Dynamic modeling and control strategies for Organic Rankine Cycle systems

Control and optimization are major issues in ORC systems applied to waste heat sources. This talk provides an overview of the current state of the art and of the main areas of R&D in that topic, including:
- Steady-state and dynamic modeling of ORC cycles (simulation platforms, modeling paradigms, numerical issues)
- Optimization of the working conditions for a given heat source and heat sink, and in particular of the evaporating temperature
- Optimal start-up and shut-down strategies (grid synchronization, pressure overshoot, ...)
- Control of the cycle under transient heat source conditions
- Traditional and advanced controllers (PID, Model predictive control)
The different adjustable working conditions (condensing/evaporating temperature, superheating, subcooling, working fluid flow rate) are listed with regard to the available degrees of freedom (pump/expander speed, secondary fluid flow rates and temperatures) and their optimal values are derived, depending on the target application.