Dynamic simulation of natural convection bypass two-circuit cycle refrigerator–freezer and its application: Part I: Component models

In order to reduce the greenhouse gas emissions, efficient household refrigerator/freezers (RFs) are required. Bypass two-circuit cycle RFs with one compressor are proved to be more efficient than two-evaporator in series cycle RFs. In order to study the characteristics and improve the design of bypass two-circuit cycle RFs, a dynamic model is developed in this paper. In part I, the mathematic models of all components are presented, considering not only the accuracy of the models but also the computation stability and speed to solve the models. An efficiency model that requires a single calorimeter data point at the standard test condition is employed for compressor. A multi-zone model is employed for condenser and for evaporator, with its wall thermal capacity considered by effective metal method. The approximate integral analytic model is employed for adiabatic capillary tube, and the effective inlet enthalpy method is used to transfer the non-adiabatic capillary tube to adiabatic capillary tube. The z-transfer function model is employed for cabinet load calculation.