Phase Change Materials For Energy Storage Research Articles

Metal foam reinforced phase change material energy storage device: A collaborative optimization strategy for porosity and container shape

Latent heat thermal energy storage (LHTES) is often employed in solar energy storage systems to improve efficiency. This method uses phase change materials (PCM) as heat storage medium, often augmented with metal foam to optimize heat transfer. In this paper, we introduce a novel approach of altering the container shape to enhance the heat storage effectiveness. LHTES tank with different coning coefficients (C) is designed by reducing the hard-to-melt bottom region. Based on the finite volume, volume averaging, and enthalpy porosity method, the transformation process of a simplified two-dimensional model of the LHTES tank is numerically simulated. Analysis focuses on the evolution of liquid-solid interface, liquid fraction, temperature field, and heat storage performance. The results indicate that the bottom region area enhances the heat storage performance when C < 0.375, whereas for C ≥ 0.375, it hinders heat transfer. When the porosity is 0.93, the newly deformed LHTES tank demonstrates a reduction of up to 6.2% in melting time compared with the basic model. Additionally, it achieves 98% of the basic thermal energy storage. Furthermore, metal foams with varying porosity are analyzed, and a cooperative optimization matching strategy between porosity and shape is obtained. By reducing the porosity to 0.87, the melting time can achieve a 61% reduction at C = 0.125. This study is expected to provide new insights and references for optimizing the design of LHTES devices.

Development of Composite Microencapsulated Phase Change Materials for Multi-Temperature Thermal Energy Storage

Phase change energy storage materials have been recognized as potential energy-saving materials for balancing cooling and heating demands in buildings. However, individual phase change materials (PCM) with single phase change temperature cannot be adapted to different temperature requirements. To this end, the concept of fabricating different kinds of microencapsulated PCM (MEPCM) and combing them to form a multiphase change material (MPCM) for multi-seasonal applications in buildings has been proposed. To prove the feasibility of this idea, three kinds of MEPCMs were fabricated and used for the development of three different composite MPCMs, classified as MPCM-1, MPCM-2, and MPCM-3. Analysis of the results shows that each MPCM sample was able to release latent heat at two different temperatures thus making them suitable for multi-temperature thermal energy storage applications. The phase change temperatures of the MPCMs were however found to be slightly reduced by 0.09–0.31 °C as compared with the MEPCMs samples. The measured energy storage capacities for the MPCMs were also reduced in the range of 6.3–11.4% as compared with the theoretical values but they displayed relatively good thermal stability behaviour of up to 197.8–218.8 °C. It was further identified that the phase change temperatures and latent heat of the MPCM was attributed to the weight percentages of individual components, as the theoretical values for the three MPCM samples were all in good accordance with the measured values. Therefore, optimizing the weight ratios of the MEPCM in MPCM samples and their corresponding thermophysical properties based on specific climatic conditions would be a necessary step to take in future investigations. Thermal performance enhancement of the MPCM is also being recommended as an essential part of further research.

Wood Lamella-Inspired Photothermal Stearic Acid-Eutectic Gallium-Indium-Based Phase Change Aerogel for Thermal Management and Infrared Stealth.

Eutectic Gallium-Indium (EGaIn) liquid metalis an emerging phase change metal material, but its low phase transition enthalpy and low light absorption limit its application in photothermal phase change energy storage materials (PCMs) field. Here, based on the dipole layer mechanism, stearic acid (STA)-EGaIn-based PCMs which exhibit extraordinary solar-thermal performance and phase change enthalpy are fabricated by ball milling method. The wood lamella-inspired cellulose-derived aerogel and molybdenum disulfide (MoS2 ) are used to support the PCMs by the capillary force and decrease the interfacial thermal resistance. The resulted PCMs achieved excellent photothermal conversion performance and leakage proof. They have excellentthermal conductivity of 0.31W m-1 K-1 (this is increased by 138% as compared with pure STA), and high phase change enthalpy of187.50 J g-1 , which is higher than the most of the reported PCMs. Additionally, the thermal management system and infrared stealth materials based on the PCMs are developed. This work provides a new way to fabricate smart EGaIn-based PCMs for energy storage device thermal management and infrared stealth.

