A two-stage, ideal cascade refrigeration system shown in Fig. 10.19 and Fig. 10.20 uses R134a as the

Question:

A two-stage, ideal cascade refrigeration system shown in Fig. 10.19 and Fig. 10.20 uses R134a as the working fluid in both cycles. The mass flow rate through the first stage is 8 kg/min.

The known properties are:
State 1: 120 kPa
State 7: 4080 Determine:
(i) The cooling load
(ii) The mass flow rate in system 42
(iii) The net compressor power required
(iv) The overall coefficient of performance