A two stage cascade refrigeration system is to provide cooling at -40C while operating the high temperature condenser at 1.6 MPa. Each stage operates on the ideal vapor compression refrigeration cycle.
The upper capor compression refrigeration system (VCRS) uses water as its working fluid and operates its evaporation at 5C. The lower cycle uses refergant 134a as its working fluid and operates its condenser at 400KPa. This system porduces a cooling effect of 20KJ/s.
Determine
- The mass flow rate of R-134a and water in their respective cycles.
- The overal COP of the cascade system.