scholarly journals Passive room conditioning using phase change materials—Demonstration of a long‐term real size experiment

2020 ◽  
Vol 44 (8) ◽  
pp. 7047-7056 ◽  
Author(s):  
Sebastian Sonnick ◽  
Lars Erlbeck ◽  
Maximilian Gaedtke ◽  
Frederik Wunder ◽  
Christoph Mayer ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Real Size

Methods for Separation of Copper Oxide Nanoparticles From Colloidal Suspension in Dodecane

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammed H. Sheikh ◽  
Muhammad A. R. Sharif
Keyword(s):  
Energy Storage ◽  
Copper Oxide ◽  
Phase Change ◽  
Phase Change Materials ◽  
Research Work ◽  
Cuo Nanoparticles ◽  
Health Hazards ◽  
Suspension Stability ◽  
Reduced Pressure

Phase change materials (PCM) are used in many energy storage applications. Energy is stored (latent heat of fusion) by melting the PCM and is released during resolidification. Dispersing highly conductive nanoparticles into the PCM enhances the effective thermal conductivity of the PCM, which in turn significantly improves the energy storage capability of the PCM. The resulting colloidal mixture with the nanoparticles in suspension is referred to as nanostructure enhanced phase change materials (NEPCM). A commonly used PCM for energy storage application is the family of paraffin (CnH2n+2). Mixing copper oxide (CuO) nanoparticles in the paraffin produces an effective and highly efficient NEPCM for energy storage. However, after long term application cycles, the efficiency of the NEPCM may deteriorate and it may need replacement with fresh supply. Disposal of the used NEPCM containing the nanoparticles is a matter of concern. Used NEPCM containing nanoparticles cannot be discarded directly into the environment because of various short term health hazards for humans and all living beings and unidentified long term environmental and health hazards due to nanoparticles. This problem will be considerable when widespread use of NEPCM will be practiced. It is thus important to develop technologies to separate the nanoparticles before the disposal of the NEPCM. The primary objective of this research work is to develop methods for the separation and reclamation of the nanoparticles from the NEPCM before its disposal. The goal is to find, design, test, and evaluate separation methods which are simple, safe, and economical. The specific NEPCM considered in this study is a colloidal mixture of dodecane (C12H26) and CuO nanoparticles (1–5% mass fraction and 5–15 nm size distribution). The nanoparticles are coated with a surfactant or stabilizing ligands for suspension stability in the mixture for a long period of time. Various methods for separating the nanoparticles from the NEPCM are explored. The identified methods include: (i) distillation under atmospheric and reduced pressure, (ii) mixing with alcohol mixture solvent, and (iii) high speed centrifugation. These different nanoparticle separation methods have been pursued and tested, and the results are analyzed and presented in this article.

Long-term thermophysical behavior of paraffin wax and paraffin wax/polyaniline (PANI) composite phase change materials

2020 ◽  
Vol 31 ◽  
pp. 101568
Author(s):  
Mathew George ◽  
A.K. Pandey ◽  
Nasrudin Abd Rahim ◽  
V.V. Tyagi ◽  
Syed Shahabuddin ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Paraffin Wax ◽  
Pani Composite ◽  
Composite Phase Change Materials

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.

scholarly journals Foamed Phase Change Materials Based on Recycled Polyethylene/Paraffin Wax Blends

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1987
Author(s):  
Patrik Sobolčiak ◽  
Miroslav Mrlik ◽  
Anton Popelka ◽  
Antonín Minařík ◽  
Marketa Ilcikova ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Mechanical Stability ◽  
Organic Peroxide ◽  
Mechanical Analysis ◽  
Paraffin Wax ◽  
Micro Computed Tomography ◽  
Scanning Calorimetry ◽  
The Real

Foamed phase-change materials (FPCMs) were prepared using recycled linear low-density polyethylene (LLDPE) blended with 30 wt.% of paraffin wax (PW) and foamed by 1,1′-azobiscarbamide. The protection of pores’ collapse during foaming process was insured through chemical cross-linking by organic peroxide prior foaming. This work represents one of very few attempts for a preparation of polymeric phase change foams without a use of micro-encapsulated phase change component leading to the enhancement of the real PCM component (PW) within a final product. The porous structure of fabricated foams was analyzed using micro-computed tomography, and direct observation, and reconstruction of the internal structure was investigated. The porosity of FPCMs was about 85–87 vol.% and resulting thermal conductivity 0.054–0.086 W/m·K. Differential Scanning Calorimetry was used to determine the specific enthalpies of melting (22.4–25.1 J/g) what is the latent heat of materials utilized during a heat absorption. A stability of samples during 10 heating/cooling cycles was demonstrated. The phase change changes were also investigated using the dynamic mechanical analysis from 0° to 65 °C during the 10 cycles, and the mechanical stability of the system and phase-change transition were clearly confirmed, as proved by DSC. Leaching test revealed a long-term release of PW (around 7% of its original content) from samples which were long term stored at temperatures over PW melting point. This is the usual problem concerning polymer/wax blends. The most common, industrially feasible solution is a lamination of products, for instance by aluminum foils. Finally, the measurement of the heat flow simulating the real conditions shows that samples containing PW decrease the energy passing through the sample from 68.56 to 34.88 kJ·m−2. In this respect, FPCMs provide very effective double functionality, firstly common thermal insulators, and second, as the heat absorbers acting through melting of the PW and absorbing the excessive thermal energy during melting. This improves the heat protection of buildings and reduces temperature fluctuations within indoor spaces.

scholarly journals Long-Term Autonomic Thermoregulating Fabrics Based on Microencapsulated Phase Change Materials

2021 ◽  
Author(s):  
Paula F. De Castro ◽  
Sergiy Minko ◽  
Vladimir Vinokurov ◽  
Kirill Cherednichenko ◽  
Dmitry G. Shchukin
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Microencapsulated Phase Change Materials

scholarly journals Use of phase change materials in concrete: current challenges

2019 ◽  
Vol 4 ◽  
pp. 9 ◽  
Author(s):  
Adeyemi Adesina
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Energy Savings ◽  
Building Industry ◽  
Negative Effects ◽  
The World ◽  
Mechanical Properties And Corrosion ◽  
Incorporation Method ◽  
Term Data

Sustainability awareness in the building industry has increased in recent years, and several initiatives have been developed. One of the areas gaining attention recently is the application of phase change materials (PCMs) in concrete. PCMs are materials capable of storing and releasing energy based on the temperature of the environment in which they are situated. This capability makes them provide heat during cold times, and absorb heat when the temperature is higher. As concrete is the most used building material in the world, the use of PCMs in concrete will be a great way to widen the application of PCMs. However, as the composition of concrete determines its properties; hence, the use of PCM in concrete can be detrimental to the properties of concrete. Some of the negative effects on the properties of concrete include reduced mechanical properties and corrosion of reinforcements. In addition, PCMs suitable for concrete are not readily available in the market, and extremely expensive when available. Also, lack of long-term data on the effect of PCM on concrete's durability has discouraged stakeholders to accept the use of PCMs in concrete. This paper explored the current challenges faced by the application of PCMs in concrete which, and possible opportunities that will open more pathway for extensive research and applications of PCM in concrete. It was concluded that the use of right type and proportion of PCM in concrete can result in similar strength to those of control samples. Also, certain methods of incorporating PCMs into the concrete were found to be more effective. Therefore, it is imperative that building engineers carry out initial tests to determine the most appropriate incorporation method to be used. Finally, huge energy savings can be achieved through the use of PCM in concrete without any significant reduction in mechanical strength.

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