Thermodynamic Properties of R744 (Carbon Dioxide - CO2)

Critical Pressure: 7.377 MPa, Critical Temperature 30.978°C
Ideal Gas Constant of Carbon Dioxide: R = 0.1889 kJ/kg.K

CO2 Property Tables:

• Saturation Properties - Temperature Table (-20°C - 5°C)
• Saturation Properties - Temperature Table (5°C - 30.978°C)
• Saturation Properties - Pressure Table (2 MPa - 5 MPa)
• Saturation Properties - Pressure Table (5 MPa - 7.377 MPa)
• Superheated Vapor Properties - (2.0 MPa - 7.0 MPa)
• Transcritical Vapor Properties - (8.0 MPa - 13.0 MPa)
• Transcritical Vapor Properties - (14.0 MPa - 20.0 MPa)

CO2 Property Tables (Excel Version)

• Saturation Properties - Temperature Table
• Saturation Properties - Pressure Table
• Superheated and Transcritical Vapor Properties

Source of data: NIST Chemistry WebBook - accessed March 2007

CO2 Property Diagrams:

• Pressure-Enthalpy (P-h) Diagram
• Enthalpy-Entropy (h-s) Diagram

Note: The current refrigerant R134a has a Global Warming Potential (GWP) of 1300 with respect to CO2. There is currently serious consideration of replacing it with R744 (Carbon Dioxide) in refrigeration and heat pump applications, as well as automotive air conditionong systems..

A typical home heat pump system is shown below, followed by the P-h plot. Notice how the transcritical cycle conveniently allows hot water heating together with space heating and air conditioning.

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Engineering Thermodynamics by Israel Urieli is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License