Properties Of Phase Change Materials Research Articles

Comparative Studies on Nano-Enhanced PCM (Ne-PCM) for Solar Energy Storage Applications

Widely used applications using Nano-enhanced Phase Change Materials (Ne-PCM) are the focused area of research in the trending modern technologies. Because of two main factors, researchers are compelled to study about Ne-PCMs. One important factor is the usage and storage of non-renewable energy sources. As it is a globally accepted fact that traditional energy sources, i.e., fossil fuels, and natural gases are the main cause of global warming and concerning the time they are extinguishing soon, this fact has led to the idea of using renewable energy sources, especially solar energy. But solar energy is intermittent and unpredictable so this energy must be stored in the form of latent heat or sensible heat using PCMs. In the flow of the study, it is observed that PCMs are lacking few thermophysical properties to achieve the desired results, for example, these materials have low conductivity. This fact gave rise to the idea of enhancing the properties of these phase-change materials. There are many methods to improve the material’s thermos-physical properties. Few to tell about encapsulation of the material, insertion of nanoparticles to the material, usage of fins, etc. An appropriate method can be selected based on the application and material properties. The present paper studies one of the methods of insertion of nanoparticles to enhance the properties of phase change materials. It will focus on the properties of PCMs, the usage of nanoparticles to enhance PCM’s properties, and how they can be used to store solar energy in various methods. Present paper focuses on the study of Organic, inorganic and eutectic phase change materials and its property enhancement using various metallic and non-metallic nanoparticles to store the energy.

Optimisation of PCM passive cooling efficiency on lithium-ion batteries based on coupled CFD and ANN techniques

Ever since the lithium-ion batteries (LIBs) outbreak, there has been an exponential bloom of application over the last decade, especially for electric vehicles, automobiles and other transportation systems. Nonetheless, as the first-generation LIBs eventually aged and became increasingly thermally unstable, the utilisation of thermal management cooling systems is essential to maintain the safe operation of LIB packs in the long term. Compared to active cooling methods, passive cooling often offers a cost-effective, easy-to-install and energy-saving solution without significant changes to the design complexity. This article focuses on the thermal management of prismatic battery packs and proposes a coupling passive cooling method that combines phase change material (PCM) cooling and immersion cooling, which proves to be cost-effective and efficient. Furthermore, the study incorporates an artificial neural network (ANN) model into computational fluid dynamics (CFD) simulations to optimize a specific battery cooling system. This optimization takes into account the PCM package method and the properties of PCM and immersion liquid. The results demonstrate that the immersion liquid exhibits different behaviours under various PCM conditions than natural convection. Overall, this modelling framework presents an innovative approach by utilizing high-fidelity CFD numerical results as inputs for establishing a numerical dataset. Through ANN optimisation, eleven input parameters are considered, and the optimised scenario confirmed that PCM material with a density of 760 kg/m3, thermal conductivity 32 W/(m K), specific heat 1691 (J/kg K), latent heat 80,160 (J/kg), liquidus temperature 302.93 K, solidus temperature 315.15 K and direct liquid density 1.4 (g/ml), thermal conductivity 0.4 (W/m K), specific heat 1220 (J/kg K) with side thickness 5 (mm) and mid thickness 2.5 (mm). With this combination, the optimised performance demonstrated considerable decreases in the maximum temperature and the temperature difference by 4.26 % and 10.8 %, respectively. This approach has the potential to enhance the state-of-the-art thermal management of LIB systems, reducing the risks of thermal runaway and fire outbreaks.

PHASE CHANGE MATERIALS (PCMs) FOR BUILDINGS AND AUTOMOTIVE APPLICATIONS: A REVIEW STUDY

Phase change materials (PCMs) play a pivotal role in various sectors, particularly in automotive engineering, electric vehicles, and building construction. In the automotive sector, phase change materials are crucial for thermal management systems, aiding in temperature regulation of components such as batteries and engines. In electric vehicles, phase change materials are instrumental in enhancing battery performance and lifespan by effectively managing thermal loads during charging and discharging cycles, thus ensuring optimal operating conditions. These materials offer significant energy efficiency benefits by absorbing and releasing large amounts of latent heat during phase transitions, which helps in maintaining stable temperatures and reducing the load on heating and cooling systems. Additionally, PCMs contribute to sustainable building practices by enhancing thermal regulation, thereby lowering energy consumption and associated costs. This study explores the diverse applications and properties of phase change materials for improving thermal management and energy efficiency in vehicles, residences, and buildings. This research provides a comprehensive review of innovative solutions, including PCM-based heat pumps, PCM-integrated cementitious composites, and hybrid active-passive battery thermal management systems.

