Developing microencapsulated 12‐hydroxystearic acid (HSA) for phase change material use

Phase change materials (PCM) have an increasingly more important role as a thermal energy storage (TES) media. However, leakage problem of PCM causes limitation during their integration in TES systems. Therefore, the encapsulation of PCMs is attracting research interest to extend usage of PCMs in real TES applications in recent years. In this study, hydroxystearic acid (HSA) was encapsulated with polymethyl methacrylate (PMMA) and different PMMA comonomer shells via emulsion polymerization method for the first time in literature. HSA with high melting temperature range (74–78°C) can widen the scope of using PCMs, and the encapsulated form can make it more versatile. The chemical structures, morphologies, and thermophysical properties of capsules were determined by FT‐IR, SEM, DSC, TGA, and thermal infrared camera. Among the produced HSA capsule candidates, PMMA‐HEMA is the most promising with latent heat of 48.5 J/g with melting range of 47 to 85°C. SEM analysis indicated that the capsules have spherical shape with compact surface at nano‐micro (100–440 nm) size range; however, some capsules exhibited agglomeration.     

Synthesis and Characterization of Disodium Hydrogen Phosphate Dodecahydrate-Lauric-Palmitic Acid Used for Indoor Energy Storage Floor Units

Organic and inorganic phase change materials(PCMs) are considered potential materials for thermal energy storage(TES) with different phase change characteristics. In this study, a novel organic-inorganic composite phase change material(PCM) called disodium hydrogen phosphate dodecahydrate-lauric-palmitic acid(D-LA-PACM) was prepared. Expanded graphite(EG) was selected as the support material, and the novel organic-inorganic form-stable PCM called D-LA-PAPCM/EG was prepared using the vacuum adsorption method. Differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffraction, leakage testing, melting and solidification cycle testing, thermal conductivity testing, scanning electron microscopy observation of the micromorphology, and other characterization methods were used to study the microstructure and morphology, thermal physical parameters, thermal conductivity, stability of the PCMs, and the comprehensive material properties of D-LA-PAPCM under the composite action of EG. Results indicated that the melting and freezing temperatures and latent heats of D-LA-PAPCM/EG were measured to be 31.6℃ and 34.3℃ and 142.9 and 142.8 J/g, respectively. Although some of the lauric-palmitic acid(LA-PA) and disodium hydrogen phosphate dodecahydrate(DHPD) separated in the multiple porous structures of EG after 1000 cycles, they could still absorb and release latent heats independently, with D-LA-PAPCM/EG still exhibiting good thermal stability. The thermal conductivity of D-LA-PAPCM/EG was 1.361 W/(m·K). Therefore, the material and thermal properties of the prepared D-LA-PAPCM/EG indicate that it could be well used as a feasible material for energy-saving phase change floor units in indoor TES systems.     

Conduction paths of backbones for thermal enhancement of nanocomposite phase change materials

Thermal energy storage (TES) based on phase change materials (PCMs) has become a research hot spot due to its high energy storage density and maintained operating temperature during the phase change. However, as PCM has a poor thermal conductivity that can be as low as 0.2~0.5 W/m· K, the charging/discharging processes of PCM modules are significantly restrained, which severely affects the application of the TES technology in industrial sectors. This study concerns the improvement of the effective thermal conductivity of composite PCM formed by adding nanoparticles with high thermal conductivity into different PCMs. A theoretical model is established to reveal the intrinsic mechanism for the promotion of thermal conductivity of composite PCM consisting of nanoparticles. The results show that aggregation and interfacial thermal resistance are the main reasons for the change of the thermal conductivity. By forming effective conduction paths composed of backbones in the composite PCM, the average thermal conductivity can be improved significantly, which can be as high as 10~50 W/m· K with a wide range of volume fraction of the additives.     

Thermal properties and characterization of palmitic acid/nano silicon dioxide/graphene nanoplatelet for thermal energy storage

Palmitic acid (PA), nano silicon dioxide (nano SiO₂), and graphene nanoplatelets (GNPs) were fabricated to composite phase change materials (PCMs) for thermal energy storage. PA acted as PCM, nano SiO₂ was used as supporting material. GNP as thermal conductivity promoter was added to modify composite PCM. Nano SiO₂ has good adsorption property and can adsorb liquid PCM to prevent leakage. Leakage measurement indicated that PA maximum content in composite PCM is 70 wt%. Chemical and crystal structures, and microstructure of composite PCM were tested by Fourier transformation infrared spectroscope, X-ray diffractometer and scanning electronic microscope, which showed that the raw materials are well mixed by physical action. Differential scanning calorimeter result presented that composite PCM possess phase change temperature at about 60°C and latent heat of 128.42 kJ/kg. Thermogravimetric analyzer and thermal cycle experiment showed that composite PCM have outstanding thermal stability and durability. Thermal conductivity apparatus measurement results indicated that thermal conductivity of composite PCM with 5 wt% GNP is 1.65 times that of composite PCM without GNP. Therefore, this composite PCM are potential materials for thermal energy storage.     

