Water Cooling Problem
Water Cooling Problem
(OP)
I am working on a problem where I need to figure out the GPM of a cooling water. A customer wants to dilute 130°F circulating water (125 GPM) with 50°F water in order to cool it to 75°F. This is a continually flowing system.
The 75°F water enters the process, which heats the water to 130°F. He then wants to add the 50°F water directly to the system to bring it back down to 75°F before re-entering the process.
I've worked with heat exchangers before, but this is a little different. I know this should be easy to figure, but I'm at a loss.
Thanks.
The 75°F water enters the process, which heats the water to 130°F. He then wants to add the 50°F water directly to the system to bring it back down to 75°F before re-entering the process.
I've worked with heat exchangers before, but this is a little different. I know this should be easy to figure, but I'm at a loss.
Thanks.





RE: Water Cooling Problem
Flow_Hot x Cp x (130-75) = Flow_cold x Cp x (75-50)
RE: Water Cooling Problem
RE: Water Cooling Problem
Over the small range of temperatures of your problem, it may be considered a constant.
RE: Water Cooling Problem
RE: Water Cooling Problem
If you dump 86 GPM of 130F water and then inject 86 GPM of 50F water, your end up with 125 GPM of 75F water. No exchanger required.
RE: Water Cooling Problem
What formula are you using?
RE: Water Cooling Problem
Correct formula is
Flow_Hot x Cp x (130-75) = Flow_cold x Cp x (130-50)
Resulting in flow_cold = 86 gpm to agree with Danberry.
RE: Water Cooling Problem
An exchanger will require more cold water but avoids dumping the hot process water; an advantage if it is contaminated.
RE: Water Cooling Problem