propane V/s propylene

[Ambrish_bajpai]

can any body tell me that whether propane or propylene will be a better refrigerant for using in a system at -35 degree evaporating temperature??

[Dacosta]

Assuming -35ºF and 90ºF condensing temp


R-1270 R-290
Evap -34 -34 ºF
Cond 90ºF 90 ºF

Liquid Enthalpy -13.206 261.59 btu/lb
Vapor enthalpy 97.731 368.2 btu/lb
Vapor entropy 1.4085 1.3649 BTU/lb-R
Suction pressure 23.62 18.562 PSIA
Condening press 199.8 165.58 PSIA

Compression ratio 8.46 8.92

Refrigeration effect 110.937 106.61 btu/lb
Mass flow rate 108.1695 112.5598 lb/hr/ton

Ideal Compression
Discharge enthalpy 143.61 141.35 btu/lb

Compressor work 45.879 43.15 btu/lb
4962.71 4856.96 btu/hr/ton

Efficiency 1.95 1.91 hp/ton

Ideally propane is sightly better, The compression ratio of propane is higher than propylene so the compressor efficiency is lower. Infact they are almost identical.

You will have to look at the compressor efficiency curves to get a better answer.

[Dacosta]

Sorry my post killed my formatting

[Josip]

Hi, Dacosta :)

... you can always edit your post and change formatting ;) to make it easier for reading :cool:


Best regards, Josip :)

[Dacosta]

Thanks i can edit now but it still takes out all my spaces to put it into nice column like format.