Phase Change Material Research Articles

Optimal design and control strategy for enhanced battery thermal management

The Battery Thermal Management System (BTMS) plays a crucial role in the safety and performance of new energy vehicles. This study proposes an innovative cooling structure design that ingeniously combines the advantages of air cooling, water cooling, and Phase Change Materials (PCMs) to enhance the cooling efficiency of the battery system. Through numerical simulations, the effectiveness of this cooling system was validated and further supported by experimental evidence confirming the accuracy of the simulation results. Subsequently, this research utilized the Response Surface Methodology (RSM) to optimize key parameters of the cooling structure, including the fin height, gap length, and PCM thickness, with their optimal values determined to be 5.20 mm, 17.69 mm, and 3.38 mm, respectively. This parameter optimization work provides precise guidance for the design of battery thermal management systems, contributing to enhanced heat dissipation performance. To further enhance the intelligence of battery thermal management, this study introduced a novel neural network model based on Temporal Convolutional Networks (TCN) and Bidirectional Long Short-Term Memory (BiLSTM) with Multi-Head Attention (MHA). This model is capable of predicting temperature changes during the battery discharge process in real-time with high accuracy. Based on the prediction results, this research designed an efficient control strategy that, compared to a scenario without a control strategy, demonstrated a reduction in energy consumption by 20.87 %, a decrease in maximum temperature by 2.52 K, and a reduction in the maximum temperature difference by 0.05 K. These results not only prove the effectiveness of the control strategy but also provide a new direction for the optimization of battery thermal management systems.

Numerical Study on the Effect of Heat Source and Fin Arrangement on the Melting Performance of Phase Change Materials in a Latent Heat Storage System

Numerical Study on the Effect of Heat Source and Fin Arrangement on the Melting Performance of Phase Change Materials in a Latent Heat Storage System

Assessment of Thermal Management Using a Phase-Change Material Heat Sink under Cyclic Thermal Loads

Phase-change materials (PCMs) are widely used in the thermal management of electronic devices by effectively lowering the hot end temperature and increasing the energy conversion efficiency. In this article, numerical studies were performed to understand how temperature instability during the periodic utilization of electronic devices affects the heat-dissipation effectiveness of a phase-change material heat sink embedded in an electronic device. Firstly, three amplitudes of 10 °C, 15 °C, and 20 °C for fixed periods of time, namely, 10 min, 20 min, and 40 min, respectively, were performed to investigate the specific effect of amplitude on the PCM melting rate. Next, the amplitude was fixed, and the impact of the period on heat sink performance was evaluated. The results indicate that under the 40 min time period, the averaged melting rate of PCMs with amplitudes of 20 °C, 15 °C, and 10 °C reaches the highest at 19 min, which saves 14 min, 10 min, and 8 min, respectively, compared with the constant input of the same melting rate. At a fixed amplitude of 20 °C, the PCM with a period of 40 min, 20 min, and 10 min has the highest averaged melting rate at 6 min, 11 min, and 19 min, saving the heat dissipation time of 3 min, 8 min, and 14 min, respectively. Overall, it was observed that under identical amplitude conditions, the peak melting rate remains consistent, with longer periods resulting in a longer promotion of melting. On the other hand, under similar conditions, larger amplitude values result in faster melting rates. This is attributed to the fact that the period increases the heat flux output by extending the temperature rise, while the amplitude affects the heat flux by adjusting the temperature.

Thermal performance investigation of microencapsulated phase change material enhanced with graphene nanoplatelets in double-glazing applications

Effective heat energy storage is crucial for thermal energy management. The utilization of latent heat storage methods is widely prevalent across various engineering applications for enhancing energy efficiency. In this study, the energy storage performances of Phase Change Materials (PCMs) achieved by incorporating graphene nanoplatelets into a microencapsulated PCM were experimentally analyzed for double-glazing applications. Changes in thermal energy storage and heat transfer performance by incorporating graphene nanoplatelets into the PCM at two different mass ratios (1 % and 0.1 %) were investigated. The results obtained from light intensity and temperature measurements, as well as thermal camera imaging, were evaluated together. The results support the contribution of graphene nanoplatelets addition to microencapsulated PCMs in enhancing thermal performance during both heating and cooling periods. Among the investigated cases, the highest mass ratio of 1 % graphene nanoplatelets addition led to a major 10 °C increase in peak temperature compared to the reference condition. In contrast, this increase in peak temperature was accompanied by a mere 14 % decrease in average light levels. This research underlines the potential of graphene-enhanced microencapsulated PCMs in optimizing thermal management systems for double-glazing applications, offering a promising pathway towards enhancing energy efficiency and thermal comfort in building environments.

