Transient system analysis of a Gen3 particle-based CSP plant with spatially resolved thermal storage charging and discharging

High-temperature thermal energy storage using solid particles is being deployed in Gen3 CSP plants to relieve intermittency and reduce the overall cost of electricity production. However, the thermal storage bin cycle adds complexity to the system because the heat transfer modes within the bin introduce non-negligible transient features. In this work, we investigate these transient features by looking at a spatially resolved dynamic model that captures the salient physics of the thermal storage bin, both in the particle domain and the bin composite material. These results are integrated into a Gen3 CSP system model to better understand the sensitivity of system-wide performance metrics to the transient features in the hot storage bin particle outlet temperature. It is shown that the receiver-to-heat exchanger efficiency varies by approximately 0.15 percent per °C change in particle outlet temperature. This change in efficiency comes from the necessary compensation needed to maintain a steady heat exchanger operation. In this compensation scheme, the marginal adaptation becomes an added challenge since the slow mass transfer transients must be accounted for and integrated directly into the control system.