Heat Storage Medium Research Articles

Bubbling triggered crystallization of xylitol phase change material for controllable heat retrieval: The subcooling effect

Towards long-term seasonal latent heat storage, the PCMs with strong supercooling are recommended as the heat storage medium. Nevertheless, the suitable techniques activating latent heat release is also of significance in the period of heat supply. The present work investigated the N2 bubbling triggered crystallization of supercooled xylitol. Special attention was paid to the subcooling effect. The N2 bubbling was identified to be a potential technique to trigger crystallization of xylitol at moderate degrees of subcooling. It was found that efficient crystallization issues were obtained with degrees of subcooling from 40 °C to 60 °C, while uncrystallization was obtained with both lower and higher subcooling. The recorded temperature history curves show that subcooling effect has strong influence on the crystallization behavior. The crystallization points tend to decline from 51.9 °C to 42.3 °C with degree of subcooling rising from 40 °C to 50 °C. The crystallization durations extend with subcooling effect enhancing. Fortunately, bubbling technique has slight influence on the properties of formed xylitol crystals. Moreover, the subcooling significantly influences the transportation behavior of bubbles. Particularly, The specific growth rates of bubbles are determined to be as low as 0.005 mm/min with the lowest degree of subcooling 10 °C, and continue to rise over 20 times when the subcooling reaches to 60 °C. The interfaces of bubbles as potential nucleation sites were deemed to be one of the important issues to activate heterogeneous nucleation, thus trigger crystallization. The present investigation is helpful to understand the fundamentals of bubbling effect on crystallization with broad range of subcooling.

An experimental investigation on winter heat storage in compact salinity gradient solar ponds with silicon dioxide particulates infused paraffin wax

Silicon dioxide particulate which is also called silica, owing to its cost-effective synthesis, abundant availability, and high heat transfer capabilities, present an eco-friendly solution with immense potential for diverse applications, including solar heating systems. This novel study explores the integration of silica microparticles infused in paraffin wax in a compact salinity gradient solar pond for enhanced heat storage during the winter season. Leveraging their biocompatibility, facile functionalization, and expansive surface area, silica microparticles exhibit outstanding attributes such as photoconductivity, optimal thermal expansion, corrosion resistance, and enduring durability, all of which synergistically contribute to system efficiency. During the first day, without any heat storage medium, the three distinctive zones of the compact salinity gradient solar pond exhibited temperatures of 31.2 °C in the upper convective zone, 32.8 °C neutral convective zone, and 35.7 °C in the lower convective zone respectively. Experimental investigations are conducted, employing both paraffin wax and silicon dioxide microparticles as augmenting agents to amplify heat storage capacity within the compact solar pond setup. While using paraffin wax without silica particulates the lower convective zone temperature was 4.2 % lower because of heat storage. The incorporation of trace amounts of silicon dioxide microparticles within paraffin wax establishes a novel hybrid approach. The outcomes highlight the profound impact of this hybridization on thermal characteristics, resulting in a discernible improvement in the compact salinity gradient solar pond's heat behavior. Notably, the phase change material introduces a temperature enhancement of approximately 1.5 %, and the amalgamation further elevates the temperature retained to 56 °C within the lower convective zone. An optimization analysis underscores the pivotal role of the solar pond configuration in dictating temperature changes, surpassing the influence of time considerations. This research underscores the transformative role of silicon microparticles in optimizing thermal performance within compact salinity gradient solar ponds, unlocking avenues for enhanced winter energy utilization.

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.

