scholarly journals Molecular structure and melting: implications for phase change materials

2018 ◽  
Vol 96 (7) ◽  
pp. 722-729 ◽  
Author(s):  
John A. Noël ◽  
Samer Kahwaji ◽  
Mary Anne White
Keyword(s):  
Molecular Structure ◽  
Phase Change ◽  
Phase Change Materials ◽  
Alkyl Chains ◽  
Melting Temperatures ◽  
Enthalpy Changes ◽  
Melting Properties ◽  
Load Leveling ◽  
The Relationship ◽  
Selection Of

Phase change materials (PCMs) offer a promising technology for thermal energy storage, load leveling, and peak shifting applications. A desirable PCM has a melting temperature within the temperature boundaries of its application and a high change in enthalpy on melting. Knowledge of the relationships between these thermodynamic properties and molecular structure would advance informed selection of PCM candidates for a given application. In the present investigation, the relationship between structure (length of alkyl chains) and melting properties has been investigated for isomeric esters, showing that esters containing longer individual alkyl chains have higher melting temperatures and higher enthalpy changes on melting. The melting entropy changes, however, are relatively independent of the alkyl chain distribution.

scholarly journals Organic Phase Change Materials for Thermal Energy Storage: Influence of Molecular Structure on Properties

Molecules ◽  
2021 ◽  
Vol 26 (21) ◽  
pp. 6635
Author(s):  
Samer Kahwaji ◽  
Mary Anne White
Keyword(s):  
Molecular Structure ◽  
Phase Change ◽  
Thermal Energy ◽  
Phase Change Materials ◽  
Lower Cost ◽  
Alkyl Chains ◽  
Melting Temperatures ◽  
Wide Range ◽  
Efficient Packing ◽  
The Relationship

Materials that change phase (e.g., via melting) can store thermal energy with energy densities comparable to batteries. Phase change materials will play an increasing role in reduction of greenhouse gas emissions, by scavenging thermal energy for later use. Therefore, it is useful to have summaries of phase change properties over a wide range of materials. In the present work, we review the relationship between molecular structure and trends in relevant phase change properties (melting temperature, and gravimetric enthalpy of fusion) for about 200 organic compounds from several chemical families, namely alkanes (paraffins), fatty acids, fatty alcohols, esters, diamines, dinitriles, diols, dioic acids, and diamides. We also review availability and cost, chemical compatibility, and thermal and chemical stabilities, to provide practical information for PCM selection. Compounds with even chain alkyl lengths generally give higher melting temperatures, store more thermal energy per unit mass due to more efficient packing, and are of lower cost than the comparable compounds with odd alkyl chains.

scholarly journals The investigation of using phase change material for solar pond insulation

2021 ◽  
pp. 185-185
Author(s):  
Ismail Bozkurt
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Salt Water ◽  
Capric Acid ◽  
Heat Energy ◽  
Solar Ponds ◽  
Solar Pond ◽  
Enthalpy Changes ◽  
Selection Of

Solar ponds are systems that store solar energy in salt water as heat energy. In order to store heat energy for a long time in solar pond, the heat insulation should be done well. In this study, the effect of phase change materials (PCMs) was investigated to improve the insulation of the pond and to store the heat energy for a longer time. The melting temperature is a key parameter in the selection of PCMs. The temperature distribution of the solar pond was examined and PCMs with melting temperatures in the range of the pond average temperature ? 10?C were selected.Three different phase change materials were used in the walls of the solar pond for insulation. The temperature and enthalpy changes of the system were calculated numerically for a year. The heat storage ratio of the solar pond was determined by using the obtained enthalpy and solar radiation data. Consequently, the heat storage ratio of the pond with glass-wool is maximum 20.95% in July and minimum 7.92% in January. The heat storage ratio of the solar pond which Paraffin C18, Capric acid and Paraffin 44 are used as PCMs is maximum 32.22%, 34.85% and 47.81% in December, respectively. It is observed that the appropriate selection of PCMs is provided a longer storage time for solar ponds.

Selection of Phase Change Materials for Latent Heat Storage

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
J. Martínez-Gómez ◽  
E. Urresta ◽  
D. Gaona ◽  
G. Guerrón
Keyword(s):  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Latent Heat Storage ◽  
Toma De Decisiones ◽  
Selection Of

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.

Selection Principles and Investigation of Substances for Synthesis of Composite Medium-Temperature Phase Change Materials for Space Heating and Domestic Hot Water

2020 ◽  
Vol 989 ◽  
pp. 165-171
Author(s):  
A.M. Morzhukhin ◽  
D.S. Testov ◽  
S.V. Morzhukhina
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Hot Water ◽  
Temperature Phase ◽  
Heat Accumulation ◽  
Medium Temperature ◽  
Domestic Hot Water ◽  
Selection Principles ◽  
Salt Hydrates ◽  
Selection Of

The types of heat accumulation and the types of heat-accumulating materials are considered. It is shown that the most promising as heat-accumulating materials for heating and hot water are the salts hydrates. Based on the conducted factor analysis, a number of criteria are excluded from further consideration, which significantly reduces the list of criteria considered for selecting phase change materials (PCM) and simplifies further work on the selection of the most promising materials. There were selected from over 160 salt hydrates as PCM for the future of composite synthesis for the heating and hot water the Na (CH3COO) •3H2O, Ba (OH)2•8H2O, Mg (NO3)2 •6H2O and Zn (NO3)2•6H2O.

