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Topic: thermodynamics of cooling water for hot process  (Read 2138 times)

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Offline mufan

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thermodynamics of cooling water for hot process
« on: July 30, 2015, 11:13:20 AM »
Hi,
I work with cooling towers where essentially cool water (85 deg F) is sent to a heat exchanger where it picks up 10 deg F and returns to the tower at 95 deg F.  My questions are:

  • if you gain 10 deg F in water temp then do you essentially cool the process by 10 deg F.  is this exchange 100% efficient like that?I'm thinking the water flow across the exchanger will play into somehow
  • and therefore, can you determine the temperature of the process being cooled from the difference in cool supply water and the hot return water?

Offline Corribus

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Re: thermodynamics of cooling water for hot process
« Reply #1 on: July 30, 2015, 11:41:27 AM »
One of our resident engineers will probably have a more specialized response, but in general even if a heat transfer process is 100% efficient, you still have to take into account heat capacities to know what actual temperature changes will be. That is to say, a 100% efficient process is not the same thing as one in which the temperature drop by the heat donor equals the temperature gain by the heat acceptor.
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline Irlanur

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Re: thermodynamics of cooling water for hot process
« Reply #2 on: July 30, 2015, 11:41:54 AM »
Quote
if you gain 10 deg F in water temp then do you essentially cool the process by 10 deg F.

If I understand you correctly then you are completely wrong.

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