Protic dialkylammonium-based ionic liquids as promising solid-solid phase change materials for thermal energy storage: Synthesis and thermo-physical characterization

The widespread deployment of renewable energies such as solar and wind implies the parallel development of energy storage systems to deal with their intermittency. Storing renewable energy as thermal energy is one of the alternatives under constant research. In this regard, phase change materials (PCMs) are able to store large amounts of energy at a nearly constant temperature in the form of latent heat. Nevertheless, most of these PCMs undergo solid-liquid transitions, which hamper their implementation due to leaking issues, forcing the need for containment and increasing the final cost of the TES system.Therefore, a class of PCMs possessing solid-solid transitions has emerged to avoid these problems, the so-called organic ionic plastic crystals (OIPCs). Currently, the scientific literature and the number of OIPCs available for TES are rather scarce. Herein, we present the synthesis, the structural, and the thermo-physical characterization of nine OIPCs based on the dioctylammonium cation combined with different organic and inorganic acids as the anions. Particular attention has been paid to the most characteristic thermal properties of PCMs (latent heat, transition temperature, subcooling, thermal conductivity, and energy storage density), evaluating their thermal stability and the reliability of the most promising materials over thermal cycling as well. Among the prepared OIPCs, 3 of them, [DOA][NO3], [DOA][Cl], and [DOA][FOR], exhibited promising properties with remarkable solid-solid transition enthalpies of 156.6 J/g (at 41.4 °C), 101.2 J/g (at 20.0 °C) and 58.4 J/g (at 29.7 °C), respectively. These 3 OIPCs showed high potential to be used and integrated as PCMs in TES systems at temperatures below 45 °C.

Preparation and Characterization of Bio-Based PLA/PEG/g-C3N4 Low-Temperature Composite Phase Change Energy Storage Materials.

As energy and environmental issues become more prominent, people must find sustainable, green development paths. Bio-based polymeric phase change energy storage materials provide solutions to cope with these problems. Therefore, in this paper, a fully degradable polyethylene glycol (PEG20000)/polylactic acid (PLA)/g-C3N4 composite phase change energy storage material (CPCM) was obtained by confinement. The CPCM was characterized by FTIR and SEM for compatibility, XRD and nanoindentation for mechanical properties and DSC, LFA, and TG for thermal properties. The results showed that the CPCM was physical co-mingling; when PLA: PEG: g-C3N4 was 6:3:1, the consistency was good. PEG destroys the crystallization of PLA and causes the hardness to decrease. When PLA: PEG: g-C3N4 was 6: 3: 1, it had a maximum hardness of 0.137 GPa. The CPCM had a high latent enthalpy, and endothermic and exothermic enthalpies of 106.1 kJ/kg and 80.05 kJ/kg for the PLA: PEG: g-C3N4 of 3: 6: 1. The CPCM showed an increased thermal conductivity compared to PLA, reaching 0.30 W/(m·K),0.32 W/(m·K) when PLA: PEG: g-C3N4 was 6: 3: 1 and when PLA: PEG: g-C3N4 was 3: 6: 1, respectively. Additionally, the CPCM was stable within 250 °C, indicating a wide appliable temperature range. The CPCM can be applied to solar thermal power generation, transportation, and building construction.

Thermal heat transfer and energy modeling through incorporation of phase change materials (PCMs) into polyurethane foam

Decreasing HVAC energy consumption through insulation effectiveness enables low energy use, low carbon emissions, and high thermal comfort in sustainable buildings. PCMs for energy storage are an innovative option, but in buildings, their high thermal conductivity is a concern.The PCM latent heat of fusion and thereby it’s transition temperature has been a key parameter in PCM selection but little is known of the effect of PCM on building energy contributions arising from increasing thermal conductivity (k), density (ρ), and specific heat capacity (Cp). To resolve this, in this paper, two PCMs with transition temperature above and below the outdoor temperature incorporated in highly porous flexible polyurethane foam were evaluated using a one-dimensional (1D) foam core panel built in COMSOL Multiphysics®. The simulations were run using the summer season in a humid subtropical climate zone with an outdoor temperature of 35 °C. It was found that apart from the latent heat of fusion, the combined effects of high ρ and Cp could mitigate the increased k of PU-PCM composites to improve the insulation performance. Building energy modeling using EnergyPlus with the foam core incorporated into a structural insulated panel (SIP), revealed that the use of PCMs regardless of the transition temperature could reduce annual electricity consumption by 15–20%, with a significant amount of energy savings arising from the cooling load in summer.