Selection of phase change materials, metal foams and geometries for improving metal hydride performance

2020 ◽  
Vol 45 (29) ◽  
pp. 14922-14939 ◽  
Author(s):  
Hafsa El Mghari ◽  
Jacques Huot ◽  
Liang Tong ◽  
Jinsheng Xiao
Keyword(s):  
Phase Change ◽  
Metal Hydride ◽  
Phase Change Materials ◽  
Metal Foams ◽  
Selection Of

scholarly journals Applicability of MCDM Algorithms for the Selection of Phase Change Materials for Thermal Energy Storage Heat Exchangers

2021 ◽  
pp. 611-622
Author(s):  
Paul Gregory Felix ◽  
Velavan Rajagopal ◽  
Kannan Kumaresan
Keyword(s):  
Energy Storage ◽  
Physical Properties ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Heat Exchangers ◽  
Phase Change Materials ◽  
Weight Estimation ◽  
Thermo Physical Properties ◽  
Selection Of

Latent heat thermal energy storage heat exchangers store heat energy by virtue of the phase transition that occurs in the thermal storage media. Since phase change materials (PCMs) are utilized as the media, there is a critical necessity for the appropriate selection of the PCM utilized. Since multiple thermo-physical properties and multiple PCMs are required to be evaluated for the selection, there arises a need for multiple criteria decision making (MCDM) algorithms to be adopted for the selection. But owing to the different weight estimation techniques employed and the voluminous quantity of selection algorithms available, there arises a need for a comparative methodology to be adopted. This study was intended to select an optimal PCM for a sustainable steam cooking application coupled with a thermal energy storage system. In this research study, six PCMs were chosen as the alternatives and five thermo-physical properties were chosen as the criteria for the evaluation. 11 different algorithms were augmented with 3 different weight estimation techniques and therefore a total of 33 algorithms were employed in this study. All of the algorithms have chosen Erythritol as the optimal PCM for the application. The outcomes of the MCDM algorithms have been validated through an intricate Pearson’s correlation coefficient study.

Suitability Assessment and Experimental Characterization of Phase Change Materials for Energy Conservation in Indian Buildings

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Rajat Saxena ◽  
Naman Agarwal ◽  
Dibakar Rakshit ◽  
S. C. Kaushik
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Thermal Capacity ◽  
Climatic Conditions ◽  
Melting Temperatures ◽  
Suitability Assessment ◽  
Efficiency Measures ◽  
Prime Concern ◽  
Change Temperature ◽  
And Performance

Abstract With increasing energy consumption in buildings, energy efficiency measures are matter of prime concern. A huge portion of energy consumed in buildings is used for regulating the thermal comfort. A solution to this is to incorporate phase change material (PCM) within the building elements which increases their overall thermal capacity. In the present study, the temperature of inner room surface, with and without PCM incorporation, is calculated for composite climate of Delhi. The analysis of PCM sandwiched walls has been performed. The performance analysis of five PCMs, having different melting temperatures, is carried out with nodal temperatures as the output. The results show that a phase change temperature range of 34–38 °C is suitable for peak summer conditions of Delhi. It is also observed that due to the low thermal conductivity of PCMs, they act as both storage medium and insulation, thus reducing temperature fluctuation during summer/winter. Based on the simulation, three PCMs were found suitable and hence were experimentally tested for their characteristic charging and discharging properties and performance, using differential scanning calorimeter (DSC). Based on the characterization results, it is concluded that two commercially available PCMs (Eicosane and OM35) are suitable for Delhi. All the other PCMs have also been simulated for different climatic conditions in India and their impact on heat gain has been assessed.

scholarly journals Multiscale Modelling Approach Targeting Optimisation of PCM into Constructive Solutions for Overheating Mitigation in Buildings

2020 ◽  
Vol 10 (22) ◽  
pp. 8009
Author(s):  
António Figueiredo ◽  
Romeu Vicente ◽  
Rui Oliveira ◽  
Fernanda Rodrigues ◽  
António Samagaio
Keyword(s):  
Phase Change ◽  
Energy Demand ◽  
Phase Change Materials ◽  
Supply And Demand ◽  
Energy Performance ◽  
Simulation Software ◽  
Rate Reduction ◽  
Melting Temperatures ◽  
Detached House ◽  
Global Energy Supply

Nowadays, the rising gap between the global energy supply and demand is a well-known circumstance in society. Exploring the solution to invert this tendency leads to several different scenarios of energy demand saving strategies that can be improved using phase change materials (PCM), especially in cold-formed steel-framed buildings. The present research reports the overheating (indoor air temperature above 26 °C expressed as an annualized percentage rate) reduction in south-oriented compartments and energy performance of a detached house located in the Aveiro region, in Portugal. An optimisation study was performed incorporating different phase change materials (PCMs) solutions and their position in the exterior envelope focusing overheating rate reduction and heating demand. The optimisations were managed by using a hybrid evolutionary algorithm coupled with EnergyPlus® simulation software. The overheating risk was reduced by up to 24% in the cooling season, for the case of the building compartments with south orientation. Thus, the use of construction solutions using PCMs with different melting temperatures revealed to be a good strategy to maximise PCM efficiency as a passive solution.

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