Orientation effect in helical coils with smooth and rib-roughened wall: Toward improved gas heaters for supercritical carbon dioxide Rankine cycles

Helical coils have gained increasingly interest in the field of supercritical carbon dioxide (SCCO2) Rankine cycles during the last decade due to the compact structure and high heat transfer rate. Past studies mainly focused on effects of operating conditions and the gravitational buoyancy, and are not sufficient to fully understand the behavior of SCCO2 helically coiled gas heaters. Influence of some other key factors, such as the coil...