An ideal two-stage cascade refrigeration system shown in Fig 10, 19 uses 0.8 kg/s of R134a as the working fluid in the first cycle and ammonia as the working fluid in the second cycle. Use Eq. 10A for the intermediate pressure.

The known properties are:
State 1: R134a at 160 kPa
State 7: Ammonia at 60 8C
Determine:
(i) The cooling load
(ii) The mass flow rate of the ammonia
(iii) The total compressor horsepower
(iv) The coefficient of performance for this system

Transcribed Image Text:

Oour to suroundings ) Condenser Compressor Throttle #2 Heat exchanger Throttle #1 Evaporator in (from cooled space)