Nanocomposite Phase Change Materials Research Articles

Influence of functionalized and non-functionalized 2D graphene nanomaterial with organic phase change materials: Thermal performance comparison

Thermal energy storage and harvesting using phase change materials (PCMs) is a crucial aspect of solar thermal utilisation and energy management. However, the intrinsic limitations associated with PCMs, such as their relatively lower thermal conductivity and sluggish thermal transport pose significant obstacles in the advancement of thermal energy harvesting and storage systems reliant on PCMs. Research explored by inclusion of nanomaterial with the PCM matrix is predominant depending on uniform diffusion and stability of the developed nanocomposite. In this research endeavour, we introduce a novel and synergistic approach to synthesis a functionalized graphene nanomaterials and compare its performance with non-functionalized graphene nanomaterial at various concentrations within organic PCMs, operating at a phase change temperature of 54 °C. The formulated nanocomposite’s thermophysical properties morphology, chemical stability, optical absorbance & transmittance, melting enthalpy, thermal stability and thermal reliability were investigated using sensitive instruments. The findings unveil a remarkable enhancement in thermal conductivity with functionalized graphene dispersed PCM exhibiting an astonishing surge of 106.7 % at a mere 0.8 wt% loading, when contrasted with conventional PCM. The optical transmittance of RT54-0.8fGr was significantly reduced from 56 % to 17.2 %, which enabled the effectiveness for solar thermal energy harnessing; meanwhile the melting enthalpy was energised to 193.4 J/g from 182.6 J/g. The developed nanocomposite with better optical property and melting enthalpy were tested for 500 numbers of accelerated thermal cycles and its chemical stability and thermal property were compared with PCM. Furthermore, a heat transfer analysis is numerically simulated to exhibit the thermal conductance performance of functionalized nanocomposite PCM over base PCM. The findings suggest that the functionalized graphene dispersed PCM matrix to exhibit highly favourable attributes for renewable thermal energy storage due to their exceptional comprehensive features.

Deployment of Dedicative Nanoadditives to Enhance the Thermal Behavior and Effectiveness of Heat Transfer Performance of Eutectic Compound

ABSTRACTTwo nanoprecursors with capping agents were incorporated in stearyl alcohol–adipic acid combination phase change material (PCM) in this study. The addition of nanomaterials made the eutectic reliable in the manner of its thermal properties like higher enthalpy, degradation point, and more compatible with the metal encapsulation materials when compared with the pristane eutectic. The importance of nano‐metal oxides in parent material was shown by the reduced time frame of the PCM's thermal energy storing and releasing process for space heating applications. The specific heat capacity of both the aluminum and titanium oxide nanocomposites were greater than the eutectic, which indicates that the material can retain more energy. The thermal conductivities of base material and nanocomposite PCMs were 0.2686, 0.2815, and 0.4395 W/mK at 40°C, and the highest percentage increment of nanocomposites was seen as 9.19% and 63.62% at varied encircled temperatures. The crystal structure and chemical disintegration were evinced with the X‐ray diffractometer results of the composites.

Heat transfer analysis and melting behavior of nano composite phase change materials (NCPCMs) in a reverse flow solar air heater

This paper presents a CFD investigation on heat transfer analysis and melting behavior of Nanocomposite Phase Change Materials (NCPCMs) in a Reverse Flow Solar Air Heater (RFSAH). Semicircular tubes filled with PCM are embedded on the top surface of the absorber plate. The study was conducted with three different nanoparticles (CuO, Al2O3, Fe3O4) based NCPCMs at three concentrations of 0.1, 0.2, and 0.3 % by weight. The constant geometrical parameters such as pitch ratio (P/e = 6), height ratio (e/Dh=0.1571), and Reynolds number (Re = 5000) is considered for this study. A 2-D transient numerical analysis using the RNG k-ε turbulence model is performed for the melting behavior of NCPCMs inside the semicylindrical tubes. The incorporation of nanoparticles into the base PCM enhances thermal conductivity but reduces the latent heat of NCPCMs. Thus, it is observed that NCPCMs have a faster melting rate. The CuO based NCPCM shows a more quick and uniform phase transition compared to the Fe3O4, and Al2O3 based NCPCMs and reached their peak value at a higher mass fraction of 0.3. Furthermore, the heat transfer and melting fraction improves with increasing in mass fraction of nanoparticles. The phase transition process of CuO based NCPCM is approximately 1.9 times, and 1.01 times, 1.03 times faster as compared to the base PCM, and Fe3O4, Al2O3 based NCPCMs respectively.