Poly-dopamine coated-cellulose/chitosan hybrid carbon aerogel composite phase change materials with efficient photothermal conversion and storage

Solar energy, being both low-cost and renewable, is a viable alternative for thermal storage and can help mitigate the energy crisis. Efficient conversion and storage for solar energy can significantly enhance energy utilization. Phase change materials (PCMs), such as paraffin (PW), are capable of harvesting and converting solar energy into thermal energy, thus playing a crucial role in solar energy utilization. However, PW faces challenges, such as solid–liquid leakage and low photothermal conversion efficiency, which hinder its applications in solar energy storage. In this study, we proposed the construction of a robust poly-dopamine (PDA)/chitosan (CS)/cellulose nanofibers (CNF) carbon aerogel with enhanced photothermal performance. This is achieved by incorporating PDA, known for its excellent light absorption properties, and cross-linking it with low-cost biomass CS and CNF via a Schiff base reaction. The resulting novel composite PCMs exhibit high photothermal conversion efficiency and shape stability by encapsulating PW within the PDA/CS/CNF carbon aerogel. Our findings demonstrate that the composite PCMs have a high melting energy-storage capacity of 209.57 J/g. Notably, the introduction of PDA significantly improved the photothermal conversion efficiency by 94.9 %. These results suggest that composite PCMs hold great potential for applications in photothermal energy conversion and storage.

Giant and reconfigurable vortical dichroism with multi-layer spiral metamaterials

In the photonics orbital angular momentum dimension, the vortical dichroism (VD) of artificial metamaterials at fixed wavelengths has been extensively investigated. However, the challenges of weak and unregulated VD magnitude still limit the development of chiral optics. Herein, we propose multi-layer spiral metamaterials with phase change material Ge2Sb2Te5 (GST), which support giant VD magnitude of −176% in the optical communication band around 1550 nm. Meanwhile, by changing the temperature to control the GST from crystalline to amorphous states, the VD magnitude rapidly decreases to −1%. This large change from extremely giant magnitude to weak magnitude indicates the advantages of reconfigurable VD response. The maximum modulation depth reaches almost 100%. The GST based metamaterials possess excellent switchable capability for VD magnitude without refabricating structures, which is promising in applications for the next generation of chiral optical communication devices.

Structural optimization and battery temperature prediction of battery thermal management system based on machine learning

Lithium-ion batteries significantly extend the driving range for electric motorcycles. The battery thermal management system (BTMS) is critical for achieving optimal battery performance. Moreover, precise battery temperature prediction is essential for efficient thermal management. Therefore, a battery thermal management system integrating air and phase change material (PCM) cooling is proposed. Initially, the impact of PCM height, PCM thickness, and air velocity on battery temperature is analyzed. Subsequently, with cost minimization as the objective and ensuring that the maximum battery temperature remains below a threshold, the Black Kite Algorithm (BKA) is employed to optimize the BTMS structure. Finally, a BKA-Convolutional Neural Network (CNN)-Self Attention (SA) model is introduced for battery temperature prediction. The results indicate that increasing the thickness of the PCM and air velocity facilitates battery heat dissipation but with diminishing marginal effects. An increase in PCM height enhances battery cooling at low air velocities but becomes detrimental at high air velocities. The optimized PCM height is 35 mm, resulting in a cost of 0.073 USD for the BTMS per battery. Additionally, the BKA-CNN-SA model achieved a maximum error of 0.45 °C on the validation set and accurately predicted battery temperature changes before and after PCM melting.

Fatty Acids as Phase Change Materials for Building Applications: Drawbacks and Future Developments

The worldwide population growth and its increasing affluence have led to an increase in global building energy consumption. Therefore, developing sustainable energy storage materials to mitigate this problem has become a high priority for many researchers. Organic phase change materials (PCMs), such as fatty acids, have been extensively studied for thermal energy storage in building applications due to their excellent performance in absorbing and releasing energy within the environment temperature ranges. However, issues related to their thermal conductivity, stability, and flammability could limit the potential and require addressing. In this review, organic PCMs, with a special focus on fatty acids, are discussed. This review covers recent studies related to PCM synthesis from bio-sources, methods for PCM incorporation in building materials, methods for enhancing organic PCM thermal properties, flammability challenges, and life cycle assessment. Finally, future opportunities are summarized.

