Phase Change Material Temperature Research Articles

Battery thermal management system optimization using Deep reinforced learning algorithm

The temperature of the battery plays a critical role in the working conditions and a suitable temperature environment can help the battery extend its capacity. Air cooling and water cooling are prevalent as positive heat dissipation methods used in research. Phase change material (PCM) has a good heat dissipation capacity because of its latent heat property. Therefore, PCM is chosen as the battery thermal management method in this study. Adding two water channels in the center of the pack strengthens the heat dissipation capacity. Deep reinforcement learning (DRL) is used to explore the multi-optimal solution of the battery thermal arrangement, and its results are compared with the classical methods such as NSGA-ii and MOPSO. Max temperature, temperature difference of the battery, and average temperature of PCM are selected as the optimization targets. A comparison between DRL optimization and the initial system shows that the increased max temperature decreased by 0.33 ℃ (2.1%), and the average temperature of PCM decreased by 0.3 ℃ (2.3%). The temperature difference of DRL optimization decreased by 1.3% compared with that of NSGA-ii and MOPSO. The max temperature decreased by 0.2% and the average temperature of PCM decreased by 0.3% compared with those of NSGA-ii. In summary, DRL has the potential application in battery thermal management system (BTMS) optimization. The most important contribution of this work is utilizing DRL in the optimization process, which shows better results than existing optimization methods.

Performance assessment and optimization of concentrated solar power plants with paired metal hydride-based thermochemical energy storage

The main objective of this study is to evaluate the innovative future concept of a concentrated solar power (CSP) plant, specifically focusing on a CSP-driven Rankine cycle. Additionally, a suggested energy storage solution for the analyzed CSP plant is the thermochemical energy storage (TCES) approach. The TCES system used paired metal hydrides integrated with phase change material (PCM). A comprehensive mathematical model has been developed to enable performance predictions for the entire CSP plant as well as each of its components. This model considers the thermal coupling between the solar field, the thermochemical storage system, and the power block in order to assess the overall performance of the CSP plant. Utilizing this successfully verified model with reference data, a parametric study is conducted on various operating parameters to identify optimal operating points for the storage system in relation to the overall efficiency of the CSP plant. Furthermore, the critical issue of appropriate and novel concepts for MHs-based TCES integration in CSP plants is discussed in detail. The CSP plant's performance was examined as a function of storage cycle duration, charging and discharging temperatures, melting PCM temperature, and thermal efficiency. Based on the findings, it has been observed that higher charging temperature and integration of PCM into the thermochemical energy storage (TCES) system can lead to a significant reduction of 13-fold in the required solar collector area and a notable increase of 77 % in the efficiency of the CSP plant. Thus, the proposed TCES system appears to be the most promising future heat storage system for CSP plants.

Graphite crucible interaction with Fe–Si–B phase change material in pilot-scale experiments

Abstract Fe–26Si–9B alloy is a promising high temperature phase change material (HTPCM), due to its high heat of fusion, small volumetric change, abundance, and low cost. Additionally, graphite has been identified as a promising candidate for use as a container material for this alloy. In this study, the feasibility of using graphite for Fe–26Si–9B HTPCM is investigated in a pilot-scale. Specifically, 4–5 kg Fe–26Si–9B master alloys were melted in graphite crucibles using an induction furnace, which underwent 2–3 thermal cycles in the temperature range of 1,100–1,375°C. The results showed that SiC and B4C precipitates were formed in the alloys. However, these carbides were found to be present only on the surface of the solidified alloys and not in the main body. Still, the chemical composition of the Fe–26Si–9B alloy remained relatively stable during the thermal cycles. It was also seen that the graphite crucible withstood the temperature cycles without cracking. Therefore, the use of graphite as a container for Fe–26Si–9B phase change material is a promising approach.

