Latent Heat Capacity Research Articles

Flexible phase-change composite films for infrared thermal camouflage and photothermal energy storage

To meet the requirement of multipurpose applications in infrared thermal camouflage and solar photothermal energy storage, we have developed a series of multifunctional composite films based on polyurethane (PU) as a flexible matrix and double-layered phase-change microcapsules as an additive. The double-layered microcapsules were first constructed by encapsulating n-docosane as a phase-change material in a titanium dioxide shell, followed by depositing a polyaniline (PANi) functional layer. Then, the microcapsules were incorporated into the PU matrix to form the composite films through in situ polycondensation. A high latent heat capacity of over 130 J g−1 was achieved by the microcapsules as a result of a high n-docosane loading. This can generate an effective thermal buffer for the composite films and thus endow them with a good thermal camouflage capability. The composite films also show good solar energy-storage performance thanks to their superior sunlight absorptivity derived from the PANi coating layer of the microcapsules. The composite films present a much higher surface temperature (68.6 °C) than pure PU film (41.9 °C) under simulated sunlight irradiation for 1488 s. In addition, the composite films exhibit a self-cleaning surface and high flexibility. Integrating the double-layered microcapsules and flexible PU matrix may provide an innovative strategy for developing flexible functional films for infrared thermal camouflage and photothermal energy storage applications.

Upcycling of PET plastics into diethyl terephthalate for applications as phase change materials in energy harvesting

Polyethylene terephthalate (PET) is an indispensable material in our everyday lives and upcycling of its waste has become a major area of research. Herein, the upcycling of PET waste into phase change materials (PCM) for thermal energy storage applications is presented. Hydrolysed and esterified PET waste affords diethyl terephthalate (DET), which when blended with UV-curing acrylic matrix, trimethylolpropane ethoxy triacrylate (TMPEOTA), forms a composite PCM. Chemical characterisation such as IR and NMR were conducted to confirm the presence of functional groups in the composites. The thermal properties of the composites, such as melting point and thermal degradation were obtained and DET exhibited a relatively high melting enthalpy of 94.1 J/g at about 39.9 °C. The form stability and thermal performance was studied for composites made of different DET loading weight percentages from 50 to 90 %. A loading rate of 80 % (D80) was found to provide best latent heat capacity while maintaining its form stability and minimizing leakage. Finally, to assess the performance of D80 as a thermal storage material, a thermal response test was performed and D80 was able to prevent significant rise in temperature for about 60s during its phase transition as opposed to TMPEOTA control.

Synthesis and Characterization of Shape-Stable Bio-Char Composite PCM Material for Solar Desalination Application

In the present study, three different D-Mannitol based activated bio-char composite shape-stable phase change materials (PCM) were developed for medium temperature energy storage applications like solar desalination, solar thermal storage and waste heat recovery with varying bio-char compositions. The activated bio-char (A-BC) composite-based samples were prepared from sawdust by using the pyrolysis method. The phase composition, morphology, latent heat capacity and phase change temperature of the fabricated samples were assessed by XRD, SEM, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). The fabricated bio-char composite materials exhibited good thermal properties and structural stability compared to pure PCM. The phase change material with a blend of minimum 15 wt.% activated bio-char and 85% D-Mannitol was observed to be leak resistant. FTIR and XRD results confirm that the chemical properties of the bio-char composite remain the same as the pure PCM, which confirms that there are no chemical interactions between the PCM and bio-char. PCM sample with 15% activated bio-char exhibited an enhanced thermal stability compared to the pure PCM.