Thermal conductivity enhancement in carbon black composite PCM for thermal energy storage

Abstract Phase Change Materials (PCMs) hold significant potential for developing next-generation energy storage technologies due to their cability to reversibly store and release thermal energy with energy density through isothermal phase transition. This work explores improving the heat conduction and thermophysical properties of PCMs, tackling issues such as low thermal conductivity, which can result in longer charge and discharge times. We demonstrated that the thermal conductivity of lauric acid-based PCM (LA-PCM) loaded with carbon black nanoparticles (CBNP) can be significantly enhanced. The PCM loading with 5 wt.% CBNP nanoparticles had an approximately 50% enhancement in thermal conductivity. Additionally, 25 wt.% of turmeric powder (Curcuma) significantly improved shape stability and stopped material leakage across the solid-liquid phase transition of composite PCM. The enhanced thermal conductivity of the composite PCM can be attributed to the development of interconnected percolation networks of CBNP particles with low thermal resistance during the freezing (solidification) of the PCM that provides a more effective phonon transport path. Sustainable energy materials (composite PCMs) with better thermal properties, shape stability, and low cast would be beneficial for practical application suitability and effective energy storage applications.

Tunable Filters Using Defected Ground Structures at Millimeter-Wave Frequencies.

This paper explores the potential of phase change materials (PCM) for dynamically tuning the frequency response of a dumbbell u-slot defected ground structure (DGS)-based band stop filter. The DGSs are designed using co-planar waveguide (CPW) line structure on top of a barium strontium titanate (Ba0.6Sr0.4TiO3) (BST) thin film. BST film is used as the high-dielectric material for the planar DGS. Lower insertion loss of less than -2 dB below the lower cutoff frequency, and enhanced band-rejection with notch depth of -39.64 dB at 27.75 GHz is achieved by cascading two-unit cells, compared to -12.26 dB rejection with a single-unit cell using BST thin film only. Further tunability is achieved by using a germanium telluride (GeTe) PCM layer. The electrical properties of PCM can be reversibly altered by transitioning between amorphous and crystalline phases. We demonstrate that incorporating a PCM layer into a DGS device allows for significant tuning of the resonance frequency: a shift in resonance frequency from 30.75 GHz to 33 GHz with a frequency shift of 2.25 GHz is achieved, i.e., 7.32% tuning is shown with a single DGS cell. Furthermore, by cascading two DGS cells with PCM, an even wider tuning range is achievable: a shift in resonance frequency from 27 GHz to 30.25 GHz with a frequency shift of 3.25 GHz is achieved, i.e., 12.04% tuning is shown by cascading two DGS cells. The results are validated through simulations and measurements, showcasing excellent agreement.

An Overview of Thermal Energy Storage (TES) Materials and Systems for Storage Applications

This paper presents an overview of thermal energy storage (TES) materials and systems for storage applications. A TES system is composed of a storage medium (TES material), a heat exchanger and a storage tank. TES systems employ storage technology by heating/cooling a medium so that the stored energy can be used later in various applications. In recent years, TES systems have attained significant interest in the scientific community, finding multiple applications in air heating/cooling, water heating, buildings, and more. TES systems depend on capacity, power, efficiency, storage period, and cost. TES systems are divided into three main categories, depending on how the energy is stored: sensible systems (with hot water), systems using phase change materials (PCMs), and systems based on chemical reactions. Among these three types, PCM-based systems are outstanding in terms of both performance and cost-effectiveness. These advanced materials contribute to the conservation of heat and solar energy, as well as improving their efficient use. This paper addresses different aspects of PCMs utilization. The classification of PCMs is based on the thermophysical properties of composite PCMs, their methods of production, the main challenges associated with them, and the solutions to these challenges. The progress in creating more efficient TES systems and finding the appropriate PCMs is also reviewed.