Preparation, characterization, and thermal cycling analyses of nanocomposite phase change materials for hot climate energy storage applications

Preparation, characterization, and thermal cycling analyses of nanocomposite phase change materials for hot climate energy storage applications

Novel nano-Y2O3/myristic acid nanocomposite PCM for cooling performances of electronic device with various fin designs

Effective thermal management is critical for enhancing the longevity and operational efficiency of electronic devices. This research introduces a novel cooling approach by incorporating Yttrium Oxide (Y2O3) nanoparticles into Phase Change Materials (PCMs) to improve thermal management in electronic devices. This study focuses on developing nanocomposite PCMs with Y2O3 nanoparticles embedded in a myristic acid (MA) matrix through melting and physical mixing. Nanoparticles were added to MA at various mass fractions: 0.5 %, 1 %, 1.5 %, and 2 %. Structural and morphological analyses were conducted using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy combined with energy dispersive X-ray spectroscopy (FE-SEM-EDX). Thermophysical properties were characterized using differential scanning calorimetry (DSC) and thermal conductivity measurements with the KD2-Pro device. The inclusion of Y2O3 nanoparticles significantly enhanced the thermal conductivity of the PCM, reaching up to 0.229 W/m·K in the solid phase and 0.177 W/m·K in the liquid phase, representing improvements of 43.125 % and 18 %, respectively, over the base PCM. The highest average specific heat capacity (Cp) values in the solid and liquid phases were 1.98 J/g·°C and 2.69 J/g·°C, respectively, for the 2 % nanoparticle-additive sample. DSC analysis indicated slight shifts in phase transition temperatures and a noticeable reduction in latent heat values, from 215 J/g to 202 J/g for solidification and from 209 J/g to 201 J/g for melting. Computational analysis using ANSYS-FLUENT software validated the enhanced thermal dissipation properties of the nanocomposite PCM. Additionally, an examination of fin configurations within the PCM containers revealed that rectangular fins provided superior cooling efficacy compared to trapezoidal ones. This study demonstrates that the development of nano- Y2O3 enhanced MA nanocomposite PCMs presents a promising avenue for applications in electronic device thermal management and thermal energy storage.

Melting performance of PCM with MoS2 and Fe3O4 nanoparticles using leaf-based fins with different orientations in a shell and tube-based TES system

Phase change materials (PCMs) are frequently utilized in the thermal sector, especially for thermal energy storage (TES) applications. The purpose of this study was to analyze the thermal efficiency and melting characteristics of a leaf-vein-shaped fin in a triplex tube heat exchanger. The analysis focused on the use of pure molten salt PCM and a combination of molten salt PCM with MoS2 and Fe3O4 nanoparticles. The study utilized ANSYS Fluent software to conduct numerical simulations and analyze seven distinct fin arrangements. The simulations were employed to visualize and examine the liquid fraction, temperature, and fluid velocity. The findings indicated that the leaf-vein fin shape greatly improved the dispersion of liquid fraction, average temperature, and velocity in comparison to alternative fin designs. The addition of MoS2 and Fe3O4 nanoparticles significantly enhanced the melting and thermal characteristics of the PCM as a result of heightened thermal conductivity. This showcases the capability of the leaf-vein fin design and PCM nanocomposites to enhance the efficiency of thermal energy storage in triplex tube systems. About 2500 s PCM melt about 36% for case A, but melting rate enhance up-to 55% using nano particles. Melting rate enhance 91% in 1000 s in case of G using 8 fins as compare to case A having no fins.