Experimental studies on the enhancement in discharging characteristics of phase change material with steatite nanoparticles

Phase change materials are latent heat energy storage systems that can store huge quantities of thermal energy in a small volume. Latent heat energy storage systems are complicated to design due to the low thermal conductivity of phase change materials for discharging to enhance the heat capacity and latent heat storage. The objective of the study is to examine the discharging of phase change material in a latent heat energy storage system for maintaining the temperature of the water. Paraffin wax utilized as the phase change material due to its higher latent heat capacity. The experiments were performed with the flow of the hot water through a phase change material container by using a copper tube to enhance the discharging of phase change material during solidification to maintain the temperature of the water. Furthermore, the steatite nanoparticle has been dispersed with phase change material to enhance the discharging of characteristics. The steatite nanoparticle has been selected due to its low thermal conductivity, and the weight percentages nanoparticles were varied viz. 10 %, 20 %, 30 %, and 40 %. The increase in water temperature from 0.1 °C to 1 °C has been taken 7 h by enhancing the discharging of phase change material with various concentrations of the steatite nanoparticle. The work shows the significant discharging characteristics of phase change material with steatite nanoparticles. The nano-phase change material has the potential to maintain the temperature of water without any external energy for a particular duration, which shows cost-effectiveness.

Polyurethane/n-Octadecane Phase-Change Microcapsules via Emulsion Interfacial Polymerization: The Effect of Paraffin Loading on Capsule Shell Formation and Latent Heat Storage Properties.

Organic phase-change materials (PCMs) hold promise in developing advanced thermoregulation and responsive energy systems owing to their high latent heat capacity and thermal reliability. However, organic PCMs are prone to leakages in the liquid state and, thus, are hardly applicable in their pristine form. Herein, we encapsulated organic PCM n-Octadecane into polyurethane capsules via polymerization of commercially available polymethylene polyphenylene isocyanate and polyethylene glycol at the interface oil-in-water emulsion and studied how various n-Octadecane feeding affected the shell formation, capsule structure, and latent heat storage properties. The successful shell polymerization and encapsulation of n-Octadecane dissolved in the oil core was verified by confocal microscopy and Fourier-transform infrared spectroscopy. The mean capsule size varied from 9.4 to 16.7 µm while the shell was found to reduce in thickness from 460 to 220 nm as the n-Octadecane feeding increased. Conversely, the latent heat storage capacity increased from 50 to 132 J/g corresponding to the growth in actual n-Octadecane content from 25% to 67% as revealed by differential scanning calorimetry. The actual n-Octadecane content increased non-linearly along with the n-Octadecane feeding and reached a plateau at 66-67% corresponded to 3.44-3.69 core-to-monomer ratio. Finally, the capsules with the reasonable combination of structural and thermal properties were evaluated as a thermoregulating additive to a commercially available paint.

The effect of PCM on mitigating thermal runaway propagation in lithium-ion battery modules

The main safety issue of lithium-ion batteries (LIBs) is thermal runaway (TR), which has greatly hindered the application of LIBs. Phase change materials (PCM) have been used in battery modules as a thermal management method due to the heat absorption function during the phase change process. However, the role of PCM in TR propagation mitigation has not been carefully examined. In this paper, a 1D heat transfer model was developed to predict the mitigation effect of PCM on TR propagation of a battery array, which shows the superiority of high simulation speed and accuracy. The effects of thermo-physical parameters of PCM on cascading cell-to-cell thermal runaway propagation behavior were investigated. In addition, we gave an optimal range of key parameters of PCM based on safe regulations of China and the United Nations regarding to the TR in electric vehicle LIBs. It was found that the latent heat, density and heat capacity of PCM have similar effects on TR propagation behavior. With the increase of the three PCM parameters, the time duration between cell-to-cell failure propagation increases linearly, which shows a slower TR propagation rate. The optimal ranges for density, heat capacity and latent heat of PCM are over 2150 kg·m−3, over 4100 J·kg−1·K−1 and over 9 × 105 J·kg−1, respectively. What’s more, the TR propagation will exacerbate with the increase of thermal conductivity of PCM, which reminds us to notice a balance between thermal management and TR mitigation in PCM-based thermal management system. Generally, through analyzing the effect of thermal diffusivity of PCM in TR inhibition, we found higher thermal diffusivity will speed up the propagation of TR. And the TR propagation speed is more sensitive to the change of density of PCM. The thermal diffusivity of PCM should be less than 9 × 10−7 m2·s−1 to satisfy the safety standards. The PCM manifests great performance in retarding TR propagation with the phase transition temperature in the range from 318.15 to 518.15 K. Moreover, we found that there exists a critical PCM thickness over which TR propagation will not occur. As the battery thickness increases from 8.8 to 56.5 mm, the critical PCM thickness shows a non-monotonic variation trend (increasing at first and decreasing later). This study demonstrates the feasibility of using PCM as a thermal runaway mitigation strategy and provides a guideline for the optimization of physical parameters of PCM.

