Closed loop cooling water system maximum return temperature
Closed loop cooling water system maximum return temperature
(OP)
Hi, I have a question related to closed loop cooling water system. In many projects I have seen the cooling water return temperature is fixed at 45degC or max 50 degC. I believe that this has something to do with scaling in cooling water system. But can anyone tell me more as why is the maximum return temperature to be designed at 50 degC?
Thanks in advance.
Thanks in advance.





RE: Closed loop cooling water system maximum return temperature
RE: Closed loop cooling water system maximum return temperature
1. Scaling (as you mentioned)
2. Corrosion
3. Materials of construction - beyond scaling and corrosion worries and not just the piping or exchanger materials. You would need to look at the entire system including the cooling tower (you might start exceeding the temperatures of the commonly non-metalic distribution / contacting components)
4. Personal Safety (having to look at your cooling water system as a burn hazard due to the high temperature)
You can start to see why "although possible" it would take some interesting economic drivers to justify running the design temperature much higher than 50 C.
RE: Closed loop cooling water system maximum return temperature
However Combined CW return to cooling tower approaching anywhere above 48 Celsius becomes difficult in many ways to safely/easily handle.
Best Regards
Qalander(Chem)
RE: Closed loop cooling water system maximum return temperature
RE: Closed loop cooling water system maximum return temperature
For the average cooling tower water system in the average chemical process plant, it was my understanding that the maximum inlet temperature is set by the cooling tower materials.
Other systems would, of course, have different maxima.
I believe that scaling is the primary reason for the maximum temperature.
-MJC
RE: Closed loop cooling water system maximum return temperature
I think this issue will also depend on the number of concentration cycles and the hardness of the makeup water. Calcium and Magnesium carbonate solubility is anomalous and decreases with increase in temperature - thus leading to scaling risk.