Multifunction integration within magnetic CNT-bridged MXene/CoNi based phase change materials

Developing advanced nanocomposite phase change materials (PCMs) integrating zero-energy thermal management, microwave absorption, photothermal therapy and electrical signal detection can promote the leapfrog development of flexible wearable electronic devices. For this goal, we propose a multidimensional collaborative strategy combining two-dimensional (2D) MXene nanosheets with metal-organic framework-derived one-dimensional (1D) carbon nanotubes (CNTs) and zero-dimensional (0D) metal nanoparticles. After encapsulating paraffin wax (PW) in three-dimensional (3D) networked multidimensional MXene/CoNi–C, the resulting composite PCMs exhibit excellent thermal energy storage capacity and long-term thermally reliable stability. Benefiting from the synergistically enhanced photothermal effects of CNTs, Co/Ni nanoparticles and MXene, PW@MXene/CoNi–C can capture photons efficiently and transfer phonons quickly, yielding an ultrahigh photothermal conversion and storage efficiency of 97.5%. Additionally, PW@MXene/CoNi–C composite PCMs exhibit high microwave absorption with a minimum reflection loss of −49.3 ​dB at 8.03 ​GHz in heat-related electronic application scenarios. More attractively, the corresponding flexible phase change film can simultaneously achieve thermal management and electromagnetic shielding of electronic devices, as well as photothermal therapy and electrical signal detection for individuals. This functional integration design provides an important reference for developing advanced flexible multifunctional wearable materials and devices.

Thermophysical properties and enhancement behavior of novel B4C-nanoadditive RT35HC nanocomposite phase change materials: Structural, morphological, thermal energy storage and thermal stability

This study aims to enhancement the thermal conductivity of RT35HC, as a commercial paraffin, by integrating boron carbide (B4C) nanoparticles for the first time, thereby producing B4C-nanoadditive nanocomposite PCMs. The B4C nanoparticles were reinforcement to RT35HC at mass fraction percentages (wt.%) of 0.5, 1, 1.5 and 2 by melting and physical mixing method. The structural and morphological characteristics of both pure and nanocomposite PCMs were examined using XRD, FT-IR, FE-SEM, and EDX. Thermal properties were investigated through DSC, TGA/DTA, and thermal conductivity measurements using the KD2-Pro device. The Gaussian process regression (GPR) model was used to analyze the Cp values in relation to temperature and additive ratio. Structural and morphological analysis results indicated a homogeneous distribution of nanoparticles within the PCM matrix, without any significant chemical or physical alterations. The introduction of B4C-nanoadditive did not markedly affect the melting and solidification temperatures. However, melting and solidification enthalpies decreased proportionally with increased nanoadditive ratios, with the greatest reductions being 7.44 % and 5.74 % at a 2 wt% nanoaddition rate, respectively. As the nanoadditive ratio increased, the thermal conductivity (k) and specific heat capacity (Cp) of RT35HC in both solid and liquid-phases enhanced significantly. Specifically, solid-phase (25 °C) k values increased by 67.51 % from 0.197 to 0.33, and liquid-phase (50 °C) k values by 15.29 % from 0.170 to 0.196. The highest Cp values in the solid and liquid-phases were measured as 3.01 and 2.49, respectively, in the nanocomposite with a high nanoadditive ratio. The GPR method yielded a success rate of 0.9015. Additionally, the nanocomposites exhibited enhanced thermal stability and higher thermal decomposition temperatures. Based on these characterizations, the fabricated B4C-nanoadditive nanocomposite PCMs show promise for application in TES and TM systems.

A study on novel dual-functional photothermal material for high-efficient solar energy harvesting and storage

The solar-heat storage efficiency of devices based on phase change materials (PCMs) is limited due to the light absorption and internal heat transfer within the PCMs, unclear thermal conductivity-enhancement mechanism within nanocomposite PCMs, and uncontrollable photothermal-interface modulation. Therefore, a novel controllable strategy was proposed in this study to fabricate dual-functional photothermal storage three-dimensional (3D) phase change blocks (PCBs) with higher thermal conductivity (27.98 W/m·K) and spectral absorption (98.03 %) compared to those of most previously reported PCM-based devices. The as-synthesized PCBs contained millimeter-sized graphite plates with horizontal Van der Waals bonds and oriented micro/nanoscale graphite nanosheets. The structural properties of thin PCM layers between the PCB sheets have synergistically reduced the internal interfacial thermal resistance of the PCBs. Laser-controllable induction was used to fabricate integrated biomimetic-forest 3D optical absorbers on the high thermal conductivity interface of the PCBs, which significantly reduced the thermal resistance of the optical-thermal interface. The resulting 3D-PCBs, integrated with thermoelectric generators, powered portable electronic devices, expanding the applications of traditional PCM heat-storage devices. Therefore, this study will guide the future design of high-performance solar-thermal storage PCMs with a wide range of practical applications.