Microencapsulated dimethyl terephthalate phase change material for heat transfer fluid performance enhancement

Micro‐phase change materials (micro‐PCMs) are proposed to increase the thermal conductivity and the thermal energy storage capacity of a heat transfer fluid (HTF). In this work, we have selected dimethyl terephthalate (DMT) to be used as a PCM for performance enhancement of a synthetic oil in the temperature range of approximately 100 to 170 °C. Silicon dioxide (SiO₂) was used as the microencapsulant, because of its desirable properties as containment material, including thermal stability. The SiO₂‐coated DMT micro‐PCM was characterized to determine relevant properties and its suitability for HTF performance enhancement. The SiO₂‐coated DMT was found to completely disperse in the synthetic oil, Therminol SP, silicone oil, at and above 100 °C. FTIR, thermal diffusivity and differential scanning calorimetry measurements were carried out on the materials, and these tests demonstrated that the coated particles can be used for HTF enhancement in the temperature range of 100–170 °C and potentially higher temperatures if pressurized pipes/vessels are utilized. Using the measured thermal diffusivity and known data for density and specific heat capacity, the thermal conductivity of the micro‐PCM was calculated. Our calculations indicate that both the thermal conductivity and the thermal energy storage heat capacity of the HTF would be enhanced by the addition of this micro‐PCM. It is expected that the thermal conductivity increase will enhance the heat transfer of the fluid when in use at temperatures above and below the melting temperature of the PCM. At the melting point, the latent heat of the PCM will increase the thermal energy storage capacity of the fluid. Copyright © 2016 John Wiley & Sons, Ltd.     

Review on heat transfer analysis in thermal energy storage using latent heat storage systems and phase change materials

Thermal energy storage (TES) is a technology that stocks thermal energy by heating or cooling a storage medium so that the stored energy can be used later for heating and cooling applications and for power generation. TES has recently attracted increasing interest to thermal applications such as space and water heating, waste heat utilisation, cooling, and air conditioning. Phase change materials (PCMs) used for the storage of thermal energy as latent heat are special types of advanced materials that substantially contribute to the efficient use and conservation of waste heat and solar energy. This paper provides a comprehensive review on the development of latent heat storage (LHS) systems focused on heat transfer and enhancement techniques employed in PCMs to effectively charge and discharge latent heat energy, and the formulation of the phase change problem. The main categories of PCMs are classified and briefly described, and heat transfer enhancement technologies, namely dispersion of low‐density materials, use of porous materials, metal matrices and encapsulation, incorporation of extended surfaces and fins, utilisation of heat pipes, cascaded storage, and direct heat transfer techniques, are also discussed in detail. Additionally, a two‐dimensional heat transfer simulation model of an LHS system is developed using the control volume technique to solve the phase change problem. Furthermore, a three‐dimensional numerical simulation model of an LHS is built to investigate the quasi‐steady state and transient heat transfer in PCMs. Finally, several future research directions are provided.     

Preparation and characterization of nano‐enhanced myristic acid using metal oxide nanoparticles for thermal energy storage