Development of novel dual functional polyurethane: Antimicrobial and thermal energy storage by phase change material

AbstractIn this study, we aim to develop a novel polyurethane (PUR) with phase changeability and antimicrobial properties for human health‐friendly thermal energy storage applications. The study consists of three steps. First, PUR prepolymer backbone was synthesized by conventional step‐growth polymerization. Second, phase change materials (PCMs) were integrated into the PUR backbone by reaction between free NCO of prepolymer and free OH and COOH of PCMs. At last, antimicrobial properties were integrated by turning nitrogen in urethane to a quaternary state by integration of iodopropane (IP) into a PUR backbone. The chemical structure was determined by FTIR. Thermal properties were determined by DSC and TGA. Antimicrobial properties were determined by the Agar well diffusion method (AWM). FTIR showed that the intended reactions were successful. PCM properties were determined by DSC. Iodopropane had no impact on phase change properties. However, DSC measurements determined the phase change enthalpy to be 28.28 J/g for the heating process and 26.12 J/g for the freezing process. AWM results showed that the prepared PUR system has antimicrobial properties.Highlights Novel PUR was developed with dual functionality. PUR shows thermal storage properties due to PCM integration. PUR shows antimicrobial and bacteriostatic properties after IP addition.

Phase-Change-Material-Based True Time-Delay System.

This study explores the achievement of a tunable true time-delay (TTD) system for a microwave phased-array antenna (MPAA) by incorporating the reversible phase-transition property of phase-change material (PCM) with Bragg gratings (BGs) and a cascade of three phase-shifted Bragg grating resonators (CPSBGRs). The goal was to design a low-power-consuming, non-volatile highly tunable compact TTD system for beam steering. A programmable on/off reflector was designed by changing a PCM-incorporated BG/CPSBGR from one phase to another. By arranging several programmable on/off reflectors in a row, a delay line was realized, and by incorporating several delay lines, the TTD system was achieved. Numerical simulations and parametric analyses were conducted for the evaluation of the TTD system's performance at an operating wavelength of 1550 nm and 1550.6 nm for programmable on/off reflectors with BGs and CPSBGRs. The findings point out the effectiveness of incorporating PCMs with BGs/CPSBGRs, thereby maintaining a high performance with less complexity.

An Analysis of the Influence of DSC Parameters on the Measurement of the Thermal Properties of Phase-Change Material.

A differential scanning calorimeter (DSC) is widely used for measuring the thermal properties of phase-change materials (PCMs). Optimizing test conditions based on material characteristics is essential for accurate results. This study investigates the effects of experimental parameters, including sample mass, heating rate, measurement modes, and atmosphere flow rate, on the phase-change enthalpy and phase-change temperature results. The findings indicate that variations in sample mass and heating rate lead to significant changes in phase-change temperatures, while an increase in purge gas flow rate reduces the phase-change enthalpy of the PCM. Based on the measurements, this study optimizes the DSC parameters and provides a reference for the accurate measurement of paraffin-based phase-change materials.

Nickel-Induced Dual Carbon Networks Encapsulating Phase Change Materials for Photothermal Conversion and Storage.

Bifunctional phase change materials (PCMs) with efficient energy storage and photothermal conversion capabilities have tremendous potential to be applied in advanced thermal management. However, classical organic PCMs with high latent heat are challenged by poor light harvesting, low thermal conductivity, and leakage risks. Here, we design a unique dual-carbon network with Ni nanoparticles (NPs), confined carbon nanotubes (CNTs) shuttling in carbon honeycombs (CH), namely, CH@Ni-CNTs, to encapsulate paraffin wax (PW) that can facilitate the light capture and photothermal conversion dynamics. Benefiting from the physical adsorption of the hierarchical porous structure, the obtained PW/CH@Ni-CNTs composite PCMs show a high phase change enthalpy of 131.0 J g-1 and long-lasting thermal stability of up to 300 heating-cooling cycles. Moreover, an outstanding photothermal energy conversion efficiency of 96.9% is achieved due to the synergistic effect of the dual carbon network and confined Ni NPs. The CNTs shuttled CH network affords multiple reflection chambers and a thermal conductive pathway, while the localized surface plasmon resonance (LSPR) effects of Ni NPs concentrate the incident light energy to generate and accelerate the transport of active "hot electron", thus collectively contributing to the excellent photothermal properties of the composite PCMs. This study presents a bifunctional Ni-induced dual-carbon network system for the controllable preparation of composite PCMs, and it sheds light on the photothermal conversion mechanisms.

