Comparison of Control Optimization Approaches for Low Exergy Heating And Cooling Systems

The paper focuses on control optimization of nonlinear system models where the differential-algebraic equations are formulated in Modelica. Two optimiziation approaches utilizing (i) direct search methods and (ii) derivative-based methods are compared. The approaches are applied to a thermohydraulic low-exergy heating and cooling system model in form of a borehole heat exchanger, a heat pump, a hydraulic distribution system, thermally activated building systems (TABS) and a simplified building model. The optimization approaches are compared concerning the found optimal solutions, the optimization performance and the requirements to the formulation of the non-linear optimal control problem.