Form-stable cold storage phase change materials with durable cold insulation for cold chain logistics of food

Every year, many foods are discarded in the process of transportation because they could not be kept fresh for a long time, resulting in great food and economic loss. Phase change technology for cold energy storage has the advantages of stable temperature and high energy storage density, and it has great application potential in cold chain logistics. However, how to endow it with shape stability before and after phase change and machinability while maintaining high cold-insulation performance is of great importance for expanding its application in the fields of cold chain logistics with higher requirements. Herein, a novel form-stable cold energy storage phase change material (FCPCM) with ice as phase change component and a polyether-based three-dimensional network as skeleton was reported. FCPCMs exhibit excellent shape stability, i.e., no water leakage, owing to the coaction of capillary forces and hydrogen bonding between two phase interfaces. FCPCM demonstrated excellent thermal properties (ΔHm = 285.9 J/g and Tp of melting = 1.9 °C) and durable cold-insulation performance, and it could maintain cold temperature 1.85 times longer than ice. FCPCM could prolong the preservation time of litchi, indicating its excellent potential in cold chain logistics of fruit, vegetables, and other foods to enhance food quality and safety.

Ultrafast microwave heated form-stable thermal package providing operating temperature for PEO all-solid-state batteries

All-solid-state batteries (ASSBs) have been regarded as satisfying future energy storage devices owing to the advantages of notably high energy density and outstanding safety. However, their attainable energy density, especially in poly(ethylene oxide) (PEO)-based ASSBs, is limited by low operating ambient temperature due to sluggish lithium-ion transport of solid electrolyte. Herein, a functional anti-leakage skeleton (alumina ceramic and boron nitride) with efficient graphene-modified phase change material (GPCM) and microwave thermal energy storage system is proposed for providing the operating temperature of ASSBs. The composite, prepared by alumina ceramic fiber, boron nitride, and GPCM, presenting excellent thermal properties such as great enhancement of thermal conductivity (64.6%) and low enthalpy loss (11.27%). The superior thermal effect is confirmed by experiments and simulations of microwave absorption. Through microwave irradiating the ASSBs wrapped with the composite, ASSBs can realize cold-starting in 1 min from room temperature in a fast, safe and low-power heating pathway. Significantly, the combination of multi-scale characteristics in graphene increases the thermal energy generated by the composite during microwave processing. Furthermore, the composite material (GPBC), used as portable auxiliary heating equipment, enables the ASSB to exhibit 92% capacity of those ASSBs placed in 55 °C ovens at 1C. This work provides a distinctive route to achieve efficient and extensive applications of ASSBs through external preheating.

Formulation and phase change mechanism of Capric acid/Octadecanol binary composite phase change materials

Fatty acids and fatty alcohols have the advantages of high latent heat of phase change, good thermal stability, no corrosion, no supercooling and phase separation. They can be used as phase change energy storage materials for passive temperature control. However, their popularization and application are limited because of their high phase transition temperature and narrow phase transition range. This study develops a novel binary composite phase change materials (PCMs) of Capric acid (CA) and Octadecanol (OD) by a melt blending method. The theoretical calculation and hot melt-step cooling were carried out to generate an optimal molar ratio, followed by DSC thermal characterization. ATR-FTIR and XRD were performed to determine the phase transformation and chemical and structure changes. The results showed the binary CA-OD binary composite PCMs has a high latent heat of fusion, a melting temperature Tm = 26.48 °C and △H = 181.06 J/g at optimal mass ratio of 85.15:14.86 (CA:OD), which is higher than the theoretically predicted latent heat of phase transition, indicating a good synergistic effect beneficial to energy storage. Solid CA exists in the form of dimer and –OH in solid OD exists in form of association, and intermolecular hydrogen bonds weakens in liquid. There are hydrogen bonds in the CA-OD binary composite PCMs, and the molecular structure changes before and after the phase transformation were similar to that of a single component CA or OD. The crystal structures of the two compounds also change and the latent heat of phase transformation is improved. Finally, through TG and high and low temperature cycle test, CA-OD binary PCMs demonstrates good thermal stability and practicability in the field of building energy conservation.

