Marta Serrano-Garcia1
CIEMAT1
Currently, the research focus regarding CSP technology worldwide is related to the development of systems that can reach temperatures close to 1000°C. The concept of particle-based receiver is regarded as a promising candidate where solid particles are both heat-transfer and thermal energy storage media showing the potential to exceed 1000°C. Meanwhile, supercritical carbon dioxide (s-CO2) Brayton cycles offer advantages of its mass density, low viscosity and favourable heat transfer properties, which reduces the cost of concentrating solar power (CSP). The Horizon 2020 project COMPASsCO2 focuses on the efficient and reliable integration of storable solar energy by solid particles into s-CO2 Brayton cycles. In COMPASsCO2, the key component for such an integration, <i>i.e.</i> the particle/s-CO2 heat exchanger, will be validated in a relevant environment. One of the main technological challenges is the selection of the heat exchange tube materials as the operating parameters of s-CO2 heat exchangers are estimated around 700°C and 25 MPa at the internal wall.<br/>In this work, the material selection criteria for the COMPASSCO2 heat exchanger tubes is summarized, the first results of the mechanical properties at high temperature of commercial alloys are discussed as well as the development of novel Cr nickel aluminide (NiAl) and Cr silicides superalloys.