Application and analysis of superconducting magnetic eddy current heater used in wind thermal power generation system

AbstractIn order to cope with the grid fluctuation caused by large‐scale wind power connected to the grid, the wind thermal power generation system has been proposed and extensively studied. The wind thermal power generation system uses a wind turbine to drive a heat generation device to heat the heat storage medium, which is further exchanged to drive a turbine to generate electricity. A superconducting magnetic eddy current heater (SMH) is proposed for the characteristics of wind thermal power generation system, which uses non‐resistive, large current‐carrying superconducting coils for excitation, and has high output efficiency and power density. The working principle of magnetic eddy current heating is analysed, and the structure of SMH with no ferromagnetic material and two heating screens inside and outside is proposed according to the characteristics of SMH. An analytical model of the SMH is established, and the influence of the structure and materials of the SMH on the magnetic field distribution is analysed. Based on this, a 22‐pole SMH was designed and analysed for output power at 10–20 rpm. A three‐dimensional magnetism‐stress combined analysis model of SMH is established, and the strain and stress characteristics of SMH are simulated under the condition of maximum output power, which verifies the feasibility of the mechanical properties of existing superconducting materials for application in SMH.

The Effect of Long-Term Corrosion on a Molten Salt Pump in Contact With a Ternary Mixture in a CSP Plant

Solar thermal plants commonly plan their operation for a period of approximately 25 years. Therefore, it is key to accurately predict and evaluate the damage and faults occurring for that long period. Among all components, we find that choosing the heat storage medium (molten salt) and the material (steel) used in the equipment and pipping plays a crucial role in the plant’s design. We tested the long-term corrosion effect of the molten salt pump in a low-melting-point ternary mixture composed of 30wt.%LiNO3+57wt.%KNO3+13wt.%NaNO3 over a period of more than 5 years, corresponding to 30,000 hours of operation in a pilot experimental facility built at the University of Antofagasta (Chile).

Erosion wear analysis of heat exchange surfaces in a falling particle-based concentrating solar power system

Next generation concentrating solar power (CSP) plants that use solid particles as the heat transfer and storage medium provide opportunities for higher temperature operation, higher efficiency, and lower levelized cost. However, falling particles over component material surfaces can cause significant erosion, severely limiting the performance and operational service life of the components. An understanding of the particle erosion wear of heat transfer surfaces is imperative for designing components and operating conditions to minimize wear. Considering a shell-and-tube heat exchanger configuration, this study presents a computational analysis coupling falling particle flow around heat exchanger tubes and particle-scale erosion of the tube surfaces governed by the Finnie model. Several tube arrangements, particle flow and geometric parameters, and tube material parameters are systematically investigated for their effects on the erosion rate spatially and with time. Parameters that influence the erosion depth, the cumulative mass loss rate and the maximum erosion rate are elucidated. The results of the study may be used to help identify locations that experience the most erosion and devise ways for targeted erosion mitigation.

Design and experimental analysis on a single tank energy storage system integrated with a cooking unit using funnel system

The paper presents a new innovation in small scale thermal energy storage system suitable for cooking application. A single tank thermal energy storage system integrated with a cooking unit has been developed and the performance analysed. The system consists of a heat storage tank, a heating chamber referred to as a funnel, and the cooking unit. The heating chamber is a pipe made of cast iron, and on top of the pipe is a cylindrical container made of Aluminium. A heating element of 1.5 kW 220 V was inserted inside the funnel and was used for heating the oil. The top of the funnel allows a cooking pot to be inserted inside it. The funnel can be raised or lowered using screws connected to the top of the tank; this regulates the temperature at which oil begins to overflow into the heat storage tank. The heat storage tank is made of stainless-steel, and contains sunflower oil as a heat storage medium. During charging, a small volume of oil about 2 L was heated inside the funnel, and the temperature rose rapidly to about 150 °C in less than 15 min. The system allows for cooking to begin immediately after charging has been started. As heating continues, the hot oil overflows into the storage tank, and cold oil at the bottom of the tank flows into the funnel where it is heated. The storage tank had 18 L of sunflower oil. During discharge, the direction of oil flow reverses; hot oil flows from the top of the tank into the funnel. The hot and the cold oil do not mix during discharge, and therefore, the heat front is preserved. Cooking tests were demonstrated during charging and discharging cycles. About 453.6 kJ of energy was used in boiling 1.5 L of water in 10 min, and 1.04 MJ was used in boiling 1 kg of dry beans in about 2 h.

