An approach to analyze and optimize the thermal performance of a refractory-lined particle receiver in response to solar resource variability has been demonstrated. A transient mathematical model has been developed, incorporating variable direct normal irradiance (DNI) and heat losses associated with a directly irradiated particle receiver. The model is employed to assess the time-dependent temperature fields of the receiver cavity walls, the particles and gas from the initial state to another equilibrium. The influence of the receiver's geometric parameters on the transient thermal response of the receiver has been assessed using real-time solar irradiance data based on the temperature changes for each phase. This can be used to support optimization of the refractory lining and insulation, to trade-off between the solar DNI input, thermal losses from the receiver, and allowable temperatures and heating rates of refractory and outer steel shell, via an energy balance. New insight is provided on the role of the material and thickness of the refractory lining on the system output when accounting for the allowable heating rate of refractory material to avoid failure due to thermal shock. (c) 2020 Elsevier Ltd. All rights reserved.