Near zero thermal performance loss of Al-Si microcapsules with fibers network embedded Al2O3/AlN shell

Al-Si alloy, a high temperature phase change material, has great potential in thermal management due to its advantages of high heat storage density and thermal conductivity. Microencapsulation of Al-Si alloy is one of the effective techniques to solve high temperature leakage and corrosion. In this paper, commercial Al-10Si alloy micro powders were encapsulated with flexible ceramic shells whose total thickness is below 1 µm by hydrothermal treatment and heat treatment in N2 atmosphere. The compositions and microstructures were characterized by XRD, SEM and TEM. The shell was composed of AlN fibers network structure embedded with α-Al2O3/AlN which prevented the alloy from leaking and oxidizing, as well as had excellent thermal stability. The latent heat of microcapsules was 351.8 J g–1 for absorption and 372.7 J g–1 for exothermic. The microcapsules showed near zero thermal performance loss with latent heat storage (LHS)/ release (LHR) was 353.2/ 403.7 J g–1 after 3000 cycles. Compared with the published Al-Si alloy microcapsules, both high heat storage density and super thermal cycle stability were achieved, showing promising development prospects in high temperature thermal management.

Grafit Matris Kompozit Faz Dönüşüm Sıcaklığının Kare Dalga Yük Altındaki Küçük Ölçekli Bir Li-iyon Batarya Paketi Performansına Etkisi

An experimental study is performed to illustrate the effect of the melting temperature of graphite matrix composite with phase change materials on the performance characteristics of a small-scale li-ion package (3s2p) under dynamic/square wave load. Paraffin (RT35 and RT42) is used as a PCM. Graphite matrix is manufactured with 75 g l-1 bulk density. The battery package is performed for three different configurations: free-air cooling case (reference case), and graphite matrix composites with RT35 and RT42. The experimental outputs present that graphite matrix composite has considerable potential for thermal management of the Li-ion pack. Safe operating time, discharge and energy capacity values are increased by 140%, 141% and 102% with the graphite composite with RT35 in the comparison reference case, respectively. It is observed that the melting temperature of PCM of graphite composite is of critical importance to the performance of the battery pack. For the graphite composite with RT35, operating time, discharge capacity and energy capacity values are enhanced by 6.2 %, 7 % and 10 % compared to the RT42 case, respectively.

Natural Convection in the Melting of Phase Change Materials in a Cylindrical Thermal Energy Storage System: Effects of Flow Arrangements of Heat Transfer Fluid and Associated Thermal Boundary Conditions

Abstract Latent thermal energy storage systems (LTESS) have received widespread attention due to their high energy density to store a significant amount of thermal energy in the form of latent heat into phase change materials (PCM) at a nearly constant melting temperature. The thermal efficiency of LTESS is usually limited by poor heat conduction in PCM but enhanced by the natural convection of molten PCM. The natural convection increases the uniformity of temperature by mixing in a PCM enclosure and therefore increases the heat transfer rates and accelerates the melting. While there is negligible natural convection, periodic reciprocation of heat transfer fluid (HTF) through the PCM enclosure has been demonstrated to increase the heat transfer rates to PCM by increasing the melt interface area and reducing temperature gradients across PCM compared to fixed-directional flow arrangements. The current study examines the effects of HTF flow direction on the strength and duration of natural convection in PCM in a vertical cylindrical shell-and-tube container. Gallium is used as the PCM because of its low melting temperature and high thermal conductivity, and water is used as the HTF. A 2-D axisymmetric numerical model developed in ANSYS Fluent was used for the study of the cylindrical LTESS. The aspect ratio of the cylindrical container is nearly 1, which allows the generation of natural convection currents of strong magnitude in molten PCM in the vertical orientation. The irregular melting front in the PCM is caused by both natural convection in molten PCM and thermal boundary conditions for different HTF flow arrangements. The temperature and melting front profiles of PCM with the reciprocating flow arrangement are compared to unidirectional flows in upward and downward directions. The influence of HTF operating parameters such as temperature, velocity, and reciprocation period on PCM melting is studied. Scale analysis is also applied to characterize the different melting regimes of PCM under different flow arrangements.

Multi-functional conductive cementitious composites including phase change materials (PCM) with snow/ice melting capability

ABSTRACT To remove snow/ice collected on surface of pavements is a must to prevent not only significant structural damages of infrastructures but also traffic accidents, however, today’s methods require higher labour and maintenance costs. Producing phase change materials (PCM)- and carbon fibre (CF)-incorporated multifunctional composites with melting snow/ice capability can be a cost effective alternative compared to mechanical methods and heating systems. In this study, the cementitious composites were produced adding 0, 2, 4, 6 and 8% PCM, by weight of the cement and 0.0, 0.1, 0.3% CF, by volume of the mixture. The composites were compared in means of ice melting performance and the damage resulted from freezing and thawing, applying two different simulations in a freeze–thaw cabinet: −10/+10°C and −20/+20°C. In addition, their compressive strength and consistency results were considered with their SEM analysis. As a result of the studies, the optimum CF ratio, which contributes the most to the melting ice performance of PCM-containing composites, was found to be 0.1% by volume. However, in freeze–thaw simulations, CFs increased the temperature amplitudes and PCMs were able to partially prevent this increase. While PCMs increased the workability of the composites and decreased their strength, CFs adversely affected both their workability and strength.

