Composite Phase Change Materials Research Articles

Synthesis and properties of biomass derived carbon/PEG composite as photothermal conversion effective phase change material for functional concrete

Mixing phase change material (PCM) into concrete is a practical strategy for functionalizing concrete as an energy-storage unit. This study aims to invent an efficient photo-thermal conversion type PCM for the manufacturing energy storage functional concrete, which meet the needs of hydration heat storage and thermal storage in service. To solve the liquid leakage problem of PCM, a novel bamboo-based hydrothermal carbon sphere (HCS) with unique mesoporous structure was prepared to pack polyethylene glycol (PEG) to make shape stable PCM. The photo-thermal material nano-Ag was successfully introduced into the composite PCM through a high-voltage electrostatic field. To understand the stability and performance of the PCM for concrete use, the structural composition and thermal storage efficiency of Ag@HCS-CNTs/PEG in simulated concrete pore solution (a highly alkaline solution containing potassium, sodium, and calcium cations) were systematically studied via multiple characterization methods. After being soaked in concrete pore solution for 7 days, the PCM shows outstanding thermal storage density (147 J/g), photo-thermal conversion efficiency (110.6%), and resistance to Na+, Mg2+, Cl− and SO42−. In addition, the biomass subtracted PCM preparation has low energy consumption and low carbon emission features. These open a window of realistic PCM application in the structural concrete, insulation porous walls and energy storage buildings.

Synthesis and Thermal Properties of Myristic Acid/Nano-TiO2/Carbon Additives Composite Phase Change Materials

Synthesis and Thermal Properties of Myristic Acid/Nano-TiO2/Carbon Additives Composite Phase Change Materials

Experimental and numerical assessments of thermal transport in phase change material embedding additively manufactured triply periodic minimal surfaces: A comparative evaluation

Phase change materials (PCMs), due to their inherent low conductivity, are presently restricted in their potential applications for thermal energy storage (TES) systems. Extensive effort has been made over the past few years to investigate the potential of porous materials, such as metal foams, as effective thermal conductivity enhancers (TCEs) for PCMs. Porous materials have superior specific surface area over conventional honeycomb structures and fins, providing great potential in thermal storage systems. In this study, taking advantage of the implicit function of triply periodic minimal surface (TPMS), new varieties of lattices with continuous surface structures were developed and then manufactured by using AlSi10Mg powder via selective laser melting (SLM). A three-dimensional transient phase-change heat storage model of TPMS (Primitive and I-WP) structure-paraffin composite PCMs was adopted to study both the phase-change heat transfer performance and heat storage capability of TPMS-PCMs during the phase transition. Meanwhile, the evolution of the solid–liquid interface and temperature–time history were investigated by utilizing the visualized thermal storage experiments. The findings revealed that embedding TPMS lattice decreased the natural convection effect, resulting in a maximum flow velocity of liquid paraffin wax (PX) within TPMS-PCMs that was only 0.1 times that of pure PX. The melting onset time of TPMS-PCMs was advanced by 82.2 %-91.1 %, and the duration of phase change was shortened by 68.3 %-75.9 %, respectively. In addition, the total heat storage of TPMS-PCMs fell from 4464.0 J to 4217.2 J compared to pure PX, but their average heat storage rate rose from 1.04 to 4.58 J/s. Primitive rod (PS)-type TPMS-PCM was the most potential among the three types of TPMS lattices as the TCE for PCM because it achieved the highest heat storage rate with the most negligible overall heat storage loss.

