Calculating Q Transferred in PV Graphs | Thermodynamics

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SUMMARY

Calculating Q transferred in PV graphs involves understanding the relationship between internal energy, work, and heat transfer. The equation U = Q - W is fundamental, where U represents internal energy, Q is heat transferred, and W is work done. In isochoric processes, Q cannot be directly calculated without considering temperature changes and the specific process type, such as adiabatic conditions. Utilizing the ideal gas equation, adiabatic equations, or saturation/compressed water/refrigerant tables is essential for accurate calculations.

PREREQUISITES
  • Understanding of the first law of thermodynamics
  • Familiarity with PV diagrams and their interpretation
  • Knowledge of ideal gas laws and equations
  • Concepts of adiabatic and isochoric processes
NEXT STEPS
  • Study the first law of thermodynamics in detail
  • Learn how to apply the ideal gas equation in various scenarios
  • Explore adiabatic process equations and their applications
  • Investigate the use of saturation/compressed water/refrigerant tables for thermodynamic calculations
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Students and professionals in thermodynamics, engineers working with heat transfer systems, and anyone involved in analyzing PV graphs for energy calculations.

Dooh
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How do i calculate Q transferred in a PV graph (Pressure / Volume)? More specifcally, when it is a slope. All that was given is pressure and volume from the graph.

Also, in an isochoric process, how would one go about finding Q? I spent so much time on thermodynamics yet i still don't know how to find it.
 
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Generally, there is no direct way to do so. You have to consider that

[tex]U = Q - W[/tex]

The internal energy is dependent on temperature. Work is always a function of pressure and change in volume. There are interesting relationships for example if the process is adiabatic, so it depends on the situation. A combination of the ideal gas equation, adiabatic equation or use of saturation/compressed water/refrigerant tables may be needed depending on your problem.
 

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