Synthesis and characterization of myristic acid - infused Al2O3/CuO/MWCNT nanocomposites for energy storage and cooling applications

Phase change materials are highly effective in improving the thermal efficiency of a heat exchanger, making them a choice for enhancing renewable energy to achieve a feasible environment. In this study, myristic acid (MA) was used as a phase change material and aluminium oxide (Al2O3), copper oxide (CuO) of 2.5, 5, 10 wt % and multi-walled carbon nanotubes (MWCNT) of 1.0, 1.5, and 2 wt % were used as the nanoparticles to produce MA-embedded nanocomposite phase change material (NCPCM). The characterization studies, namely x-ray diffraction, Thermal Conductivity, field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) were performed on nanocomposite phase change materials to ensure their homogeneous distribution and property enhancement of the fabricated samples. In addition, a Computational Fluid Dynamics (CFD) analysis was conducted to assess the impact of NCPCM on the rates of solidification and melting. The field emission scanning electron microscopy analysis confirms the homogeneous distribution of micro/nanoparticles Al2O3, CuO, and MWCNT with MA. From the x-ray diffraction (XRD) analysis, the homogeneous nature of the fabricated NCPCMs was identified. Fourier transform infrared spectroscopy (FTIR) and Raman Spectroscopy results confirmed the absence of new particle formation due to the physical interaction between nanocomposites and myristic acid. The fabricated NCPCM samples were undergone 500 thermal cycles to ensure their thermal reliability. It is evident from the test results that the addition of nanoparticles to base PCM enhances the thermal properties. The thermal performance of 2 wt% MWCNT-embedded MA was superior to that of aluminium oxide and copper oxide. DSC results revealed that the 2 wt% MWCNT added MA possessed the highest variation of 8.6% in its latent heat storage value compared to pure MA and had a significant variation compared to other fabricated NCPCM compositions. Adding 2 wt% MWCNT to MA has increased the thermal conductivity of pure PCM from 0.15 W mK−1 to 0.38 W mK−1.

Thermally enhanced nanocomposite phase change material slurry for solar-thermal energy storage

This paper investigates the photothermal conversion performance of an innovative heat transfer fluid containing nano-encapsulated phase change material (PCM) with metallic shell materials in a solar thermal energy storage system. The influences of shell thickness, core size, shell material type, PCM mass and shell volume concentrations on the thermal performance of the heat storage medium are investigated and compared. The results show that the heat transfer rates of water-based Ag, Au, Cu and Al nanofluids are 6.89, 5.86, 7.05 and 6.99 W, respectively, while slurries formed by adding paraffin@Ag, Au, Cu and Al nano capsules to pure water enhance heat transfer by 6.18, 13.38, 10.8 and 11.33 %, respectively. The metallic nanoparticle-based shell materials further augment the temperature and energy storage gains by enhancing the solar radiation capture capability of the heat storage medium. Specifically, depending on the mass concentration of PCM, the storage capacity of paraffin@Cu slurry is augmented by up to 290 %. As the shell thickness of the Ag particles also decreases from 8 to 2 nm, it augments the slurry's storage ability for thermal energy by 7 %. The enhancement in the dimensions of the nano capsules, however, causes the surface area-to-volume ratio (SA:V) to reduce the photothermal conversion of the slurry by clustering. Therefore, the thermal energy storage behaviour of the Paraffin@Cu slurry is diminished by 5 % as the core size enhances from 10 to 40 nm. Further, the augmentation in the volume concentration of Al particles in the shell surprisingly reduces the thermal energy storage by 5 %. Finally, paraffin-based solid PCM is also experimentally tested for validation of the specific heat capacity model at various wind speeds and solar radiation.