A Brief Review and Its Incorporation with Bibliometric Analysis of Phase Change Materials for Thermal Energy Storage

Reduction of Food Losses and Wastes (FLW) through the use of cold chain is one strategy applied in accelerating the SDGs goals of zero hunger. The application of Thermal Energy Storage (TES) based on PCM (Phase Change Material) is considered as one of best efforts for the simultaneous reduction of food losses and wastes, reduction of energy consumption as well as preserve the right temperature for food product. This paper presents the review of phase change material for thermal energy purposes and its bibliometric analysis. Bibliometric analysis on term of cold chain logistics show that there is correlation between cold chain and terms of optimization, vehicle routing, carbon emission, refrigeration, and phase change materials. The definition of TES and PCM, as well as the advantages of TES based on latent material are described in this paper. PCMs is classified into solid-solid, solid-liquid, solid-gas and liquid-gas based on its phase. The potential generation of gas and larger volume on solid-gas and liquid-gas PCMs limits the application of those two types of PCMs. PCMs is also classified according to the phase change temperature in which low, medium and high temperature PCMs. Organic, inorganic and composite based PCMs are the classification of PCMs based on the chemical composition. Among the types of PCMs, this paper present a deep review of paraffin based organic PCMs. The appearance of term of thermal conductivity in bibliometric analysis on term of organic phase change materials is due to organic PCMs commonly have low thermal conductivity

Evaporative and non-evaporative droplet impact on a heated phase change material pool: A comparison between ethanol, acetone, and distilled water

The interaction between liquid droplet and phase change material (PCM) underlies the direct contact approach, which is an efficient way for precipitating the melting and solidification processes of PCMs. In this experimental research, to comprehend the direct contact method more profoundly, the impingement of a single droplet on the heated paraffin pool, having a temperature of 70–95 °C, is scrutinized systematically for the first time. Droplet impact solidifies a portion of the pool and may lead to droplet evaporation. Acetone, ethanol, and distilled water are exploited as droplet liquids, whose diameter and impact velocity range from 2.32 to 3.36 mm and from 1.70 to 2.28 m/s, respectively. Through impact visualizations, six distinct regimes are observed, whose regime maps are constructed. Moreover, the effects of fluid properties, pool temperature, and the Weber number on the evolution of crater and jet, crater depth, crater shape, and solidified PCM area (A) generated after the impingement are investigated. It is ascertained that the low PCM temperature instigates the coalescence phenomenon regardless of the Weber number. Additionally, the crater depth is a function of the PCM temperature, Weber number, and Ohnesorge number; thus, a dimensionless correlation is proposed for the maximum crater depth. Furthermore, droplet evaporation augments the extracted heat from the paraffin, provoking a more sizeable solidified area. Interestingly, though absorbing the greatest amount of heat from the PCM, ethanol droplet generates a smaller solidified area than acetone since acetone favorably spreads on the pool surface, enhancing the effective heat exchange area.

Transient solidification and melting numerical simulation of lauric acid PCM filled stepped solar still basin used in water desalination process

It is crucial to produce potable water from salt water in arid places using a stepped solar still desalination process. This work presents the temperature distribution and phase transformation of lauric acid PCM in inclined stepped solar still desalination system. A second-order finite volume method is employed for discretizing the two-dimensional geometry, while energy, continuity, and momentum equations are solved and then coupled using the second-order PRESTO algorithm. The solidification and melting CFD models have been used to capture the melting stages of lauric acid PCM. Four steps with an inclination of 30° to ground and two different cases with saline water levels of 10 mm and 40 mm have been reported. The results reveal that the temperature and mass fraction of lauric acid PCM strongly depends on the saline water level at each step, the number of steps, the angle of inclination, and the location of the solar still step. The maximum percentage increase in PCM melting fraction is 50%, and a PCM temperature rise of 4 °C is observed in the case of SWL-max compared to SWL-min. The total enthalpy of lauric acid PCM is increased by 30% for the SWL-max water level compared to the SWL-min water level.

