Characterization Of Phase Change Materials Research Articles

Ag nanomaterials enabled simultaneous thermal storage and heat transfer enhancement of CH3COONa·3H2O/vermiculite composite phase change material

Filling thermally conductive materials (TCMs) is an effectivity way to enhance the thermal conduction of phase change materials (PCMs). However, it always has negative effects on heat storage behavior of PCMs. Balance of latent heat and thermal conduction capacity plays a vital role in practical application of thermal storage management. To study the effect of dimensional features of TCM on thermal characteristic of PCM, Ag nanomaterials (Ag NMs) which including 0-dimensional Ag nanoparticles (AgNP), 1-dimensional Ag nanowires (AgNW) and 2-dimensional Ag nanosheets (AgNS) acted as TCM, were used to modify the flaky expended vermiculate (EVM-Ag NMs), a series of CH3COONa·3H2O (SAT)/EVM-Ag NM composite PCMs (SAT/EVM-Ag NM CPCMs) were prepared. It was found that the Ag NMs contributed to the phase change behavior of hydrated salts. Wherein, the SAT/EVM-AgNW CPCM possessed high latent heat (∼200.9 J/g) and great thermal reliability (heat enthalpy loss was 6.9 % after 500 thermal cycles). Besides, Ag NMs also improved the thermal conductivity of the CPCMs. The Ag NWs formed interconnected thermal highways which was benefited to enhance thermal conductivity (0.8153 W·K−1·m−1). This work provides a new strategy for simultaneously improving the thermal conductivity and heat storage behavior of PCM, finds a new perspective to explore the mechanism of TCMs on phase change behavior and heat conduction of PCM.

Identification of synthetic parameters for the thermal characterization of Phase Change Materials in MH-PCM hydrogen storage systems

Abstract The present work adopts a multidimensional CFD methodology to investigate the thermal coupling between Phase Change Materials coupled and intermetallic Metal Hydrides, for hydrogen storage and delivery. In contrast to the currently available literature on this topic, the focus here is shifted from specific application-oriented modeling towards the systematic identification of a minimum set of parameters to highlight eventual similarity patterns among different PCM families. To achieve this goal, a representative cylindrical-type MH-PCM system model has been defined for a discharge-mode configuration, taking into account engineering-related constraints like the optimal hydrogen pressure delivery and hydrogen massflow control. The results obtained are expected to significantly improve design practices based on standard CFD methods, as well as to pave the way for the derivation of fast and accurate data-driven model surrogates for real-time modeling applications.

Experimental and numerical investigation of a double spiral tube heat exchanger in a novel composite phase change material

Phase change energy storage technology effectively harnesses energy, and phase change materials have been garnered significant attention due to their high latent heat capacity. The heat transfer capacity and phase transition of HCNT−CH3COONa·3H2O/Na2HPO4·12H2O composites in a double spiral tube heat storage unit were investigated. The effects of different flow rates and temperatures on the heat transfer characteristics of phase change materials were studied, and the thermal performance of the storage units was evaluated by calculating the power, energy and energy efficiency ratios. The phase change process of the composite during heat transfer was further revealed via simulation, and the heat storage and heat release of the composite were compared with those of other phase change materials. The results show that the effects of the flow velocity on the transformation time and power of the phase change material are negligible. However, an increase in flow rate can significantly increase the heat storage and heat release of the phase change unit. In particular, when the flow rate is 4 LPM, the energy efficiency ratio can reach 76.6 %. When the temperature increases from 80 °C to 90 °C, the melting time decreases by 30.23 %, indicating that increasing the temperature has a significant effect on the phase transition process. Through simulation calculations, the composite phase change material shows significant performance advantages under the same working conditions; its heat storage capacity is 108 % greater than that of the other materials, and the heat release capacity is 206 % greater, which indicates that it has greater energy storage and release efficiency and a better thermal energy conversion capacity. In addition, the experimental and simulation results also reveal the existence of a diagonal region of slow phase transition in the heat storage unit. In summary, this paper analyses the heat transfer performance of a double spiral tube heat storage device, provides a theoretical basis for practical application, and provides an important reference for improving the performance of a phase–change energy storage system.

