Modeling of Arbitrary-Shaped Specific and Latent Heat Curves in Phase-Change Storage Simulation Routines

1990 ◽  
Vol 112 (1) ◽  
pp. 29-33 ◽  
Author(s):  
G. C. J. Bart ◽  
P. C. van der Laag

In solar heat storage, use is often made of the latent heat of phase-change materials (PCM) with a wide temperature transition range. In this paper the heat withdrawal of a slab of such a phase-change material after a step-wise change in wall temperature, and as a function of the shape of the specific and latent heat curve, has been studied with a computer simulation. It will be outlined that various shaped curves show the same heat withdrawal character as an equivalent rectangular-shaped specific heat curve. A procedure to obtain this equivalent curve will be given.

1986 ◽  
Vol 108 (4) ◽  
pp. 310-315 ◽  
Author(s):  
G. C. J. Bart ◽  
C. J. Hoogendoorn ◽  
P. B. J. Schaareman

In this paper a comparison is made between an approximate analytical solution and the numerical finite difference solution for the one dimensional solidification of a phase change material of finite size. The analytical model is not only capable of handling materials with a fixed melting temperature but is also extended to cope with materials with a transition range. In the approximate analytical model, use is made of the well known Neumann solution for the solidification in a semi-infinite region. A characteristic dimensionless time has been derived that can be used in a simplified description of the solidification of a phase-change material. With this description the testing of latent heat storage devices can be simplified and the results can also be used in simulation programs of solar energy installations with a latent heat storage.


Author(s):  
Mr. Omkar Jadhav

An experimental study using paraffin wax as a phase change material (PCM) was performed to analyse thermal physiognomies on the latent heat storage system (LHS). The use of phase change materials through latent heat storage is an unusual approach to maintaining thermal energy. There is the advantage of considerably high energy storage and the uniform temperature of the storage process. Tube & shell type heat exchanger (HE) has been used in this experimentation. Water circulates in tubes and around the tube’s paraffin wax as phase change material is filled. The focus is on heating (charging) and cooling (discharging) of PCM (paraffin wax), which is the melting and solidifying of paraffin wax. The temperature distribution in paraffin is studied consistent with the various flow rates of the warmth transfer fluid.


Author(s):  
J. Martínez-Gómez ◽  
E. Urresta ◽  
D. Gaona ◽  
G. Guerrón

Esta investigación tiene como objetivo seleccionar un material de cambio de fase (PCM) que cumplen mejor la solución del almacenamiento de energía térmica entre 200-400 ° C y reducir el costo de producción. El uso de métodos multicriterios de toma de decisiones (MCMD) para la evaluación fueron proporcionales implementados como COPRAS-G, TOPSIS y VIKOR. La ponderación de los criterios se realizó por el método AHP (proceso analítico jerárquico) y los métodos de entropía. La correlación de los resultados entre los tres métodos de clasificación ha sido desarrollada por el coeficiente de correlación de Spearman. Los resultados ilustran el mejor y la segundo mejor opción para los tres MCDM fueron NaOH y KNO3. Además, tenía valores de correlación de Spearman entre los métodos excede de 0.714.


Author(s):  
Yuran Shi ◽  
Mihael Gerkman ◽  
Qianfeng Qiu ◽  
Shuren Zhang ◽  
Grace G. D. Han

We report the design of photo-responsive organic phase change materials that can absorb filtered solar radiation to store both latent heat and photon energy via simultaneous phase transition and photo-isomerization....


Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 241
Author(s):  
Raul-Augustin Mitran ◽  
Simona Ioniţǎ ◽  
Daniel Lincu ◽  
Daniela Berger ◽  
Cristian Matei

Phase change materials (PCMs) can store thermal energy as latent heat through phase transitions. PCMs using the solid-liquid phase transition offer high 100–300 J g−1 enthalpy at constant temperature. However, pure compounds suffer from leakage, incongruent melting and crystallization, phase separation, and supercooling, which limit their heat storage capacity and reliability during multiple heating-cooling cycles. An appropriate approach to mitigating these drawbacks is the construction of composites as shape-stabilized phase change materials which retain their macroscopic solid shape even at temperatures above the melting point of the active heat storage compound. Shape-stabilized materials can be obtained by PCMs impregnation into porous matrices. Porous silica nanomaterials are promising matrices due to their high porosity and adsorption capacity, chemical and thermal stability and possibility of changing their structure through chemical synthesis. This review offers a first in-depth look at the various methods for obtaining composite PCMs using porous silica nanomaterials, their properties, and applications. The synthesis and properties of porous silica composites are presented based on the main classes of compounds which can act as heat storage materials (paraffins, fatty acids, polymers, small organic molecules, hydrated salts, molten salts and metals). The physico-chemical phenomena arising from the nanoconfinement of phase change materials into the silica pores are discussed from both theoretical and practical standpoints. The lessons learned so far in designing efficient composite PCMs using porous silica matrices are presented, as well as the future perspectives on improving the heat storage materials.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6176 ◽  
Author(s):  
Hamidreza Behi ◽  
Mohammadreza Behi ◽  
Ali Ghanbarpour ◽  
Danial Karimi ◽  
Aryan Azad ◽  
...  

Usage of phase change materials’ (PCMs) latent heat has been investigated as a promising method for thermal energy storage applications. However, one of the most common disadvantages of using latent heat thermal energy storage (LHTES) is the low thermal conductivity of PCMs. This issue affects the rate of energy storage (charging/discharging) in PCMs. Many researchers have proposed different methods to cope with this problem in thermal energy storage. In this paper, a tubular heat pipe as a super heat conductor to increase the charging/discharging rate was investigated. The temperature of PCM, liquid fraction observations, and charging and discharging rates are reported. Heat pipe effectiveness was defined and used to quantify the relative performance of heat pipe-assisted PCM storage systems. Both experimental and numerical investigations were performed to determine the efficiency of the system in thermal storage enhancement. The proposed system in the charging/discharging process significantly improved the energy transfer between a water bath and the PCM in the working temperature range of 50 °C to 70 °C.


2013 ◽  
Vol 683 ◽  
pp. 106-109
Author(s):  
Xiao Gang Zhao ◽  
Ying Pan

Phase change materials, abbreviated as PCM, due to the excellent heat storage performance, have been used as building materials and got more and more attention in recent years. The article introduce the building application of phase change material, and discuss its contribution to the building energy saving.


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