Experimental and numerical investigation of PCMS on ceilings for thermal management

In this study, experimental investigation of phase change materials (PCM) integrated into building on ceilings was assessed for thermal management capabilities by comparing two building test models with and without PCM based on fluctuation in PCM temperatures owing to ambient temperature variations. Commercial organic PCM (OM-30) with a peak melting point of 31.10 C was used as PCM with high-density polyethylene (HDPE) as the encapsulation. Differential scanning calorimeter (DSC) was used to examine the thermophysical characteristics of PCM such as phase transition temperature, latent heat, and specific heat capacity. The various PCM temperature ranges included for the study are (i) Above phase change melting temperature range ii) within Phase Change melting temperature range iii) Proximity to PCM onset melting temperature range iv) proximity to PCM end melting temperature range. Under free-floating ambient Condition, the indoor air temperature was dropped in PCM installed room up to 1.69 °C, 5.79 °C, 2.26 °C, & − 2.87 °C compared to without PCM room for a PCM Melting temperature difference of 8.77 °C,1.55 °C, 1 °C & 0.44 °C respectively. Also, it was divulged that the PCM utilized 3.2%, 31.4%, 6.9%, & 12.27% of the total latent heat energy deployed in order to produce a temperature difference of 1.69 °C, 5.79 °C, 2.26 °C, & − 2.87 °C compared to without PCM room.

Thermal performance enhancement methods of phase change materials for thermal energy storage systems – A review

Phase Change Materials (PCMs) have emerged as a promising solution for efficient thermal energy storage and utilization in various applications. This research paper presents a comprehensive overview of PCM technology, including its fundamental working principles, classification and different shapes of container used for PCM storage. The study investigates the optimal melting temperature of PCMs and explores various Thermal Energy Storage (TES) methods and their types. This paper discusses novel approaches to enhance the thermal performance of PCMs, such as incorporating high-conductivity materials, Nano-encapsulation, Composite formation, and Shape stabilization. These innovative techniques have shown great potential in enhancing efficiency of PCM-based TES systems. The information presented in this paper is an in-depth analysis of research papers published over the last five years (2019 to 2023). It is a valuable source for researchers seeking to stay current with the modern advancements in PCM technology and its applications. This research contributes to advancing sustainable and efficient thermal energy utilization by promoting a deeper understanding of PCM's capabilities and challenges.

Two phase simulation of solar still in the presence of phase change materials in its bottom and aluminum nanoparticles in the water

This article performs a numerical study on a transient solar still (SOST) by utilizing a variable heat flux using COMSOL software. A phase change material (PCM) layer with a thickness of 10–50 mm is placed at the bottom of the desalination. Some aluminum nanoparticles are added to the water in the water desalination, and the two-phase method is used to simulate this part of the desalination water. Other variables include the angle of the glass that changes from 10 to 45⁰ and the heat transfer coefficient (HTFC) on the glass that varies from 5 to 300 W/m2. The effect of these variables on the average PCM temperature (T-PCM), PCM volume fraction (VOF-PCM), average moisture (AV-MO) temperature, and AV-MO concentration is examined in 12 h. The simulations are done using the finite element method (FEM). The results demonstrate that the average temperature and VOF-PCM, AV-MO concentration, and AV-MO temperature are enhanced from morning to noon and decreased from noon to evening. An increment in the thickness of PCM causes the VOF-PCM in desalination water to reduce by 35%. An enhancement in the glass angle reduces the average temperature of PCM, especially in the morning and afternoon. The change in PCM thickness, especially in the evening, significantly enhances the AV-MO temperature.

