| Utilization of low grade thermal energy in refrigeration is helpful for solving the problem of energy crisis. Among the existing techniques, ejector based refrigeration system is a very promising and effective technique of using low grade energy. However, no effective control model of ejector refrigeration system restricts the development of this technique. The main work of this paper lists in the following:Firstly, a new hybrid modeling method is proposed in this paper.1) Build the theoretical model by analyzing the modeling object and use of conservation laws of mass and energy and laws of physics theory; 2) Select the input and output parameters of modeling objects; 3) Combine the parameters which are not measurable and controllable; 4) Identify the combining parameters by experimental data to complete the modeling.Secondly, the control model of ejector-compressor is built based on the proposed modeling method in this paper. Develop the ejector-compressor theoretical model based on analysis of operation mechanism of the system; Set the pressure of primary flow, second flow and compressor inlet and compressor motor speed as input and output parameters; Variables in the model which are not measurable or controllable are simplified into measurable and controllable parameters based principle of thermodynamic and lumped parameter method. The simplified control model only requires three or four parameters and measurement of four variables.Then the model is validated by experimental data which are obtained from experimental platform. Based on parameter identification method, undetermined parameters are identified using adequate, wide range of experimental data and the effectiveness of the established model is validated as well. Results show that the model is simple and robust in the entire operating range.Finally, we analyze the system based the built model and the model is promising to be used to forecast, optimize and control of the system. |
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