Controlling Temporally and Spatially Homogeneous Temperature Distribution of Paper Substrates by Biogenic Phase Change Hybrid Material Coatings

AbstractHere the performance of phase change material (PCM)‐coated paper made from unbleached kraft pulp is introduced. The applied PCM consists of a mixture of ethylene glycol distearate (EGDS), a well‐known PCM wax material, and a fully substituted cellulose stearoyl ester (CSE). Transfer of the PCM material onto/into paper is achieved by spray as well as blade coating of EGDS + CSE mixture. It is shown that the kind of coating method used does not interfere with observed PCM properties. The significantly higher melt viscosity of the EGDS + CSE blends ensures that the EGDS wax is not bleeding out of the paper, which avoids the use of further encapsulation processes. The PCM behavior, as observed by thermal load measurements, and the thermal buffering of the coated paper is a function of the applied mass of the PCM material applied. The thermal retention exhibited a quasi‐isothermal behavior at ≈65 °C with EGDS + CSE coatings. These effects can offset fluctuations in temperature, and the PCM papers can be employed to achieve a more uniform temperature setting. PCM‐modified papers are therefore interesting candidates for paper‐based packaging or for use in paper‐based sensors, where overheating can strongly affect reliability of results.

Experimental investigation on the thermophysical properties and solidification characteristics of n-octadecane in a spherical capsule

A thorough understanding of the thermophysical properties of phase change materials and the natural convection effect during the phase transition process is crucial for the accurate modeling and designing latent heat storage systems. However, research findings on the thermophysical properties of n-octadecane and the natural convection effect during the solidification process remain insufficient. In this study, the thermophysical properties of n-octadecane, including latent heat, thermal conductivity, density, thermal expansion coefficient and dynamic viscosity, were systematically measured under varying temperature conditions. Subsequently, a comprehensive solidification experiment of n-octadecane in a spherical capsule was conducted to assess the temporal and spatial temperature distribution characteristics and the evolution patterns of the solidification front. Finally, numerical techniques were employed to quantify the impact of natural convection. The results indicate that, the relationship between solidification mass fraction and time follows a quartic polynomial pattern. Based on the temperature curve at the central point, the solidification process of n-octadecane can be divided into four distinct stages. The first two stages account for 98.2 % of the total heat release, with natural convection primarily concentrated in the sensible heat release stage of liquid phase, contributing only 2.3 % to the entire solidification process, making its effect essentially negligible.

Integrating phase change materials in buildings for heating and cooling demand reduction – A global study

This study aims to analyse the integration of Phase Change Materials (PCMs) in building envelopes globally, focusing on its ability to reduce the energy demand and its economic viability. The study conducted extensive simulations using the DesignBuilder software across 5684 locations globally and utilising artificial intelligence (AI) models to extend the simulation further to 73,515 locations, evaluating the impacts of PCM properties such as melting temperature (MT) and thickness. The main findings indicate that pronounced annual energy savings, 2500 to 3000 kWh, are observed in equatorial regions including northeast Brazil, central Africa, and the Malay Archipelago. Additionally, the optimal utilisation of increased PCM thickness is contingent upon selecting the correct MT and is most effective in regions with high average maximum temperatures, while the most common effective thickness is 20 mm. The study demonstrates that MT significantly affects energy savings, more than PCM thickness, highlighting the importance of selecting appropriate MT based on climatic conditions. The 25 °C MT is most effective within lower latitude range (−15°–30°), averaging 743.2 kWh greater savings than the 21 °C option. The 21 °C MT shows superior performance outside of this range, however the advantage is marginal as the average savings is 251.0 kWh. Economically, regions such as the USA, southern Europe (Spain and Italy), Brazil, and northern Australia show the best viability for PCM integration, aligning energy efficiency improvements with substantial economic returns. This comprehensive analysis suggests that tailored PCM integration strategies are essential for maximising energy savings and advancing sustainable building practices.

