What is Supercritical Heat Exchanger

Due to the unique thermal and transport properties, supercritical natural circulation loop (NCL, or thermosyphon) has been proposed in many energy systems, such as solar heater, nuclear cooling, waste heat recovery, geothermal, etc. This chapter presents the principals of supercritical natural circulation loop and its application challenges. A specially designed experimental prototype system is introduced and compared with numerical findings. The system is operated in wide range of pressures from around 6.0 MPa to 15.0 MPa in the near-critical region. It is found that in a supercritical natural circulation system, very high Reynolds number natural convection flow can be achieved only by simple heating and cooling. Thermal performance analysis and parameter effects are carried out along with the experimental development. The heat transfer dependency on operation and its mechanisms are also explained and summarized in this chapter. The comparison of experimental and numerical results contributes to better understanding of NCL stability phenomena and applications in energy systems.