Performance evaluation of MPC for Waste Heat Recovery applications using organic Rankine cycle systems

peer reviewedOrganic Rankine Cycle (ORC) technology has demonstrated to be a suitable tool for recovering waste heat at low temperatures. The fluctuating nature of the waste heat source (varying temperature and mass flow) makes of waste heat recovery applications a challenging task. In this contribution Model Predictive Control (MPC) and more classical PID-like controllers are investigated, where special attention is paid to the analysis of the control performance for heat source profiles coming from different applications. A dynamic model of a real regenerative ORC unit equipped with a single screw expander developed in the Modelica language is used to test and compare the PID and MPC based control strategies. Results show that for low amplitude variations PID and MPC can perform equally good, but in case of large variations MPC is a more effective control strategy as it allows a safer and more efficient operation, operating close to the boundary conditions where production is maximized.project The Next Generation Organic Rankine Cycles (www.orcnext.be