PERFORMANCE ANALYSIS OF SUPERCRITICAL ORGANIC RANKINE CYCLES (ORCS) BASED ON THE VARIATIONS IN THERMAOPYSICAL PROPERTIES IN THE PSEUDOCRITICAL REGION asme-orc2015 Tracking Number 53Presentation: Session: Session 5: Supercritical ORC Room: 1B Europe Session start: 14:40 Mon 12 Oct 2015 Ran Tian tianr13@mails.tsinghua.edu.cn Affifliation: Qingsong An anqingsong@tsinghua.edu.cn Affifliation: Lin Shi rnxsl@mail.tsinghua.edu.cn Affifliation: Huixing Zhai lioncleverstar@163.com Affifliation: Xiaoye Dai daixy14@mails.tsinghua.edu.cn Affifliation: Topics: - System Design and Optimization (Topics), - Simulation and Design Tools (Topics), - I prefer Oral Presentation (Presentation Preference) Abstract: Supercritical organic rankine cycles (ORCs) appear to be more attractive compared with subcritical ORCs in terms of lower exergy destruction and higher thermal efficiency and work output. However, the heat transfer mechanisms about supercritical cycle around the critical point is still less known due to the significant variations in thermophysical properties. The strong variations in thermophysical properties have great influence on the heat transfer and thus significantly affect the determination of ORCs operating parameters. The physical mathematical model considering supercritical pressure heat transfer is developed. The aim of this paper is to investigate the influence of the significant changes in thermophysical properties in the pseudocritical region on the ORC performance, providing guidelines for system design. Convection heat-transfer coefficient of the working fluid, pinch point location, heat exchanger area and work output are analyzed based on the changes of thermophysical properties in the pseudocritical region for different heat source temperature. |