Magnetic Phase-Change Microcapsules with High Encapsulation Efficiency, Enhancement of Infrared Stealth, and Thermal Stability

Due to energy shortages and the greenhouse effect, the efficient use of energy through phase-change materials (PCMs) is gaining increased attention. In this study, magnetic phase-change microcapsules (Mag-mc) were prepared by suspension polymerization. The shell layer of the microcapsules was formed by copolymerizing methyl methacrylate and triethoxyethylene silane, with the latter enhancing the compatibility of the shell layer with the magnetic additive. Ferric ferrous oxide modified by oleic acid (Fe3O4(m)) was added as the magnetic additive. Differential scanning calorimetry (DSC) testing revealed that the content of phase-change materials in microcapsules without and with ferric ferrous oxide were 79.77% and 96.63%, respectively, demonstrating that the addition of Fe3O4(m) improved the encapsulation efficiency and enhanced the energy storage ability of the microcapsules. Laser particle size analysis showed that the overall average particle sizes for the microcapsules without and with ferric ferrous oxide were 3.48 μm and 2.09 μm, respectively, indicating that the incorporation of magnetic materials reduced the size and distribution of the microcapsules. Thermogravimetric analysis indicated that the thermal stability of the microcapsules was enhanced by the addition of Fe3O4(m). Moreover, the infrared emissivity of the microcapsule-containing film decreased from 0.77 to 0.72 with the addition of Fe3O4(m) to the shell of microcapsules.

ESTUDIO DE LA RESPUESTA I-V EN CELDAS DE MEMORIA DESb70Te30

Chalcogenide glasses are within the group of phase change materials and are promising in their application to non-volatile electronic memories. Under electrical pulses, they can circulate between two amorphous and crystalline structural states that are well differentiated in their conductivity. Assuming that the phase change mechanisms depend on the energy per unit volume delivered to the sensitive material, it is desirable to build cells on a micrometer scale, also considering that they could eventually be integrated into microelectronic manufacturing processes. In a previous work, we observed an abrupt decrease in the resistance of Sb70Te30base thin films deposited by laser ablation in a temperature range of approximately 445 K when the sample is heated at low rates. From the results of differential scanning calorimetry and X-ray diffraction on samples obtained by the same method, we associate the change in resistivity with the crystallization process. In this work, we build micrometric devices with rectangular surface with Sb70Te30assensitive material, deposited on coplanar electrodes with spacing L (8 and 16μm) and width W (4, 8, 16, 32 and 64μm). We measure the voltage response of the devices when excited by scanning of increasing current and, between consecutive scanning, we measure the remaining resistance by applying a constant voltage value. In curves I-V, we identify a transformation from the original state to one of lower resistance, attributable to crystallization, but it was not possible to perform the reverse transformation to a state of higher resistance. Starting from the lack of knowledge about the conductivity of the material, we simulate the electric field in the cell using the Finite Element Method. The electrical conductivity of the chalcogenide glass in its initial state (amorphous) was estimated by adjusting its value in the simulations with different geometries, minimizing the difference between the measured and simulated resistances.

Comprehensive effective thermal conductivity correlation and fast model for the melting of a phase change material inside a horizontal shell-and-tube unit

The effective thermal conductivity is a robust alternative to include the effect of natural convection during the melting of a phase-change material, while solving only the energy equation. With this approach, significant time savings may be obtained, maintaining satisfactory accuracy. However, it remains unclear how well the existing equations predict the enhanced conductivity for horizontal shell-and-tube heat exchangers, particularly in terms of accurately estimating the liquid fraction. In this paper, a simplified model for the melting of a phase-change material is developed based on the pure conduction formulation while considering natural convection. The model was solved using the finite volume method and implemented in Python. A previously validated computational fluid dynamics (CFD) model was used to calculate the enhanced conductivity, which was then applied to the simplified model. The simplified model was found to be 3500 times faster than the CFD model, with a maximum deviation of only 8.2%. Subsequently, existing correlations to predict the effective thermal conductivity were assessed. The results for the liquid fraction predictions indicated maximum deviations ranging from 33.6% to 144.8%, for predictors developed under melting conditions, and from 35.6% to 231.1%, for equations developed without considering phase-change. Further, new correlations, spanning all melting regimes, were proposed, revealing maximum deviations of 17.73% and 10.24% for the different scenarios evaluated. Therefore, the new correlations demonstrated to be the preferred choice to obtain more accurate models for the melting of phase-change materials inside horizontal shell-and-tube units.