Al–Si–Fe alloy-based phase change material for high-temperature thermal energy storage

Abstract Carnot batteries, a type of power-to-heat-to-power energy storage, are in high demand as they can provide a stable supply of renewable energy. Latent heat storage (LHS) using alloy-based phase change materials (PCMs), which have high heat storage density and thermal conductivity, is a promising method. However, LHS requires the development of a PCM with a melting point suitable for its application. For the Carnot battery, the reuse of a conventional ultra-supercritical coal-fired power plant with a maximum operating temperature of approximately 650°C is considered. Therefore, developing a 600°C-class alloy-based PCM is crucial for realizing a highly efficient and environmentally friendly Carnot battery. Using thermodynamic calculation software (FactSage), we found that Al-5.9 mass% Si-1.6 mass% Fe undergoes a phase transformation at 576–619°C, a potential 600°C-class PCM. In this study, we investigated the practicality of an Al–Si–Fe PCM as an LHS material based on its heat storage and release properties and form stability. The examined Al–Si–Fe PCM melted until approximately 620°C with a latent heat capacity of 375–394 J·g−1. Furthermore, the PCM was found to have a thermal conductivity of approximately 160 W·m−1·K−1 in the temperature range of 100–500°C, which is significantly better than that of conventional sensible heat storage materials in terms of heat storage capacity and thermal conductivity.

Transient thermal behavior of a passive heat sink integrated with phase change material: A numerical simulation

This paper presents a numerical investigation of the thermal performance of a heat sink augmented with phase change material (PCM) for passive electronic cooling applications. The PCM-based heat sink employed N-eicosane as the PCM, which has a suitable melting temperature and high latent heat capacity for electronic cooling applications. A numerical simulation based on the enthalpy-porosity method was developed to analyze the impact of both PCM inclusion and induced natural convection airflow on the base temperature of the heat sink. The operational conditions were selected as three constant heat fluxes of 2, 3, and, 4 kW/m2 and four critical base temperatures of 40, 45, 50, and 55 °C. The influence of fin numbers on the thermal behavior of both PCM-based and conventional (without PCM) heat sinks was also investigated by considering the three fin numbers of 4, 5 and, 6. The PCM integration into the heat sink effectively delayed the rise of base temperature and extended the safe operation time compared to a conventional one. The thermal performance enhancement ratio of the PCM-based heat sink over the conventional heat sink ranged from 1.53 to 2.81, depending on the selected heat flux and critical temperature. The effect of fin numbers on thermal performance was more significant at lower heat fluxes. It was observed that the PCM-based heat sinks achieved a higher time-averaged heat transfer coefficient than the conventional heat sinks, and this coefficient increased with the heat flux and decreased with the fin number. For both PCM-based and conventional heat sinks, it was observed that increasing the fin number reduces the heat transfer coefficient value due to the suppressing effect of fins on natural convection current. The results demonstrate the potential of using passive PCM-based heat sinks for improving the reliability and efficiency of electronic devices compared to conventional heat sinks.

