Heat Transfer Calculation for Vapor Flow in a Cylinder-Piston System

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Discussion Overview

The discussion revolves around a heat transfer calculation for a vapor flow process in a cylinder-piston system involving R-134a. Participants explore the conditions under which the vapor remains at a constant temperature while flowing from a tank to a cylinder, and the implications for calculating heat transfer during this process.

Discussion Character

  • Homework-related, Technical explanation

Main Points Raised

  • One participant states the problem involves a tank with saturated vapor R-134a at 30˚C and a cylinder requiring a pressure of 200 kPa.
  • Another participant inquires whether the original poster has been using thermodynamic tables to gather information about the properties of R-134a.
  • A request is made for additional information or a visual representation of the problem to facilitate understanding.
  • Further clarification is sought regarding the methods the original poster has been using to approach the problem.

Areas of Agreement / Disagreement

Participants have not reached a consensus on how to approach the problem, and there are multiple viewpoints regarding the necessary information and methods to solve it.

Contextual Notes

There is a lack of clarity on the specific methods or tables being used by the original poster, which may affect the ability to provide a comprehensive solution.

marquis24
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Homework Statement



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)


Homework Equations


E2-E1 = Q - W
Work = Pressure * Change in volume

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
 
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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?
 
picture is attached as a file
 

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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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