Experimental study of thermal energy storage system for solid particles/ heat transfer oil in shell and tube heat exchangers with H-shaped fins

The solid-state sensible heat storage method is cost-effective, technically simple, and works well across wide temperatures. Using return fines (RFs) as the heat storage medium (HSM) can ease problems like RFs in excess and high energy consumption in the sintering process. This article first characterizes the thermal properties of RFs. Results show a specific heat capacity of 0.67–0.97 kJ/(kg·°C) within 20–380 °C, with stable thermal properties from 100 to 1000 °C. Then, the heat transfer performance of RFs and heat transfer oil (HTO) in a shell and tube heat exchanger is experimentally investigated. H-shaped fins are added to enhance the heat transfer. Stacking solid particles on the shell side can avoid direct contact between the HSM and HTO, the tiny size limitations of HSM particles, and cracking problems caused by thermal expansion. The thermal energy storage (TES) unit operates within 170–270 °C. Effects of different flow rates (30, 20, 10 L/min) and charging/discharging temperatures (300/160, 290/150, 280/140 °C) on system performance are explored. Increasing the HTO flow rate and charging temperature and lowering the discharging temperature can reduce charging/discharging time and enhance average power. Cycle efficiencies for flow rates of 30, 20, and 10 L/min are 86.9%, 85.2%, and 79.5% respectively. The 30 L/min working condition shows the best performance. Remarkably, system performance improvements are relatively limited compared to the 20 L/min setting. Regarding charging/discharging temperatures of 300/160, 290/150, and 280/140 °C, cycle efficiencies stand at 73.3%, 85.2%, and 70.6%, respectively, with the 290/150 °C setting displaying the most favorable characteristics, including the shortest total charge and discharge time of 59.3 min and the highest cycle efficiency. Efforts to enhance the system's insulation and maintain a substantial temperature differential between HTO and HSM are pivotal in accelerating the charge/discharge process and minimizing heat loss.

Development of photothermal-heat storage concrete incorporating super absorbent polymer

Solar energy absorbed and stored in building materials can reduce heating/cooling loads and energy consumption in buildings. In this study, photothermal-heat storage concrete (PHSC) was developed by using carbon black as the photothermal material and pre-soaked super absorbent polymer (SAP) as the heat storage medium. The resulting photothermal conversion performance and heat storage performance of PHSC were investigated. The results showed that PHSC exhibit excellent photothermal conversion performance, specific heat capacity and heat storage capacity. The heat stored in the PHSC was 1.48 times higher than control concrete when both were exposed to sunlight during the day. PHSC converts and stores the absorbed sunlight during the day and releases the stored heat at night when the temperature drops. PHSC is a ‘green’, low-carbon and eco-friendly building material, its application in building structures can effectively reduce energy consumption by lowering heating and cooling loads.

Efficient solar-thermal conversion and thermal energy storage towards personal thermal management and thermoelectric power generation enabled by massive screen printing of carbon nanotube dopped energy storage gels

Converting clean solar energy into thermal and electrical energy can effectively alleviate energy shortages and environmental crises. However, the intermittency and low utilization of solar energy are currently urgent issues that need to be addressed. The combination of solar-thermal conversion, heat energy storage, and heat energy utilization has been exploited as an emerging methodology of solar energy utilization. Herein, high-performance solar-harvesting energy storage gels composed of light-absorbing carbon nanotubes, a heat storage medium of an octadecanoic and flexible matrix of SEBS are fabricated by massive screen printing on textiles. The solar absorbance and solar-thermal conversion efficiency of the energy storage gel reach high levels of 96.4 % and 94.8 %, respectively. The printable textiles demonstrate an ultra-high latent heat of 71.12 Jg−1 to enable the large heat storage capacity. The high self-healing efficiency of 92 % ensures its reuse after damage. Due to its efficient photothermal conversion ability and high heat storage capacity, the stored heat can be used for effective thermal compression, providing heat for the human body, and also for thermoelectric conversion. The carbon nanotube dopped energy storage gels provide a state-of-the-art solar-thermal conversion device for the next generation of personal thermal management and thermoelectric power generation.