Advancing heat management in proton-exchange membrane fuel cells through hybrid nano-composite phase change materials

Heat management challenges in proton-exchange membrane fuel cells (PEMFC) leads to performance degradation, particularly during operational fluctuations and vehicle downtime. This study examines the use of Nano-additive phase change materials (PCMs) as an innovative approach to thermal management in PEMFCs. It addresses a research gap, as PCMs' advantages in batteries and electronics are well-known, but their application in PEMFCs remained relatively unexplored. Hence, using the ChtMultiRegionFoam solver from OpenFOAM, two heat transfer aspects in PEMFCs are studied. The first examines PEMFC cooling under normal conditions, combining liquid cooling with a hybrid Nano-composite phase change material (HNCPCM). The results indicate the HNCPCM cools the PEMFC for 11 min before reaching saturation, after which liquid cooling starts. Moreover, with HNCPCM, the PEMFC's thermal efficiency and temperature uniformity enhance by 7.04 % and 39.76 %, respectively. Therefore, the HNCPCM contributes to cooling as the temperature and voltage fluctuate under real conditions. The second aspect evaluates PCM and insulation to maintain the PEMFC stack's operating temperature range (OTR) during downtime. Using 4 mm PCM and 11 mm insulation, the stack stays within the OTR for nearly 4 h, extending the OTR duration by 49.2 %. Consequently, the waste energy stored by PCM ensures the stack remains within the OTR, averting performance degradation upon restart.

Experimental study on the performance enhancement of PV/T by adding graphene oxide in paraffin phase change material emulsions

Traditional water-based PV/T systems have low heat storage density, high PV backsheet temperatures, and low energy utilization in practical applications. In this work, nanoparticles were applied to improve thermal conductivity and simultaneously emulsions were added to enhance energy storage density of the conventional heat transfer media. Furthermore, the synergistic effect of nanocomposite Phase Change Material Emulsions (PCME) as the heat transfer medium on the thermoelectric efficiency of PV/T was studied in a real system. Specifically, the water-based 30 % paraffin emulsions with graphene oxide (GO) concentration of 0.01, 0.02 and 0.03 wt% were prepared by ultrasonic stirring and their thermophysical properties were characterized. The results show that the 30 wt% paraffin emulsion with addition of 0.02 wt% GO has the phase change temperature of 35 °C, latent heat of 42.93 J/g, thermal conductivity of 0.505 W/(m·K) and viscosity coefficient of 0.91. It shows the thermal efficiency of the paraffin/GO emulsion increased by 92.28 %, the electrical efficiency increased by 8.87 %, the comprehensive efficiency increased by 45.75 %, and 15.8 % increase in heat collection for the heat exchange tank in comparison with the water. It is concluded application of PCME would improves the thermoelectric performance of the system than traditional water-based PV/T systems.

Phase change material nanocomposites as an internal curing aid for nano-modified concrete under cold weather

Ultrafine nano-silica particles can improve the hydration process and concrete performance due to its high surface area and potent reactivity, which may be utilized to counteract the adverse effects of cold temperatures. In the current study, five nano-modified concrete mixtures were prepared to investigate the effect of a curing freezing temperature (−15 ℃) on their mechanical and physical properties, durability, and microstructure features. All mixtures comprised calcium nitrate-nitrite as a cold weather admixture system (CWAS) to depress the freezing point of mixing water. In addition, nano-silica or nano-clay powders impregnated with phase change material (PCM) were added to the mixtures as internal curing nanocomposites. All mixtures were cured at − 15ºC to simulate winter conditions in cold regions. The mixtures’ performance was assessed based on setting times, 7 and 28 days compressive strengths, fluid absorption, and resistance to frost damage in water and salt solution. Furthermore, thermogravimetry, scanning electron microscopy associated with energy-dispersive X-ray spectroscopy, and mercury intrusion porosimetry were performed to assess the hydration, microstructural development, and pore structure features of the produced concrete, respectively. The coexistence of nano-silica and CWAS with the nanocomposites, especially in the case of nano-silica powder as a host for PCM, markedly improved the overall performance of concrete. This highlights the promising use of nano-modified concrete cured internally with nanocomposites for cold weather construction applications (down to −15 ℃), without the need for heating practices.

Organic/carbon and organic/carbon-metal composite phase change material for thermoelectric generator: Experimental evaluation

