Computational Evaluation of the Effects of Voids on a Thermal Energy Storage System Using Molten Silicon as the Phase Change Material

2013 ◽  
Author(s):  
Thomas R. Amundson ◽  
David B. Scharfe ◽  
Rebecca N. Webb
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Low Earth Orbit ◽  
Heat Energy ◽  
Temperature Phase ◽  
Molten Silicon ◽  
Computational Evaluation ◽  
Change Material

Latent heat energy storage is one of the most efficient ways to store solar thermal energy. A system capable of receiving, absorbing, and collecting solar energy and storing it within a high temperature phase change material has been designed as part of a power system to be used on a low Earth orbit satellite. The system employs silicon as the phase change material and thermophotovoltaic cells for the conversion of stored heat energy into electrical energy. The effect of a void, in the phase change material, on system temperature and the associated thermophotovoltaic power production is determined through computational evaluation.

Computational Evaluation of Latent Heat Energy Storage Using a High Temperature Phase Change Material

2012 ◽  
Author(s):  
Michael R. Reid ◽  
Rebecca N. Webb ◽  
Taylor C. Lilly ◽  
David B. Scharfe
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Latent Heat ◽  
Simulation Software ◽  
Heat Energy ◽  
Solar Irradiation ◽  
Temperature Phase ◽  
Molten Silicon ◽  
Change Material

Latent heat energy storage systems have higher energy density than their sensible heat counterparts and have the added benefit of constant temperature operation. This work computationally evaluates a thermal energy storage system using molten silicon as a phase change material. A cylindrical receiver, absorber, converter system was evaluated using the heat transfer in solids with surface-to surface radiation physics module of the commercially available COMSOL Multiphysics simulation software. The progression of the solidification and melting fronts through the phase change material was modeled for two different methods of concentrated solar irradiation delivery. Heating the core of the PCM rather than the top of the PCM decreased the required solar input by 17%, decreasing the solar collector area required as well as lowering overall system weight.

Thermal Energy Storage Through Melting of a Commercial Phase Change Material in an Annulus with Radially Divergent Longitudinal Fins

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Storage System ◽  
Operating Conditions ◽  
Melting Time ◽  
Bottom Part ◽  
Change Material

This study reports on the unsteady two-dimensional numerical investigations of melting of a paraffin wax (phase change material, PCM) which melts over a temperature range of 8.7oC. The PCM is placed inside a circular concentric horizontal-finned annulus for the storage of thermal energy. The inner tube is fitted with three radially diverging longitudinal fins strategically placed near the bottom part of the annulus to accelerate the melting process there. The developed CFD code used in Tabassum et al., 2018 is extended to incorporate the presence of fins. The numerical results show that the average Nusselt number over the inner tube surface, the total melt fraction, the total stored energy all increased at every time instant in the finned annulus compared to the annulus without fins. This is due to the fact that in the finned annulus, the fins at the lower part of the annulus promotes buoyancy-driven convection as opposed to the slow conduction melting that prevails at the bottom part of the plain annulus. Fins with two different heights have been considered. It is found that by extending the height of the fin to 50% of the annular gap about 33.05% more energy could be stored compared to the bare annulus at the melting time of 82.37 min for the identical operating conditions. The effects of fins with different heights on the temperature and streamfunction distributions are found to be different. The present study can provide some useful guidelines for achieving a better thermal energy storage system.

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