The innovative application of phase change materials in heat storage products: warmer pads

As the issue of energy shortage becomes increasingly severe, energy storage technology has gradually attracted global attention, with the application of phase change materials (PCMs) being particularly widespread. This paper focuses on a common daily product: the warmer pad, and investigates the selection and ratio of suitable PCMs to achieve a recyclable heat storage solution. The study first outlines the research background, significance, and methods, then summarizes the basic principles of phase change and the role of differential scanning calorimetry (DSC) in the study of phase change heat storage. Finally, the properties of PCMs with different proportions were tested, and the DSC curves were analyzed. The results showed that the phase change material mixture with a ratio of paraffin: OBC: expanded graphite = 77:20:3 exhibits excellent performance in heat storage, with a thermal conductivity of 0.547 W/mK, a phase change latent heat of 150 J/g, and a phase change temperature of 41.9C. The warmer pad achieved a surface temperature close to 40C and a heat release duration of nearly one hour. This study aims to promote the industry's transformation towards sustainable development and provide a reference for research in the field of daily-use products with phase change heat storage.

Unveiling the boson peaks in amorphous phase-change materials

The Boson peak is a universal phenomenon in amorphous solids. It can be observed as an anomalous contribution to the low-temperature heat capacity over the Debye model. Amorphous phase-change materials (PCMs) such as Ge-Sb-Te are a family of poor glass formers with fast crystallization kinetics, being of interest for phase-change memory applications. So far, whether Boson peaks exist in PCMs is unknown and, if they do, their relevance to PCM properties is unclear. Here, we investigate the thermodynamic properties of the pseudo-binary compositions on the tie-line between Ge15Te85and Ge15Sb85from a few Kelvins to the liquidus temperatures. Our results demonstrate the evidence of the pronounced Boson peaks in heat capacity below 10 K in the amorphous phase of all compositions. By fitting the data using the Debye model combined with a modification of the Einstein model, we can extract the characteristic parameters of the Boson peaks and attribute their origin to the excess vibrational modes of dynamic defects in the amorphous solids. We find that these parameters correlate almost linearly with the Sb-content of the alloys, despite the nonmonotonic behaviors in glass forming abilities and thermal stabilities. In a broader context, we show that the correlations of the characteristic parameters of the Boson peaks with Tg and kinetic fragility, vary according to the type of bonding. Specifically, metallic glasses and conventional covalent glasses exhibit distinct patterns of dependence, whereas PCMs manifest characteristics that lie in between. A deeper understanding of the Boson peaks in PCMs holds the promise to enable predictions of material properties at higher temperatures based on features observed in low-temperature heat capacity.

Design optimization of a phase-change capacitive sensor for irreversible temperature threshold monitoring and its eco-friendly and wireless implementation

Monitoring the temperature of perishable goods during transport and storage is essential to prevent waste and maintain product quality. Exploiting the unique property of phase-change materials (PCM), altering their physical state at specific temperatures, we optimize a capacitive sensor design based on a copper on polyimide interdigitated spiral (IDE) structure coated with a PCM to irreversibly detect temperature thresholds. The effect of the sensor dimensioning on its response is analyzed using a finite element model simulation. The model predicted up to 51% capacitance variation for optimal coverage of the PCM after spreading over the IDE, which was validated experimentally within a 5% error. Two melting concepts utilizing the spreading or the removal of the melted PCM over the IDE are investigated based on a capillary retention mechanism to maintain sensor sensitivity under inclination. Finally, an eco-friendly implementation of the capacitive structure and its wireless operation at 460 MHz is demonstrated on paper with a printed zinc transducer passivated with beeswax and covered with jojoba oil. Melting of the oil at a threshold temperature of 12.3 °C resulted in an irreversible shift in resonance frequency of 14 MHz. This study provides guidelines for the design and implementation of irreversible temperature monitoring capacitive sensors.

Performance Characterisation of Thermal Energy Storage Containing a Phase Change Material (PCM) Sphere with Low Conductivity Fins: Simulation-Based Analysis

