Help with refrigeration properties table

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SUMMARY

The discussion centers on discrepancies in enthalpy values for R-22 refrigeration properties between a textbook and online sources. Users noted a consistent difference of approximately 154 kJ/kg for both saturated liquid and vapor, as well as superheated vapor. The conversation highlights that enthalpy is defined relative to a reference state, which may explain the variations in reported values. Participants emphasized the importance of using reliable online resources for accurate thermodynamic data.

PREREQUISITES
  • Understanding of thermodynamics, specifically enthalpy concepts.
  • Familiarity with refrigerants, particularly R-22 properties.
  • Knowledge of reference states in thermodynamic calculations.
  • Ability to interpret refrigeration properties tables.
NEXT STEPS
  • Research the thermodynamic properties of R-22 using NIST Chemistry WebBook.
  • Learn about the significance of reference states in thermodynamic measurements.
  • Explore the differences between various refrigerant property tables and their sources.
  • Investigate the impact of temperature and pressure on enthalpy values for refrigerants.
USEFUL FOR

Engineers, HVAC professionals, and students studying thermodynamics or refrigeration systems will benefit from this discussion, particularly those working with R-22 and enthalpy calculations.

VooDoo
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Hey guys,

Just a bit stuck with getting enthalpy values off a table I have in a textbook.

If we look at R-22 for example, the textbook gives me different answers than what is available on the net. If I use the values that are given to me on the net I get the correct value.

The blue ones are what seem to be the correct enthalpys, the red is what my textbook has given to me. Why is there always a ~154kJ/kg difference for the enthalpies between my book and the correct answer?(for both saturated liquid and vapour and it seems the same for superheated vapour)
 

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enthalpy is defined relative to a reference state, it isn't the absolute value.
 

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