A compact dynamic model for vapor compression refrigerated systems

In the paper a simplified dynamic lumped model for the simulation of a refrigerator working according to an inverse cycle between two thermal sources with finite thermal capacity is presented. A variable capacity compressor (VCC) is considered. The model is compact enough to be employed in actual regulation systems, but sufficient to describe all the underlying physical phenomena relevant to the transient response of the refrigerated cell. The dynamic behaviour of the system is simulated taking into account all the heat capacities involved in the heat transfer processes between the system, the refrigerating fluid and the outside. On the other hand the dynamic of the physical phenomena having time constants smaller than a few seconds has been neglected. The validity of this approach is proved by comparing the numerical results with the transient experimental data coming from an instrumented chest-freezer (one kind of small refrigerator often used in household and super-market applications).