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This study established a methodology for designing a cascade latent heat thermal energy storage system. The latent heat thermal energy storage has been investigated by numerous researchers as an energy-dense and lower cost alternative to the two-tank molten salt sensible heat thermal energy storage for concentrated solar power plants. However, in order to achieve a high storage efficiency without decreasing the efficiency of the receiver and power block, many design restrictions should be applied in the design, including the total storage capacity, charging/discharging rate, charging/discharging period and the temperature difference of heat transfer fluid between the inlet and outlet of the storage system for both the charging and discharging process. There is no methodology or guideline currently available in the literature to design such a storage system. Therefore, a new methodology has been proposed, and it was successfully demonstrated in a case study. To achieve the final design, three major steps are involved: preliminary design, coarse optimization and fine optimization. Though intensive simulation is needed, the proposed methodology is appropriate to design the cascade latent heat thermal energy storage system. [ABSTRACT FROM AUTHOR]

In the current study a novel geopolymer created from waste materials (namely fly ash and black slag) has been characterised as a potential high temperature thermal energy storage material option. Several geopolymer samples have been fabricated and characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Additionally, the density and heat capacity have been determined. Lastly, the cost of the material and packed bed system was estimated showing that the geopolymer-based systems are potentially 35% cheaper than the traditional 2-tank molten salt systems. [ABSTRACT FROM AUTHOR]

A numerical heat transfer analysis of the phase change material (PCM) in a high temperature vertical triplex tube thermal energy storage system (TTTESS) was performed, using ANSYS FLUENT 15.0. The model has been validated against experimental data using a low temperature PCM in a TTTESS. The numerical results agree well with experiment. The validated model was used to analyse a high temperature PCM in a TTTESS. Supercritical CO2 was assumed for the heat transfer fluid (HTF) which flows in the inside and outside tubes, whereas the lithium and potassium carbonate (Li2CO3-K2CO3) (35%-65%) PCM with a melting temperature of 505°C was enclosed between them. This study provides a comprehensive parametric analysis to demonstrate the effect of adding more fins relative to the case of no fins on the melting and solidification processes to find the optimum design of the TTTESS. The TTTESS with eight fins is the design that has substantial performance and is cost competitive compared with two-tank system [ABSTRACT FROM AUTHOR]

In the current study the feasibility of using concentrated solar power (CSP) coupled with thermal energy storage (TES) to displace gas for heating was explored. To assess the feasibility, a numerical model of an air-based encapsulated phase change storage system was developed, validated, optimised, and economically costed. The optimised air-based EPCM system utilised a high and low melting temperature PCM with a sensible filler. It was found that a capsule radius of 10 mm and PCM volume of 13 % resulted in the lowest cost of discharged energy of $25.55/kWht. This system was then coupled to typical meteorological year (TMY) solar data for Adelaide, South Australia, to simulate performance of a 1 MWt heat load over a year. By solving an hourly system generation and demand profile, it was found that the system could provide an economical alternative to gas when the gas price was $20/GJ for a variety of demand profiles. [ABSTRACT FROM AUTHOR]