A novel carbon reducing natural composite phase change material for effective energy storage

The development of fatty acid made from natural composite materials Lac, Rosin, Flowers of silk cotton, Red ochre, Cinnabar, Beeswax, and Butter as a novel bio-based Natural Composite Phase Change Material (NCPCM) is the subject of the present study. This bio-based material was produced for the first time using natural, readily available, inexpensive, and eco-friendly with a peak phase transition temperature of 75 °C and 194 J/g as the latent heat capacity of fusion. Three distinct compositions, 2 %, 3 % and 5 % of NCPCM to the weight of the binder, were produced by the direct incorporation method into the natural hydraulic lime matrix. The newly developed NCPCM-incorporated lime mortar specimens were characterized based on their physical, mechanical, and thermal properties, and their results were compared with reference lime mortar (RLM). The compressive strength of NCPCM2 and NCPCM3 at 28 days increased by 22.64 % and 47.42 %, respectively. The produced NCPCM retains good thermal stability in its temperature operating range. The XRD findings showed that adding Lac and Rosin containing carboxylic acid esters of fatty acids increased the calcium carbonate formation. The produced FTIR validated the produced material's chemical stability, and SEM images demonstrated that the developed matrix's morphology successfully retains the added bio-additives. From an environmental perspective, the prepared NCPCM in lime mortar can reduce CO2 emissions by 296 kg·CO2/kg and 286 kg·CO2/kg. Furthermore, adding the produced NCPCM as bio-additives to lime mortar can explore the creation of sustainable mortar, which leads to environmental and economic benefits.

A critical experimental evaluation of hexagonal boron nitride, graphene oxide and graphite as thermally conductive fillers in organic PCMs

Composite phase change materials (CPCMs), consisting of nanofillers embedded inside conventional PCMs such as salt hydrates or paraffins, are emerging candidates for large-scale latent heat storage systems or electrochemical applications. High thermal conductivity and thermal diffusivity of CPCMs are crucial prerequisites for practical utilization, in addition to good intrinsic enthalpy of fusion and volumetric heat capacity of the pristine PCMs. This paper presents an exclusive evaluation of graphite, hexagonal boron nitride (HBN), and graphene oxide nanoparticles as thermally conducting nanofillers across different loading ranges inside the paraffin matrix. The thermal performance of these CPCMs is compared by investigating multiple thermal properties, such as the melting temperature, degradation rate, and dispersion efficiency. Despite the similar intrinsic thermal properties of graphite, HBN and graphene oxide, their incorporation enhances the thermal performance of pure paraffin to different extents, by 137.6 %, 192.2 % and 344.1 % in thermal conductivity as well as by 189.0 %, 204.1 % and 202.1 % in thermal diffusivity, respectively, which is attributed to the conductive channels established by these nanofillers and the much-reduced thermal contact resistance across the interphase. Although these three types of particles possess analogously hexagonal structures, it was found that they interacted differently with the paraffin matrix at low (1 wt%) and high (15 wt%) filler loadings. The latent heat capacity of paraffin/GO was 3.8 % higher than that of paraffin/HBN and paraffin/graphite. Overall, this study provides a novel understanding of the transport mechanisms of heat carriers inside CPCMs, so the thermal performance for wider applications can be predicted, which will be invaluable for catering future sustainable energy needs.

Experimental and numerical investigation of PCMS on ceilings for thermal management

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

Effects of alkali-activated slag binder and shape-stabilized phase change material on thermal and mechanical characteristics and environmental impact of cementitious composite for building envelopes

A tremendous quantity of energy has been used in the building and a huge amount of CO2 emitted to maintain comfortable indoor temperatures. In order to lower existing level of CO2 emissions, using eco-friendly alternative binders instead of ordinary Portland cement (OPC) and improving buildings’ energy efficiency are indispensable. The thermal characteristics of cementitious composite have been improved by the use of phase change materials (PCMs) via its latent heat capacity. PCMs can also be incorporated with alkali-activated binding materials of industrial by-products such as alkali-activated slag (AAS), which can result in an efficient carbon reduction compared to the use of ordinary Portland cement (OPC) as a binder. To better comprehend the practical feasibility of AAS in PCM-incorporated composites as an alternative building component, it is necessary to study the one-part AAS system holistically by assessing its fundamental material characteristics, environmental impact (CO2 emission), and energy efficiency. This work uses an experimental-computational method and a case study to evaluate the effects of one-part AAS binder and shape-stabilized PCMs on thermal and mechanical properties and environmental impact. The experimental results demonstrate that AAS binder can reduce thermal conductivity by up to approximately 20% compared to the OPC case. Incorporating thermal energy storage aggregate (TESA) in the AAS binder can further decrease the thermal conductivity. In addition, the AAS-based composite can significantly reduce CO2 emissions by more than 10% than the OPC-based case due to the improved thermal properties and the consequent reduction in carbon footprint from raw materials and annual energy consumption. The results of this study infer the feasibility of AAS binder and TESA as eco-friendly, energy-saving cementitious composites for building envelopes.