Introduction of sustainable food waste-derived biochar for phase change material assembly to enhance energy storage capacity and enable circular economy

Production and utilization of renewable materials receive considerable attention to achieve the goals of carbon neutrality and carbon peaking and create a sustainable society. Phase-change materials (PCMs) have emerged as a novel energy storage technology but usually suffer inherent insufficient thermal stability and liquid leakage, thereby requiring solid supporting materials. However, there are complications in the synthesis of PCM-supporting materials, including environmental issues. In this regard, upcycling biowaste into higher value carbon materials, inspired by the low cost and availability of feedstocks, is a promising strategy for dealing with challenges caused by waste and global climate change. Thus, we designed food waste-derived biochar-supported PCMs using a facile vacuum impregnation method to overcome these limitations. Porous biochar materials with a certain degree of graphitization, high specific surface area (SSA), (up to 1195 m2 g−1), and micro-/mesopore distribution were prepared from sustainable and commercially available food waste through carbonization and activation. They displayed greater carbon lattice expansion after undergoing KOH activation and being washed than that shown by carbon materials synthesized without activation. Thereby, the graphitic carbon materials presented high loading ratios and corresponding enthalpy values that were 243.9, 302, 346.9, and 251.4 % higher than those of the composites prepared without activation, encapsulated only 15 wt% of octadecane. Additionally, the composite PCMs exhibited high thermal stability without leakage above the melting temperature of pristine PCM. Textural properties, including the SSA, interconnected pores, activation, graphite-like characteristics, and intermolecular interactions between the composite constituents, were integral to the enhanced thermal performance of the as-synthesized composite PCMs. Furthermore, the composite demonstrated high durability, showing potential for thermal management, sustainable management of food waste, and mitigation of climate change.

Research on Optimization Model of Heat Exchange Fin Structure in Energy Storage System

Aiming at the thermodynamic problem of heat transfer fin in heat storage system, the solidification and melting model and thermodynamic conventional model are established by using simulation software, thermodynamic image processing and other methods. MATLABAB, COMSOL and other software are used to program the optimal rectangular fin spacing Angle and the optimal heat exchange fin structure. Firstly, based on the reason that the simulation software can simulate the heat transfer process of phase change material (PCM) in the actual process to the greatest extent, the plane modeling and thermodynamic equation method are used to analyze the distance Angle of the rectangular fin, and the melting solidification model is established, and the optimal solution is obtained. Finally, combined with the analytic hierarchy model and TOPSIS method, the triangular fin structure and rectangular fin structure were compared from three levels, namely, the heat sink area, temperature rise time and PCM maintenance time of different shapes. And create a heat transfer rate of return to more favorably analyze the data and visually present the comparative results.

Experimental assessment of low temperature phase change materials (PCM) for refrigerating and air conditioning applications

Refrigeration, air conditioning and heat pump sector represents between 25 and 30% of the global consumption of electricity and this figure is expected to rapidly grow due to the current trend of electrification. To increase the efficiency of these systems or to maximize the use of renewable energy, latent thermal storage systems are being studied and recommended. However, there is a lack of reliable design rules based on trustable data that could help the thermal experts to design efficient and cost-effective latent thermal energy storage. This paper follows a previous work recently published (Longo et al., 2022) where the thermo-physical and transport properties of a few low temperature PCMs (i.e. 2–9 °C of melting temperature) were measured and discussed. In the present work, the attention is focused on two other fundamental aspects: the PCMs’ compatibility with the most common construction materials and their thermal behaviour during the solid/liquid phase change. The collected results will contribute to add currently unavailable data in the literature and to highlight interesting insights on the performance of the selected PCMs.

Characterization by differential scanning calorimetry of thermal storage properties of organic PCMs with operating temperature of 150 °C

The involvement of Phase Change Materials (PCMs) in energy storage systems leads to more sustainable and efficient use of energy. Medium operating temperature (melting point 100–400 °C) find various applications in industrial waste heat recovery and hybrid compressed air - thermal energy storage systems. However, there is still a lack of detailed knowledge in terms of their thermal storage properties that hinders them from being more integrated in industry. In this study, thermal properties such as melting point, enthalpy and heat capacity of three medium temperature PCMs were characterized using Differential Scanning Calorimetry (DSC). The enthalpy-temperature graph for each PCM is presented that contains key information on sensible and latent heat contribution in the total energy storage. The selected organic PCMs are adipic acid with two different purities 99%, 99.5%, and its chemical equivalent PureTemp151® with a melting point of (150.5 ± 0.5 °C) and a latent heat of (230 ± 10 J/g). Furthermore, the effect of heating rate and sample mass in DSC procedures on transition temperatures and enthalpy were evaluated. Finally, thermal performance of PCMs was quantified through 150 cycles of melting and solidification. The tested PCMs show a significant storage capacity and good thermal stability with less than 10 % enthalpy loss.

