High Temperature Thermal Energy Storage Using EPCM: The Effect of Void

2014 ◽  
Author(s):  
Laura Solomon ◽  
Ali F. Elmozughi ◽  
Sudhakar Neti ◽  
Alparslan Oztekin
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Liquid Interface ◽  
Heat Of Fusion ◽  
Steel Shell ◽  
Initial Location ◽  
Solid Liquid Interface ◽  
Solid Liquid

Heat transfer simulations and predictions of the thermal energy storage capability using encapsulated phase change materials (EPCM) at high temperatures are conducted. NaNO3 is considered as a phase change material (PCM). The PCM is encapsulated by a stainless steel shell. Two dimensional simulations of a cylindrical capsule are considered. The effects of the buoyancy driven convection in the molten PCM as well as the thermal and volume expansions due to phase change are included in the thermal analysis. An initial void level of 20% is considered in the simulations of the EPCM capsules. EPCM capsules store energy not only by sensible heat but also by the latent heat of fusion as heat is stored or extracted from the capsule. The solid/liquid interface inside the PCM propagates radially inward during the melting process. The effect of a void on the thermal energy storage and on the evolution of the solid/liquid interface is characterized. Two cases are presented, that of a local void initially at the top of the EPCM capsule and an initially random void distribution. The initial location of the void within the capsule has a profound effect on the shape of the solid/liquid interface and the isotherms within the capsule. The results of these simulations can be the basis for the design of an EPCM based thermocline for thermal energy storage (TES) at a concentrated solar power plant and other applications.

scholarly journals Edible Oils as Practical Phase Change Materials for Thermal Energy Storage

2019 ◽  
Vol 9 (8) ◽  
pp. 1627 ◽  
Author(s):  
Samer Kahwaji ◽  
Mary Anne White
Keyword(s):  
Thermal Stability ◽  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Edible Oils ◽  
Coconut Oil ◽  
Heat Of Fusion ◽  
Vegetable Shortening

Edible oils could provide more accessible alternatives to other phase change materials (PCMs) for consumers who wish to build a thermal energy storage (TES) system with sustainable materials. Edible oils have good shelf life, can be acquired easily from local stores and can be less expensive than other PCMs. In this work, we explore whether margarine, vegetable shortening, and coconut oil are feasible PCMs, by investigations of their thermal properties and thermal stability. We found that margarine and vegetable shortening are not useful for TES due to their low latent heat of fusion, ΔfusH, and poor thermal stability. In contrast, coconut oil remained thermally stable after 200 melt-freeze cycles, and has a large ΔfusH of 105 ± 11 J g−1, a low degree of supercooling and a transition temperature, Tmpt = 24.5 ± 1.5 °C, that makes it very useful for TES in buildings. We also determined coconut oil’s heat capacity and thermal conductivity as functions of temperature and used the measured properties to evaluate the feasibility of coconut oil for thermal buffering and passive heating of a residential-scale greenhouse.

Galactitol hexa stearate and galactitol hexa palmitate as novel solid–liquid phase change materials for thermal energy storage

Solar Energy ◽  
2011 ◽  
Vol 85 (9) ◽  
pp. 2061-2071 ◽  
Author(s):  
Ahmet Sarı ◽  
Alper Biçer ◽  
Özgür Lafçı ◽  
Mustafa Ceylan
Keyword(s):  
Energy Storage ◽  
Liquid Phase ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Solid Liquid

Enhanced thermal conductivity of phase change materials with ultrathin-graphite foams for thermal energy storage

2014 ◽  
Vol 7 (3) ◽  
pp. 1185-1192 ◽  
Author(s):  
Hengxing Ji ◽  
Daniel P. Sellan ◽  
Michael T. Pettes ◽  
Xianghua Kong ◽  
Junyi Ji ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Energy Storage ◽  
Phase Change ◽  
Specific Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Heat Of Fusion ◽  
Change Material ◽  
Enhanced Thermal Conductivity

Embedding continuous ultrathin-graphite foams (UGFs) with volume fractions as low as 0.8–1.2 vol% in a phase change material (PCM) can increase the effective thermal conductivity by up to 18 times, with negligible change in the melting temperature or mass specific heat of fusion.

Ultraviolet-Visible Light-Thermal Conversion Organic Solid-Liquid Phase-Change Materials

2013 ◽  
Vol 679 ◽  
pp. 29-34
Author(s):  
Yun Ming Wang ◽  
Bing Tao Tang ◽  
Shu Fen Zhang
Keyword(s):  
Energy Storage ◽  
Liquid Phase ◽  
Solar Radiation ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Thermal Conversion ◽  
Organic Solid ◽  
Solid Liquid

UV-vis light-driven organic solid-liquid phase change materials exhibited excellent performances of UV-vis light-harvesting, UV-vis light-thermal conversion and thermal energy storage, which is promoted by UV absorbing dye as an effective ‘‘photon capture and molecular heater’’ for direct and efficient use of solar radiation.

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