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The paper aims to study the impact of Thermal Energy Storage (TES) technology on the dynamic characteristics of Concentrated Solar Power (CSP). An integrated dynamic model of a CSP plant is firstly established, which combines the concentrating system, the TES system, and S–CO 2 Brayton power cycle system. Three TES alternatives are considered: two-tank molten salt TES (TT-TES), packed-bed TES with solid fillers (PBS-TES), packed-bed TES with phase change materials (PBP-TES). Using this integrated dynamic model, the thermal performance and economic feasibility of different TES technologies applied to CSP are compared and analyzed. The results indicate that utilization of packed-bed TES primarily impacts the optical efficiency of the heliostat field and the thermal efficiency of the power cycle, while having minimal effect on the receiver's thermal efficiency. Furthermore, during the vernal equinox, the daily average system efficiencies of CSP configurations integrating TT-TES, PBS-TES, PBP-TES technologies are 26.0 %, 25.5 %, and 24.5 %, respectively. Meanwhile, the use of packed-bed TES systems significantly reduces the material cost of the TES. In comparison to the TT-TES, the PBP-TES and the PBS-TES can reduce cost by 21.2 % and 42.3 %, respectively, and decrease TES volume by 83.0 % and 63.8 %, respectively. • An integrated dynamic model of a concentrated solar power is established. • The influence of three TES technologies on the dynamic characteristics of CSP is studied. • The TES technologies include two-tank molten salt TES, packed-bed TES with solid fillers, and packed-bed TES with PCMs. • Packed-bed TES affects charging and discharging processes, causing energy loss. • Packed-bed TES reduces cost and volume compared to two-tank molten salt TES. [ABSTRACT FROM AUTHOR]

Packed-bed thermal energy storage (PBTES) systems utilizing phase change capsules have found extensive applications in thermal energy harvesting and management to alleviate energy supply-demand imbalances. Nevertheless, the sluggish thermal charging rate of phase change materials (PCMs) capsules remains a significant impediment to the rapid advancement of PBTES. Here, bionic PCMs capsules are proposed by mimicking the internal and external structure of chloroplast-granum. The heat transfer and flow characteristics of the bionic PCMs capsules in the packed-bed are analyzed by experiments and numerical simulations. The results illustrate that the chloroplast-fin type PCMs capsule exhibits significantly faster heat storage compared to the sphere type PCMs capsule. This improvement is attributed to the bionic folded shape and inner membrane structure, which generate multiple local vortices to enhance heat convection, and shorten the heat transfer distance between the capsule wall and center PCMs to facilitate heat conduction. The PCMs capsules are further filled into the packed-bed in a staggered arrangement, resulting in increased heat transfer area and enhanced disturbance flow as compared to an aligned arrangement. Consequently, the melting time of the packed-bed filled with chloroplast-fin type capsules is reduced by 33.2%, meanwhile the average exergy storage rate and exergy efficiency are enhanced by 48.4% and 8.3%, respectively, compared to the packed-bed filled with sphere type capsules. This research offers a novel approach for designing high-performance PBTES system utilizing bionic capsules. • Chloroplast-granum inspired PCMs capsules are proposed for fast thermal charging. • Heat transfer mechanism is revealed for the bionic capsules and the packed-beds. • Chloroplast-fin type PCMs capsules reduce the melting time by 49.9%. • Packed-beds with bionic capsules increase the exergy efficiency by 8.3%. [ABSTRACT FROM AUTHOR]

Packed-bed single-tank thermocline system with reduced cost is an alternative to the conventional two-tank system for thermal energy storage. This work systematically explores the wall impact on thermocline behavior of packed-bed tanks. For this purpose, adapted transient models were developed and fully exploited for the first time. Two tank configurations were investigated and compared: a high-temperature pilot-scale tank with a steel wall and a low-temperature lab-scale tank with a polycarbonate wall, both tanks being insulated by mineral wool. Results showed that the maximum energy stored in the wall at fully charged state can be up to 10% of the total stored energy. This part of stored energy has a negative impact on the discharging, causing up to 15% increase of the thermocline thickness. The energy stored in the insulation is very small so that this phase can be simplified as a thermal resistance in the modeling. The optimal wall parameters for packed-bed TES tanks were obtained that a thinner wall has a smaller impact on the energy and exergy efficiencies at the discharging cutoff time. The findings of study could provide useful design guideline for pack-bed thermocline TES tanks for different industrial applications. • Wall effect in packed-bed thermocline storage tank is studied by dynamic modeling. • Stored heat inside wall before discharging can be up to 10%. • Longitudinal wall heat conduction can be ignored. • In discharging, the stored heat in wall increase thermocline thickness by up to 15%. • Decrease wall thickness can achieve higher energy and exergy efficiency. [ABSTRACT FROM AUTHOR]