scholarly journals Storage Capacity in Dependency of Supercooling and Cycle Stability of Different PCM Emulsions

2021 ◽  
Vol 11 (8) ◽  
pp. 3612
Author(s):  
Stefan Gschwander ◽  
Sophia Niedermaier ◽  
Sebastian Gamisch ◽  
Moritz Kick ◽  
Franziska Klünder ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Melting Temperatures ◽  
Dsc Measurements ◽  
Storage Media ◽  
Crystallisation Behaviour ◽  
Temperature Ranges ◽  
The Stability

Phase-change materials (PCM) play off their advantages over conventional heat storage media when used within narrow temperature ranges. Many cooling and temperature buffering applications, such as cold storage and battery cooling, are operated within small temperature differences, and therefore, they are well-suited for the application of these promising materials. In this study, the storage capacities of different phase-change material emulsions are analysed under consideration of the phase transition behaviour and supercooling effect, which are caused by the submicron size scale of the PCM particles in the emulsion. For comparison reasons, the same formulation for the emulsions was used to emulsify 35 wt.% of different paraffins with different purities and melting temperatures between 16 and 40 °C. Enthalpy curves based on differential scanning calorimeter (DSC) measurements are used to calculate the storage capacities within the characteristic and defined temperatures. The enthalpy differences for the emulsions, including the first phase transition, are in a range between 69 and 96 kJ/kg within temperature differences between 6.5 and 10 K. This led to an increase of the storage capacity by a factor of 2–2.7 in comparison to water operated within the same temperature intervals. The study also shows that purer paraffins, which have a much higher enthalpy than blends, reveal, in some cases, a lower increase of the storage capacity in the comparison due to unfavourable crystallisation behaviour when emulsified. In a second analysis, the stability of emulsions was investigated by applying 100 thermal cycles with defined mechanical stress at the same time. An analysis of the viscosity, particle size and melting crystallisation behaviour was done by showing the changes in each property due to the cycling.

Research on the Feasibility of Shape-Stabilized Phase-Change Materials at Lower Temperature Used in the Phase Change Wall

2012 ◽  
Vol 446-449 ◽  
pp. 1559-1562
Author(s):  
Quan Ying Yan ◽  
Ran Huo ◽  
Li Li Jin
Keyword(s):  
Phase Change ◽  
Mass Fraction ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Critical Mass ◽  
Practical Engineering ◽  
Change Temperature ◽  
Save Energy ◽  
Lower Temperature ◽  
The Stability

The shape-stabilized phase-change paraffin at lower temperature is an ideal material used in the phase-change wall. It can enhance the thermal storage capacity of the wall and save energy. The thermal properties of shape-stabilized phase-change paraffin were studied experimentally in this paper. The phase change temperature, latent heat and the stability of shape-stabilized phase-change paraffin with different component were analyzed. The critical mass fraction of paraffin required in the materials was discussed. The results may provide the basis for the application in the practical engineering in the future.

Next Generation Phase Change Materials as Multifunctional Watery Suspension for Heat Transport and Heat Storage

2009 ◽  
Vol 1188 ◽  
Author(s):  
Milka Markova Hadjieva ◽  
Metodi Bozukov ◽  
Ivan Gutzov
Keyword(s):  
Phase Transition ◽  
Thermal Cycling ◽  
Phase Change ◽  
Heat Transport ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Heat Storage ◽  
Thermal Storage ◽  
Temperature Range ◽  
Cooling Technology

AbstractThe phase change materials (PCM) are known since years with high thermal storage capacity but with limited applications. The modified PCM mainly paraffin watery suspensions, so called PCM slurry, improve some PCM drawbacks (thermal conductivity) and as paraffin multifunctional fluids can work in both, heat transport and heat storage for cooling technology applications. The structural and thermophysical properties of two types PCM slurry were good basis for comparison of their efficiency: paraffin microcapsule slurry (A) and paraffin emulsion slurry (B), both working in temperature range of phase transition from 2-12 degreesC. The equipments as differential scanning calorimetry (DSC), model NETZSCH DSC 200 PC; scanning electron microscopy (SEM), JOEL model JSM-5510; hot stage optical microscopy, LINKAM model TMS 94 and hand made thermal cycling system operational with Danfoss cooling machine that ensured 2 kW cooling capacity at 40oC; gave accurate results, characterizing completely, from structural and thermal point of view both types of PCM multifunctional structured fluids. Structural stability of the advanced phase change multifunctional fluids was discussed on sample imaging in variable magnifications made by method of Hot Stage microscopy and precise SEM study. Systematization of the DSC results obtained, including temperature range of phase transition and thermal storage capacity, measured before and after repeatable thermal cycling of the PCM multifunctional fluids, allowed selection of the PCM slurry working samples with relatively high thermal capacity applicable to further development in prototypes. Heat absorbed/released, calculated by NETZSCH DSC software, was for PCM slurry A in the range of 80 to 82 kJ/kg, while PCM slurry B showed thermal storage capacity from 56 to 53 kJ/kg. Correlation between the structural properties and thermal storage capacity of the phase change multifunctional fluids led to practical conclusions concerning: homogeneity; crystal growth/conditions; structural compatibility between components; prediction of the heat flow behavior of multifunctional PCM slurries in cooling technology for storage and transport of heat.

scholarly journals Phase change materials and their use for energy accumulation

2021 ◽  
Vol 338 ◽  
pp. 01006
Author(s):  
Agnieszka Dzindziora ◽  
Jacek Cieślik ◽  
Jerzy Wojciechowski
Keyword(s):  
Phase Transition ◽  
Energy Storage ◽  
Chemical Composition ◽  
Phase Change ◽  
Phase Change Materials ◽  
Storage Capacity ◽  
Heat Removal ◽  
Industrial Applications ◽  
Transition Enthalpy ◽  
Unstable Temperature

Problems with overheating and unstable temperature of industrial equipment are the reasons for generating significant costs that for companies. Solving the problems related to heat removal is a challenge in modern industry. Phase change materials are the solution to these challenges (PCM). These substances can accumulate and release large amounts of thermal energy during the phase change transition. The value of the phase transition enthalpy determines the energy storage capacity. The paper presents the results of phase transitions of selected materials. The measurements were carried out on a stand for testing phase change materials. The laboratory stand made it possible to determine the thermodynamic parameters of the phase transition. The substances analysed are kinds of paraffin of different chemical composition. Due to the diversity of substances, it is possible to analyse the influence of the chemical composition on possible uses in industrial applications for energy storage.

scholarly journals Combining Switchable Phase‐Change Materials and Phase‐Transition Materials for Thermally Regulated Smart Mid‐Infrared Modulators

2021 ◽  
pp. 2100417
Author(s):  
Xinrui Lyu ◽  
Andreas Heßler ◽  
Xiao Wang ◽  
Yunzhen Cao ◽  
Lixin Song ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Phase Change Materials ◽  
Mid Infrared

Sunlight-Activated Phase Change Materials for Controlled Heat Storage and Triggered Release

2021 ◽  
Author(s):  
Yuran Shi ◽  
Mihael Gerkman ◽  
Qianfeng Qiu ◽  
Shuren Zhang ◽  
Grace G. D. Han
Keyword(s):  
Phase Transition ◽  
Solar Radiation ◽  
Phase Change ◽  
Latent Heat ◽  
Photon Energy ◽  
Organic Phase ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Triggered Release

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....

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