An appraisal of phase change materials: characteristics, categorization, benefits, drawbacks and utilizations. A review

A new era of energy-efficient solutions has arrived thanks to the revolutionary class of substances known as phase change materials (PCMs), which have the extraordinary capacity to store and release thermal energy during phase transitions. The defining characteristics of PCMs, such as their well-defined melting and freezing temperatures, high latent heat of fusion, and variety of material types, including organic and inorganic PCMs, as well as eutectic combinations, are thoroughly examined in this thoroughly analysis. PCMs are divided into groups according to the physical shape they take and the temperature range in which they are used. These groups include low-temperature variations, high-temperature variants, encapsulated forms, and nanocomposite forms. PCMs provide a wide range of advantages, including effective thermal energy storage, cost-effective energy use, consistent temperature maintenance and small light designs. However, they do have some restrictions, such as compatibility issues and slow heat transfer rates. However, PCMs are used in a wide range of industries, from electronics and renewable energy to building and construction, revolutionizing temperature control, thermal management and energy efficiency. The future of PCM technology offers promise, with ongoing improvements aiming at improving heat transmission, integrating with renewable energy sources and enhancing encapsulation processes. This technology's vital position in a sustainable and efficient energy future is apparent, as it continues to transform our world in the hunt for responsible and green energy solutions.

Effect of dual NEPCM and tapered fins on thermal runaway control in lithium-ion batteries

This research investigates the thermal performance of dual phase change materials (PCMs) RT82 (PCM1) and RT27 (PCM2) using tapered fins and nanoparticles to improve their thermal management capabilities, specifically for controlling excessive heating in lithium-ion battery cells. The primary objective is to enhance heat transfer efficiency and melting characteristics of dual PCMs by incorporating alumina (Al2O3), molybdenum disulfide (MoS2), and single-walled carbon nanotubes (SWCNTs) nanoparticles at varying volume fractions and configuring tapered fins in different arrangements. A series of parametric studies were conducted to analyze the impact of these modifications on the thermal transport and solid-liquid transition characteristics of the PCMs. The key findings indicate that the incorporation of nano-sized particles significantly enhances the thermal conductivity of PCMs, with SWCNTs showing the highest improvement. The PCM system with 6 % SWCNTs nanoparticles exhibited a 41.85 % increase in melting characteristics compared to the baseline PCM. The study also reveals that increasing the number of fins from two to eight results in a 94.28 % increase in the melting rate for RT82 and a 50 % increase for RT27. Furthermore, the combination of increased nanoparticle concentration and fin number leads to a 12.17 % rise in melt pool temperature distribution for 2 % SWCNTs and 14.08 % for 6 % SWCNTs. The enhanced thermal conductivity and efficient heat transfer due to the synergistic effect of fins and nanoparticles result in faster phase transitions and improved temperature regulation within the system. These findings underscore the potential of optimized PCM configurations with advanced materials for superior thermal management solutions in high-heat applications, effectively extending the operational efficiency and lifespan of thermal systems like lithium-ion batteries.

Heat transfer in a non-uniformly heated enclosure filled by NEPCM water nanofluid

PurposeThis paper aims to focuses on by investigate the heat transmission and free convective flow of a suspension of nano encapsulated phase change materials (NEPCMs) within an enclosure. Particles of NEPCM have a core-shell structure, with phase change material (PCM) serving as the core.Design/methodology/approachThe enclosure consists of a square chamber with an insulated wall on top and bottom and vertical walls that are differently heated. The governing equations are investigated using the finite element technique. A grid inspection and validation test are done to confirm the precision of the results.FindingsThe effects of fusion temperature (varying from 0.1 to 0.9), Stefan number (changing from 0.2 to 0.7), Rayleigh number (varying from 103 to 106) and volume fraction of NEPCM nanoparticles (changing from 0 to 0.05) on the streamlines, isotherms, heat capacity ratio and average Nusselt number are investigated using graphs and tables. From this investigation, it is found that using a NEPCM nano suspension results in a significant enhancement in heat transfer compared to pure fluid. This augmentation becomes more important for the low Stefan number, which is around 16.57% approximately at 0.2. Secondary recirculation is formed near the upper left corner as a result of non-uniform heating of the left vertical border. This eddy expands notably as the Rayleigh number rises. The study findings indicate that the NEPCM nanosuspension has the potential to act as a smart working fluid, significantly enhancing average Nusselt numbers in enclosed chambers.Research limitations/implicationsThe NEPCM particle consists of a core (n-octadecane, a phase-change material) and a shell (PMMA, an encapsulation material). The host fluid water and the NEPCM particles are considered to form a dilute suspension.Practical implicationsUsing NEPCMs in energy storage thermal systems show potential for improving heat transfer efficiency in several engineering applications. NEPCMs merge the beneficial characteristics of PCMs with the enhanced thermal conductivity of nanoparticles, providing a flexible alternative for effective thermal energy storage and control.Originality/valueThis paper aims to explore the free convective flow and heat transmission of NEPCM water-type nanofluid in a square chamber with an insulated top boundary, a uniformly heated bottom boundary, a cooled right boundary and a non-uniformly heated left boundary.

