engleski

A Dynamic Numerical Model of a Shell and Tube Refrigerant Condenser

A dynamic numerical model of a shell and tube refrigerant condenser is presented. An explicit method has been used to solve a set of differential equations for energy and mass conservation. Using earlier developed compressor model with a variable time step, which depends on the time gradient of considered variables important for compressor operation, the instability coupled with the selected numerical approach has been solved. Software is developed for the model implementation on computer. The condenser model is verified by using it as a part of a heat pump model. A comparison between simulation results and experimental data for the heat pump operation with compressor cylinder unloading, as well as with variable flow of the cooling liquid is performed. Results of the condenser model present the temporal changes of inlet and outlet refrigerant flows and variations of pressure, temperature, enthalpy, density and heat transfer coefficients at each control volume. Results of simulations are presented in a graphical form. The present model allows for the changes in condenser geometry, boundary and initial conditions in order to analyze various influences on a refrigeration process and to optimize the construction of the refrigeration machine.

dynamic modelling, condenser, capacity control, refrigeration machine

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