“…FB solar receivers have been investigated as early as in the '80s, with layouts spanning from the proof-of-concept to the lab-scale levels: dense stationary gas FB, dilute-or dense-phase circulating FB (Flamant, 1982;Bachovchin et al, 1983;Megahed et al, 1988;Haddad and Elsayed, 1988;Koenigsdorff and Kienzle, 1991;Sasse and Ingel, 1993;Werther et al, 1994;Baud et al, 2012;Chirone et al, 2013;Flamant et al, 2013;Ma et al, 2014;Marti et al, 2015;Reyes-Belmonte et al, 2019;Farsi and Dincer, 2019;Díaz-Heras et al, 2020a). The extension of these concepts to the industrial scale is a matter still deserving thoughtful investigation.…”