Anisotropic and hierarchical porous boron nitride/graphene aerogels supported phase change materials for efficient solar-thermal energy conversion

The formation of shape-stabilized composite phase change materials (CPCMs) with special structure is an efficient strategy to prevent the leakage of phase change materials (PCMs) and improve the solar-thermal conversion ability. In this work, graphene and boron nitride nanosheets (BBNS) were prepared by the magnesiothermic reduction SHS method in CO2 and N2 atmosphere, respectively. Then, an anisotropic and hierarchical porous boron nitride/graphene aerogel with three-dimensional network was constructed by directional ice-freezing method using carboxymethyl cellulose as supporting framework and adhesive, and polyethylene glycol (PEG) was impregnated to prepare novel CPCMs. The CPCMs had enthalpies of 150∼160 J/g, and a highest thermal conductivity of 0.390 W/(m·K), which was around 47% higher than that of pure PEG. The ability of the CPCMs to convert solar energy to thermal energy was significantly enhanced. Under a simulated light intensity of sunlight (100 mW/cm2), its solar-thermal conversion efficiency reaches 94.92%, and after 20 min of irradiation, the surface temperature can reach 72 °C. These CPCMs are promising for the efficient use of renewable solar energy due to their high solar-thermal conversion efficiency and thermal storage capabilities.

Study on the Workability and Mechanical Properties of Pavement Concrete Modified with Graphite-tetradecane Phase Change Material

In this paper, the effect of graphite-tetradecane phase change material (G-t PCM) on pavement concrete's mechanical properties and frost resistance was investigated. Different dosages of G-t PCM (0%, 4%, 8%, and 12%) were used to prepare modified concrete, and the effects of G-t PCM on the properties of concrete were systematically evaluated by compressive strength, flexural strength, and rapid freeze-thaw tests. The findings demonstrated that as the dosage of G-t PCM increased, concrete's compressive and flexural strengths tended to drop; the most significant loss was seen at a dosage of 12%. However, the introduction of G-t PCM significantly improved the frost resistance of concrete, especially the composite phase change material with 8% dosage (phase change temperatures of 5°C and -5°C, respectively), which showed the best frost resistance. The study showed that precise regulation of the dose of G-t PCM may significantly improve the frost resistance of concrete without considerably compromising its mechanical qualities, offering a novel approach to increase the longevity of pavement concrete.

A data-driven model on the thermal transfer mechanism of composite phase change materials

Phase change materials (PCMs) that are incorporated with highly conductive nanomaterials to fabricate composite phase change materials (CPCMs), received much focus as a promising energy strategy for latent heat storage and conversion systems, due to their excellent thermophysical properties such as oxidation resistance and large enthalpies of fusion. However, the correct prediction of the thermal conductivity of these CPCMs remains deficient, mainly due to the lack of knowledge on the microscopic heat transfer mechanisms between the nanofiller and matrix interphase. Herein, a data-driven, modified Maxwell model is proposed to determine the thermal conductivity of these CPCMs, using milled carbon fiber (MCF)-reinforced PCMs as validation. This new model incorporates the aspect ratio and morphology smoothness of MCFs and introduces compatibility factors for different types of PCM matrices, which are paraffin and polyethylene glycol (PEG) respectively. At filler loadings above 15 wt%, the theoretical model gave poorer forecasts (with an average prediction error of 0.075) due to the random agglomeration of MCF nanoparticles, which can obstruct the phonon pathway. Regardless, this model accurately estimated the thermal conductivities of MCF/PCMs up to 9 wt% and 11 wt% MCF loading, with percentage fit values being 0.983 and 0.996 for PEG and paraffin systems, respectively. This model also eliminates the limitations of existing models, that were only suitable for composites with low filler loadings (<5 wt%). Hence, this work provides a vital prediction guide for the thermal conductivity of commercial CPCMs.

