Calcium-looping systems can be integrated in concentrated solar power (CSP) plants as an alternative for thermal energy storage. This storage concept is based in the high temperature reversible calcination-carbonation reactions, in which limestone and lime are alternatively converted. Energy from CSP can be stored by limestone calcination (endothermic reaction) at high temperatures producing pure streams of CaO and CO2. This energy can be later released when demand increases by means of carbonation reaction (exothermic) at relatively high temperatures. Calciner reactor is a complex system where heterogeneous chemical reactions take place while absorbing heat from solar concentrating equipment. It is a key element of the process. Depending on the design and the distribution of heat along the calciner, the amount of energy required to store the same amount of chemical energy in the form of lime varies, as well as the temperature of the solids. Optimal design and operating conditions will minimize average temperature in the calciner for a given flow of produced lime. In this work, the modelling of a multi-stage solar calciner is described in the frame of a new solar-based CSP plant. (C) 2020 Elsevier Ltd. All rights reserved.