Heat transfer enhancement of PCM in the triple-pipe helical-coiled latent heat thermal energy storage unit and complete melting time correlation

Secondary flows induced in helical-coiled pipes significantly enhance the thermal storage performance of latent heat thermal energy storage units. This paper presents a three-dimensional model of a triple-pipe helical-coiled system to investigate the melting characteristics of phase change material within it. A correlation for the complete melting time was developed based on the simulation results. The findings indicate that the thermal-hydraulic fields of the heat transfer fluids and phase change material deflect from the vertical central axis at cross-sections. The secondary flows within the inner pipe are more effective in enhancing melting than those in the outer pipe. Melting performance improves with increasing inner pipe diameter, coil diameter (from 100 mm to 160 mm), inclination angle, or heat transfer fluid temperature, or decreasing helical pitch. The inner pipe diameter, helical pitch and heat transfer fluid temperature exhibit more pronounced influences. An inner pipe diameter of 30 mm, a coil diameter of 160 mm, a helical pitch of 80 mm, an inclination angle of 90°, a heat transfer fluid temperature of 360 K, and a heat transfer fluid Reynolds number of 2000, respectively produce a faster melting process. The developed correlation for the triple-pipe helical-coiled pipe thermal storage unit accurately predicts 96 % of the 45 data within ±11 %.

Optimizing Hybrid Active–Passive Thermal Management of Prismatic Li‐Ion Batteries Using Phase Change Materials and Porous‐Filled Mini‐Channels

ABSTRACTTackling climate change is crucial, and electrifying the vehicular transportation sector is essential to reduce greenhouse gas emissions. Lithium‐ion (Li‐ion) batteries are highly efficient for electric vehicles (EVs) but face challenges such as thermal management, risk of thermal runaway, and high costs of lithium and cobalt. Overcoming these challenges is vital for the widespread adoption of hybrid and EVs. To overcome this drawback, this article proposed a large‐kernel attention graph convolutional network (LKAGCN) with leaf in wind optimization algorithm (LWOA) named as LKAGCN‐LWOA technique, which enhances the thermal management of prismatic Li‐ion batteries by integrating both active and passive cooling techniques. The system incorporates phase change materials (PCMs) with porous‐filled mini‐channels to regulate battery temperature effectively. The LKAGCN analyze thermal properties, battery conditions, and PCM characteristics to predict and optimize the thermal behavior of the battery pack using LWOA. The proposed methods tune the parameters of the hybrid thermal management system, ensuring efficient thermal regulation and improved performance. The proposed method is compared to various existing methods such as convolutional neural network (CNN), Taguchi method, and Finite element model (FEM).

Water retention and heat storage characteristics of phase change hydrogel in cooling pavement

Phase change hydrogel (PCH) combines the heat storage characteristics of phase change material with the water retention capacity of hydrogel, showing great potential in cooling pavement applications. This study aims to investigate the water retention and heat storage properties of PCH in cooling pavement, providing new insights for mitigating the urban heat island effect. Based on the principle of osmotic pressure, polyethylene glycol (PEG) solution was actively absorbed by superabsorbent polymers (SAP) to form stable PCH. By infusing the asphalt mixture skeleton with PCH-containing phase change grouting material (PCGM), a temperature-regulating phase change grouting pavement (PCGP) can be obtained. Morphological characterization showed that PCH was uniformly distributed in PCGM and effectively locked PEG during high temperature and water absorption/release processes without leakage. PCH imparted excellent water retention properties to PCGM, with a saturation water absorption rate of 44.1 %, which is 6.2 times higher than the control group, and a water retention rate of 34.31 % after heating at 60 °C for 12 hours. Furthermore, PCGM exhibited considerable heat storage performance, with a melting enthalpy of 15.74 J/g and a crystallization enthalpy of 12.07 J/g. Based on these, PCGP demonstrated outstanding temperature-regulating ability, reducing surface temperatures by 9.3 °C and 11.6 °C under dry and saturated conditions, respectively, compared to control pavement. In conclusion, this study provides a theoretical basis for the development of novel cooling pavement materials and shows great potential for its wide application in urban infrastructure construction.