Thermal performance investigation of a novel medium-temperature pilot-scale latent heat storage system at different charging and discharging temperatures

Large-capacity medium-temperature latent heat storage (LHS) systems have the potential to be extensively utilized for waste heat recovery and peak load shifting. However, the phase change behavior and mechanism of medium-temperature phase change materials (PCMs) in shell-and-tube LHS systems, as well as the impact of charging and discharging temperatures on the thermal performance, are still unclear. To address these issues and verify the reliability of the cylindrical pilot-scale LHS system, this article designed and constructed a novel cylindrical medium-temperature (up to 300 °C) LHS system with a large capacity (approximately 1 GJ) equipped with spiral and H-shaped fins. The research focused on investigating the impact of various charging and discharging temperatures on the thermal behavior of the LHS system to adapt different temperature scenarios in waste heat recovery while also analyzing the coupling effect of heat conduction and natural convection during charging and discharging and depicting the PCM liquidus based on thermocouple data. The experimental findings indicated that increasing the charging temperature could effectively shorten the charging duration, with a decrease from 5.99 h at 280 °C to 4.00 h at 300 °C, representing a reduction of 33.22%. In contrast, the impact of decreasing the discharging temperature on the discharging duration was less significant than that of increasing the charging temperature. Besides, the differences in heat transfer mechanisms between the charging and discharging processes were analyzed. In the charging process, the heat transfer was initially dominated by heat conduction, followed by natural convection. Conversely, heat conduction predominantly governed the heat transfer process in the discharging process. The heat transfer process dominated by heat conduction would increase the non-uniformity of PCM temperature on the horizontal plane, while the heat transfer process dominated by natural convection would alleviate this non-uniformity. Moreover, the accumulative stored energy under the charging temperature of 290 °C was 952.37 MJ, while the released energy under the discharging temperature of 160 °C was 648.72 MJ, which was approximately 10–200 times greater than those documented in existing studies.

A hybrid battery thermal management system coupling with PCM and optimized thermoelectric cooling for high-rate discharge condition

The lithium-ion battery is now abundantly available in the market due to its excellent performance. However, battery overheating is increasingly prominent when the battery discharges at high speed. In this study, an active-passive BTMS (Battery Thermal Management System) combining PCM (Phase Change Material) and TEC (Thermoelectric Cooler) was proposed. The effects of different TEC currents and delayed cooling at different PCM melting rates were analyzed under the 4C discharge condition to enhance the thermal performance. The results demonstrate that battery temperature gets effectively controlled as the TEC current increases, but the temperature difference and PCM utilization are poor. However, applying a delayed current after the PCM melting rate reaches 80% reduces energy consumption and provides better temperature uniformity. Considering the large battery heat under 4C discharge, combined with the transient supercooling effect of TEC, a continuous pulse current was used to provide additional cooling power. Results show that the battery with TEC pulsed current operates 57.8% longer at 40 °C with a temperature difference maintained at 2.5 K under 4C discharge conditions compared with the PCM model.

Performance optimization for a novel two-stage thermoelectric generator with different PCMs embedding modes

In this study, a novel two-stage TEG with different phase change materials (PCMs) embedding modes is proposed to improve the efficiency of TEG systems. The output power and electrical energy of single-stage and two-stage TEG combined with different PCMs is firstly compared at the limit of total length of the PCM containers. Furthermore, the effect of different PCMs embedding modes, including arranged at the heat source side, between two TEGs and heat sink side, on the performance of two-stage TEG system was discussed. Finally, the amount of different PCMs arranged at different locations was optimized. The results showed that although application of high temperature PCM on the heat source side can alleviate the effect of heat source fluctuations to provide more stabilized output power, the total electrical energy is seriously reduced in the two-stage TEG system. Compared with the single-stage TEG system, the two-stage TEG system provides a much higher output power and electrical energy, in which the harvested total electrical energy of the optimum two-stage TEG system is increased by 44.8% with a conversion efficiency of 6.9%. These results are of great significance to the design of advanced TEG system for waste heat recovery.