Melting-solidification cycle of finned heat storage tank: Optimization of fin structure by response surface method

The impact of the enhanced heat transfer performance of longitudinal fins on the entire process of melting and solidification in a phase change heat storage unit is investigated through experiments and numerical simulations in this paper. The position and structure of the longitudinal fins are optimized by using the response surface method while ensuring that the total volume of the heat storage medium remains unchanged. Studies have identified that some challenging zones in melting and solidification significantly impact the heat transfer of the entire heat storage cycle. Specifically, the challenging zone in melting primarily exists in the lower part of the unit during the charing process, while the challenging zone in solidification is mainly distributed around the unit during the discharging process. Through optimization, the optimized structure (fin spacing is 22.5 mm, fin width is 6.05 mm) can reduce the charging and discharging time by 16.94 % and 45.90 %, respectively. Additionally, the round trip time is significantly reduced by 39.19 %, and the mean heat absorption rate during the melting process is enhanced by 20.28 %. Moreover, the mean heat release rate during solidification is enhanced by 80.23 %.

Hybrid sensible-latent heat thermal energy storage using natural stones to enhance heat transfer: Energy, exergy, and economic analysis

Latent heat thermal energy storage addresses the mismatch between energy supply and demand; however, phase change materials (PCM) commonly have the issue of low thermal conductivity. Natural stones, as low-cost and environmentally friendly sensible heat storage media, are used to enhance the heat transfer of the PCM in the current study. Different stone types, sizes, and filling heights are tested, and a comprehensive energy, exergy, and economic analysis is performed. Results indicate that granite has the best heat transfer enhancement performance owing to superior thermal diffusivity, which accelerates the melting by 108 % (initial temperature: 23 °C; heating temperature: 75 °C). Basalt with high specific heat contributes to the large energy capacity. The total exergy is hardly influenced by the stone size ranging from 15 mm to 40 mm, where the minimum is only 5.1 % lower than the maximum. The exergy storage rate benefits from stones surrounding the inner tube and is increased by 246 % with a filling height of 112.0 mm. The 40 mm-sized stones are the most cost-effective in the current testing conditions, and a 560 % increase in the economy is achieved. This study demonstrates a high-performance, low-cost, environmentally friendly energy storage configuration and provides comprehensive information for potential energy recovery applications.

Performance assessment of compressed air energy storage systems with and without phase change materials

In this study, two integrated hybrid solar energy-based systems with thermal energy storage options for power production are proposed, thermodynamically analyzed and comparatively evaluated. The first system uses an underground cavern to store compressed air energy. When electricity production is high during the day, a compressor set pressurizes the air and directs it to the storage unit. A heat transfer model is developed to determine temperature variations and heat losses through the cavern walls. During the insufficient solar radiation period, the compressed air inside the cavern is discharged to meet the energy needs. The second energy storage system employs a cascade latent heat storage approach to reduce heat dissipation within the cavern. The temperature of the compressed hot air gradually decreases as it passes through three-stage phase change material (PCM) units. The cascaded PCMs help reduce the temperature differences between the storage media and minimize the exergy destruction rates. Similar to the first energy storage option, the pressurized air is stored in an underground cavern. The compressed air is then discharged and passes through the latent heat storage medium in the energy recovery mode, eventually reaching the turbine inlet temperature. Finally, the high-pressure and high-temperature air drives the gas turbine and hence generator to generate electricity. The thermodynamic quantities, including energy and exergy efficiencies and exergy destruction rates, are determined for all system elements and comparatively assessed. Furthermore, a comprehensive evaluation of the thermodynamic performance criteria of these energy storage options is carried out.

