INSTITUT INTERNATIONAL DU FROID
INTERNATIONAL INSTITUTE OF REFRIGERATION
Organisation intergouvernementale pour le développement du froid
Intergovernmental organization for the development of refrigeration
177, boulevard Malesherbes, F-75017 PARIS, France - Tél. 33-(0)1 42 27 32 35 - Fax 33-(0)1 47 63 17 98 - E-mail:
[email protected] - Web site: www.iifiir.org
Thermophysical properties of refrigerants: Isobutane General: Composition
Isobutane
Formula
CH(CH3)2-CH3
Family
Hydrocarbons
Main application fields (in compliance with the legislation in force)
domestic refrigeration
Molar mass
58,1 kg/kmol
Thermophysical properties: Normal boiling point (at 0.1013 MPa)
–11,6°C
Critical temperature
134,7°C
Critical pressure
3,64 MPa
Properties at 0°C (at saturation)* Pressure Specific volume Specific heat capacity • at constant pressure • at constant volume Viscosity Thermal conductivity Surface tension Heat of vaporization
Unit (SI)
Liquid
Vapour
MPa dm3/kg
0,16 1,72
0,16 235,69
kJ/(kg K) kJ/(kg K) 10-6 Pa s W/(m K) N/m kJ/kg
2,31 1,63 199,33 0,107
1,64 1,45 6,97 0,014 0,013 355,7
* These data are derived from the brochure Thermodynamic and Physical Properties of Isobutane published by the IIR. You can order it on line.
Environmental properties: ODP (R11=1)
0
GWP (CO2=1)
20
The GWP used as a reference here is the GWP of CO2 over an integration period of 100 years. Safety groupe: A3
Flammability limits: Lower limit
1.8% of total volume
Upper limit
8.5% of total volume