Experimental study of phase change microcapsule-based liquid cooling for battery thermal management

Thermal management of power battery is important to ensure the safety of electric vehicle. Coupling phase change materials (PCMs) with liquid cooling technology is an efficient temperature uniformity strategy. In this paper, a self-made microencapsulated PCM (MPCM) was used to prepare MPCM slurry (MPCMS), and three base liquids (water, ethanol, and silicone oil) were evaluated, which confirmed that the silicone oil could maintain slurry without sedimentation for 7 days, providing the best stability. Also, graphene (GE) was introduced to increase the heat transfer rate of slurry. Then the prepared slurries were applied to the prismatic lithium-ion battery module to verify their thermal management performance. The results indicated that the prepared slurries' latent heat, thermal conductivity, and specific heat capacity were all rose with the increase of MPCM concentration. In addition, the slurries' viscosity changed little when the concentration was below 40 wt%. Compared with the blank module, GE-MPCMS-Si could reduce the battery module temperature and the temperature variance by 14.49 °C and 3.8 °C2, respectively. Besides, the influence of flow rate was further investigated, which showed 6 mL/s is the most economical and efficient flow rate option.

Investigation on properties of phase change foamed concrete mixed with lauric acid-hexadecanol/fumed silica shape-stabilized composite phase change material

This experimental study developed a phase change foamed concrete (PCFC) with suitable temperature regulation and heat storage capabilities utilizing experimental design and numerical simulation. With the porous material adsorption method, a shape-stabilized composite phase change material (PCM) was prepared using fumed silica to absorb Lauric acid-Hexadecanol (LA-HD) binary eutectic. Through the Differential Scanning Calorimetry (DSC), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectrometer (FT-IR), Thermal Gravimetric Analyzer (TGA) and liquid leakage tests, the results indicate that the best mass ratio of LA to HD in LA-HD binary eutectic is 53:47. The maximum adsorption ratio of fumed silica for LA-HD is 60 % (wt). The adsorption process is only a physical combination without chemical reaction, and the proposed composite PCM has stable morphological structures and physical properties. The effect of composite PCM on the dry density, compressive strength and thermal properties of PCFC was explored by changing the content (5 %, 10 %, 15 %, 20 %, 25 %, 30 %) of composite PCM in PCFC. The finite element software ABAQUS was used to establish the model of the PCFC wall, and its heat storage and temperature regulating performance was studied. The experiment results show that the dry density, compressive strength and thermal conductivity of the PCFC gradually decrease with the increase of composite PCM. When the content of composite PCM is 30 %, the dry density, compressive strength and thermal conductivity reach the minimum values of 579.6 kg/m3, 1.192 MPa and 0.105 W/(m·K), respectively. With the increase of composite PCM, the phase change temperature, latent heat and specific heat capacity of foam concrete also increase. When the content of composite PCM is 30 %, the phase change temperature is 36.13 °C, the latent heat is 35.02 J/g, and the specific heat capacity is 2467 J/(kg·°C). The finite element simulation results show that when the PCFC with 30 % composite PCM is placed in the middle of the wall, the inside surface temperature fluctuation range of the PCFC-wall-2 is 27.293 °C ∼ 28.707 °C, and the temperature difference is 1.414 °C, which is 0.0738 °C and 0.047 °C lower than that of PCFC-wall-1 and PCFC-wall-3, respectively; the time for PCFC-wall-2 to reach the peak and valley temperature is delayed by 0.1667 h than the other two walls. The results indicate that using PCFC in buildings can reduce the energy required for building cooling or heating and affect energy saving and environmental protection. Moreover, PCFCs arranged in the middle of the wall has better heat storage and temperature regulation effect than those arranged on both sides.

