The persistent goal, towards combating climate change, has mandated an increasing need for carbon neutralized energy production by non-conventional or renewable methods. Since 50% or even more of the conventional heat energy being dissipated as waste heat, utilizing the waste could play an exceptional role in reducing emissions. Through efficient recovery methods, exploiting energy with these waste heat sources are becoming significantly increased in recent years. Organic Rankine Cycle (ORC) technology is one of the most effective methods, specifically when it comes to low and medium grade waste heat recovery (WHR).  To obtain the maximum possible cycle efficiency from an ORC plant, effective operation of the turbomachinery and heat exchanger components are necessary. Dynamic modeling is increasingly becoming substantial in power plants especially during the design phase, as it helps in better assessment of the system performance and therefore to present control methodologies for its operation. Besides, it can also be used to investigate the transient behavior of the plant when operating in variable conditions. Dynamic behavior is important, especially in small-scale WHR applications.

In the present work, a dynamic model has been developed for the small-scale high-temperature ORC experimental test rig at the LUT University that utilizes waste heat from a heavy-duty diesel engine exhaust. The experimental facility consists of a high-speed Turbogenerator with a supersonic radial-inflow turbine, a barske type main-feed pump and a permanent magnet type generator components connected on a single shaft addition to heat exchanger components such as recuperator, condenser, and evaporator with a pre-feed pump to boost the working fluid pressure after the condensation process constituting a cycle. Octamethyltrisiloxane (MDM) is the chosen organic working fluid in this cycle. Matlab-Simulink environment along with the open-source thermodynamic and transport database CoolProp has been chosen for calculating the thermodynamic properties of the dynamic model. A lumped parameter model approach has been followed for modeling each block component namely, Turbogenerator, recuperator, condenser, pre-feed & main-feed pumps and the evaporator by predefined input and output parameters. Also, it is aimed at modeling the performance characteristics with a limited number of inputs for both design and off-design operations of the cycle. The dynamic model will be validated with the experimental data, which together will help build an optimized performance and control characteristics of the process.


Dynamic Modelling of Small Scale and High Temperature ORC System Using Simulink and CoolProp

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

Turbo Expo - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.