200 MW_th and 1 MW_th chloride salt to supercritical carbon dioxide heat exchanger and test integration designs Free

The Generation 3 Concentrating Solar Power Liquid Pathway (G3LP) proposes the use of a ternary chloride molten salt as a heat transfer fluid and thermal energy storage (TES) media with heat input from a sodium receiver loop and heat removal by a supercritical carbon dioxide (sCO₂) Brayton cycle to reduce the levelized cost of energy of commercial CSP plants to 6 ¢/kW-hr in line with the U.S. Department of Energy SunShot targets. This system architecture requires a primary heat exchanger (PHX) between the ternary chloride salt TES and the sCO₂ working fluid of the power cycle operating up to 720 °C with a 30-year lifetime, high reliability, and low cost. The combination of a highly corrosive high-temperature fluid on one side and a high pressure and temperature fluid on the other suggests the need for a compact high-performance heat exchanger in order to reduce the amount of corrosion-resistant material required for fabrication and allow for small channel diameters to more easily contain the operating pressure of the sCO₂ at high temperatures (>700C). This paper presents the results of the G3LP design for a compact salt to sCO₂ heat exchanger scalable to a 200 MW_th commercial plant size with a 1 MW_th detailed design for demonstration with a G3LP Phase 3 pilot plant.