Consider the steady operation of a refrigeration "package" for a shipping container (on a train, truck or ship). The package is self contained and is fueled by a tank of propane. The unit is composed of an internal-combustion engine (power cycle) that drives an R134a refrigeration cycle. The engine drives the refrigerator by producing 10 kW of shaft power with a thermal efficiency of 20% when operating with a maximum temperature of 2000 F. and cooled by the +59 oF atmosphere. The refrigeration cycle has a COP of 2.5 when cooling the contents of the shipping container at -20 oF and rejecting waste heat into the +59 oF atmosphere.Determine the cooling capacity of the device and the actual COP of the combined-cycle package = useful effect/expensive input. (Notice that the 10 kW of power produced is entirely absorbed to drive the refrigerator so the net external work is zero. The engine thermal efficiency definition is based on the energy available from the propane fuel.)
Draw a complete schematic diagram for each of the two cycles. (show arrows, symbols & show numeric values for each W& & Q&).
Calculate the overall COP of the combined-cycle package = useful effect/expensive input?