Fatty acids have been broadly used as phase change materials (PCMs) for thermal energy storage. However, low thermal conductivity limits their performances. This paper investigates the influence of metal oxide nanoparticle addition on myristic acid (MA) as nano‐enhanced PCM (NEPCM). Stability, chemical, and thermal properties were considered. Four types of nanoaprticles, TiO₂, CuO, Al₂O₃, and ZnO, were dispersed in MA at 0.1, 0.5, 1, and 2 wt%. Stability and dispersion were checked by sediment photograph capturing and scanning electron microscopy/energy‐dispersive spectroscopy. The Fourier‐transformed infrared (FTIR) and X‐ray diffraction analysis confirmed no chemical interaction between the nanoparticles and MA. The results revealed a ratio of thermal conductivity of 1.50, 1.49, 1.45, and 1.37, respectively, for 2 wt% of ZnO, Al₂O₃, CuO, and TiO₂. The T‐history method confirmed this enhancement. The latent heat thermal energy storage (LHTES) properties of the nano‐enhanced MA were evaluated using differential scanning calorimetry. The latent heat capacities of nano‐enhanced MA samples have dropped between 9.64 and 5.01 % compared with pure MA, and phase change temperature range was not affected significantly. The NEPCM was subjected to 500 thermal cycling, it showed a good thermal reliability as LHTES properties remained unchanged, while FTIR analysis showed similar characteristics compared with uncycled samples, indicating a good chemical stability. Based on the results regarding with the LHTES properties, cycling thermal reliability, and higher thermal conductivity improvement, it can be achieved that the MA/Al₂O₃ (2.0 wt%) and MA/ZnO (2.0 wt%) composites could be better PCMs for solar TES applications.     

Medium‐ and high‐temperature latent heat thermal energy storage: Material database,system review,and corrosivity assessment

Latent heat thermal energy storage refers to the storage and recovery of the latent heat during the melting/solidification process of a phase change material (PCM). Among various PCMs, medium‐ and high‐temperature candidates are attractive due to their high energy storage densities and the potentials in achieving high round trip efficiency. Although a few review studies on high‐temperature PCMs have emerged in the past few years, the quantity, completeness, and accuracy of the presented data are relatively poor. Also, an efficient indexing methodology for retrieving useful PCM data is missing in the open literature. In this article, we created an up‐to‐date PCM database following a holistic review of the PCMs in medium‐ and high‐temperature applications over a temperature range of 100°C to 1680°C. Such effort then allows us to develop an accurate indexing tool for the fast selection of suitable PCM candidates and extraction of the related property data. More specifically, the created PCM database covers 496 entries of PCM materials, which are extracted from the scattered research works published during the year 1956 to 2017. The collected information includes both the basic thermo‐physical properties of PCMs (eg, melting temperature, heat of fusion, and thermal conductivity) and crucial design factors during construction and engineering phases (eg, energy storage density, volume expansion, liquid/solid densities, and cost). The reviewed PCMs comprise a wide variety of materials, including fluorides, chlorides, hydrates, nitrates, carbonates, metals and alloys, and other uncommon compounds and salts. In addition, the current work presents a brief review on high‐temperature latent heat thermal energy storage systems categorized into metallic and non‐metallic systems. The corrosivity and stability of PCMs, which are commonly ignored in previous studies, are also examined.     

Eutectic compound (KNO3/NaNO3 : PCM) quasi‐encapsulated into SiC‐honeycomb for suppressing natural convection of melted PCM

The phase change eutectic compound, KNO₃/NaNO₃ (50/50 mol%) (phase change material (PCM)), which is used as the thermal energy storage material in the solar thermal power plant, was quasi‐encapsulated into the SiC‐honeycomb (SCH) for suppressing the natural convection occurring at the liquid state of PCM. The performance of the SCH as the material suppressing natural convection of PCM was investigated experimentally. PCM with three kinds of mixing ratios of SCH of 10%, 20%, and 30%, was prepared and packed in their respective stainless can with oil‐flowing pipe in the center, which is called thermal energy storage unit (TESU). Three units were linked together and stacked vertically by the connector at the inlet/outlet oil pipe. The time variation of temperature at the fixed positions inside the TESU in charging/discharging process and temperature gradient in the radial direction inside TESU when PCM was liquid state were investigated. It is concluded that the natural convection is suppressed by mixing the SCH with PCM up to around 30% in weight, because the PCM is quasi‐encapsulated into cell holes and porous structures of SCHs. And thus, the heat transfer of the PCM + 30%SCH composite is controlled mainly by its thermal conduction, which is also supported through comparison of simulation result with experimental one. And so, we conclude that SCH has a function as the quasi‐encapsulating material for suppressing the natural convection of PCM. Copyright © 2015 John Wiley & Sons, Ltd.     