Structural characteristics and thermal performances of lauric-myristic-palmitic acid introduced into modified water hyacinth porous biochar for thermal energy storage

Water hyacinth (WH) was used to prepare biochar for phase change energy storage field to realize encapsulation and enhance thermal conductivity of phase change materials (PCMs) in this work. The maximum specific surface area of modified water hyacinth biochar (MWB) obtained by lyophilization and carbonization at 900 °C was 479.966 m2/g. Lauric-myristic-palmitic acid (LMPA) was used as phase change energy storage material, LWB900 and VWB900 were used as porous carriers respectively. Modified water hyacinth biochar matrix composite phase change energy storage materials (MWB@CPCMs) were prepared by vacuum adsorption method, with loading rates of 80 % and 70 % respectively. The enthalpy of LMPA/LWB900 was 105.16 J/g, which was 25.79 % higher than that of LMPA/VWB900, and the energy storage efficiency was 99.1 %. Moreover, the introduction of LWB900 increased the thermal conductivity (k) of LMPA from 0.2528 W/(m·K) to 0.3574 W/(m·K). MWB@CPCMs have good temperature control capability, and the heating time of LMPA/LWB900 was 15.03 % higher than that of LMPA/VWB900. In addition, after 500 thermal cycles, the maximum change rate of enthalpy of LMPA/LWB900 was 6.56 %, and it maintains a phase change peak, showing better durability than LMPA/VWB900. This study shows that the preparation process of LWB900 is the best, and the adsorption of LMPA has high enthalpy value and stable thermal performance, realizing the sustainable development of biochar.

Structural Analysis of Phase Change Materials (PCMs)/Expanded Graphite (EG) Composites and Their Thermal Behavior under Hot and Humid Conditions.

Expanded graphite (EG) has been used to store phase change materials (PCM) to enhance thermal conductivity and avoid leakage. However, systematic investigation on physical structure of various embedded PCMs in EG is not reported. Besides, the effect of environment on thermal behavior of PCM/EG composites has not been investigated yet. In this work, three common PCMs (including myristic acid (MA), polyethylene glycol (PEG) and paraffin wax (PW)) were embedded in EG and three PCM/EG composites were obtained. As a result, capillary force between EG and PCMs supported encapsulation of PCMs in EG. PCM/EG composites had narrower phase change range while supercooling degree values were different when various PCMs were used. Besides, the hot and humid environment had a side effect on thermal energy storage of PCMs and PCM/EG composites. The inherent hydrophilicity of PCMs was essential for resistance against side effect of moisture on thermal energy storage.

Experimental study of screening polyols and their binary eutectic phase change materials for long-term thermal energy storage