Phase change materials (PCMs) are regarded as a promising choice for thermal energy storage and thermal regulation applications owing to their extensive range of operational temperature. Nevertheless, the effective utilization of PCMs is primarily limited by their inadequate thermal conductivity. Present study investigates the efficacy of employing graphene (Gr) mono nanoparticles and graphene-silver (Gr:Ag) hybrid nanoparticles as an approach to enhance thermal features and establish a comparative analysis in energy storage performance of organic phase change material (PCM). The comparative study suggest the addition of 0.8 weight% (wt%) of hybrid Gr:Ag nanoparticles (NPs) enhanced the thermal conductivity of PCM (RT54HC) by 96 %, while 0.8 wt% addition of mono graphene NPs increases thermal conductivity by 83 %. Hybridization of Ag nanoparticle over Gr nanoparticle surface ensures uniform dispersion of nanoparticle into the PCM matrix overcoming the issue of floating in graphene mono nanoparticle and settling in silver nanoparticle. Subsequently, energy storage enthalpy of nanocomposite PCM with 0.8 wt% NPs of Gr and Gr:Ag nanoparticle results in increase in latent heat by 11 % and 8.5 % respectively. Likewise, inclusion of Gr nanoparticles resulted in a decrease in optical transmissibility by 71 %, while Gr:Ag hybrid nanoparticles led to a slightly lower decrease of 65 %. The composites also exhibited a minor alteration in their thermo-physical properties following 500 thermal cycles, thus validating the reliability of prepared nanoparticle enhanced PCMs. Further, hybrid nanocomposite applied in thermoelectric generator (TEG) that produced 425 mV in comparison to base PCM 325 mV. Therefore, the prepared nanocomposites, with their established capabilities, have the potential to make a substantial contribution to the advancement of energy storage requirements in the future.

MXene-based eutectic salt hydrate phase change material for efficient thermal features, corrosion resistance & photo-thermal energy conversion

Salt hydrate phase change materials (PCMs) possess low thermal conductivity, degree of supercooling, lack of corrosion resistance and poor photo thermal conversion ability. To overcome these challenges, a two dimensional, chemically stable, optically & thermally efficient MXene@eutectic salt hydrate composite PCM is developed for effective harnessing of solar energy and thermal energy storage (TES) applications. Low temperature eutectic salt hydrate PCM with phase transition temperature of 27.6 °C and 216 J/g melting enthalpy is developed using sodium sulphate decahydrate (SSD) and sodium phosphate dibasic dodecahydrate (SPDD) based on Schrader equation. Advanced 2D layered material, MXene (Ti3C2) is synthesised from MAX phase (Ti3AlC2). Furthermore, MXene based PCM nanocomposite is developed with binary eutectic PCM of SSD/SPDD at different weight fractions through two step technique. Developed nanocomposite PCM exhibits better chemical stability, high optical absorbance of (1.1), low transmissibility (10.2 %), reliable thermal conductivity (0.621 W/m⋅K), improved melting enthalpy (161.2 J/g) and considerable cycle stability. The optical absorbance and thermal conductivity demonstrated a superior photo-thermal conversion capability and thermal networks for the developed MXene based composite sample at 0.9 wt% of MXene. The above properties are experimentally inferred by evaluating the developed MXene@ eutectic salt hydrate and base eutectic PCM under the solar simulator. The interfacial attraction between the two dimensional MXene nano flakes and the developed eutectic PCM ensures a promising ability to trap solar energy effectively for thermal regulation in a sustainable direction. Subsequently, the effect of MXene with SSD/SPDD in regard to the issue of corrosion is explored for copper and aluminium metal surface.

Thermodynamic and thermal degradation kinetics analysis of coconut shell biomass based phase change material

Phase change materials (PCMs) stores and releases thermal energy in the form of latent heat during phase transition. Though PCMs are durable in nature, they suffer commercial application owing to low thermal conductivity. Inclusion of metal and carbon based nanoparticles are typically adopted to overcome the complication of poor conducting nature of organic PCMs. In this experimental research we develop a bio based nanoparticle using coconut shell in an environmental friendly manner to enhance the thermal conductivity of organic PCM polyethylene glycol 1000. Bio nanoparticle (BNP) improves the thermal conductivity of the developed nanocomposite PCM by 73.1% with 0.9 wt% of coconut shell BNP hence we evaluate the thermodynamic and thermal kinetics parameter of the nanocomposite PCM sample with 0.9 wt% biochar based nanoparticle. In addition the authors have analysed the thermal decomposition kinetics of the optimized PCM composite using Coats and Redfern method to exhibit the reaction mechanism, thermodynamic and kinetic parameter.