This paper presents the outcomes of a simulation study aimed at investigating the thermal performance of modified phase change material (PCM) structures within a sphere with integrated fins. The escalating global warming crisis and its associated weather anomalies necessitate urgent measures to mitigate its impacts. Numerous research endeavours have been undertaken to address this issue, including the utilization of thermal energy storage systems (TES) augmented with PCM. PCM can be incorporated into building walls to counteract rising temperatures. However, inadequate heat transfer caused by poor thermal conductivity has been a persistent challenge in these systems. The addition of high conductivity fins has found to improve the overall performance of TES. Yet, this study proposes the addition of low conductivity fins to study for the effect of shape factor to its performance. The research evaluates the phase change of 2-fins and 4-fins with varying thicknesses within the PCM structure. A comprehensive simulation framework is employed to analyse the thermal behaviour of the PCM-enhanced sphere without considering ambient temperature nor PCM properties, but fin dimensions and configurations. The simulation results reveal that the inclusion of fins significantly improves heat transfer within the system by cutting a minimum of 20% in phase change time and could promote the phase change process to happen earlier by a maximum of 38% in starting time. By optimizing the fin configuration and thickness, the overall thermal conductivity of the PCM-based TES can be enhanced. These findings contribute to the development of efficient thermal energy storage systems, offering potential solutions to combat global warming and promote sustainable thermal management.

Enhancing MIMO-VLC system performance using reflective phase change materials

Abstract In this paper, the impact of phase change materials (PCM) as reflecting surfaces on the bit error rate (BER) performance of multiple-input multiple-output (MIMO) visible light communication (VLC) systems has been investigated. The optical properties of PCM, including absorption and reflection characteristics have been analyzed to optimize the design and functionality of PCM-based VLC systems. The current study investigates the BER performance of 4 × 4 and 8 × 8 MIMO-VLC systems using non-line of sight (NLoS) signal under varying refractive index, temperature, and incidence angle conditions. Additionally, different types of PCM has been assessed, such as organic compounds, salt hydrates, and paraffin wax, to determine their suitability for implementation in MIMO-VLC systems.

Development, characterization and themo-physical analysis of energy storage material doped with TiO2 and CuO nano-additives

The paper presents the results of an experimental investigation on chemical stability, surface morphology, and thermo-physical properties of phase change material integrated with nano additives. The research aims to evaluate impact of varying nano-particle concentration on thermal performance of phase change material. The phase change material magnesium dichloride hexahydrate and potassium chloride mixed in different mass ratio along with different wt% concentration of nano-additives titanium dioxide and copper oxide to prepare novel phase change material. Characterization methods such as Fourier Transform Infrared Spectroscopy, Scanning electron microscope, Energy-dispersive X-ray analysis, and Differential scanning calorimeter analysis were employed. The Fourier transform infrared spectra indicated physical interactions between phase change material and nano-additives, while Energy-dispersive X-ray analysis confirmed elemental composition, and Scanning electron microscope demonstrated uniform distribution. The improved thermal properties of samples were reflected in their phase change enthalpy (284.57 J/g to 324.63 J/g), minimal energy loss (0.91 %–2.96 %), and low supercooling (0.3 %–5.26 %). Notably, doping with 1.5 wt% of titanium dioxide and copper oxide enhanced thermal conductivity by up to 117.07 % and specific heat capacity by up to 48.09 %. The introduction of nanoparticles significantly improves heat transfer characteristics, resulting in enhanced energy retention, reduced energy loss during phase transitions, decreased supercooling, and increased physical stability. These results suggest that optimized phase change material with nano-additives is highly effective for applications requiring stable and efficient thermal management.

Improvement of the Thermal Performance of PCM-Based Heat Sink Used in Electronic Cooling by Adding Nano-Particles

Recently, thanks to the technological advances, electronic devices are getting smaller in size. This causes an increase in the heat generation per unit area. This heat has to be removed from electronic devices for them to be longer-lasting, more efficient and more reliable. There are many active and passive methods designed for this objective. One of them is embedding phase change material (PCM) in the heat sink. PCM, during the phase change stage, absorbs the heat generated in the system and thus aids in keeping the temperature at a certain value. The biggest downside of PCM is its rapid conduction of heat. PCM properties can be improved by using nanoparticles. In this study, nanoparticles such as TiO2 and CuO were added to PCM and such a modified PCM is used in a finned heat sink. The thermal behavior of the PCM with addition of 1%, 2% and 5% TiO2 and CuO was investigated numerically in three dimensions. RT-28HC was used as the PCM in the study. It was shown that as the nanoparticle ratio increases, heat transfer coefficient of the PCM rises and the melting time of Nanoparticle PCM (NPPCM) is less than that of pure PCM. However, it was observed that, the melting time of PCM with CuO added is longer than that of the PCM with TiO2 added.