New library of phase-change materials with their selection by the Rényi entropy method

The secret to the successful and widespread deployment of solar energy for thermal applications is effective and affordable heat storage. The ability to provide a high energy storage density and the capacity to store heat at a constant temperature corresponding to the phase transition temperature of the heat storage material (phase-change material or PCM) make latent heat storage one of the most alluring methods of heat storage. Today, it can be challenging to obtain all the published data on PCM qualities, including relevant non-thermodynamic properties in addition to thermodynamic ones. The developed new PCM library contains various types of PCMs which possess broad range of operation temperatures. This new library consists of 500 substances along with nine associated properties such as phase change temperature, solidification temperature, maximum operation temperature, density, latent heat and specific heat capacity, thermal conductivity, cycleability and ignition temperature. Furthermore, a new PCM selection method, based on calculating the Rényi entropy for a given set of selection criteria, has been proposed. The newly developed selection method requires no subjective judgements. The idea of the method is inspired by earlier applications of fractal analysis methods in many areas of research.

Heating efficiency enhanced by combination of phase change materials and activated carbon for dry floor heating system

Phase change materials (PCMs) have diverse applications in energy storage, buildings, cooling, and heat exchangers. In this study, n-docosane and activated carbon (AC) were combined using the vacuum impregnation method to form an aggregate, which was then injected into a Poly vinyl chloride container and applied to a dry floor heating system. Thermal storage, gravimetric, conductivity, and specific heat analyses were performed to evaluate the thermal performance of n-docosane and AC-based heat-storage aggregate (D-HSA). The dynamic heat transfer performance and power consumption of the dry floor heating system after D-HSA application were then evaluated. Pure n-docosane and D-HSA showed latent heat capacities of 242.7 J/g and 235.1 J/g and 92.10 J/g and 92.66 J/g during heating and cooling. In terms of thermal durability, D-HSA was more stable than pure n-docosane. Thermal conductivity analysis revealed that D-HSA had a high thermal conductivity (approximately 597 %) in the liquid state. In the field-based dynamic heat transfer analysis experiment, the PCM dry floor heating system filled with D-HSA had the advantages of both dry and wet floor heating systems, namely, a fast surface temperature increase rate and the time-lag effect, respectively. Therefore, the PCM dry floor heating system can compensate for the disadvantages of the dry and wet floor heating systems and can be considered an efficient heating system in terms of energy savings.

Economics and lifecycle carbon assessment of coconut oil as an alternative to paraffin phase change materials in North America

Globally, almost 40% of carbon emissions are attributable to building operation and embodied carbon. Phase change materials (PCMs) can store solar energy during peak periods to decrease summer cooling loads and overnight winter heating loads and emissions. At present, most PCMs are non-renewable paraffins with high embodied carbon; plant-based oils such as coconut oil may maintain the conditioning load reductions, while reducing the sustainability and embodied carbon of PCMs. The objective of this study was to determine the economic and emissions of coconut oil as an alternative to paraffins via full house simulations in three North American locations within different climate zones. It was found that paraffin PCM had greater embodied carbon and annual heating and cooling reductions than the coconut oil, causing the lifecycle carbon footprint to be lower with paraffin PCM than with the coconut oil over the house lifetime. This indicates the importance of developing bio-based PCMs with latent heat capacity that more closely compare to paraffins, in order to minimize total building carbon footprint. It was also found that the economic payback period of both PCMs may exceed the lifetime of the house and thus render the PCMs infeasible without reductions in capital costs or increased carbon pricing.

