The Design Study of Supercritical Carbon Dioxide Integral Experiment Loop

Abstract

The Supercritical Carbon Dioxide cycle (S-CO2 cycle) can achieve relatively high efficiency in the moderate temperature (450–750°C) region because the cycle takes advantage of non-ideal properties variation near the critical point. The S-CO2 cycle was originally considered as an attractive candidate for power conversion cycle of the next generation reactors. However due to many benefits of the S-CO2 cycle, it is not only limited to the nuclear application but also considered in other conventional and renewable energy system applications including fossil fuel power plant systems, ship propulsion applications, concentrated solar power systems, fuel cell bottoming power cycles and so on. The major studies settle on the S-CO2 recompressing cycle (also known as Feher cycle) which reduces the waste heat and increases the recuperated heat by recompressing some portion of the flow without heat rejection to increase the thermodynamic efficiency of the cycle. To develop and verify the characteristics of the S-CO2 recompressing cycle, Korean Atomic Energy Research Institute (KAERI) and KAIST research team designed a Supercritical Carbon Dioxide Integral Experiment Loop (SCIEL). 550°C turbine inlet temperature and 20 MPa compressor outlet pressure condition are expected for SCIEL operation and the layout is recompressing cycle but other layouts will be studied as well. The experimental loop facility is designed for studying unique phenomena in components under various conditions and developing the strategy to improve the component performance and overall cycle efficiency. The operating condition and thermodynamic efficiency for SCIEL are evaluated from an in-house code developed by KAIST research team. The effect of the split flow, component sensitivity, and optimum cycle pressure ratio will also be analyzed for the preliminary design of SCIEL. Furthermore, turbomachinery sizes and heat exchanger sizes are estimated from other in-house codes developed by KAIST research team. The overall component specification and performance of SCIEL will be compared to other S-CO2 test loop facilities in other research institutes.