A novel solar desalination system equipped with thermoelectric generator, reflectors and low-cost sensible energy-storage for co-production of power and drinking water

The present study aimed to improve the efficiency of the solar desalination unit by employing mirrors, waste material as a heat storage material, and thermoelectric generator by waste heat from the absorber sheet. Two mirrors were used to reflect the solar radiation into the absorber sheet and enhance the water temperature. The iron scraps painted in black color as a heat storage media were immersed to the basin of the solar still to raise the evaporation rate. Two thermoelectric generators (TEG) were attached under the basin to commute the loss of thermal energy of the absorber sheet to electrical power. The experiments were carried out for conventional solar desalination (CSS), solar still using TEG (SS-TEG), solar still using TEG and iron scraps (SS-TEG-WI), and solar still using TEG, iron scraps and mirrors (SS-TEG-WI-M). The results showed that the freshwater produced by CSS, SS-TEG, SS-TEG-WI, and SS-TEG-WI-M was 0.64 L/m2, 0.63 L/m2, 0.652 L/m2 and 0.796 L/m2, respectively. Also, the CO2 removal of the SS-TEG-WI-M improved by 24.5 %. Moreover, the daily power output of SS-TEG, SS-TEG-WI, and SS-TEG-WI-M was 2.13 W, 2.17 W, and 2.5 W, respectively. In addition, the SS-TEG configuration had the highest cost per liter (CPL) of 0.075 $/L.

Carbon nanoparticle facilitated functional pyramid solar distillation unit for wastewater treatment

This paper proposes an efficient treatment of reverse osmosis reject (RO reject) and kitchen wastewater (KWW) in a locally developed single-stage functional pyramid solar distillation unit (FPSDU). The working mechanism of the designed and developed solar distillation unit, its specifications, treated water characteristics, novelty over conventional units, and economic analysis have been discussed in detail. The concept of coating glass beads is attempted for its functional application in solar still for generating photothermal heat. Carbon nanomaterials (CNP) coated glass beads were used as a heat storage medium. FPSDU produced approximately 6003 mL/m2day of treated water for KWW and 5868 mL/m2day for RO reject wastewater vis-a-vis output of 3000 mL/m2day for conventional solar distillation unit with an input of 7000 mL/m2day of wastewater in each case. This demonstrates that the FPSDU shows an improved performance than conventional distillation units, recovering about 85% of the treated water from KWW and RO reject wastewater as compared to 43% for conventional distillation units. The basin surface showed no signs of corrosion and the coating remained stable even after multiple cycles. The treated water met the criteria as per Indian standards, free with microbial contamination and can be used for different non-potable uses. Findings of the current research supports the improved effectiveness of FPSDU for RO reject and KWW treatment with immobilized carbon nanoparticles.

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

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

Nanoadditives induced enhancement of thermal energy storage properties of molten salt: Insights from experiments and molecular dynamics simulations

Current concentrated solar power (CSP) plants use molten salts as heat storage and heat transfer medium. The thermal property enhancement of molten salts can increase the efficiency and lower the investment cost of CSP plants. In this study, the experiments and molecular dynamics (MD) simulations were employed to investigate the effect of doping Al2O3, SiO2 nanoparticles or multi-walled carbon nanotubes (MWCNTs) on the specific heat capacity (SHC) of ternary carbonate salt. The results show that the SHC of molten salt can be enhanced by adding nanoadditives. The addition of MWCNTs has the largest SHC enhancement in both solid and liquid states. Based on MD simulations, the radial distribution functions, number density distribution and vibrational density of states were further analyzed to reveal the effect of nanoadditive, base salt and interface thermal resistance between them on SHC at different temperatures. It is found that the nanoadditive agglomeration, the ion spacing of base salt, and the thermal resistance between base salt and nanoadditive is independent on temperature and cannot result in the enhanced SHC of liquid nanocomposites. Moreover, the thickness of interfacial layer changes with temperature. The thicker interfacial layer leads to the higher SHC of liquid nanocomposites. The interfacial layer also has a decisive influence on SHC of solid nanocomposites. The scanning electron microscopy images show that the layered, needle-like, and network-like interfacial layers are observed in Al2O3, SiO2 and MWCNT nanocomposites, respectively. The present findings are helpful to understand the mechanisms governing thermal energy storage, and provide guidelines for the performance optimization of molten salt based nanocomposites.