Role of microstructure in the exploitation of self-healing potential in form-stable composite phase change materials based on immiscible alloys

Metallic Phase Change Materials (PCMs), based on solid-liquid transitions, represents one of the most promising technologies for efficient Thermal Energy Storage (TES), due to their superior thermal conductivity and energy storability per unit volume, but suffer of limited solutions for their handling at the molten state. The use of Miscibility Gap Alloys (MGAs) allows to manage PCM volume expansion and keep it confined when molten, preventing interaction with the environment. A relevant example is provided by the Al-Sn system, where Al covers the role of the high-temperature stable and highly thermal-conductive passive matrix and Sn the active PCM. The alloy can thus be considered a Composite PCM (C-PCM). The response fastness of these systems depends on their thermal diffusivity, subjected to abrupt variations under the presence of discontinuities and damages. In this sense, the authors investigated the possibility to employ molten Sn mobility in a potentially damaged C-PCM for self-healing purposes, aimed to restore, at least partially, the material continuity and thus its thermal diffusivity. Exudation heat treatments above the melting temperature of Sn were performed on sets of Al-40%wt. Sn metallic composites, produced either with powder metallurgy or liquid metal routes, in order to quantify and assess the mobility of the Sn under simulated operating conditions. Exudation tests assess Simple Mixed powders and liquid metal routes sample as the ones with the highest healing potential. Al dissolution and re-deposition was established by EDS analyses as one of the principal Sn mobility mechanisms. Laser Flash Analysis tests, as well as microstructural investigations, were performed on the samples before and after both healing-focused and simulated service heat treatments to evaluate the changes of thermal diffusivity. Healing-focused treatment at 250°C for 1 hour generally displayed a moderate thermal diffusivity recovery and simulated service by shorter cycles between 170°C and 270°C slightly reduce it. The beneficial role of healing focused heat treatments at 250°C for 1 hour suggests that the presence of fully molten Sn phase during service for relatively long time could be beneficial for functional healing. The requirements of suitable Al-Sn microstructures for self-healing purposes, granting at the same time the C-PCM functionalities, i.e., thermal energy storage and form-stability, were set.

Investigations on paraffin wax/CQD composite phase change material - Improved latent heat and thermal stability

The growing disparity between energy demand and supply has rendered the storage of thermal energy essential. In this study, experiments have been conducted on novel composite Phase Change Materials (PCMs) comprising Paraffin Wax (PW) as base PCM dispersed with 1 %, 5 %, 10 %, 15 %, and 20 % weights of Carbon Quantum Dots (CQDs) to investigate their latent heat and thermal stability. These studies are crucial to determine the energy storage capacity of the composite PCMs. Latent heat and melting temperatures were determined using a Differential Scanning Calorimeter (DSC). The latent heat of all composite PCMs increased when compared with PW with a maximum enhancement of 65.1 % for 1 wt% composite PCM. The melting temperature range of composites is higher than PW. Thermogravimetric analysis showed an improved thermal stability of all composite PCMs than PW. These results unequivocally suggest the employability of these PCMs for thermal energy storage in the medium temperature range.

Thermal performance enhancement of lauric acid using nanomaterials as composite phase change material.

In the present work, lauric acid was taken as a phase change material (PCM), and different nanoparticles (NPs) such as SiO2, TiO2, CuO, and ZnO were taken as the supporting materials. CuO NPs were prepared through the co-precipitation technique; SiO2, TiO2, and ZnO NPs were synthesized via the sol-gel technique. These NPs with different weight fractions were dispersed into molten lauric acid, individually. The variations in thermal properties (phase change temperature and latent heat for solid and liquid) of the prepared composite PCMs due to the dispersion of NPs were observed by DSC analyses. An increase in thermal conductivity of the composite PCMs was observed with the increasing weight fraction of NPs. In order to ascertain the long-term utility, a thermal reliability test was conducted on the composite PCMs with repeated heating and cooling cycles. Also, the specific heats of the pure PCM and the composite PCMs were determined as a function of temperature. Further, the experimental investigation was performed on the pure PCM and the prepared composite PCMs to assess their phase change behavior, and the test results clearly proved that the time required for the complete melting and freezing process of the composite PCMs was less when compared to pure PCM. By considering the above facts, the newly prepared composite PCMs can be recommended as a potential candidate for low-temperature solar heating applications.