Polyols are appealing long-term thermal energy storage materials due to their severe supercooling properties and high energy density. However, spontaneous crystallization during storage and slow crystallization during crystallization hinder their reliability and applicability. In this article, two single polyols (xylitol and sorbitol) and nine binary eutectic mixtures, prepared by a method based on Gibbs excess energy, were screened as long-term thermal energy storage phase change materials. The results conclusively demonstrated that xylitol and its binary eutectic mixtures (xylitol + inositol, xylitol + mannitol, and xylitol + dulitol, with a 150 g bulk scale) could be stored at room temperature in isolation from the air for more than 300 days without any crystallization. However, other samples either transformed into a glassy state (xylitol + sorbitol and sorbitol + erythritol) or crystallized (sorbitol, xylitol + erythritol, sorbitol + inositol, sorbitol + mannitol, and sorbitol + dulcitol). The exothermic performance test showed that three additives (xylitol particles, ethanol, and acetone) could effectively trigger the crystallization of xylitol and its binary eutectic mixtures after reheating to an appropriate temperature before or after storage. This process excludes sorbitol and its binary eutectic mixtures. Simultaneously, the exothermic performance test also indicated that xylitol, xylitol + erythritol, xylitol + inositol, xylitol + mannitol, and xylitol + dulcitol had attractive crystallization heat (164.71, 165.56, 130.58, 145.56, and 147.89 kJ/kg), high maximum crystallization temperatures (84.94, 73.75, 83.85, 83.52, and 83.13 °C), short times to reach maximum crystallization temperatures (186, 477, 204, 198, and 183 s), and satisfactory energy efficiency (57.77%, 56.68%, 51.01%, 54.52%, and 54.84%). After 300 days of storage, the crystallization heat of the supercooled samples decreased by merely 4.377%, 3.358%, 4.511%, 4.314%, and 6.309%. Finally, 30 cyclic tests were conducted on newly prepared xylitol and xylitol + erythritol. The pair exhibited relatively stable crystallization heat (145.60–175.64 kJ/kg and 134.52–169.97 kJ/kg, respectively) and high maximum crystallization temperature (82.8–88.1 °C and 72.3–76.2 °C, respectively).

Utilization of carbonized water hyacinth for effective encapsulation and thermal conductivity enhancement of phase change energy storage materials

In this work, a biochar carrier was developed to adsorb phase change materials and enhance thermal conductivity. Six kinds of modified carbonized water hyacinth were prepared by freeze drying (or vacuum drying) combined with high-temperature carbonization. The pore volume and specific surface area (SSA) of FC900 are the highest, reaching 0.3153 cm3/g and 479.966 m2/g, which are 32% higher than those of VC900. The load rates of FC900 and VC900 on lauric acid-myristic acid-paraffin section (LMPS) are 75% and 65% respectively. Meanwhile, the phase transition enthalpy of LMPS/FC900 is 104.36 J/g, which is 20.75% higher than that of LMPS/VC900, and the phase transition temperatures are 25.93 and 26.77 °C respectively. After 500 times of heat storage and release experiments, LMPS/FC900 maintains a stable phase change peak, which has good thermal performance stability. Notably, the thermal conductivity of LMPS/FC900 is 0.4168 W/(m·K), which is 56.93% higher than that of LMPS. Otherwise, under the constant temperature environment of 50 °C, the heating time of LMPS/FC900 is 11.89% longer than that of LMPS/VC900, which has more excellent temperature control performance. This study concludes that the carbonization temperature of 900 °C and freeze-drying measures are the best preparation process for carbonized water hyacinth, and LMPS/FC900 has good thermal conductivity and phase change energy storage performance.

Numerical Study of a Phase Change Material Energy Storage Tank Working with Carbon Nanotube–Water Nanofluid under Ha’il City Climatic Conditions

A numerical investigation of a phase change material (PCM) energy storage tank working with carbon nanotube (CNT)–water nanofluid is performed. The study was conducted under actual climatic conditions of the Ha’il region (Saudi Arabia). Two configurations related to the absence or presence of conductive baffles are studied. The tank is filled by encapsulated paraffin wax as the PCM, and CNT–water nanofluid flows through the capsules. The main goal is to increase the temperature of the PCM to 70 °C in order to store the thermal energy, which can then be used during the night and cloudy weather. Numerical computations are made using the finite element method (FEM) based on actual measured weather conditions. Climate conditions were collected from a weather station located on the roof of the engineering college’s building at the University of Ha’il. The collected data served as input to the numerical model, and the simulations were performed for three months (December, March, and July). The solid CNT volume fraction range was (0 ≤ ϕ ≤ 0.05) and the nanofluid volume flow rate ranged was (0.5 L/min ≤ V ≤ 3 L/min). For both considered cases (with and without baffles), it was found that the use of CNT–nanofluid led to a reduction in the charging time and enhanced its performance. An increase in the volumetric flow rate was found to accelerate the melting process. The best performances of the storage tank occurred during July due to the highest solar irradiation. Furthermore, it was found that the use of baffles had no beneficial effects on the melting process.

