In the before-CFC-time Natural refrigerants have been used in large amounts in US and around the world /1/. Nowdays they haven been rediscoverd in the course of the discussion about the R22 and R502 substitution. Due to their good thermodynamical properties the use of natural refrigerants in energy safe equipments is interesting more than ever.

Theoretical and experimental investigations have been carried out to check the ability and behaviour of hydrocarbons as refrigerants /2, 3/.

Substances:

• Propane (C₃ H₆ )
• Propene (C₃ H₄ )
• n-Butane (C₄ H₈ )
• Iso-Butane (C₄ H₆ )
• Mixture Propane / n-Butane

Some experimental results

These results have been presented on the 1996-DKV meeting in Leipzig /3/.

 
COP Comparison (Propane, Propene, R22) @ constant Condensation Temperature (+30°C)

Thermodynamical Properties of Propene

• Vapour-Liquid Properties Table
• Best-Fit Equations (VP, dens, viskos, conduct., ...)
• Ignitions Limits
  ...2,0 - 11,1 vol%
• Vapour Pressure Diagram:

• Liquid Density Diagram:
   
• Vapour Density Diagram:

• Heat of Evaporation Diagram:

 

Thermodynamical Properties of Propane

• Vapour-Liquid Properties Table
• Best-Fit Equations (VP, dens, viskos, conduct., ...)
• Vapour Pressure
• Liquid Density
• Vapour Density
• Heat of Evaporation
• Caloric Properties
• Transport Properties
• Heat Transfer Coefficients

Pressure drop in a double pipe evaporator

still in work

Literature:

/1/ Plank, R.: , Handbuch der Kältetechnik in 12 Bänden, Springer, here Vol. I and IV

/2/ Oellrich L.R.: Propane and Butane as possible Alternatives to R12 and R22, R502, Int.Inst.Refrig. (IIR)-Conf. May 10-13 1994: New Applications of Natural Working Fluids in Refrigeration and Air Conditioning

 

/3/ Engler T., Hong Ha T., Oellrich L.R.: Vergleich des Verhaltens alternativer Kältemittel in einer Kälteanlage mit Berechnungsergebnissen, DKV-Jahrestagung 1996, Vol. II/1

/4/ Leisenheimer B., Leuckel W., Oellrich L. R.:Explosibility Perfomance of alternative refrigerants Proceedings of the 2nd Int. Specialists Meeting on Fuel-Air Explosions, Chr. Michelsen Research AS, Bergen, Norwegen, (23.-28.6.1996), p.4.1-4.8

/5/ Oellrich L.R. , Engler T., Murthy S.S., Venkatarathnam G., Balakrishnan A.R.: Refrigerant Mixtures as Alternatives to HCFC22& R502: Systematic Screening & Pinch Point Studies, Forschungsberichte des Deutschen Kältetechnischen Vereins Nr. 54, Stuttgart 1997, 138

/6/ Engler T., Oellrich L.R., Murthy S.S., Venkatarathnam G.: Screening of single Component and Mixture Working Fluids for Compression Heat Pump Applications, Proceedings 20th Intl. Congr. of Refrigeration IIR, 19.-24.9.99, Sydney, Vol. II, Paper 171

/7/ Murthy S.S., Venkatarathnam G., Oellrich L.R., Engler T.: Performance of Some Mixtures as working Fluids for High Temperature Compression Heat Pump Applications, Proceedings 20th Intl. Congr. of Refrigeration IIR, 19.-24.9.99, Sydney, Vol. II, Paper 154