A 3D self-floating evaporator loaded with phase change energy storage materials for all-weather desalination

Today, humanity is confronted with two interrelated crises: water and energy scarcity. The utilization of solar energy to evaporate seawater enables the acquisition of freshwater resources while minimizing energy consumption. However, the solar energy hitting the ground is associated with different weather patterns and the alternation of day and night. This work is based on chitosan (CS) aerogel, loaded with phase change material octadecane (ODE) and coated with epoxy resin glue and electrospinning fiber photothermal layer for continuous evaporator operation. Using the characteristics of phase change materials, the ODE undergoes a change from solidification to liquefaction, during which it absorbs and stores energy at elevated temperatures. Conversely, when the temperature decreases, the ODE reverts to solidification and releases stored energy. This enables the evaporator to be utilized in a broader range of scenarios, thereby enhancing the continuity of evaporation. The temperature of the evaporator remained higher than the initial temperature 2 h after the light source was switched off, achieving a light absorption of 94 % and an evaporation rate of 1.74 kg m−2 h−1. Furthermore, it exhibits purification capabilities for different kinds of solutions. The interfacial evaporator is capable of facilitating all-weather evaporation, and it has the potential to become a pivotal instrument in the domain of seawater desalination, with a vast array of applications.

Sustainable hydrogen production by integrating solar PV electrolyser and solar evacuated tube collector with hybrid nanoparticles enhanced PCM

The investigation is motivated to analyze the influence of Phase change material (PCM), nano PCMs, and hybrid Nano PCM in sustainable hydrogen production systems. An emerging and highly effective method for hydrogen production involves the use of proton exchange membrane (PEM) technology, which separates water into its constituent parts through electrolysis. Its susceptibility to performance deterioration over time, however, demandsroutine maintenance and component replacement, which negatively impacts operational effectiveness and cost-effectiveness. In this study, the PEM system for electricity and water heating was integrated with the evacuated tube collector and photovoltaic panel to produce hydrogen. Additionally, hybrid Al2O3 and SiO2 nanoparticles with a combined concentration of 0.1 % in equal shares improved the thermal characteristics of PCM in heat exchangers. The research result shows that the heat exchanger of the ETSC circuit with the hybrid nanoparticles enhanced PCM demonstrated improved thermal performance as well as increased hydrogen production. With hybrid nanoparticles enhanced PCM in the heat exchanger, the maximum energy and electrical energy were observed as246.5 kWh and 44.7 kWh, respectively. The ETSC efficiency, electrical efficiency, and PEM electrolyser efficiency reached their highest points at 93.1 %, 15.5 %, and 39.2 %, respectively. Furthermore, hybrid nanoparticle-enhanced PCM produces an average of 25.9 g of hydrogen.

Effect of nanomaterials on the melting/freezing characteristics of phase-change material

A novel variant of composite phase-change material (PCM) was developed by incorporating 0.5 wt% aluminum oxide (Al2O3), silicon dioxide (SiO2), copper (II) oxide (CuO) and silver (Ag) nanomaterials into myristic acid. In this formulation, myristic acid served as the foundational material, while aluminum oxide, silicon dioxide, copper (II) oxide and silver were employed as supporting components. The morphology and crystalline structure of the nanomaterials were studied using field-emission scanning electron microscopy and X-ray diffraction analysis, respectively. The composite PCMs were fabricated using a two-step process. The phase-change properties of the composite PCMs were assessed using differential scanning calorimetry. The nanomaterials (0.5 wt% aluminum oxide, silicon dioxide, copper (II) oxide and silver) were suspended in myristic acid separately to investigate the heat-transfer performance of the composite PCMs during phase-change processes (melting and freezing). The results clearly indicated that the duration of the melting and freezing processes of the composite PCMs decreased compared with that of the pure PCM. Thus, the newly prepared composite PCMs are potential candidates for harvesting solar energy for low-temperature heating applications.