Fatty acid/poly(methyl methacrylate) (PMMA) blends as form-stable phase change materials for latent heat thermal energy storage

Fatty acids such as stearic acid (SA), palmitic acid (PA), myristic acid (MA), and lauric acid (LA) are promising phase change materials (PCMs) for latent heat thermal energy storage (LHTES) applications, but high cost is the most drawback which limits the utility area of them in thermal energy storage. The use of fatty acids as form-stable PCM will increase their feasibilities in practical LHTES applications due to reduced cost of the energy storage system. In this regard, a series of fatty acid/poly(methyl methacrylate) (PMMA) blends, SA/PMMA, PA/PMMA, MA/PMMA, and LA/PMMA were prepared as new kinds of form-stable PCMs by encapsulation of fatty acids into PMMA which acts as supporting material. The blends were prepared at different mass fractions of fatty acids (50, 60, 70, 80, and 90% w/w) to reach maximum encapsulation ratio. All blends were subjected to leakage test by heating the blends over the melting temperature of the PCM. The blends that do not allow leakage of melted PCM were identified as form-stable PCMs. The form-stable fatty acid/PMMA (80/20 wt.%) blends were characterized using optic microscopy (OM), viscosimetry, and Fourier transform infrared (FT-IR) spectroscopy methods, and the results showed that the PMMA was compatible with the fatty acids. In addition, thermal characteristics such as melting and freezing temperatures and latent heats of the form-stable PCMs were measured by using differential scanning calorimetry (DSC) technique and indicated that they had good thermal properties. On the basis of all results, it was concluded that form-stable fatty acid/PMMA blends had important potential for some practical LHTES applications such as under floor space heating of buildings and passive solar space heating of buildings by using wallboard, plasterboard or floor impregnated with a form-stable PCM due to their satisfying thermal properties, easily preparing in desired dimensions, direct usability without needing an add encapsulation and eliminating the thermal resistance caused by shell and thus reducing cost of LHTES system.     

Development of pentadecane/diatomite and pentadecane/sepiolite nanocomposites fabricated by different compounding methods for thermal energy storage

Global warming is one of the most important consequences of excess energy consumption. Phase change materials (PCMs) have prominent advantages in thermal energy storage owing to their high latent heat capacities and small temperature variations during the phase change process. However, leakage is a major problem that limits the use of PCMs. Leakage may occur in encapsulated PCMs or in composites where the PCM is attached to the surface of a supporting material or within the pores of that material. In this study, pentadecane/diatomite and pentadecane/sepiolite nanocomposites were fabricated by using unmodified and microwave‐irradiated diatomite and sepiolite samples and by using different compounding processes, such as direct impregnation, vacuum impregnation, and ultrasonic‐assisted impregnation methods. The microstructures and the chemical and thermal properties of the composites were characterized by scanning electron microscopy, Fourier‐transform infrared spectroscopy, and differential scanning calorimetry. Subsequently, the thermal reliability and stability and the thermal conductivity of the PCM composites were also investigated. A melting temperature of 9.25°C and a latent heat capacity of 58.73 J/g were determined for the pentadecane/diatomite composite that was prepared with the direct impregnation method using a microwave‐treated diatomite sample. The pentadecane/sepiolite composite prepared in the melting temperature range 7.98°C to 8.53°C and latent heat capacity range 41.05 to 46.02 J/g. The results of the thermal analysis indicate that fabricated diatomite‐based or sepiolite‐based PCM composites have good potential as thermal energy storage materials.     

RETRACTED: Preparation and thermal properties of form-stable paraffin phase change material encapsulation

Form-stable paraffin phase change materials (PCMs), in which the paraffin as a latent heat storage material and the polyolefins as a supporting material, have to be encapsulated because of the paraffin leakage and lipophilicity. A novel microencapsulated PCM in which form-stable paraffin is encapsulated into inorganic silica gel polymer is prepared successfully by in situ polymerization. A differential scanning calorimeter (DSC) is used to measure the thermal properties of the PCM. Moreover, the Washburn equation associated with the wetting properties of powder materials, is used to test the hydrophilic–lipophilic properties of PCM. The results indicate that the optimum microencapsulated PCM is endowed with good hydrophilicity, and its specific enthalpy maintains 123.78 J g⁻¹.     

Numerical Analysis of Phase Change Material Characteristics Used in a Thermal Energy Storage Device

In this study, a numerical analysis is performed to investigate the freezing process of phase change materials (PCM) in a predesigned thermal energy storage (TES) device. This TES device is integrated with a milk storage cooling cycle operating under predefined practical conditions. Using this cooling unit, 100 litres of milk is kept cool at 4°C for 48 hours before it is collected. A 2-D model of the TES device is developed in COMSOL Multiphysics to analyze the phase change performance of water-based PCMs. The variations of thermal properties with temperature during the phase change are considered in the analysis. The model is used for exploring the solidification process of PCMs inside the TES device. Temperature variations with time, ice formation, and the impacts of boundary conditions are investigated in detail. Water PCM shows better characteristics in the solidification process in comparison to eutectic PCMs, which is mainly due to the differences between phase change temperatures of the PCMs.     

