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Homework Help: Thermostatic mixing problem

  1. Oct 25, 2011 #1
    Heres the problem.

    I have a tap supplying water at 41°c and at a flow rate of 0.17 l/s. The tap is connected to a Termostatic Mixing Valve (TMV) with a hot and cold water supply.

    The hot water is at 60°c and the cold water is being supplied at 10°c.

    What are the flow rates for the hot water supply and the cold water supply?

    Have tried many things to find the answer but still no luck, if someone can please let me know a formula would be very greatful!
  2. jcsd
  3. Oct 25, 2011 #2
    Hint: If you have 1 liter of water at 20 C and 2 liters of water at 30 C and mix them, what is the final temperature? Mixing flows is handled in a similar manner.

    With this problem you have the total flow rate. Therefore the sum of the two flow rates must equal the total flow.
    Last edited: Oct 25, 2011
  4. Oct 25, 2011 #3
    You can also look at the problem from a First Law standpoint. You have a control volume which is the valve. You have energy entering from two pipes. Energy leaves through another pipe. Is there any work being done? Is there any heat transfer? You also have to consider conservation of mass.
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