Optical performance and chemical stability evaluation of new era phase change material: Activated by hybrid nanoparticle

Inorganic salt hydrate phase change materials (PCMs) are ahead of organic PCMs in terms of energy storage ability and safety as they are non-flammable. However the major hindrance with inorganic PCM are degree of supercooling and low thermal conductivity though better than organic PCM. The common technique to enhance the thermal conductivity is via dispersion of metal and carbon nanoparticle. Though they enhance the thermal conductivity of the nanocomposite, with continuous operation the nanoparticle agglomerate and settles down owing to their density. Henceforth, in the current research work we conduct an experimental investigation to enhance the optical and thermal performance of commercialised inorganic salt hydrate PCM using metal-carbon hybrid nanoparticle. We disperse graphene silver nanoparticle at different weight ratio adopting a two-step method followed by probe sonication to ensure uniform dispersion. We achieve a highly stable nanocomposite with 584% increase in optical absorbance of electromagnetic waves and 86% decrease in transmittance. Thermal management of electronic gadgets has evolved to be a major consideration of research as overuse of gadgets lead to rapid temperature rise and is in need of passive cooling system. Henceforth the newly developed nanocomposite phase change materials (PCMs) not only acts as thermal batteries but can also be opted as energy materials for thermal regulation and heat mitigation.

Lauric acid/stearic acid/nano-particles composite phase change materials for energy storage in buildings

Composite organic phase change materials (PCMs) have gained wide applications in buildings due to their superior latent heat capacity, stable properties, and most notably, the ability to adjust their melting temperatures as required. In this study, lauric acid (LA) and stearic acid (SA) were selected as the matrix of PCM, which is used to store and release thermal energy. The step-cooling curve method was utilized to test and draw the binary equilibrium phase diagram of the two materials. The composite PCM achieved its lowest eutectic temperature of 31.2 °C when the weight ratio of LA/SA was 7:3, demonstrating suitability for building envelopes. To enhance the thermal conductivity of the composite PCM, nano‑copper oxide (nano-CuO) and nano‑silicon dioxide (nano-SiO2) were added into the composite PCM as thermal conductivity enhancing materials. The study compared the effects of different dispersants, different nanoparticle to dispersant ratios, and nanoparticle concentrations on the stability and uniformity of the experimental materials. The thermal properties were analyzed using Fourier Transform Infrared Spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), thermal conductivity measurement, and thermal absorption and release process analysis. The findings indicate that the 0.2 %nano-CuO/PCM had remarkable stability, with reduced latent heat of melting and solidification by 5.91 % and 5.44 %, respectively, compared to the composite PCM. The thermal conductivity of the material was increased by 30.0 %. This study provides valuable insights for the development of novel nanocomposite PCMs specifically designed for thermal active building wall applications.

Expanded graphite intersperse reliable binary eutectic phase change material for low temperature thermal regulation systems

Inorganic phase change materials (PCMs) frequently stuck by ineffaceable thermal conductivity and degree of supercooling for thermal energy storage (TES) accomplishment. The present research work is dedicated to resolve this problem by developing a unique inorganic salt hydrate based binary eutectic PCM employing sodium sulphate decahydrate (SSD) and sodium phosphate dibasic dodecahydrate (SPDD) in eutectic mixture ratio 62:38 mass percentage. The peculiar eutectic composition of SSD/SPDD developed with melting and bath sonication technique manifests eutectic latent heat of 207.4 J/g and eutectic melting point of 27.8 °C. Furthermore, to elevate thermal performance and to descent degree of supercooling three dimension expanded graphite (EG) is interspersed as nanoparticle. Optical absorbance of composite PCM elevated from 0.16 for SSD/SPDD to 0.92 with SSD/SPDD + EG nanoparticles; inversely transmissibility of the composite reduced by 82.13 %. Heat flow curves ensures the melting temperature (26.9 °C–28.7 °C) of EG dispersed composite to be within the operating condition with latent heat of 220.4 J/g at 2.0 % of EG owing to the intermolecular binding force of attraction increases as nano-sized sheets effectively disperse with the base PCM. Subsequently, thermal conductance of nano composite eutectic PCM upraised from 0.453 to 0.855 W/m⋅K. After 200 thermal cycle's chemical optical and thermal stability of the PCM composite was degraded insubstantially due to the presence of impurities with longer service; this affirmed the stability thermal perks of nanocomposite PCM. Numerical analysis on heat transfer propagation of heat source within SSD/SPDD PCM layer with and without EG nanoparticle provides inference on the importance of thermal conductivity.