Techno-economic Comparison of Reciprocating-piston Expanders and Radial-inflow Turbines in Small- to Medium-scale ORC Systems orc2019 Tracking Number 119Presentation: Session: Session 1A: Turbines-Design Aspects (1) Room: Olympia Session start: 10:30 Mon 09 Sep 2019 Dauda Ibrahim d.ibrahim@imperial.ac.uk Affifliation: Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK Michael Simpson m.simpson16@imperial.ac.uk Affifliation: Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK Jian Song jian.song@imperial.ac.uk Affifliation: Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London Paul Sapin p.sapin@imperial.ac.uk Affifliation: Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK Antonio Pantaleo a.pantaleo@imperial.ac.uk Affifliation: Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK & Department of Agro-environmental Sciences, University of Bari, Via Amendola 165/A, 70125 Bari, Italy Pietro De Palma pietro.depalma@poliba.it Affifliation: Department of Mechanics, Mathematics and Management, Polytechnic of Bari, Via Re David 200, 70125 Bari, Italy Christos Markides c.markides@imperial.ac.uk Affifliation: Clean Energy Processes (CEP) Laboratory, Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK Topics: - Applications and Energy Sources (Topics), - System Design and Optimization (Topics), - Working Fluids, including mixtures (Topics), - Turbines (Topics), - Volumetric expanders (Topics), - Simulation and Design Tools (Topics), - Waste heat recovery (Topics), - Oral Presentation (Preferred Presentation type) Abstract: Designing feasible and economically-viable organic Rankine cycle (ORC) systems for applications such as high-grade heat recovery from the exhaust gases (400 600 °C) of stationary internal combustion engines (ICEs) has two main challenges: (i) selecting and designing an appropriate expansion technology, amongst the other system components, and (ii) selecting the optimal working fluid, and operational system parameters. In this work, comprehensive component models are integrated into an ORC system model to evaluate the on- and off-design performance of a 2.5-MWe ORC engine using either a reciprocating-piston expander or a radial-inflow turbine. The performance of the reciprocating-piston expander is predicted using a dynamic lumped-mass model, and a one-dimensional model based on the mean-line method is used to predict the performance of the turbine. An initial working-fluid screening leads to R1233zd being selected for further consideration, given the minimal specific investment costs and low-pressure ratio of the resulting ORC systems, thus assisting the design of suitable expansion devices. The approximate design point obtained from the screening study is used to obtain optimised piston and turbine designs that are then used to produce full- and part-load performance maps that are integrated into the ORC system model. The ORC engine with a turbine is found to deliver 127 kW at full load, at a specific investment cost of 1660 £/kW, while the piston expander produces a lower net power of 68 kW, but at a lower cost of 1250 £/kW, while also showing greater robustness to variations in the heat-source conditions. |