Preparation and Photothermal Properties of Accordion‐Like MXene/Sodium Acetate Trihydrate Composite Phase Change Materials

Phase change materials (PCMs) are promising options for thermal energy storage. Combining sodium acetate trihydrate (SAT) with MXene, the composite phase change materials (CPCMs) have been prepared. The surface morphology, thermal storage performance, and solar energy photothermal conversion efficiency of the CPCMs with various MXene contents are analyzed. According to the microstructure morphology analysis, MXene is accordion‐shaped, and tightly associated with SAT. Differential scanning calorimetry measurement results show that CPCMs possess high latent heat and suitable phase change temperature for the applications of solar heat storage. The absorption wavelength range of SAT/MXene is extended from 200–258 nm to 200–497.7 nm with a photothermal conversion efficiency of 81.3%. SAT/MXene‐2%, SAT/MXene‐8%, and SAT/MXene‐14% have thermal conductivities of 0.84, 1.14, and 1.47 W/ (m · K), respectively, which are higher by 44.9%, 96.6%, and 153.4% than 0.59 W/ (m · K) of pure SAT. CPCMs exhibit excellent thermal stability and reliable cycling stability after 50 cycles, which show that MXene can prevent leakage during the solid‐liquid phase transition process. The expansion of PCM's practical applicability and MXene/SAT composites with good photothermal characteristics create a theoretical foundation for the effective use of renewable energy sources.

Nano-silver@polydopamine carbonized melamine foam supported polyethylene glycol phase change materials: With simultaneous improved photo-thermal conversion ability

Ag nanoparticles are commonly used for phase change material (PCM) modification to improve the photo-thermal convertibility in composite phase change materials (CPCM) owing to enhance carrier's ability to absorb photons by virtue of its unique localized Surface Plasmon Resonance effect (LSPR). Currently, redox method is considered to be the most effective method for the preparation of Ag nano-coating. However, it is still challenging to obtain a dense and uniform Ag nano-coating on the carrier surface due to the difference in the binding force between Ag nanoparticles and different carriers. Herein, a new preparation strategy is demonstrated, in which the carrier is pre-modified by adding a polydopamine (PDA) coating to enhance the bonding between the carrier and the silver nanoparticles, and then a stable three-dimensional silver nano-conducting network is obtained by redox. Consequential stable architecture contributes to polyethylene glycol (PEG) loadings reach 98%, simultaneously with an ultra-high photo-thermal conversion efficiency of 97.9%. Furthermore, this paper demonstrates the effect of carbonization temperature on the flexibility of melamine carbon foam (CMF), and different nano-Ag concentrations on the thermal conductivity of CPCM. This finding provides valuable guidance for the engineering of high photo-thermal conversion performance CPCM and strengthens their practical implementation in solar energy storage and thermal management.

Numerical simulation and optimization of compact latent heat exchanger with micro-channel plate in shape-stabilized composite phase change material

To enable the rapid provision of domestic hot water, this study presents the independent design of a plate heat exchanger featuring a large heat exchange area and a compact structure. Utilizing a sandwich structure, the thermal storage unit integrates two shaped composite phase change materials (CPCM), namely sodium acetate trihydrate (SAT)/expanded graphite (EG) blocks of identical thickness — in conjunction with a micro-channel heat exchange plate. Multiple thermal storage units are stacked to create the heat exchanger. Experimental validation of the heat transfer performance of this thermal energy storage heat exchanger is conducted, accompanied by the establishment of a heat transfer model elucidating the interaction between the phase change material (PCM) and the fluid. The investigation explores the impact of varying thicknesses of shape-stabilized CPCM, thermo-physical parameters of CPCM, and flow rates on enhancing the thermal efficiency of the thermal energy storage heat exchanger. Results indicate a competitive relationship between the phase change enthalpy and thermal conductivity of CPCM under constant density. Increasing the mass fraction of SAT effectively boosts its heat storage density. However, this improvement is counterbalanced by a reduction in CPCM's thermal conductivity, resulting in diminished heat transfer rates within the material and reduced efficiency in transferring heat between the material and the fluid. Optimal performance is achieved when the mass fraction of sodium acetate trihydrate is 80 wt% and the CPCM thickness is 20 mm. At these parameters, the thermal energy storage heat exchanger exhibits the highest heat transfer efficiency. Furthermore, the heat exchanger is capable of producing 197.86 kg of hot water in 1365 s at an inlet flow rate of 300 L/h, achieving an impressive discharging efficiency of 82.73 %. These findings underscore the feasibility of employing the mini-channel plate thermal energy storage heat exchanger for the rapid preparation of domestic hot water.