Expression of Concern for article entitled “Entropy generation characteristics of phase change material in a variable wavy walled triplex tube latent heat storage unit for battery thermal management system”

Expression of Concern for article entitled “Entropy generation characteristics of phase change material in a variable wavy walled triplex tube latent heat storage unit for battery thermal management system”

Research on one-dimensional phase change heat transfer characteristics based on instrument compartment structure

To address the issue of electronic equipment failure inside the instrument compartment due to aerodynamic heating during high-speed flight. Combining the heat transfer characteristics of phase change materials, a new instrument compartment structure was proposed as the research subject based on phase change materials. While studying the heat transfer characteristics of this structure, one-dimensional phase change heat transfer theoretical model was constructed based on the Lightfoot integral equation method, and the corresponding analytical solution was obtained. To explore the temperature change law of the instrument compartment structure and verify the rationality of the theoretical model, the new thermal experiment was carried out for the instrument compartment structure. Compared with the aluminum alloy instrument compartment structure, the experimental results show that the instrument compartment structure design based on phase change materials could effectively reduce the temperature of the structure itself, and the experimental data are in good agreement with the theoretical calculation results, which verified the rationality of the theoretical model and provided a scientific basis for the practical application of phase change materials in instrument compartment structures.

A review on thermal energy storage with phase change materials enhanced by metal foams

Due to the mismatch between energy demand and energy production, in the last years the study of latent thermal energy storage systems has been significantly growing. This work aims to provide an overview of the studies and the experiments carried out on thermal energy storage systems, that use phase change materials combined with metal foams. A histogram that shows how the number of works on these subjects has been increasing over the years is reported; consequently, a general survey on phase change materials is conducted, identifying the temperature ranges and the latent heat which are most used in thermal energy storage systems and defining the strengths and weaknesses of the various types of phase change materials. Furthermore, the paper illustrates the models and methods currently used to describe the phase transition of phase change materials in metal foams. Subsequently, how metal foams improve the desirable characteristics of phase change materials is described, and then it is represented in what percentage the different pore sizes (PPI) are used and what the most functional porosity is for individual works. Lastly, through the summary of the analyzed papers some specific articles are considered, in order to explain the state-of-the-art and to clarify some fundamental concepts.

Investigation of Thermal Performance of Optimized Tree-Shaped Fins in Latent Heat Storage Units

An innovative tree-shaped fin is proposed to address the problem of low thermal conductivity of phase change materials (PCMs) in latent heat energy storage units. Numerical methods are applied to investigate the thermal properties of the melting process of PCMs. This paper investigates the effects of fin arrangement, fin geometry parameters, and temperature of the heat source on melting characteristics of PCMs in the latent heat energy storage unit. Results show that the melting time of PCMs with the inwardly-tilted fins at the top increases by 21.3% compared to the outwardly-tilted fins at the bottom. The response surface methodology is adopted to obtain the fin parameter combination with lower quality and better performance. The optimal fin dimensions are a thickness of 1.06 mm, a length of 3.38 mm, and a spacing of 12.61 mm. The reduction of the ambient temperature from 35 °C to 30 °C increases the melting time of the latent heat energy storage unit by 85%, and from 35 °C to 40 °C decreases the melting time by 29%.

Experimental and numerical assessment of thermal characteristics of PCM in a U-shaped heat exchanger using porous metal foam and NanoPowder

The utilization of Latent Heat Thermal Energy Storage (LHTES) has gained significant attention to address the disparity between energy supply and demand. One of the key advantages lies in the use of phase change materials (PCM). The purpose of this research is to overcome this obstacle by focusing on enhancing the thermal efficiency of an advanced thermal energy storage system specifically designed for solar domestic and industrial application. to overcome this obstacle by focusing on enhancing the thermal efficiency of an advanced thermal energy storage system specifically designed for solar domestic and industrial application. Through computational and experimental studies, a novel and small LHTES system with parallel U-shaped heat exchanger (USHX) has been created and investigated. To improve performance, two approaches are employed: optimizing thermal efficiency by dispersing nano-sized graphite powders into the paraffin material, and/or incorporating metal foams. The PCM is RT35HC, and the hot/cold heat transfer fluid is H2O, which travels via the U-shaped tube. The model incorporates the enthalpy-porosity technique to account for phase change phenomena. After comparing the numerical outcomes with the experiments herein run, data are shown in terms of liquid fraction, temperature evolution, stored energy, and a dimensionless parameter that characterizes the phase change process. The findings suggest that the proposed methods for enhancing heat transfer can enhance the thermal efficiency of systems. The outcomes illustrate that by addition of all methods, reduces the melting time by 13.39 %, 60.77 %, and 71.93 %, when compared to system with pure PCM.

