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Homework Help: Heat Transfer of water tank

  1. Oct 7, 2008 #1
    1. The problem statement, all variables and given/known data

    A tank A is connected to a cylinder/piston as shown. The tank has a volume of 100 L and contains saturated vapor R-134a at 30˚C. When the valve is cracked open, the vapor slowly flows into the cylinder B. The piston requires a pressure of 200 kPa in the cylinder to raise it. The process ends when the pressure in tank A has fallen to 200 kPa. During the process, heat is transferred with the surroundings such that the R-134a always remains at 30˚C. Calculate the heat transfer for the process. (101.3 kJ)

    2. Relevant equations
    E2-E1 = Q - W
    Work = Pressure * Change in volume

    3. The attempt at a solution
    i know that the Temp remains at 30˚C throughout the process
    volume = 100 L

    My question is i never know where to start with these types of problems
  2. jcsd
  3. Oct 7, 2008 #2
    Am I correct in assuming that you have been working with tables? The ones that give all kinds of information about various substances at various states. Such as U, H, v, T...

    Is there any way you could take a picture of the problem or scan and upload it?
  4. Oct 7, 2008 #3
    picture is attached as a file

    Attached Files:

  5. Oct 8, 2008 #4
    You need to include a little more information. There are too many different ways to solve these and you still have not answered my question: are you studying tables? If, so what do you know from the tables? If not, what methods have you been using.
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