Real-time Efficient Operation of a Micro-scale Organic Rankine Cycle Unit via Extremum Seeking Control

The boost to the development of micro-scale Or-ganic Rankine Cycles (ORCs) as effective waste heat recovery systems poses new challenges in their design and management. This paper presents the Real-time Optimisation (RTO) of a micro-scale ORC unit to maximise the overall electrical efficiency under different operating conditions. The implicit RTO performs in a model-free fashion using the Extremum Seeking Control (ESC) approach, which exploits only system output measurements, to directly adapt the process input. In particular, two control schemes, i.e. the Gradient-based ESC and the Newton-like ESC, are designed and assessed through simulations thanks to the availability of a Matlab-based ORC model.