Optimal Design for Thermodynamic System with OpenModelica and MATLAB/Simulink

Abstract

The complicated thermodynamic system includes nonlinear characteristics and is expressed by high order differential algebraic equations. Therefore, it is difficult to carry out numerical analysis such as optimization. To deal with this problem, we verify an integrated design support environment incorporating OpenModelica for a centrifugal chiller as an example. In this paper, it is shown that the parameters of the model and the control logic can be adjusted by the coupled simulation of the chiller model written in the Modelica language and the control logic on MATLAB/Simulink. We also simplify the centrifugal chiller model by approximating the nonlinear characteristics with a smooth polynomial, and by reducing the order of the differential algebraic equation by the Pantelides method. Then, a case study of a startup profile optimization is shown.