Thermal Properties and Characterization of n-Decanol-Capric Acid/Expanded Graphite/Boron Nitride for Thermal Energy Storage

To find a low temperature phase change material (PCM) that can be applied to the middle constant temperature chamber of the three chamber refrigerator, this study proposes a binary eutectic PCM of n-decanol and capric acid as a base liquid, expanded graphite as a support material, and boron nitride as a thermal conductivity enhanced particle to modify the material. The composite PCM with suitable phase change temperature and high phase change latent heat is prepared by the solution blending method. The leakage rate experiment determines the maximum adsorption ratio of expanded graphite to be 92 %. The chemical structure, microstructure and thermodynamic properties are characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, thermal conductivity analyzer and thermogravimetric analyzer. The results show that the n-decanol and capric acid binary eutectic PCM is fully wrapped in the porous structure of expanded graphite, and boron nitride thermal conductivity enhanced particles are well adsorbed on the surface and pores of expanded graphite. The n-decanol and capric acid phase change material, boron nitride thermal conductivity enhanced particles and expanded graphite support material are only physically combined and no chemical reaction occurred. The phase change temperature of CPCM-2 with 3 % boron nitride thermal conductivity enhanced particles is -3.68 °C, the phase change latent heat is 129.2 J/g, and the thermal conductivity is 0.75 W/m·K. It has good thermal stability and reliability in the application temperature range.

Advanced multifunctional Co/N co-doped carbon foam-based phase change materials for wearable thermal management

To cope with the complex and changeable extreme environments, extending multifunctionality is crucial for potable smart wearable composite phase change materials (PCMs). Herein, we developed advanced Co/N co-doped carbon foam-based multifunctional “five-in-one” composite PCMs integrating dual-temperature thermal management, light-triggered heating, waterproof, flame retardant, and microwave absorption through high-temperature calcination of melamine foam@ZIF67 and melting encapsulation of paraffin wax (PW). Benefiting from the strong full-spectrum absorption, fast photon and phonon transport, and local surface plasmon resonance effect, our designed foam-based composite PCMs exhibited an ultrahigh photothermal conversion efficiency of 95.17 %. More importantly, foam-based composite PCMs demonstrated excellent thermal management, structural stability and thermal storage stability after undergoing 300 heating–cooling cycles. Furthermore, foam-based composite PCMs showed superior microwave absorption (RLmin = -57.93 dB), good flame retardancy and satisfactory hydrophobicity (contact angle > 100°). Thus, our developed multifunctional foam-based composite PCMs provide great potential for personalized thermal management and anti-radiation smart wearables even in harsh environments (e.g., rain, snow, sweat, fire, extreme cold, extreme heat and electromagnetic interference), creating a versatile platform for smart wearable light-triggered phase change heater with on-demand properties.

