scholarly journals Effectiveness of Thermal Properties in Thermal Energy Storage Modeling

2021 ◽  
Vol 7 ◽  
Author(s):  
Law Torres Sevilla ◽  
Jovana Radulovic
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Energy Storage ◽  
Specific Heat ◽  
Melting Temperature ◽  
Latent Heat ◽  
Specific Heat Capacity ◽  
Thermal Energy ◽  
Thermal Energy Storage

This paper studies the influence of material thermal properties on the charging dynamics in a low temperature Thermal Energy Storage, which combines sensible and latent heat. The analysis is based on a small scale packed bed with encapsulated PCMs, numerically solved using COMSOL Multiphysics. The PCMs studied are materials constructed based on typical thermal properties (melting temperature, density, specific heat capacity (solid and liquid), thermal conductivity (solid and liquid) and the latent heat) of storage mediums in literature. The range of values are: 25–65°C for the melting temperature, 10–500 kJ/kg for the latent heat, 600–1,000 kg/m3 for the density, 0.1–0.4 W/mK (solid and liquid) for the thermal conductivity and 1,000–2,200 J/kgK (solid and liquid) for the specific heat capacity. The temperature change is monitored at three different positions along the tank. The system consists of a 2D tank with L/D ratio of 1 at a starting temperature of 20°C. Water, as the heat transfer fluid, enters the tank at 90°C. Results indicate that latent heat is a leading parameter in the performance of the system, and that the thermal properties of the PCM in liquid phase influence the overall heat absorption more than its solid counterpart.

Investigation of Thermal Properties in Nanofluids for Thermal Energy Storage Applications

2013 ◽  
Author(s):  
Aitor Zabalegui ◽  
Bernadette Tong ◽  
Hohyun Lee
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Energy Storage ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Working Fluid ◽  
Traditional Theory ◽  
Energy Storage Applications ◽  
Particle Addition

Phase change materials (PCMs) are promising for thermal energy storage applications, but low thermal conductivity limits their heat exchange rate with a working fluid. The nanofluid approach has been established as a method of thermal conductivity enhancement, but particle addition may have an adverse effect on specific energy storage capacity. Latent heat reduction beyond traditional theory has been observed experimentally for carbon nanotubes dispersed in paraffin wax. Nanofluid latent heat and effective thermal conductivity were analyzed to investigate the effects of particle addition on thermal properties affecting PCM energy storage performance. It is shown that particle diameter significantly impacts nanofluid latent heat, with smaller particles generating greater degrees of reduction, but has a negligible effect on thermal conductivity. A method to approximate nanofluid latent heat of fusion is presented, considering the diameter-dependent reduction observed.

Experimental Characterization of the Thermal Diffusivity of Paraffin Phase Change Material Embedded With Herringbone Style Graphite Nanofibers

2012 ◽  
Author(s):  
Ronald J. Warzoha ◽  
Anthony Rao ◽  
Rebecca Weigand ◽  
Amy S. Fleischer
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Thermal Diffusivity ◽  
Phase Change ◽  
Specific Heat ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Melt Temperature ◽  
Graphite Nanofibers

Phase change materials (PCMs) are promising candidates for thermal energy storage due to their intrinsically high values of latent heat. However, PCMs are unable to effectively utilize all of their energy storage capacities due to their poor thermophysical properties. In this study, the effect of graphite nanofibers (diameter = 2 to 1000 nm, length = 100μm) on the bulk thermal properties of paraffin PCM (Tmelt = 56 °C) is investigated. Material properties including effective thermal conductivity, specific heat, latent heat, melt temperature and thermal diffusivity are measured using a Differential Scanning Calorimeter (DSC) and comparative reference bar apparatus. Results suggest that the addition of nanostructures not only increases thermal conductivity by up to 180%, but also reduces the specific heat capacity and density of nano-enhanced paraffin, leading to improved thermal diffusivity and thus greater utilization of its latent heat for transient thermal energy storage.

scholarly journals Synthesis and Characterization of Molten Salt Nanofluids for Thermal Energy Storage Application in Concentrated Solar Power Plants—Mechanistic Understanding of Specific Heat Capacity Enhancement

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2266
Author(s):  
Binjian Ma ◽  
Donghyun Shin ◽  
Debjyoti Banerjee
Keyword(s):  
Heat Capacity ◽  
Energy Storage ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Solar Power ◽  
Alumina Nanoparticles ◽  
Concentrated Solar Power

Molten salts mixed with nanoparticles have been shown as a promising candidate as the thermal energy storage (TES) material in concentrated solar power (CSP) plants. However, the conventional method used to prepare molten salt nanofluid suffers from a high material cost, intensive energy use, and laborious process. In this study, solar salt-Al2O3 nanofluids at three different concentrations are prepared by a one-step method in which the oxide nanoparticles are generated in the salt melt directly from precursors. The morphologies of the obtained nanomaterials are examined under scanning electron microscopy and the specific heat capacities are measured using the temperature history (T-history) method. A non-linear enhancement in the specific heat capacity of molten salt nanofluid is observed from the thermal characterization at a nanoparticle mass concentration of 0.5%, 1.0%, and 1.5%. In particular, a maximum enhancement of 38.7% in specific heat is found for the nanofluid sample prepared with a target nanoparticle mass fraction of 1.0%. Such an enhancement trend is attributed to the formation of secondary nanostructure between the alumina nanoparticles in the molten salt matrix following a locally-dispersed-parcel pattern. These findings provide new insights to understanding the enhanced energy storage capacity of molten salt nanofluids.

Effect of Nano-TiO2 on Mechanical and Thermal Properties of Cement Composites for Thermal Energy Storage Materials

2015 ◽  
Vol 804 ◽  
pp. 115-118
Author(s):  
Pongsak Jittabut
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Compressive Strength ◽  
Thermal Properties ◽  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Energy Storage Materials ◽  
Mechanical And Thermal Properties ◽  
Storage Materials

This research article presents the mechanical and thermal properties of cement-based composite for thermal energy storage materials enriched with containing nanoTiO2 particle size (25 nm) and concentration (1-5 wt.%) were systematically investigated. Thermal properties coefficients were tested using a direct measuring instrument with surface probe (ISOMET2114). The influence of nanoTiO2 on the performance, such as compressive strength, bulk density, thermal conductivity, volume heat capacity and thermal diffusivity of hardened composite cement pastes were studied for future solar thermal energy materials with better performance. According to the development of thermal storage materials and their application environment requirement in solar thermal power, the specimens were subjected to heat at 350°C and 900°C. It was observed that, before heating, the compressive strength is optimized at nanoTiO2 amount of 2 wt%. Moreover, after heating at 350 °C and 900°C, the thermal conductivity and volume heat capacity of the cement paste enriched with nanoTiO2 were significantly lesser than that of the before heating one.

Mechanism Exploration of the Enhancement of Thermal Energy Storage in Molten Salt Nanofluid

2021 ◽  
Author(s):  
Zhao Li ◽  
Liu Cui ◽  
B. R. Li ◽  
xiaoze du
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Energy Storage ◽  
Specific Heat ◽  
Molten Salt ◽  
Specific Heat Capacity ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Md Simulations

The enhancement of the specific heat capacity of molten salt-based nanofluid is investigated via molecular dynamics (MD) simulations. The results show the addition of the nanoparticle indeed enhances the specific...

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