scholarly journals RECOVERING OF ANISOTROPIC THERMAL PROPERTIES IN PHASE-CHANGE MATERIALS USING DIRECT AND INVERSE MATHEMATICAL MODELLING

2021 ◽  
Author(s):  
Sergey Markov
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Mathematical Modelling ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Materials ◽  
Conductivity Tensor ◽  
Thermal Conductivity Tensor

We present the results of applying the developed algorithms for direct and reverse mathematical modelling to calculate the effective thermal conductivity tensor in samples of phase-change materials.

scholarly journals Investigation of Thermal Properties of Novel Phase Change Material Mixtures (Octadecane-Diamond) with Laser Flash Analysis

2019 ◽  
Vol 26 (4) ◽  
pp. 211-218
Author(s):  
Mateusz Sierakowski ◽  
Wojciech Godlewski ◽  
Roman Domański ◽  
Jakub Kapuściński ◽  
Tomasz Wiśniewski ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Power Plants ◽  
Large Scale ◽  
Phase Change Materials ◽  
Heat Dissipation ◽  
Electronics Cooling ◽  
Diamond Powder ◽  
Heat Of Fusion

AbstractPhase change materials (PCMs) are widely used in numerous engineering fields because of their good heat storage properties and high latent heat of fusion. However, a big group of them has low thermal conductivity and diffusivity, which poses a problem when it comes to effective and relatively fast heat transfer and accumulation. Therefore, their use is limited to systems that do not need to be heated or cooled rapidly. That is why they are used as thermal energy storage systems in both large scale in power plants and smaller scale in residential facilities. Although, if PCMs are meant to play an important role in electronics cooling, heat dissipation, or temperature stabilization in places where the access to cooling water is limited, such as electric automotive industry or hybrid aviation, a number of modifications and improvements needs to be introduced. Investigation whether additional materials of better thermal properties will affect the thermal properties of PCM is therefore of a big interest. An example of such material is diamond powder, which is a popular additive used in abradants. Its thermal diffusivity and conductivity is significantly higher than for a pure PCM. The article presents the results of an analysis of the effect of diamond powder on thermal conductivity and diffusivity of phase change materials in the case of octadecane.

Study on Dispersion Stability Characteristics of TiO2 Nanoparticles in PCM for Use in Cold Storage Air-Conditioning

2019 ◽  
Vol 972 ◽  
pp. 159-164
Author(s):  
Xiao Yan Li ◽  
Xin Yue Miao
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Cold Storage ◽  
Air Conditioning ◽  
Phase Change Materials ◽  
Ultrasonic Time ◽  
Nanoparticles Concentration ◽  
Dispersion Condition ◽  
Nanocomposite Pcm

A new organic phase change materials (PCM) for cool storage was developed for use in cold storage air-conditioning. The thermal properties of the new organic PCM were measured with a differential scanning calorimeter (DSC). To improve the thermal conductivity of the new organic PCM, the further research of using nanocomposite technology to the organic PCM SSW-4 was made. The effects of nanoparticles concentration on dispersion, ultrasonic time and consistence of dispersant in the best ultrasonic time on the dispersion were investigated by experiment. The results showed that the thermal conductivity of the nanocomposite PCM TiO2 /SSW-4 increased by approximately 16.27% compared to that of the organic PCM SSW-4. The best dispersion condition of preparation for TiO2 /SSW-4 was confirmed.

scholarly journals Improvement of Phase Change Materials (PCM) Used for Solar Process Heat Applications

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1260
Author(s):  
Cristina Prieto ◽  
Anton Lopez-Roman ◽  
Noelia Martínez ◽  
Josep M. Morera ◽  
Luisa F. Cabeza
Keyword(s):  
Thermal Conductivity ◽  
Solar Energy ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
High Temperatures ◽  
Phase Change Materials ◽  
Material Selection ◽  
Inert Atmosphere ◽  
Enhancement Effect ◽  
Process Heat

The high intermittency of solar energy is still a challenge yet to be overcome. The use of thermal storage has proven to be a good option, with phase change materials (PCM) as very promising candidates. Nevertheless, PCM compounds have typically poor thermal conductivity, reducing their attractiveness for commercial uses. This paper demonstrates the viability of increasing the PCM effective thermal conductivity to industrial required values (around 4 W/m·K) by using metal wool infiltrated into the resin under vacuum conditions. To achieve this result, the authors used an inert resin, decoupling the specific PCM material selection from the enhancement effect of the metal wools. To ensure proper behavior of the metal wool under standard industrial environments at a broad range of temperatures, a set of analyses were performed at high temperatures and an inert atmosphere, presenting a thorough analysis of the obtained results.

The Experimental Research and Numerical Simulation on Thermal Properties of Molten Salt at Melting Point

2009 ◽  
Author(s):  
Yannan Liang ◽  
Jiemin Zhou ◽  
Ying Yang ◽  
Ye Wu ◽  
Yanyan He
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Properties ◽  
Phase Change ◽  
Molten Salts ◽  
Phase Change Materials ◽  
Heat Storage ◽  
Phase Interface ◽  
Measuring System ◽  
Solid Liquid

The use of phase-change materials for latent heat storage is a new type of environmentally-friendly energy-saving technologies. Molten salts, one kind of phase-change materials, which have high latent heats, and whose phase transition temperatures match the high temperatures of heat engines, are the most widely used high-temperature phase-change heat storage materials. However, the heat transfer at solid/liquid phase interface belongs to Micro/Nanoscale Heat transfer, lots of the thermal properties of molten salt at melting point is difficult to test. In this investigation, based on the theory that the thermal conductivity can be determined by measuring the speed of the propagation of the solid/liquid phase interface during phase change, a set of system is developed to investigate the thermal conductivity of molten salts at liquid/solid phase transformation point. Meanwhile, mathematical calculation is applied to intuitively simulate the melting and solidifying process in the phase change chamber, by which the error could be analyzed and partly corrected and the result precision could also be increased. And a series of verification experiments have been performed to estimate the precision and the applicability of the measuring system to evaluate the feasibility of the method and measuring system. This research will pave the way to the follow-on research on heat storage at high temperature in industry.

Development of plug-ins to predict effective thermal conductivity of woven and microencapsulated phase change composite

2016 ◽  
Vol 51 (6) ◽  
pp. 733-743
Author(s):  
Muhammad Owais Raza Siddiqui ◽  
Danmei Sun
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Phase Change ◽  
Effective Thermal Conductivity ◽  
Phase Change Materials ◽  
Research Work ◽  
Element Analysis ◽  
Microencapsulated Phase Change Materials ◽  
Automatic Model Generation

The thermal property of textile structures plays an important role in the understanding of thermal behaviour of the clothing. In this work, user-friendly GUI plug-ins have been developed to generate both microscopic and mesoscopic scale models for finite element analysis. The plug-ins were developed by using Abaqus/CAE as a platform. The GUI Plug-ins enable automatic model generation and prediction of the effective thermal conductivity of woven composite and microencapsulated Phase Change Materials composites via finite element analysis by applying boundary conditions. The predicted effective thermal conductivities from plug-ins have been compared with the results obtained from published experimental research work based on an established mathematical model. They are correlated well. Moreover, the influence of phase change materials on heat transfer behaviour of microencapsulated Phase Change Materials composites was further analysed.

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