High latent heat phase change materials composites based on MXene/biomass-derived cellulose nanocrystalline aerogel for solar-thermal energy conversion and storage

In this study, novel tetradecylamine/MXene/cellulose nanocrystal composite phase change materials (TDA/MXene/CNC CPCMs) were prepared using a vacuum impregnation method. For the first time, lightweight MXene/CNC composite aerogel was employed as a support material in energy storage, with TDA serving as the phase change material. The latent heat of TDA/MXene/CNC CPCMs reached 221.5 J/g. Furthermore, the density of the MXene/CNC-2 composite aerogel was 0.0614 g/cm3, and its loading rate for TDA was as high as 90.6 wt%. Additionally, the thermal conductivity of TDA/MXene/CNC CPCM-5 was 0.491 W/(m·K), 1.87 times higher than that of pure TDA. The TDA/MXene/CNC CPCMs exhibited exceptional thermal stability up to 120 °C and maintained excellent shape stability at 60 °C. The composites exhibit a superior solar-thermal conversion ability with the conversion efficiency as high as 94.1%, The incorporation of MXene significantly enhances the photothermal conversion capability, providing an important avenue for the high-efficiency utilisation of solar energy.

Enhancing the thermal storage performance of biochar/paraffin composite phase change materials: Effect of oleophobic modification of biochar

Composite phase change materials (PCMs) possess excellent temperature-regulating capabilities, which can effectively reduce building energy consumption, ultimately contribute to energy saving and carbon reduction. In this study, oleophobic modification was carried out on the Zn modified - white pine biochar. The resultant oleophobic material (Zn-WPC-A) showed excellent supporting capability in the preparation of paraffin wax (PW)/biochar composite PCMs (PW/Zn-WPC-A). The oleophobic properties of biochar could effectively prevent PW leakage, and resulted in a high PW loading rate of 84.26% and an encapsulation efficiency of 82.26%. Zn-WPC-A demonstrated good physical and chemical compatibility with PW. The inclusion of Zn-WPC-A effectively promoted the nucleation in the crystallization process of PW. PW/Zn-WPC-A exhibited a thermal conductivity 3.28 times that of pure PW, displaying excellent thermal responsiveness. The fusion enthalpy of PW/Zn-WPC-A was 107.2 J/g. Furthermore, it displayed excellent stability within the working temperature range with no leakage observed. Simulated housing application experiments illustrated that the use of PW/Zn-WPC-A as building insulation material effectively slowed down the variation rate of indoor temperature. Therefore, the composite PCM using oleophobic modified biochar as supporting material showed excellent thermal performance and strong temperature-regulating capability.

All-climate battery thermal management system integrating units-assembled phase change material module with forced air convection

Phase change material (PCM) is widely adopted to construct integrated battery thermal management systems (BTMSs) for all climates. However, integrated BTMSs in cylindrical battery modules remain arduous challenges due to the compact/massive cuboid-shaped PCM module and the curved surface of the cells. Herein, we propose a novel all-climate BTMS integrating units-assembled composite PCM (CPCM) module with force air convection. The CPCM module assembled by sleeve-like CPCM units provides developed airflow channels and enlarged heat transfer surface from 1.17 × 10−3 to 3.63 × 10−3 m2 for enhancing convective heat transfer. Consequently, compared to conventional cuboid-shaped module, the thermal resistance of the units-assembled module is remarkably reduced by 52.0% and 60.1%, and the heat flux is enhanced by 7 times under both cooling and preheating modes. In cooling tests, this BTMS demonstrates superior performance by controlling the temperature and temperature difference below 40.30 and 2.80 °C at 3-C discharge, respectively. In preheating tests, it effectively preheats the battery module from 0 to 10 °C in 302 s with a low temperature difference of 3.82 °C. Furthermore, this units-assembled CPCM module saves 53.8 wt% of the CPCM dosage, and thus the energy density of the battery module is increased from 75.6 to 94.4 Wh·kg−1.