Optimizing thermal performance of sodium acetate trihydrate phase-change-materials through synergistic effects of binary graphene nanoadditives for prolonged hot beverage maintenance

Sodium acetate trihydrate (SAT) is a promising candidate for thermal energy storage due to its high latent enthalpy and economic viability. However, limitations like supercooling and low thermal conductivity hinder its practical application. Herein, these challenges are addressed by developing a novel SAT-based composite phase change material (PCM) through incorporation of binary nanoadditives—graphene oxide (GO) and graphene nanoplatelets (GNP) to mitigate supercooling and enhance thermal conductivity, respectively. Notably, the optimal composite, SAT/0.25GO/0.75GNP, identified through systematic formulation optimization, retains a high latent enthalpy (281.09 J/g), comparable to pure SAT (290.47 J/g), with improved thermal conductivity and substantially reduced supercooling and phase separation issues. The combined effects of GO and GNP, likely due to noncovalent interactions, enhanced heat transfer in the composite, which was further tested in a vacuum mug. The SAT/0.25GO/0.75GNP composite achieved ideal drinking temperatures (60–50 °C) for hot water in just 4 minutes–18 times faster than the PCM-free control mug and 6 times faster than the Mug containing pure SAT. While the PCM-free mug maintains hot water within this interval for only 49 min, MugPCM, encapsulating pure SAT, retains heat for 76 min, and that with SAT/0.25GO/0.75GNP keeps remarkably hot for as long as 100 min.

Advancements in Thermal Energy Storage: A Review of Material Innovations and Strategic Approaches for Phase Change Materials

Advancements in Thermal Energy Storage: A Review of Material Innovations and Strategic Approaches for Phase Change Materials

Assessing the Potential of Phase-Change Materials in Energy Retrofitting of Existing Buildings in a Mediterranean Climate

Assessing the Potential of Phase-Change Materials in Energy Retrofitting of Existing Buildings in a Mediterranean Climate

Thermal performance of multifunctional louver window integrated phase change material and spherical louver

The integration of phase change material (PCM) into glazed envelope is an effective measure to enhance its thermal inertia and reduce energy consumption. However, the inefficient utilization of latent heat stored in double-glazed unit filled with PCM (PCMW) in winter and overheating in summer restricts the adoption of PCM in cold regions. Therefore, this work proposed a multifunctional new phase-change louver window integrating PCM and spherical louvers, and numerically investigated its thermal behaviour in summer and winter seasons. The effects of different melting temperatures and ventilation mechanisms on the thermal performance and energy efficiency of phase change louvers were analyzed. The results show that the new phase-change louver window can significantly improve the thermal comfort and energy efficiency of the window. In winter, insulated PCM louver window has the best performance, reducing heating energy consumption by 2618.56kJ/(m2·d) compared to hollow window, with energy saving of 54.03 %, whereas in summer, reflective PCM louver window performed best, reducing cooling energy consumption by 3584.47 kJ/(m2·d) compared to hollow window, with an energy saving rate of 37.08 %. The analysis of various melting temperatures shows that the melting temperature of RT14 is the most suitable in the annual basis, and the introduction of ventilating mechanism for ventilated reflective PCM louvers window can significantly enhance the performance of the window.

Molecular dynamics method to investigate the interaction energy and mechanical properties of the reinforced graphene aerogel with paraffin as the phase change material in the presence of different external heat fluxes

BackgroundGraphene aerogels (GA), known for their exceptional lightweight and sturdy characteristics, present a promising avenue for improving thermal energy (TE) storage and transfer efficiency. It might be possible to make better thermal management systems in fields like electronics, aerospace, and energy storage by studying how heat flux (HF) affects the strength and stability of graphene aerogels. MethodsThe study used molecular dynamics (MD) simulation to investigate how the mechanical properties of graphene aerogels strengthened with paraffin as phase change material (PCM) change in response to external heat flux (EHF). These simulation methods provided a detailed view of molecular interactions and dynamics at the atomic level, allowing researchers to understand the behavior of materials under various conditions. The change in toughness, interaction energy (IE), Young's modules (YM), and ultimate strength (US) was examined for this reason. Significant findingsThe results indicate that when the HF increased from 0.1 to 0.3 W/m2, the ultimate strength and Young's modules increased from 8.91 and 5.37 GPa to 14.546 and 8.59 GPa, respectively. These values declined when HF increased by more than 0.3 W/m2. When EHF went up to 0.3 W/m², these graphene aerogel properties went up. This was because the atoms moved around more and there were more bonding contacts among the graphene sheets, which made the structure of material stronger. However, at heat flux levels exceeding 0.3 W/m², excessive thermal energy may lead to thermal degradation, causing bond breakage and loss of structural integrity, ultimately resulting in a decrease in these mechanical properties. Also, the results reveal that interaction energy increased from -1522.098 to -1546.325 eV as external HF increased to 0.3 W/m2. The thermal motion of atoms enhanced as the HF increased, enabling closer clustering and better alignment of graphene sheets, thereby strengthening their interactions. This study gave us useful information about how to improve the mechanical properties of graphene aerogels in different HF conditions. This made it more likely that these materials can be used in energy storage systems and thermal management.

