falls and the water comes back to the pool. so due to that the water will be expose to atmospheric condition there will be some heat rejections. the ambient wet bulb is 30 DegC.

 

[IRstuff]

So what's the difference? You are running a cooling tower, but you'll be losing 0.71 CMH, which will need to be replenished. So, you're running a real cooling tower.

TTFN

FAQ731-376

 

[cry22]

Sounds like a Dubai/UAE application with 30C wet bulb.

1. I worry about the chemical treatment of your water fall and pool. Lots of contaminated water in the surrounding environment.
2. Without some kind of fan (iunduced or forced draft), you will be vey limited in heat rejection, especially since your atmospheric temperature is close to saturation at 30C wet bulb.

 

[navas72]

Yes its in gulf countries . instead of cooling tower we thought to use this pool water as a measure of water conservation.
could you help me in doing the calculation like using a large water storage as a heat sink instead of cooling towers.

 

[rmw]

Cooling towers are specially designed to cool the water by a variety of means of exposing the water to the ambient air (baffles, fill, etc). Your waterfall(s) may or may not do a sufficient job of adequately exposing the water to the air in order to get the heat rejection that you need. Without knowing the extent of the waterfalls' capability to reject your heat load it is impossible to say other than to say that if it can reject enough heat, then it should work for you other than the makeup/blowdown issues that you may or may not already have with the pools.

See if you can figure out a way to heat up the water going to the waterfalls to your supposed Hx outlet temperature and see what temperature it returns at.

rmw

 

[IRstuff]

A big chunk of the heavy lifting of a cooling tower would be from evaporation. If there's to be no evaporation, then you'll need in excess of 9000 m^2 of effective convection area.

TTFN

FAQ731-376

 

[KiwiMace]

Not possible, and you have been given good responses. Water quality conflict is enough to give up on this scheme. Heat rejection will also be insufficient.

 

[cry22]

Try to see it diferently instead of being stuborn (sorry about the word stuborn, I could not a find a more diplomatic word) with the idea of absolutely using the waterfall instead of a cooling tower.

I can see you from here, you are pressed to come up with some serious LEED points, and you really want to contribute, which is nice, very nice on your part.

Can't you consider some type of chemical free water treatment? such as the Dolphin water treatment system.
Use your pool water for make-up to the tower. Those are the kind of green features I'd pursue instead of jopardizing the system's operability.

In addition, your blow-down will be reduced and chemical free. You could reclaim the blow-down for site irrigation (a big deal in that part of the world).

But I would not try to eliminate the cooling tower altogether.

 

[mauricestoker]

Have you looked into soil temperature? Geothermal may be possible, especially if you have land availability. Using the pool as a supplemental cooling source, perhaps with wet bulb control going against a buried, closed loop heat exchange, might be considered. If you have any large pipe volume of underground water distribution, that might prove to be a suitable secondary heat exchange.
I would add that if complete load cannot be satisfied, geothermal to reduce the load might still be acceptable.

 

[willard3]

ASHRAE has calculations for heat rejection from swimming pool surface in natatorium design.

It's mostly latent exchange and it's a lot higher that you would guess.