低温相变储能材料及其应用研究

利用相变储能材料（PCMs）潜热的热能存储（TES）是一种有效的热量利用方式。目前研究较多的储能材料包括无机体系（盐和水合盐）及有机化合物（石蜡、脂肪酸等）。本文对PCMs进行了归类并介绍了各类PCMs的基本特征;针对单纯的PCMs易泄漏的特点,介绍了多孔材料吸附PCMs形成复合PCMs及微胶囊封装技术;概括了PCMs在温度调控、热量储存等方面的应用;对目前PCMs的发展情况进行了总结,并对其未来的发展趋势进行了展望。     

The effects of various carbon derivative additives on the thermal properties of paraffin as a phase change material

The storage of thermal energy in phase change materials (PCMs) has found wide applications that enable energy conservation and management. Paraffin is a major PCM with its low cost, wide availability, and relatively high latent heat, yet its low thermal conductivity may become a drawback in high‐power applications. In this study, composites of paraffin were prepared with multiwalled carbon nanotubes and activated carbon by a dispersion technique to overcome these drawbacks. Thermal, chemical, and physical influences of incorporating carbon additives with varying structures in paraffin composites on thermal storage capacity were determined. Results indicated that the thermal conductivities of paraffin‐activated carbon composites (PACC) and paraffin multiwalled carbon nanotube composites (PCNC) were improved by a factor of 39.1 and 34.1%, respectively, compared with the conductivity of pure paraffin. As a bonus, the thermal energy storage capacities of PCNCs were enhanced by 9.6%, whereas this remained unchanged for PACCs. Copyright © 2015 John Wiley & Sons, Ltd.     

Encapsulated phase change materials for thermal energy storage: Experiments and simulation

In the present study, encapsulated phase change materials (PCMs) were used for the storage of thermal energy. Both experiments and simulation were performed to evaluate the characteristics of encapsulated PCMs. Tests were conducted in a packed bed to determine the performance of the encapsulated PCM. In the preparation of encapsulated PCMs, the coacervation technique was used. The performance of the encapsulated PCM was evaluated in terms of encapsulation ratio, hydrophilicity, and energy storage capacity. The experiments were designed, based on surface response method, to optimize the processing conditions. It was found that a higher coating to paraffin ratio led to a higher paraffin encapsulation ratio. The hydrophilicity value of encapsulated paraffin depended mainly on the ratio of paraffin to coating. The higher the ratio, the lower was its product hydrophilicity. When the paraffin to coating ratio was constant, the higher concentration of HCHO led to a lower hydrophilicity of the product. The encapsulated paraffin has shown large energy storage and release capacity (20–90 J g^?1) during its phase changes depending on different ratios of paraffin to coating. Thermal cyclic test showed that encapsulated paraffin kept its geometrical profile and energy storage capacity even after 1000 cycles of operation. In the experiments and simulation of fluid heating process in encapsulated PCM charged packed bed, results showed that Eulerian granular multiphase model in FLUENT 4.47 is suitable for simulation of such a system. Copyright © 2002 John Wiley & Sons, Ltd.     

Hydrophilic expanded graphite–magnesium nitrate hexahydrate composite phase change materials: Understanding the effect of hydrophilic modification on thermophysical properties

Expanded graphite (EG) has shown excellent performances in compression resilience, thermal conductivity, and adsorption ability. EG can adsorb liquid phase change materials (PCMs) mainly because of capillary action; however, EG is hydrophobic, which makes it less compatible with hydrated salts. Herein, hydrophilic EG (HEG) was prepared with Triton X‐100 (TX‐100) as surface modifier. The HEG–magnesium nitrate hexahydrate (HEG‐MNH) composite as a PCM was investigated for thermal energy storage (TES) to understand the effect of hydrophilic modification on thermophysical properties. The powder‐state HEG is added into MNH to prepare HEG‐MNH composite PCM, which contains 1.71 wt% of TX‐100, 7.29 wt% of EG, and 91.00 wt% of MNH by control variable method. The melting point and latent heat of HEG‐MNH composite PCM were 89.05°C and 137.28 J/g, respectively. The endothermic enthalpy change of HEG‐MNH composite PCM only decreased by 0.90%, along with the exothermic values of HEG‐MNH composite that increased by 3.80% after 100 cycles. The thermal conductivity is higher 5.17 times than that of the pure MNH. Our work suggests that the HEG‐MNH composite PCM has a great potential to be used as a PCM for TES.     