High value utilization of waste peanut shell: Prepared novel shape stable composite phase change materials with high thermal conductivity

To address the leakage and low thermal conductivity issues of phase change materials (PCMs), this study aims to prepare high thermal conductivity shape stable composite phase change materials (sscPCMs) using waste peanut shell. Employing pyrolysis technology, waste peanut shell has been successfully converted into high-performance framework materials. In addition, it also compared the thermal energy storage performance of shape stable composite stearic acid/peanut shell biochar (ss-cSA/PSC) with that of shape stable composite stearic acid/peanut shell (ss-cSA/PS). Excitingly, the thermal energy storage performance of ss-cSA/PSC has been significantly improved. Specifically, the thermal conductivity of ss-cSA/PSC reached 0.527 W/(m·K), which is 3.2 times higher than that of pure SA and 2.4 times higher than that of ss-cSA/PS. In addition, the phase change latent heat of ss-cSA/PSC can reach 70.59 J/g, which is 27.2% higher than that of ss-cSA/PS. The high thermal conductivity and phase change latent heat highlighted its significant superiority in the field of thermal energy storage. Furthermore, ss-cSA/PS and ss-cSA/PSC have been characterized by SEM, FTIR, XRD, and TGA. The results indicated that both two kinds of sscPCMs have excellent chemical compatibility, thermal reliability, and thermal stability. In summary, PSC is an economical, environmentally friendly, and sustainable framework material which used to prevent the leakage of PCMs and improve the thermal performance.

Novel integration of recycled-hemihydrate phosphogypsum and ethyl palmitate in composite phase change material for building thermal regulation

This study investigates the properties of novel heat storage gypsum composites composed of waste Hemihydrate phosphogypsum (HP) incorporated with Ethyl Palmitate (EP) Phase Change Material (PCM) at varying concentrations of 25 wt %, 50 wt %, and 75 wt %. The focus of the research revolves around evaluating key characteristics, including leakage properties, chemical stability, microstructural analysis, heat storage characteristics, mechanical properties, and the thermal regulation performance of these novel composites. The investigation of leakage properties aimed to find the optimum EP ratio within the composite structure without causing any potential EP leakage, and it was determined to be 25 wt %. Furthermore, thermal regulation tests are conducted to assess the heat storage and release capabilities of the composites with varying HP/EP content. The latent heat storage of the HP/EP composite was determined as 46.12 J/g, even after the 750th cycle, the value only decreased to 46.03 J/g. With the porosity filling effect of EP additive in HP, as the EP additive increased, the amount of porosity decreased, and the compressive strength values increased by almost 10 %. In hot weather conditions, the EP additive provided a cooler environment between 2 and 4 °C according to thermoregulation results. This study not only holds promise in the context of developing novel heat storage composites for applications in energy-efficient building materials, thermal energy storage systems, and related sustainable technologies but also in harnessing industrial waste byproducts. It particularly highlights the value of HP as a waste material, which has a high potential for evaluation in the production of gypsum and other building materials.

Development of form-stable natural composite phase change material for effective thermal energy storage and anti-leakage behaviour

There is currently a demand in various sectors of the industry for high-performance, reliable, and sustainable bio-based materials. In this context, a naturally derived biodegradable phase change material (NCPCM) was prepared with composite, low-cost, eco-friendly materials, and characterization was done to increase its Thermal Energy Storage (TES). This study presents a Form-Stable Natural Composite Phase Change Material (FS-NCPCM) that was produced using a melt-blending approach with bentonite clay as a carrier material and graphite powder as an additive to enhance the composite's thermal conductivity. Different mass fractions of bentonite clay and graphite were added to the NCPCM to produce form-stable composites. The produced samples were tested for anti-leakage behaviour, and it was found that bentonite can contain a maximum of 45 % of NCPCM without leakages. Thermal energy storage characteristics, thermal reliability, chemical and physical stability, surface morphology, and thermal conductivity were investigated. Graphite and bentonite clay provided good morphology due to their large surface area and effective dispersion with NCPCM. FS-NCPCM5 composite retained its high latent heat values and excellent thermal energy storage potential of 243.54 J/g from the results of DSC analysis. The thermal conductivity of FS-NCPCM5 was enhanced considerably by 219.43 times compared with raw NCPCM. The thermal cycle results showed that the produced FS-NCPCM5 had good thermal/chemical stability after 2000 cycles. Thus, the developed FS-NCPCM5 can potentially be considered as an additive material for creating green construction components with TES capability.