Latent heat storage composites composed of Al‐Si microencapsulated phase change material and alumina matrix

AbstractLatent heat storage (LHS) using phase change materials (PCMs) is expected for application to heat utilization at high‐temperature because it can provide a heat source of high density and constant temperature. Even among PCMs, metals/alloys are promising for high‐temperature operation. However, metals and alloys PCM are concerned about corrosion reactions with structural materials. As a result, micro‐encapsulated PCMs (MEPCMs) have been created in which the surface of alloy PCM is encased in a stable oxide coating. Since the surface of MEPCM is an oxide, the creation of structures with the function of LHS in a variety of shapes by combining MEPCM with sintering aids is also possible. In this study, composite PCMs were prepared by combining Al‐25 mass% Si MEPCM with fine α‐Al2O3 particles as a sintering aid. Consequently, PCM composites containing 70‐90 vol.% of the MEPCM and heat‐treated at 1200°C or 1300°C were successfully fabricated. In particular, a high heat storage density of 0.47 GJ m−3 was obtained under conditions containing 90 vol.% of the MEPCM and a heat treatment temperature of 1200°C, which is 1.6‐fold higher than that of existing sensible heat storage materials. Additionally, the composite PCM retained its shape and the latent heat capacity even after 300 cycles of cyclic testing. Thus, the high heat storage density and high durability of the composite PCM are expected to further promote the expansion of high‐temperature heat utilization in future studies.

New graphical method for assessing the integration of phase change materials into building envelope

One technique to reduce the demand for cooling load in buildings is inserting phase change materials (PCM) into building envelopes. In this study, a new method is performed to facilitate the selection of the type of PCM. The hypothesis is tested through a case of a traditional wall in Cairo, Egypt. The merit of each case is assessed based on the peak and average heat flow to the studied room. The outcome of this study is presented in the form of selection graphs to facilitate the selection of PCM type with no need for detailed calculations. Guidelines were drawn from the results and are directly reflected in the graphical representation. The average load is represented in one graph that depends only on the thermal resistance of the added layer. On the other hand, the peak load could be estimated through two graphs. The graphs combine the effect of the melting temperature, the latent heat capacity, the sensible heat capacity, and the thermal resistance of the PCM.

Review on PCM Heat Sink for Electronic Thermal Management Application

A significant challenge in thermal management has arisen as a result of the rising demand for high-performance electronic devices. The efficiency, size, and weight of conventional cooling methods like liquid and air cooling are constrained. Due to their high storage of latent heat capacity and isothermal phase transition behavior, phase change materials (PCMs) have become a promising thermal management solution. The purpose of this experimental study is to evaluate the performance of a PCM heat sink for electronic thermal regulation. The PCM heat sink is made up of a PCM module attached to a typical heat sink. To improve heat dissipation capabilities, the PCM module uses a PCM material with a suitable phase change temperature and encapsulation. The experimental setup involves simulating real-world operating conditions by applying controlled heat loads to electronic components. By observing temperature changes, thermal resistance, and transient response, the PCM heat sink’s thermal performance is assessed. To evaluate the superiority of the PCM heat sink, a comparison is made with traditional air-cooled and liquid-cooled heat sink configurations. The experimental investigation’s findings show that the PCM heat sink performs better in terms of thermal management than traditional cooling techniques. The phase change process used by the PCM efficiently absorbs and stores extra heat produced by electronic parts, improving temperature regulation and lowering temperature gradients. Lower component temperatures and higher operational reliability are the results of the PCM heat sink’s improved thermal resistance and heat dissipation efficiency. A further benefit of the PCM heat sink’s isothermal behavior during the phase transition is that it prevents temperature spikes and lessens the effects of heat stress on the electronic devices. The long cooling times provided by the PCM material’s high latent heat storage capacity allow for prolonged operation without affecting device performance. This experimental study concludes by demonstrating the efficiency of a PCM heat sink for electronic thermal management. The design of heat sinks with PCM integration offers notable enhancements in temperature control, thermal resistance, and system overall reliability. The results of this research help to advance thermal management strategies, which makes it easier to create efficient electronic devices with better cooling capacities.