Performance analysis on industrial refrigeration system integrated with encapsulated PCM‐based cool thermal energy storage system

Cool thermal energy storage (CTES) is an advanced energy technology that has recently attracted increasing interest for industrial refrigeration applications such as process cooling, food preservation and building air conditioning systems. An experimental investigation on the performance of an industrial refrigeration system integrated with encapsulated phase change material (PCM)‐based CTES system is carried out in the present work. In the experimental set‐up a vertical storage tank is integrated with the evaporator of the vapour compression refrigeration system. Effect of the inlet temperature of heat transfer fluid (HTF) on the temperature variation of the PCM and the HTF in the storage tank and the performance parameters namely average rate of charging, energy stored, specific energy consumption (SEC) of the chiller with and without storage system are studied in detail. The effect of porosity variation in the storage tank is also studied. A 1°C decrease in evaporator temperature results in about 3–4% increase in SEC and 1°C decrease in condensing temperature leads to 2.25–3.25% decrease in SEC. The range of HTF inlet temperature and porosity values for optimum performance is reported. Copyright © 2007 John Wiley & Sons, Ltd.     

Lipid‐derived monoamide as phase change energy storage materials

One of the major shortcomings of current organic phase change materials (PCMs) is their relatively low melting points, typically below 80°C, which limits their integration into thermal energy storage (TES) systems. The present work was aimed at developing lipid‐derived PCMs with increased melting points which would be suitable for TES applications requiring higher melting points without compromising other key properties such as enthalpy. The introduction of an amide group into the structure of linear saturated fatty acids was used as a means to increase intermolecular interactions and therefore crystallization and melting points. A series of six linear monoamides with differing chain length and symmetry about the amide group were investigated for thermal stability, thermal transition, flow behavior, and crystal structure to establish the structure‐property relationships relevant to TES. The presence of the highly polar amide group in the aliphatic fatty acid–derived molecules resulted in notable improvement in performance compared with the analogous monofunctional molecules: Increases in melting points (79°C‐96°C) and high enthalpies of fusion (155‐201 J/g) were recorded. Fundamental relationships between structure, processing, and macroscopic physicochemical properties, never before elucidated, were revealed in the study. The study revealed a step‐like variation of macroscopic properties: a surprising outcome of the competition between intermolecular attractions, symmetry effects, and mass transfer limitations. The predictive structure‐function relationships established in this work will allow the straightforward engineering of monoamide architectures that can extend the range of organic PCMs and deliver thermal properties desirable for TES applications.     

Analysis of an encapsulated phase change material‐based energy storage system for high‐temperature applications

The capability of an encapsulated phase change material (EPCM)‐based thermal energy storage (TES) system to store a large fraction of latent energy at high temperatures was examined. A 3‐dimensional simulation of a prototype heat exchanger was conducted employing sodium nitrate as the phase change material (PCM). The k‐ω SST model was used to capture the turbulent flow of the HTF, while the melting front was tracked using the enthalpy‐porosity method. The results show that the use of metal deflectors yields a nearly constant heat transfer coefficient over the capsule's surface. Despite this, the presence of the void in the capsule and natural convection within the molten PCM influenced the storage characteristics of the system affecting the shape of the isotherms and melting front. Furthermore, the EPCM capsules consecutively undergo the same heat transfer starting from the capsule closest to the inlet. The EPCM capsules store 80% of the energy lost by the HTF. The 17.7 kg of sodium nitrate stores 14.5 MJ of energy where 20% of the energy stored is via latent heat. Of the energy released by the heat transfer fluid, 80% was absorbed by the EPCM capsules with the remaining energy going into the test section walls. A total of 14.5 MJ of energy was stored by the 17.7 kg of NaNO₃, of which 20% is attributed to the latent heat. The fraction of energy stored as latent heat would be larger if a smaller operating temperature range was used. Thus, an EPCM‐based latent heat TES system is capable of storing a large fraction of the supplied energy and presents efficient means of storing thermal energy for high‐temperature applications. Additionally, the strong agreement between the numerical and experimental works demonstrates that the numerical methods employed can predict the behavior of an EPCM capsule not only within a single capsule but on the system scale as well. Therefore, the applied numerical methods can be used for further design and optimization of EPCM‐based latent heat TES systems.