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Solar water heater problem

  1. May 31, 2009 #1
    I thought Wolfram Alpha might be able to help me with this problem, however
    so far I have had no luck, with the web site nor their community:

    I have a 1230 gal pool heated by the sun to 70 degrees F, If I remove 30 gal
    and let the 30 gal be heated in my solar collector to 100 degree F, and then add it back to the pool.

    What will my new pool temperature be?
    Is this raise in temperature linear? meaning if continue to do this once every hour via a timer and a pump can I extrapolate how long it will take to raise the pool temperature to 80 degrees?

  2. jcsd
  3. May 31, 2009 #2
    Temperature is linear in average energy, so yes.
    But, heat transfer [with the outside environment, rather than by direct mixing of enclosed fluids] is not linear. The solar heater will be more efficient if the water constantly pumps through it instead of overheating a smaller volume (and the pumping heats the water too). On the other hand, heat sinking pipes could reverse this. Also, the higher the pool temperature gets, the faster it will be cooling.
    Last edited: Jun 1, 2009
  4. Jun 1, 2009 #3
    thanks for your reply! I presume then that I really need to look for is a generalized heat transfer formula for water, if there is such a thing?
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