Numerical investigation and optimization of battery thermal management systems based on phase change material coupled with heating plates in low temperature environment

Low temperature environment has a significant impact on the performance and reliability of lithium-ion batteries (LIBs), particularly in terms of capacity, posing challenges to their safety and availability. However, existing studies primarily focus on cooling technologies for high temperatures, while less attention is paid to the preheating and heat preservation performance under low temperatures. In this study, a simple and effective battery thermal management system (BTMS) combines phase change material (PCM) and heating plates (HPs) is developed. The influence of structures, PCMs, composite phase change material (CPCM), and battery spacing is investigated. Additionally, the essential of insulation is emphasized. Furthermore, the utilization of natural thermal insulation material in BTMS is explored, and the influence of insulation thickness during both preheating and insulation stages are researched. The results indicate that the proposed BTMS can preheat the batteries to 20 °C under four typical low temperatures of 0 °C (480 s), −10 °C (720 s), −20 °C (900 s), and − 30 °C (1200 s). The temperature differences can be controlled below 3 °C. Moreover, the temperature can be maintained above 10 °C for approximately 4 h in the parking stage. A thickness of 10 mm is found to be sufficient. Overall, the energy compensation value above 5 is achieved under most low temperatures.

Numerical study on the heat transfer features of concurrent forced nano-PCM emulsion/water flows in a double concentric-tube configuration

To provide a feasible heat dissipation solution for a high heat flux, in this study, the internal flow and heat transfer characteristics of an externally heated concentric double tube were numerically studied via the implicit finite difference method. The outer ring and inner tube were filled with a phase change nanofluid and water, respectively. The parameter ranges were as follows: the mass fractions of the phase change material (PCM) emulsions were 2.04 %, 2.91 %, and 7.11 %, the relative flow ratio was 0.33–4.0, the heat power inputs were 70 W and 150 W, and the total tube flow rates were 304.83 cm3/min and 465.98 cm3/min. The results showed that incorporating PCM emulsions can effectively improve heat transfer performance; however, the PCM concentrations, heating conditions, and outer-annulus/inner-tube flow rates (relative flow ratios) must be properly matched so that the phase change of the working fluid occurs in the expected section. Within these parameter ranges, in the heated section, the latent heat utilization of the PCM emulsion is lower than that of the sensible heat, and only when the flow ratio is greater than 1 is the latent heat utilization of the 7.11 % PCM emulsion similar to that of the sensible heat.

Sodium nitrite-sodium nitrate eutectic based composite phase change material (CPCM) for medium-temperature thermal energy storage (TES): Exploring the relationship between microstructures and thermal properties

This paper is concerned with a novel medium-temperature composite phase change material (CPCM). More specifically, the CPCM contains a sodium nitrite‑sodium nitrate phase change material for latent and sensible heat storage, magnesium oxide as a ceramic matrix material for shape-stabilisation and sensible heat storage, and expanded graphite as a thermal conductivity enhancer material (TCEM) to improve heat transfer. The focus is on understanding the relationship between the CPCM microstructures and their thermal properties. This CPCM was found to be unique, exhibiting both a reversible solid-solid transition (≈175 °C) and a reversible solid-liquid transition (≈223 °C), with a total latent heat of fusion of ∼120 J/g. In-depth microstructural characterisation of the CPCM indicated adequate thermal stability during thermal cycling in air up to 350 °C, which was also confirmed by their stable latent heat and thermal conductivity. The results highlighted a correlation between microstructures of the CPCMs and their thermal properties, as well as potential thermal decomposition reactions in high temperature industrial applications of molten salts such as concentrating solar power.

Enhancing Energy Efficiency in Moroccan Construction through Innovative Materials: A Case Study in a Semiarid Climate

Rising global energy demand has intensified the need for sustainable building practices and reduced energy consumption in the construction sector. This study investigates the energy-saving potential of integrating innovative materials into building wall structures in semiarid climates. Specifically, we examine the combination of thermal insulation made from recycled textile waste and phase change materials (PCMs) in exterior walls. Using the dynamic simulation tool TRNSYS, we analyzed heat transfer through the modified wall assembly under semiarid climate conditions typical of Marrakech, Morocco. Our results show that this “bioclimatic” design significantly impacts cooling loads more than heating demands. The modified building achieved a 52% reduction in summer energy usage compared to a conventional reference building. This energy saving translates to a 39% decrease in greenhouse gas emissions. Importantly, this study confirms that this configuration maintains thermal comfort for occupants, with particular effectiveness during the hot summer months when cooling demands are highest.