Conserving Water by Condensing Steam from Cooling Towers

I've looked at this a couple of time myself.

The problem I have always found is that it become non-viable from a financial perspective.

It would take more energy to Condense the water back to a liquid state than the financial value of the water recovered.

Better would be to divert the heated water to use in the Water heating or Space heating. This would not elimiate the cooling towers but would reduce thier load and therefore lose less water to the atmosphere.

With a bit of Luck, someone on the forum will tell me I'm wrong, but most of the Mechanical services Engineers and specialists have so far agreed with this line of thinking.

Regards,
Sapper

Sameer point is valid. I suggest that the heat of the hot water may be transfered to liquid ammonia to vaporise it and drive an ammonia turbine to generate power. The economic viability needs to be studied. There are following aspects:

Higher head for CW pump

Maximum pressure ammonia can attain

water and power required to condense ammonia

Any such heat exchanger is to be associated with CW Treatment without chemicals to increase the heat transfer efficiency. Write to save@ecospecindia.com

Incidentally the system will reduce the blow down requirements by half. This is again a water saving. The system can be installed without reference to the vapor conservation

I never thought of that, but it seems like a good idea.To remove the latent heat from the saturated air would require a large surface area heat exchanger, but if properly designed, gravity should provide flow without need of pumps.Of course, you cannot recover all of the water, or it would be more efficient to simply use the heat exchanger instead of the cooling tower, but even half of it would be worth recovering.It could even be fed back into the cooling tower reservoir to reduce water and chemical consumption.

Go for it!

I saw once a report that how the cooling water from a nuke power station is being dumped back into the river while it's temp is over 100Celsius; naturally killing all the vegetation in its path.

If that's the same for the other power stations as well then it is criminal not to utilise it for heating or anything else for that matter.

But such is the thinking of the modern world leaders to whom nothing matters while there are other, often trivial, things to keep their popularity and their profiles running high.

Raising this issue is a very good one, however due to the lack of right financial back up from governments.

I'm afraid human kindness does allow in some parts of the world for people to carry on both live in slumps and drinking next to sewerage quality water.

It is a shame but a sad fact.

How do you dump "water" into a river at temperatures in excess of 100C?

Isn't that called "steam" ?

If you ever hear anyone ask:"Why don't they do so-and-so" the answer is always MONEY.If you can show a 5 year return on an investment, someone will buy it.

I am thinking along the lines of letting natural convection air flow cool the exchanger, not as effective as fans, but no energy consumption, and let gravity move the water , since cooling towers are mostly on the roof.Moist warm air rises.Cooler dense air falls.The principal is there. OK all you M.E's out there,Design it. If it were my field of endeaver, I would at least consider it.

Maybe one should view the water loss as compared to other uses. The green irrigation field next to the tower may actually loose more water,

At 2mm per day the irrigation may loose 20 cubic meter / ha / day.

1000 and more cubic meter on a small field of 50 ha.

Noble ideas Sganesh but I'm afraid misplaced. The cooling tower's task is to remove heat from some system. Removing the latent heat from the vapor plume to condense water will require transferring some heat plus the latent heat somewhere else. If there was a cost effective technique that didn't involve utilizing latent heat characteristics, I can assure you that a cooling tower would likely not exist there in the first place. Also, unless local conditions around the cooling tower have changed over the years, the cooling tower was built in a location that has plenty of water. Condensing that steam to get water at a site that has water seems to defeat your purpose.

My point is that by vaporizing that water at the cooling tower, more moisture is being made available for rain somewhere else. Transferring water from places that do have water to places that don't is where water shortages come in.

One idea I've always wondered about for co-generation, why not utilize a Sterling engines to run generators to reduce waste heat dumping?

Why not simplify the entire process and use an air-cooled condenser directly? A closed-loop cooling system completely eliminates water loss. It might not be ideal in all environments, but I'm seeing more and more of these devices being specified for new plants, mainly because of the expense of complying with environmental regulations.

I too have seen many new facilities specify Air Cooled units.

These are effective upto about 35-38degC depending on Humidity.

In places like Oz this becomes a problem through the hotter months.

There are Hybrid Towers which I will specify if I get to do another Data Centre.

These run as Air Cooled up to 30degC ambient and then a recirculating pump is used to spray water over the coils which then drains to a sump and is resprayed until no longer required.

Once the ambient temperature drops to below the kick in point, the water is sprayed until evaporated to elimiate standing water bodies and the associated biologicals.

The system then returns to Air Cooled mode.

The down side is that the system unually needs to be oversized by approx 5% to run effectively in Air Cooled Mode.

But I believe that the water saved would be worth the investment.

Regards,
Sapper.