A calibrated organic Rankine cycle dynamic model applying to subcritical system and transcritical system. (15th December 2021)

• Record Type: Journal Article
• Authors: Cai, Jinwen; Tian, Hua; Wang, Xuan; Wang, Rui; Shu, Gequn; Wang, Mingtao
• Is Part Of: Energy. Volume 237(2021)
• Publication Date: 2021-12-15
• Subjects: Organic Rankine cycle -- Model calibration -- Subcritical system -- Transcritical system -- Evaporator; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2021.121494
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: The organic Rankine cycle (ORC) technology is an attractive candidate for waste heat recovery and clean energy utilization. The operating condition of ORC system would change constantly under fluctuant heat source and a dynamic model is able to predict the transient behavior. The ORC dynamic model generally contains some unknown parameters while their identification is often ignored. This paper proposes a detailed calibration mechanism for ORC dynamic model including subcritical and transcritical system. Component models including pump, expansion valve and evaporator are well calibrated and the integrated calibrated system model is validated based on experimental data. Results indicate that calibrated model can capture the system dynamic behavior well. For key system state parameters such as working fluid evaporator pressure and outlet temperature, model prediction can achieve mean absolute relative deviation of less than 2% for both subcritical and transcritical system. Meanwhile, the conventional expansion valve model for transcritical system is found not efficient enough and a modification form is provided. This work can contribute to the calibration mechanism of similar thermodynamic system and enhance the confidence in model application. Highlights: An ORC dynamic model applying to subcritical and transcritical system. A modified expansion valve flow equation for transcritical system. Two types of correction multipliers in evaporator calibration. The mean absolute relative deviation of less than 2% for model prediction.