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Need help in solving thermo problem

  1. Aug 26, 2013 #1
    The thermo problem is as follow:
    I have a fireplace and I have an underfloor water pipe heating. currently the underfloor water is heated by gas burner.
    I want that the water will also be heated by the fireplace, so I plane to place a chopper pipe inside the fireplace and run the underfloor water trough it.
    I need to find out what should be the length of the chopper pipe inside the fireplace.
    Here are the parameters:
    Fireplace temperature = ~ 1000'C
    Chopper pipe diameter: Inside = 11mm, Outside = 13mm.
    water speed in the pipe = 2500L/hour.
    water temp at the start of the pipe is 23'C.
    water temp at the end of the pipe should be 55'C.

    what should be the length of the chopper pipe inside the fireplace so water entering the pipe in 23'C exit the pipe in 55'C?

    Whats I'm asking is, how long it takes for a 23'C water to heat up to 55'C in a 1000'C oven.

    Please replay with the relevant equations and the way to solve the problem.

    Tnx a lot
  2. jcsd
  3. Aug 26, 2013 #2


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    Staff Emeritus
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    I take it that 'chopper pipe' is actually copper pipe, that is pipe made from copper (Cu).

    I would advise against using copper, especially since its melting temp. is 1085 C. You also could not use solder to join any pipe sections, since the M.P. of solder is much lower than the M.P. of copper. You would probably need to use steel pipe, since that material can be threaded or welded and doesn't work-harden like Cu.
  4. Aug 26, 2013 #3
    Yes, sorry not chopper but copper.
    The pipe with running water inside will never rich the 1085'C.
    there will not be any solders or joints.
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