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 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 Cost/Performance Analysis of Commercial-Grade Organic Phase-Change Materials for Low-Temperature Heat Storage

Energies ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 5
Author(s):  
Tomáš Hásl ◽  
Ivo Jiříček ◽  
Michal Jeremiáš ◽  
Josef Farták ◽  
Michael Pohořelý
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Thermal Capacity ◽  
Scanning Calorimetry ◽  
Cost Performance ◽  
Temperature Range ◽  
The Relationship

Alkanes are widely used as phase change materials (PCMs), especially for thermal energy storage (TES), due to their high thermal capacity, stability, availability, and non-corrosiveness. However, the drawbacks of alkanes are low heat conductivity and high cost. Our aim was to explore alternative organic PCMs for TES and to compare such compounds based on the relationship between their performance and cost. For this purpose, we analysed several commercially available products, including long chain alkanes, alcohols, monocarboxylic acid, amines, ethers and esters in high purities. Differential scanning calorimetry and thermogravimetry (DSC and TGA) were used to measure the melting point, melting enthalpy and thermal stability of these compounds. The materials were classified according to their melting temperature. In order to compare the compounds, we calculated from the measured enthalpies and the price list provided by producers a coefficient that represents factors in both the performance and cost of the material. This method was used to identify the most suitable organic compound for thermal energy storage in each temperature range. As the main result of this work, it has been revealed that various organic compounds can be considered as a vital alternative to the alkanes in temperatures from −10 to 50 °C. On top of that, alcohols and carboxylic acids can cover the temperature range from 50 to 75 °C, which cannot be covered by alkanes.

scholarly journals Experimental Devices to Investigate the Long-Term Stability of Phase Change Materials under Application Conditions

2020 ◽  
Vol 10 (22) ◽  
pp. 7968
Author(s):  
Christoph Rathgeber ◽  
Stefan Hiebler ◽  
Rocío Bayón ◽  
Luisa F. Cabeza ◽  
Gabriel Zsembinszki ◽  
...  
Keyword(s):  
Phase Change ◽  
Thermal Energy ◽  
Phase Change Materials ◽  
Term Stability ◽  
Long Term Stability ◽  
Wide Range ◽  
Solidification Processes ◽  
The Stability ◽  
Solid Liquid

An important prerequisite to select a reliable phase change material (PCM) for thermal energy storage applications is to test it under application conditions. In the case of solid–liquid PCM, a large amount of thermal energy can be stored and released in a small temperature range around the solid–liquid phase transition. Therefore, to test the long-term stability of solid–liquid PCM, they are subjected to melting and solidification processes taking into account the conditions of the intended application. In this work, 18 experimental devices to investigate the long-term stability of PCM are presented. The experiments can be divided into thermal cycling stability tests, tests on PCM with stable supercooling, and tests on the stability of phase change slurries (PCS). In addition to these experiments, appropriate methods to investigate a possible degradation of the PCM are introduced. Considering the diversity of the investigated devices and the wide range of experimental parameters, further work toward a standardization of PCM stability testing is recommended.

Review on solid-solid phase change materials for thermal energy storage: Molecular structure and thermal properties

2017 ◽  
Vol 127 ◽  
pp. 1427-1441 ◽  
Author(s):  
Ali Fallahi ◽  
Gert Guldentops ◽  
Mingjiang Tao ◽  
Sergio Granados-Focil ◽  
Steven Van Dessel
Keyword(s):  
Molecular Structure ◽  
Thermal Properties ◽  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Solid Phase

Layout of Phase Change Materials in a Thermal Energy Storage System

2018 ◽  
Author(s):  
Habeeb Ur Rahman Khan ◽  
Taha K. Aldoss ◽  
Muhammad M. Rahman
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Latent Heat ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Storage System ◽  
Energy Storage System ◽  
Melting Temperatures ◽  
Thermal Energy Storage System

The objective of this work is to investigate the performance of a thermal energy storage system using multiple phase change materials (PCMs). This study is based on latent heat thermal energy storage. Three phase change materials namely, Potassium Hydroxide (KOH), Potassium Nitrate (KNO3), and Sodium Nitrate (NaNO3) have been selected for this study. These PCMs have been chosen because of their inherent thermal stability, high melting point, high latent heat of fusion per unit mass, relatively high thermal conductivity, high specific heat, non-flammable properties, and availability. In this work, the performance of the thermal energy storage system is analyzed by evaluating key parameters such as liquid fraction and the amount of energy stored and extracted during charging and discharging respectively. Two types of PCM layouts, uniform and cascaded, have been employed. In case of uniform PCM layout, only one type of PCM is used at a time throughout the bed. In case of cascaded PCM layout, multiple PCMs are used at a time throughout the bed. The cascaded layout further has two types of arrangement. The first type of arrangement is the slope down arrangement where the PCMs are placed in the descending order of their melting temperatures. The second type of arrangement is the slope up arrangement where the PCMs are placed in the ascending order of their melting temperatures. Overall, the cascaded layout excels in performance when compared to the uniform layout in terms of PCM melting and solidification time and in terms of energy stored and extracted. Keeping these factors in mind, we recommend using a cascaded layout in a Thermal Energy Storage System (TESS) as opposed to a uniform layout.

Polymers in Molten Inorganic Salt Hydrates Phase Change Materials: Solubility and Gelation

2021 ◽  
Author(s):  
Kartik Kumar Rajagopalan ◽  
Parvin Karimineghlani ◽  
Xiuzhu Zhu ◽  
Patrick Shamberger ◽  
Svetlana Sukhishvili
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Inorganic Salt ◽  
Melting Temperatures ◽  
Salt Hydrates ◽  
Latent Heats

Inorganic salt hydrates are of interest as phase change materials (PCMs) for thermal energy storage because of their unique properties such as high latent heats of fusion, moderate melting temperatures,...

Review on Development and Investigations of Phase Change Materials in Thermal Energy Storage

2008 ◽  
Vol 1100 ◽  
Author(s):  
Zhu Xiaoqin ◽  
Hu Jin ◽  
Cao Zhaosheng ◽  
Lu Jiansheng ◽  
Sun Jialin ◽  
...  
Keyword(s):  
Energy Storage ◽  
Phase Change ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Phase Change Materials ◽  
Storage Temperature ◽  
Available Energy ◽  
Wide Range ◽  
Isothermal Operation ◽  
Thermal Energy Storage Systems

AbstractThermal energy storage with phase change materials is one of the most efficient ways of storing available energy because of its advantages such as providing higher heat storage capacity, lower storage temperature, isothermal operation and less storage space. This paper reviews the development and investigations of phase change materials in thermal energy storage systems of various engineering applications. There are many phase change materials that melt and solidify at a wide range of temperatures, making them attractive in a lot of applications. Various categories of phase change materials suitable for thermal energy storage are introduced, and the investigations on their important enhancement techniques are also discussed.

Various Applications of Phase Change Materials: Thermal Energy Storing Materials

2017 ◽  
Vol 6 (4) ◽  
pp. 167-171 ◽  
Author(s):  
M. A. Boda ◽  
◽  
R. V. Phand ◽  
A. C. Kotali ◽  
◽  
...  
Keyword(s):  
Phase Change ◽  
Thermal Energy ◽  
Phase Change Materials
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