CH-99-23-4 -- Second-Law Analysis of Refrigeration Cyclic Open Systems PDF

Two periodic refrigeration processes, based on gas flow, are discussed in this paper. The nature of the irreversibilities differ in both cases. To analyze the processes, in both cases open subsystems are considered. In the reference case of vapor compression refrigeration, the driving energy is mechanical energy and it is shown, as is well known, that the actual cycle departs from the ideal Carnot cycle due to external thermal coupling entropy production (vapor desuperheating) and to internal entropy production (throttling). In the case of adsorption, the driving energy is thermal energy. The basic actual cycle departs strongly from the ideal Carnot cycle corresponding to the heat reservoir temperatures. The main entropy production is the external thermal coupling entropy production due to the adsorbers thermal swings. A rather small internal entropy production does exist.

Units: SI