Model-based predictive control of multi-stage air-source heat pumps integrated with phase change material-embedded ceilings

This paper presents a model-based predictive control strategy to optimize the operations of phase change material (PCM) ceiling panels coupled with a multi-stage air-source heat pump. A three-stage prototype heat pump unit has been built and tested in the laboratory, with the low and medium stages designed for space heating/cooling and the high compression stage dedicated to charging of the PCM energy storage. To facilitate optimal control of the integrated heat pump system, a mixed-integer linear programming formulation is derived through linearization of the heat pump model and a mixed-integer reformulation of the PCM dynamic governing equations. A predictive control strategy is synthesized based on the resultant control formulation and implemented in a receding horizon scheme that optimizes the PCM charging and the zone temperature schedules simultaneously to leverage both the passive (associated with building construction materials) and active (PCM) storage capacities of a building. The control strategy has been tested along with three benchmarking control scenarios using a co-simulation platform for a prototypical detached house in Atlanta, GA. Test results showed that application of the proposed control strategy to the PCM-integrated heat pump could provide 27.1% electricity cost savings while a fine tuned rule-based control strategy could achieve cost savings of 20.4%, compared to a baseline case without PCM storage, under a time-of-use rate tariff.

Dynamic absorption of bulk phase-change materials for photothermal solar energy storage based on reversible thermochromic

<p indent="0mm">Phase change materials (PCMs) are expected to solve the problems in thermal energy storage and thermal management. However, the energy density and power density of the transient melting front decrease as it moves away from the heat source. In the process of direct solar thermal utilization, the completion of the traditional heating totally depends on the thermal diffusion process of the PCM, and the low thermal conductivity limits the heating rate of the PCM. In this study, a dynamic phase-change material (Dyn PCM) based on reversible thermochromic properties is proposed that can automatically control the displacement of the light-thermal interface to follow the melting frontier. The thermal conductivity of the material would not limit the heating rate of the phase transition material during photothermal conversion. Dyn PCM is composed of two parts: a thermochromic agent and the main PCM. The thermochromic agent uses 2-phenylamino-3-methyl-6-dibutylaminofluoran as the electron donor, 2,2-bis(4-hydroxyphenyl)propane as the electron acceptor, and 4-benzyloxy Phenyl Ethyl Decanoate as a solvent to successfully achieve the transformation from transparent to black. The main PCM takes paraffin as an example. The latent heat of Dyn PCM_5, which contains 83.3 wt.% paraffin, is <sc>154.38 kJ/kg,</sc> which is only 6.6% lower than that of paraffin, and its transparent state shows transmittance of 91.2%, which is close to paraffin. The comparison shows that the charging rate of the Dyn PCM₅ is 260% faster than that of paraffin. The Dyn PCM groups remained unchanged after 80 cycles. The Dyn PCM did not change. Dyn PCM still has good reversible discoloration ability, maintains excellent thermal charge and discharge performance, and has stable light transmittance. As a result, the thermochromic composite Dyn PCM₅ developed in this study is a potential solar heat storage material that may also be used for direct solar energy absorption.

Evaluation and optimization on heat transfer performance of a composite phase change material embedded in porous ceramic skeleton: A lattice Boltzmann study

The thermal performances of phase change materials (PCMs) are of great importance to latent heat thermal energy storage applications. In order to improve the thermal properties, the composite PCM of inorganic salt embedded in porous ceramic skeleton was proposed and investigated in this study. The numerical model for the phase change process of PCM was developed by applying the lattice Boltzmann method. Simulation results indicate that the existence of porous ceramic materials could not only enhance the heat conduction of PCM but also hinder the convective heat transfer. In addition, the results show that Rayleigh number has a significant effect on the melting process of PCM. At low Rayleigh number, the existence of ceramic skeleton can significantly improve the thermal conductivity of composite PCM. However, at high Rayleigh number and porosity, the reduction of convective heat transfer might be greater than the heat conduction enhancement due to the addition of porous skeleton materials. By designing an appropriate non-uniform pore network of porous skeleton materials, further enhancement of heat conduction without obvious loss of convective heat transfer has been achieved. The research results obtained in this study could provide useful guidance for designing high-performance phase change energy storage materials.

