Dynamic Simulation of a 2 MW ORC for Industrial Waste Heat Recovery with a Large-Scale Thermal Energy Storage System

Waste heat recovery (WHR) technologies play a crucial role in enhancing energy efficiency and reducing CO2 emissions in energy-intensive industries. The DECAGONE project addresses this by developing a state-of-the-art Organic Rankine Cycle(ORC)-based WHR system, which is scheduled for demonstration at an iron and steel plant in the Czech Republic. The design must address significant challenges posed by fluctuating heat source conditions, which can lead to off-design operation of the ORC. To overcome these challenges, the study introduces a novel integration of a Thermal Energy Storage (TES) system model with an intermediate thermal oil loop positioned between the flue gas stream and the ORC into the existing ORC model. The TES functions as a buffer that mitigates large fluctuations in temperature and volume flow, ensuring a more stable heat input and less off-design performance. Concurrently, the thermal oil circuit facilitates safe and efficient heat transfer from the variable flue gas source to the ORC, while decoupling heat input from power generation to further stabilise system performance. This work in progress delivers valuable results and insights for the community by focusing on the performance of the integrated ORC and TES system under fluctuating flue gas conditions. This study explores the influence of varying TES charge and discharge states on ORC efficiency and transient behaviour. The results offer valuable insights for developing more resilient and adaptable WHR systems for industrial applications and demonstrate that TES can effectively dampen thermal input fluctuations, thereby reducing ORC downtime and mitigating the impact of off-design operation. This emphasises the importance of thermal storage in enhancing performance stability and operational reliability under dynamic flue gas conditions.     «

Waste heat recovery (WHR) technologies play a crucial role in enhancing energy efficiency and reducing CO2 emissions in energy-intensive industries. The DECAGONE project addresses this by developing a state-of-the-art Organic Rankine Cycle(ORC)-based WHR system, which is scheduled for demonstration at an iron and steel plant in the Czech Republic. The design must address significant challenges posed by fluctuating heat source conditions, which can lead to off-design operation of the ORC. To ov...     »