ORC on tour: Integrated design of dynamic ORC processes and working fluids for waste-heat recovery from heavy-duty vehicles

Abstract Organic Rankine Cycles (ORC) convert low temperature heat into power. To maximize conversion efficiency, both ORC process and working fluid have to be tailored to the specific application. Common solution approaches for the resulting integrated design of ORC process and working fluid are limited to steady-state applications. However, for applications in dynamic settings, steady-state design approaches can lead to suboptimal solutions due to the neglect of the dynamic behavior. In this work, we present an approach for the integrated design of ORC process and working fluid considering the dynamics. The approach is based on the Continuous-Molecular Targeting–Computer-aided Molecular Design (CoMT-CAMD) framework. Herein, the physically based Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT) is used as thermodynamic model. To capture the ORC behavior under dynamic conditions, dynamic models for the ORC equipment are integrated into the process model. The result is an optimal control problem (OCP) yielding an optimal working fluid and the corresponding optimal process control for a given dynamic input. This so-called dynamic CoMT-CAMD approach is applied to an ORC for waste-heat recovery on a heavy-duty vehicle. Whereas steady-state design approaches fail, the presented approach identifies the optimal working fluid and the corresponding optimal control of the ORC process.

[1]  Marina Stavrou,et al.  Comparison between a Homo- and a Heterosegmented Group Contribution Approach Based on the Perturbed-Chain Polar Statistical Associating Fluid Theory Equation of State , 2014 .

[2]  Patrick Linke,et al.  Computer-Aided Molecular Design: Fundamentals, Methods, and Applications , 2018 .

[3]  Gabriele Sadowski,et al.  Perturbed-Chain SAFT: An Equation of State Based on a Perturbation Theory for Chain Molecules , 2001 .

[4]  André Bardow,et al.  Continuous-Molecular Targeting for Integrated Solvent and Process Design , 2010 .

[5]  Patrick Linke,et al.  The Impact of Novel and Conventional Working Fluids on the Control Performance in Organic Rankine Cycles , 2017 .

[6]  André Bardow,et al.  Computer-aided molecular design in the continuous-molecular targeting framework using group-contribution PC-SAFT , 2015, Comput. Chem. Eng..

[7]  Ben Sharpe,et al.  Overview of the heavy-duty vehicle market and CO₂ emissions in the European Union , 2015 .

[8]  Antti Uusitalo,et al.  Organic Rankine Cycle Power Systems: From the Concept to Current Technology, Applications, and an Outlook to the Future , 2015 .

[9]  Junqiang Zhou,et al.  Nonlinear Model Predictive Control of an Organic Rankine Cycle for Exhaust Waste Heat Recovery in Automotive Engines , 2015 .

[10]  Johannes P. Schlöder,et al.  An efficient multiple shooting based reduced SQP strategy for large-scale dynamic process optimization: Part II: Software aspects and applications , 2003, Comput. Chem. Eng..

[11]  Wolfgang R. Huster,et al.  Validated dynamic model of an organic Rankine cycle (ORC) for waste heat recovery in a diesel truck , 2018 .

[12]  Yousef Jeihouni,et al.  Fuel Economy Benefits for Commercial Diesel Engines with Waste Heat Recovery , 2015 .

[13]  Rafiqul Gani,et al.  Chemical product design: challenges and opportunities , 2004, Comput. Chem. Eng..

[14]  Paolino Tona,et al.  Optimal Control for an Organic Rankine Cycle on board a Diesel-Electric Railcar , 2015 .

[15]  Francesco Calise,et al.  Design and simulation of a prototype of a small-scale solar CHP system based on evacuated flat-plate solar collectors and Organic Rankine Cycle , 2015 .