heat exchanger, transient simulation, Finite Volume Method
To further increase the energy efficiency of domestic refrigeration systems, it is not sufficient anymore to optimize the single cycle components on their own. On the contrary, due to the strong system interactions, an integral consideration of the whole cooling cycle is necessary to capture the system dynamics in detail and to understand them. Just by understanding the occurring physical effects, loss mechanisms can be identified and efficient optimizing measures could be taken. In this work a transient model for the simulation of the evaporator and the condenser of domestic refrigeration appliances, based on the Finite Volume Method (FVM) is presented. The requirements for cycle simulations differ from design or optimization problems because the models have to be as fast as possible so that the computational results can be used as boundary conditions for the simulation of the other components. Thus, it is challenging to find a satisfying trade-off between the computation speed and the accuracy of the results. The developed algorithm solves the governing equations for mass and energy in combination with some simplifying assumptions (e.g. 1- dimensional fluid flow, negligence of the pressure drop, homogeneous two-phase flow) which have been necessary to keep the computation time within limits.