Loacation of makeup for cooling tower
Loacation of makeup for cooling tower
(OP)
For a new facility, the fresh water source is about 300ft from the cooling tower so I would need to run that length of pipe for the makeup. However, I could avoid that pipe if the makeup is injected in the return line.
Is there any reason why this is not a good idea? The water flow through the cooling tower would be increased by the makeup water, but it does not feel as being a big problem, considering that the temperature of the makeup water will be lower than the temperature downstream the cooling tower and the flow rate would be proportionally small.
Thanks for any comment.
Is there any reason why this is not a good idea? The water flow through the cooling tower would be increased by the makeup water, but it does not feel as being a big problem, considering that the temperature of the makeup water will be lower than the temperature downstream the cooling tower and the flow rate would be proportionally small.
Thanks for any comment.





RE: Loacation of makeup for cooling tower
However, I suspect that in practice you will not notice any difference because of the large difference in the flowrates of the return water and the makeup water. The only way to be sure is to run the numbers, and your cooling tower supplier should have software that could calculate this for you.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Loacation of makeup for cooling tower
I assume that you are controlling makeup flowrate by a level device in the tower.
Yes, you may save the cost of underground pipe, but you now have to get a signal to the valve supplying the makeup water.
This 300 ft distace, of course, will increase the expense of the system over the "tried and true" ball-float device commonly used in this application.
You may not have the significan savings you expect.
My opinion only
-MJC
RE: Loacation of makeup for cooling tower
Point being, both Katmar's observation and mine above are minor in the overall scheme of things, if faced with the need to inject at that location, other factors being equal, I would select the supply line to put the make up into.
The point is made more as a point about the thermodynamics of it all rather than the practicality. If you have to pump it 300 ft to get it to the tower, you may have enough head already, and running an instrument pair is less expensive than running pipe. IMHO.
rmw
RE: Loacation of makeup for cooling tower
RE: Loacation of makeup for cooling tower
RE: Loacation of makeup for cooling tower
RE: Loacation of makeup for cooling tower
In reality, that level does not need to be controled by a level controller. Setting make-up rate to a fixed flowrate and allowing the (oil) skimmer blades for blow-down achieves the same result. Cycles of concentration can be adjusted by increasing or decreasing water make-up. Level is self regulating. Independent High / Low level alarms are needed advise of an unusual operation.
RE: Loacation of makeup for cooling tower
RE: Loacation of makeup for cooling tower
certainly letting the tower overflow is an easy solution. Anymore, though, the cost of water is increasing, especially treating before going to the city or river (or where-ever). That's why I've generally seen CT that try to avoid constant over flow. We didn't use cooling water in many oil situations, so I don't have experience with oil skimmers.
(I've been mainly in food plants)
RE: Loacation of makeup for cooling tower
A clarification on setting the rate is due. You can set the inlet flowrate and adjust it for cycles of concentration (based on lab results) periodically. Excess water will overflow as CT blowdown needed to maintain cycles of concentration.
As an alternate (method #2), you can set and adjust the CT blowdown abd allow a level controller to make-up water. The blowdown rate is set to maintain cycles of concentration.
Now that the process was written out, I realize that method #2 is much better in controlling level. Blowdown from a CT is a small fraction of the make-up rate.
RE: Loacation of makeup for cooling tower
Anybody has an opinion about this?