Dynamic Modeling and Experimental Validation of a Domestic Refrigeration Cycle

Performance analysis and design optimization of refrigerators are primarily carried out by time-consuming experiments. The current study presents an alternative method to analyze refrigerators by modeling the refrigeration cycle using a software called DYMOLA, based on an object-oriented programming language, called MODELICA. The main components of a domestic refrigerator, i.e., compressor, condenser, evaporator, cabinet, and capillary tube-suction-line heat exchanger are first individually modeled and validated. The full dynamic refrigeration cycle model is then created. Both the simulations and the experiments are conducted using R600a as the refrigerant with on-and off-modes of the reciprocating, single speed compressor. An algorithm block is also included to represent the dynamic cyclic behavior of the refrigerator. The algorithm controls the operation using two set-point temperatures of the cabinet. To validate the one-dimensional dynamic model, experiments are carried out on a single door refrigerator with an internal volume of 343l. Results show that the cabinet air, evaporation temperature, condensation temperature, power and energy values deviate from experimental values by less than 2 °C and 2%, respectively. The dynamic modeling is found to be in good agreement with the experiments in the on-mode of the compressor and a promising and rapid tool to represent the transient behavior of the refrigerator.