Storage and release of heat in a single spherical capsule containing phase change material of high melting point.

AbstractIn this study, suspension polymerization is described to fabricate microcapsules containing n-hexadecane as phase change material. In the suspension polymerization, casein is employed as emulsifier and stabilizer instead of synthetic surfactant. Microcapsules with polystyrene as shell and n-hexadecane as core have an average diameter of 3~15μm and the size distribution are narrow. Thermal properties are investigated by differential scanning calorimetry (DSC) showing that the microcapsules can store and release an amount of latent heat over a temperature range nearing the melting point of pure n-hexadecane. The latent heat of fusion of microencapsulated n-hexadecane decreases after microencapsulation. The melting point of microencapsulated n-hexadecane is near but higher than that of pure n-hexadecane, and the polymerization time has little effect on the melting point.

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Physical Property and Thermal Physical Property of Microencapsulated Phase Change Material Slurry

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.110-116.571 ◽

2011 ◽

Vol 110-116 ◽

pp. 571-576 ◽

Cited By ~ 1

Author(s):

Yan Lai Zhang

Keyword(s):

Heat Transfer ◽

Melting Point ◽

Phase Change ◽

Phase Change Material ◽

Physical Property ◽

Melamine Resin ◽

The Core ◽

Microencapsulated Phase Change Material ◽

Thermal Physical Property ◽

Change Material

Microencapsulated phase change material (PCM) slurry is a kind of novel heat transfer fluid called latent functionally thermal fluid. Unlike conventional (sensible) materials, when the PCM reach the temperature at which they begin phase change (its melting point), they absorb large amounts of heat with little or no temperature change. Due to this, the heat transfer ability and energy transport ability can be obviously improved. Therefore, they have many potentially important applications in some fields such as energy storage, thermal conditioning of buildings, waste heat recovery, off peak power utilization, heat pump systems, space applications. In present study, the core materials are encapsulated with membrane of synthetic material. And the core materials are composed of several kinds of n-paraffin waxes (mainly nonadecane) and the membrane is a type of melamine resin. The range of diameter of the PCM particles is distributed from 0 μm to 4.5 μm, and its average diameter is 0.74 μm. The thickness of melamine resin is about 11nm. The melting point of the PCM is about 304K. Physical properties, such as density, diameter and its distribution of microencapsulated PCM slurry are investigated. Meanwhile, the thermal physical property, apparent specific heat, is determined by a Differential Scanning Calorimeter (DSC). Also, the influence of mass concentration has been discussed.

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Thermodynamic Optimization of Phase-Change Energy Storage Using Two or More Materials

Journal of Energy Resources Technology ◽

10.1115/1.2905925 ◽

1992 ◽

Vol 114 (1) ◽

pp. 84-90 ◽

Cited By ~ 44

Author(s):

J. S. Lim ◽

A. Bejan ◽

J. H. Kim

Keyword(s):

Energy Storage ◽

Melting Point ◽

Phase Change ◽

Phase Change Material ◽

Finite Thickness ◽

Melting Process ◽

Two Phase ◽

In Series ◽

Optimal Melting ◽

Change Material

This paper documents the relative merits of using more than one type of phase-change material for energy storage. In the case of two phase-change systems in series, which are melted by the same stream of hot fluid, there exists an optimal melting point for each of the two materials. The first (upstream) system has the higher of the two melting points. The second part of the paper addresses the theoretical limit in which the melting point can vary continuously along the source stream, i.e., when an infinite number of different (and small) phase-change systems are being heated in series. It is shown that the performance of this scheme is equivalent to that which uses an optimum single phase-change material, in which the hot stream remains unmixed during the melting process. The time dependence, finite thickness and longitudinal variation of the melt layer caused by an unmixed stream are considered in the third part of the paper. It is shown that these features have a negligible effect on the optimal melting temperature, which is slightly higher than (T∞Te)1/2.

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Numerical and Experimental Investigations of Melting and Solidification Processes of High Melting Point PCM in a Cylindrical Enclosure

Journal of Heat Transfer ◽

10.1115/1.1800492 ◽

2004 ◽

Vol 126 (5) ◽

pp. 869-875 ◽

Cited By ~ 17

Author(s):

Ahmed Elgafy ◽

Osama Mesalhy ◽

Khalid Lafdi

Keyword(s):

Melting Point ◽

Solidification Process ◽

Heat Of Fusion ◽

Experimental Investigations ◽

High Melting ◽

High Melting Point ◽

Space Applications ◽

Solidification Processes ◽

Change Material ◽

Melting And Solidification

In the present work, a computational model is developed to investigate and predict the thermal performance of high melting point phase change material during its melting and solidification processes within a cylindrical enclosure. In this model the phases are assumed to be homogeneous and a source term, S, arises from melting or solidification process is considered as a function of the latent heat of fusion and the liquid phase fraction. The numerical model is verified with a test problem and an experiment is performed to assess the validity of the assumptions of it and an agreement between experimental and computational results is achieved. The findings show that utilizing of PCMs of high melting points is a promising technique especially in space applications.

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