Dynamic Model Linearization and Model Predictive Control of an Organic Rankine Cycle

Authors : Mert Sinan Turgut, Oğuz Emrah Turgut
Pages : 865-878
Doi:10.24012/dumf.1691147
View : 62 | Download : 114
Publication Date : 2025-12-30
Article Type : Research Paper
Abstract :This research investigates the control of an Organic Rankine Cycle (ORC) system, which consists of four main components: a condenser, a turbine, a pump, and an evaporator. The heat exchangers are designed as double-pipe configurations, and their dynamic behavior is modeled using the moving boundary approach. The pump and turbine, due to their significantly faster dynamics compared to the heat exchangers, are represented with static equations. The cycle’s mathematical model is linearized by computing the Jacobian of the nonlinear function with respect to state, input, and disturbance variables. Model validation is performed by generating pseudo-random input sequences and applying them to both the developed ORC model and an Aspen model with identical specifications. The validation results show strong agreement between the two models, with only minor discrepancies. Subsequently, a linear model predictive control framework is established to regulate the linearized ORC model, incorporating several inequality constraints to ensure safe and efficient operation. Four control strategies are introduced, each focusing on distinct objectives such as enhancing thermodynamic efficiency or reducing entropy generation, while all share the common goal of tracking the turbine work output trajectory. Simulation results indicate that all four controllers effectively follow the specified turbine work output trajectory. The first law and second law controllers achieve the highest average efficiencies, with first law efficiency at 0.10250 and second law efficiency at 0.31732, respectively. The turbine work controller exhibits the highest total exergy destruction rate, recorded at 2100.17 W.
Keywords : Organik Rankine Çevrimi, Model Öngörülü Kontrol, Model Lineerizasyonu, Enerji Verimliliği, Termal Sistemler

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