A dynamic model of a vapor compression cycle with shut-down and start-up operations

This paper presents an advanced switched modeling approach for vapor compression cycle (VCC) systems used in Air Conditioning and Refrigeration. Building upon recent work (McKinley and Alleyne, 2008), a complete dynamic VCC model is presented that is able to describe the severe transient behaviors in heat exchangers (condenser/evaporator), while maintaining the moving-boundary framework, under compressor shut-down and start-up operations. The heat exchanger models retain a constant structure, but accommodate different model representations. Novel switching schemes between different representations and pseudo-state variables are introduced to accommodate the transitions of dynamic states in heat exchangers while keeping track of the vapor and liquid refrigerant zones during the stop–start transients. Two model validation studies on an experimental system show that the complete dynamic model developed in Matlab/Simulink can well predict the system dynamics in shut-down and start-up transients.