Waste Plastic Polypropylene Activated Jujube Charcoal for Preparing High-Performance Phase Change Energy Storage Materials.

The research on the high-value utilization of biomass has good application prospects and is conducive to sustainable development. In this paper, three different types of activators (potassium hydroxide, phosphoric acid, and polypropylene) were used to carbonize jujube branches at high temperatures of 600 °C and 800 °C, and then the PEG/jujube charcoal composite phase change materials (PCM) were prepared by vacuum impregnation of polyethylene glycol (PEG). The results showed that the carbon support activated by polypropylene (PP) had a richer pore size distribution than the other two activation methods, and the 800 °C carbonization carrier loaded PEG had a higher phase change enthalpy than the composite material at 600 °C. The mesoporous and macroporous structures were staggered with PP-activated jujube charcoal at 800 °C, with a specific surface area of 1082.2 m²/g, the melting enthalpy of the composite material reached 114.92 J/g, and the enthalpy of solidification reached 106.15 J/g after PEG loading. The diffraction peak of the composite phase change material was the superposition of PEG and carbon matrix, which proved that the loading process was physical adsorption. After 200 thermal cycles, the melting enthalpy and crystallization enthalpy were only reduced by 4.3% and 4.1%, respectively, and they remained stable and leak-free at the melting point of PEG for 2 h, demonstrating good thermal stability of the composite phase change materials. In summary, PP has obvious advantages over traditional activation, and the carbon-supported PEG phase change composite after PP activation is a biochar energy storage material with excellent performance.

Phase Change Materials Energy Storage Enhancement Schemes and Implementing the Lattice Boltzmann Method for Simulations: A Review

Utilizing phase change materials (PCMs) is one of the most effective methods of storing thermal energy and is gaining popularity in renewable energy systems. In order to analyze PCM performance, various numerical methods have been deployed to study the transient behaviour during phase changes. PCMs’ low thermal conductivity prevents their use as pure PCMs in industrial applications. There are various efficient methods of enhancing PCM thermal conductivity, which are addressed in this article. On the other hand, the lattice Boltzmann method (LBM) is very inclusive in the numerical simulation of complex fluid flows, thermal transport, and chemical interactions because of its ability to simply represent various complex physical phenomena, suitability for parallel programming, and easy coding and implementation. Many numerical studies have been conducted on PCMs using the LBM. This study aims to review these studies and categorize them in a way so that one may thoroughly understand the LBM’s capabilities in the simulation of PCM-related investigations. First, PCM characteristics and applications are presented, then the LBM implementation in PCM problems is addressed. Afterward, the fabrication and types of PCMs are mentioned. Next, the improvement of thermal energy storage methods of PCMs is stated. Furthermore, governing equations are reviewed. Lastly, the opportunities and challenges of the LBM in PCMs are discussed.

Energy, exergy, economic and environmental (4E) analyses of solar still with paraffin wax as phase change energy storage material

The dearth of clear and potable water is one of the most critical problems experienced all over the world. There is an urge that the existing problem be addressed immediately. Pure water resources are getting depleted day by day with an increase in pollution and population. The possible way to get rid of this problem is to transform the accessible sea/brackish water into fresh water through energy utilization. The conventional way of utilising energy is also a persisting problem in which the world is shifting towards sustainable energy sources for sustainable development. Solar energy is more efficient and abundant when compared to other renewable sources. Thus, in this context, a single slope solar desalination system with energy storage (phase change materials – PCMs) is designed and developed to analyze the Energy, Exergy, Economic and Environmental (4 – E) performance. The 4 – E analysis of the developed solar still system resulted in a 26.51% average energy efficiency, of 2.58% of exergy efficiency, the cost per one litre is $0.0084 and the carbon credit obtained from the system is $ 183.5.