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Homework Help: Counter flow heat exchanger lab

  1. Nov 26, 2007 #1
    1. The problem statement, all variables and given/known data
    in practice is is assumed well insulated heat exchangers are adiabatic. With reference to this heat exchanger, carry out the necessary calculations and then give an opinion as to the validity of this assumption.

    2. Relevant equations

    Thotin 55.88, Thotmid 51.84 Thotout 22.47 Tcoldin 29.37 Tcoldmid Tcoldout 47.41
    Hot water flow rate 2800 cold water flow rate 1750

    internal tube external diameter 15mm wall thickness 0.7mm
    outer tube external dia 22mm, wall thickness 0.9mm
    insulation wall thickness 20mm
    heat transmission length 1.5m
    heat transmission area 0.067m squared

    3. The attempt at a solution

    can someone point me in the right direction with this question thanks
  2. jcsd
  3. Nov 26, 2007 #2
    If it is well insulated and adiabatic (no heat transfer out of the system), then all of the heat energy in the hot fluid will be gained by the cold fluid.

    Find the heat lost by the hot fluid and gained by the cold fluid. If they do not match up (which they won't), then talk about possible losses in the system.
  4. Nov 26, 2007 #3
    any equations to use?
  5. Dec 2, 2007 #4


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    Staff Emeritus
    Science Advisor
    Gold Member

    What do you think? What are the equations that describe the total heat gained or lost by a body?

    Also, what are the units on the various quantities in the question (you're missing some units)?
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