Phase change materials in textiles: synthesis, properties, types and applications – a critical review

Phase change properties of clothing gain attention of the researcher now for their significant unique ability to absorb, release, store, and deposit temperature during phase transition. Phase change materials have been widely used and utilized now in various fields, as well as in textiles. In apparel products, phase change materials are used to introduce various special features, especially its make garments smart or have technical functions. Various researchers pay attention to this area for its large organic and inorganic resources. This review paper summarizes the road map of phase change materials in textiles, including the way of synthesis, the characteristics of phase change materials, and their applications in smart textiles. In addition, the diverse usage of phase change materials in different textiles is discussed. It also tries to cover the principles of phase change behavior, phase change material types, and their thermal properties. After that, the paper will try to mention the potential benefits and challenges associated with utilizing phase change materials in various applications that have been discussed here. Finally, this paper concludes with the mass acceptance of phase change materials in various technological advancements, along with a short note about future research opportunities.

Thermal performance and optimization of an integrated collector–storage solar air heater based on lap joint-type flat micro-heat pipe arrays

This study seeks to optimize the performance of an integrated collector–storage solar air heater (ICSSAH) based on lap joint-type (LJT) flat micro-heat pipe arrays (FMHPAs) and latent thermal storage through numerical simulation. A novel dynamic heat transfer model is developed by incorporating the heat transfer correlation describing the thermal characteristics of phase change material (PCM) in narrow and elongated confined spaces within plate fins and validated using experimental data to address the issue of deviation caused by the fixed thermal resistance of the PCM in conventional numerical simulation methods. The validated model is used to simulate and predict the dynamic performance of LJT-FMHPA-ICSSAH under different heat transfer structures. Several optimization parameters, including the air gap thickness, the optical properties of the collector and glass cover plates, and fins structure, are considered. Simulation results indicate that the heat lost to the external environment through the glass cover plate accounted for over 70 % of the total heat dissipation. The optimal combination included a 50 mm gas layer; copper-based blue titanium coating; ultra-white glass; and fin spacing, thickness, height, and length of 5, 0.2, 60, and 195 mm, respectively. Under autumn/winter operating conditions, the optimized thermal performance is 1.13–1.35 times higher than the performance prior to optimization.

Pore-scale study of melting characteristic of phase change material embedded with novel open-celled metal foam

Metallic porous structure is a prevailing heat transfer enhancer for the melting of phase change material (PCM), while the effect of the structure on the enhancement performance is yet to be understood. In this work, a pore-scale numerical study on PCM melting embedded in a truncated cuboctahedron porous structure, referred as TCD metal foam, was performed. The solid–liquid interface, temperature and the variation of liquid fraction were analyzed and compared with those with the tetrakaidecahedron porous structure, referred as TKD metal foam. The effects of natural convection, porosity, pore density and heating temperature are explored. It is found the natural convection shortens the PCM melting time by about 7 % with the considered porosity range and thus cannot be ignored. Results also show that the TCD metal foam better enhances PCM melting near the porous cell corners compared to the TKD metal foam. Further analysis shows the TCD metal foam can better enhance melting at the former stage due to the larger surface area, while the TKD metal foam can better enhance melting at the later stage due to the thicker metallic ligaments. With essentially the same melting time at ɛ = 0.941, the half-melting takes 17.2 % of the complete melting time for TCD metal foam and 20.3 % of the complete melting time for TKD metal foam. A critical porosity value exists when comparing the enhancement performance of these two metal foams, below which the better melting enhancement is shifted from the case with TCD metal foam to the case with TKD one. The critical porosities are 0.941, 0.923 and 0.899 at the pore densities of 10, 20 and 30 PPI respectively.