Experimentation on enhancement of solar still performance

This work presents new results from controlled experiments using well-designed and constructed single-inclination solar stills. The aim of these experiments is to explore methods for enhancing still performance by studying the individual effects of three types of methods. Specifically, the experiments investigate the actual effects of still basin water depth, the use of a sensible heat storage medium, and the treatment of the inner glass surface with waxy substances. The main distinction in this work is the use of solar stills that can achieve thermal efficiencies in excess of 40% under favourable weather conditions without any modification. This high efficiency level allows for meaningful analysis of the impact of modifications on still performance. The results indicate that still yield, productivity, and thermal efficiency decrease significantly when the water depth in the basin exceeds 6 cm. additionally, introducing black gravel in excess of a 2% gravel to water mass ratio in the still basin does not produce a significant change in still thermal efficiency. Treatment of the still inner glass surface with two types of waxy materials resulted in large drop in still performance.

Influence of different rotational speeds of inner and outer tubes on phase change heat storage: An optimization study

The implementation of the solar phase change heat storage evaporation heat pump system with a latent heat energy storage system has shown promising potential in enhancing solar heating and facilitating the efficient utilization of solar energy. Nevertheless, the utilization of a heat storage medium phase change material with low thermal conductivity in the latent heat energy storage system has hindered its broad-scale application. This present study focuses on a triplex-tube latent heat energy storage unit with N-eicosane serving as the phase change material. A subzone rotation strategy has been developed to improve the melting properties of the unit, and a numerical model of the energy storage unit has been constructed and authenticated. The Taguchi method has been utilized to examine the effect of inner tube speed, outer tube speed, and fin/wall material on melting properties, and the interaction between control variables has been scrutinized. The research findings indicate that the optimized structure, according to the Taguchi method, significantly shortens the melting time by 26.22%, and increases the average rate of temperature response and average heat storage rate by 22.98% and 32.39%, respectively. It should be noted, however, that there is a certain decrease in the total heat absorption during the melting period. By examining the internal dynamic temperature/velocity response, this study displays that the augmentation of the rotation speed in the zone improves the overall convective intensity and heat transfer performance in the unit.

Tree-inspired and scalable high thermal conductivity ethylene–vinyl acetate copolymer/expanded graphite/paraffin wax phase change composites for efficient thermal management

Bioinspired fabrication of high thermal conductivity phase change composites has great prospects for efficient thermal management. However, the direct and partial imitations of nature are not facile to the full realization of natural systematic advantages and scalable production. Herein, inspired by the tree’s transportation system, this study adopted a bottom-up strategy to mimic the tree’s sophisticated hierarchy at both micro and bulk dimensions. The composites employed a phloem-mimic crosslinking ethylene–vinyl acetate copolymer/paraffin wax (EVA/PW) film as the intelligent heat storage and release medium, and the xylem-imitated roll-to-roll directional EVA/expanded graphite (EVA/EG) film with enhanced high thermal conductivity (51.1 W m−1 K−1 with the enhancement of 26,894 %) as fast heat conduction pathway. Above two components were assembled to develop phase change composites (PCCs) with annual-ring and multilayered structures. Both computational and experimental results revealed that the assembled tree-inspired structures significantly improve the heat conduction performances of PCCs. The tree-inspired PCCs showed significantly high thermal conductivity (7.01 W m−1 K−1 with the enhancement of 2821 %) with a low filler content (9.0 vol%). Meanwhile, obtained PCCs with high phase change enthalpy exhibited excellent temperature regulation performance. This work offers a promising route for the scalable manufacture of advanced PCCs for efficient thermal management, and a general strategy to realize the natural systematic advantages via the bottom-up strategy.