Heat Storage Cycle Research Articles

High-density and anti-clogging three-phase absorption heat storage with crystallization management

Three-phase sorption heat storage can significantly enhance the energy storage density (ESD) through the crystallization of salt-water working pair. However, the crystals will cause the clogging of solution circulation, making it difficult to be realized in absorption heat storage with liquid absorbent. In this work, the crystal management strategy is proposed for three-phase absorption heat storage. By controlling the crystallization ratio, energy storage enhancement and clogging prevention can be achieved simultaneously. Both theoretical and experimental analyses were carried out. A detailed thermodynamic model of the three-phase absorption heat storage cycle was established, by considering the change of crystallization ratio. A prototype of LiBr-water three-phase absorption heat storage with crystallization management which includes crystal filtering, high-level solution intake, crystal fusion by electric heating rods, and water flushing, was designed and fabricated. The anti-clogging design ensures the circulation of solution, efficient vapor absorption and crystal dissolution in discharging process, thus achieving high energy storage density and stable heat output simultaneously. The three-phase absorption heat storage prototype demonstrated high ESD of 220 kWh/m3 and 178 kWh/m3 with crystallization ratio of 0.41 and 0.26 under the space heating and hot water supplying conditions, respectively. Comparing with the absorption heat storage prototype without crystallization, this represents ESD enhancement of 102% ∼ 210%, which confirms the feasibility and superiority of the proposed crystal management strategies.

Analysis on the effect of novel topological optimization fin structures considering eccentricity on the heat storage and release characteristics of shell and tube phase change heat accumulator

Shell and tube phase change accumulator (STPCA), as a common type of heat accumulator, can effectively solve the mismatching of time and space in solar thermal power generation by using phase change storage technology. However, the low thermal conductivity of phase change materials (PCMs) reduces its heat storage and release rate. To achieve a rapid latent heat energy storage and release, it needs to carefully modify the structure of STPCA. In the existing literature, insufficient attention has been given to simultaneously addressing the heat storage and release processes, while there is a scarcity of topological optimization methods employed in fin design. On one hand, it is difficult to find the optimal structure. On the other hand, the optimized structure is suitable for melting process but may not be suitable for solidification process. In this contribution, we initially integrated topological optimization and eccentricity to derive fin structures suitable for respective melting and solidification processes. Then, we compared and analyzed the effects of eccentricity and objective function on melting and solidification processes. Finally, we summarized the topology optimization process, objective function and eccentricity suitable for fast heat storage and release. The findings indicated that as the eccentricity increases, the rate of heat storage and release initially rises before subsequently declining. In this work, it is found that an eccentricity of 5 mm is the best. From the whole heat storage and release cycle, when the eccentricity is 5 mm, the objective function is the minimum temperature difference and the topological optimization fin structure calculated during solidification process shows the best heat storage and release performance. Compared with the topology optimization structure without eccentricity, the heat storage speed is increased by 36.43 %, and the heat release speed is increased by 15.53 %. The design law of the STPCA based on combined with the eccentricity influence and topology optimization method is summarized to help improve its heat storage and release performance.

Experimental investigation of two-stage NH3–H2O resorption heat storage system with solution concentration difference

Widespread application of solar energy is severely restricted to its instability in time and space. Heat storage system is considered to be one of the most effective pathways to achieve long-term heat supply. Among all the heat storage technologies, solution concentration difference storage technologies stand out for low heat loss and high energy density. By substituting condenser and evaporator in conventional absorption cycle with a high-pressure absorber and low-pressure generator, a resorption cycle could be established. Compared with absorption heat storage cycle, working pressure of resorption heat cycle is lower, making it possible to utilize low-pressure heat source. Two-stage heat source cycle is further proposed to lower working pressure and upgrading supply water temperature. Resorption energy storage cycle with solution concentration difference is established and studied. A prototype based on two-stage ammonia-water resorption heat storage cycle was set up and tested. The result shows that the constraint relation between ambient temperature and heat source temperature of the proposed system. In single-stage mode, the lowest working ambient temperature is 5 °C when heat source temperature is 90 °C. The lowest working ambient temperature could be declined to 0 °C when heat source temperature rises to 120 °C. In two-stage mode, the lowest working ambient temperature is 0 °C when heat source temperature is only 110 °C, which proves the adaptability of two-stage cycle. The highest ESCOP appears in the 15 °C–120 °C single-stage mode, which is 0.742. The highest COP is 1.324 under the same condition. The highest energy density occurs in two-stage mode, which is 467.07 kJ/kg when ambient and heat source is set as 15 °C, 120 °C. The advantage that two-stage mode could enlarge solution concentration difference is verified.

Thermochemical heat storage performance of Fe-doped MgO/Mg(OH)2: Experimental and DFT investigation

MgO/Mg(OH)2 thermochemical heat storage system can realize large-scale energy storage by repetitive hydration/dehydration reactions to enhance the stability of solar energy utilization. However, slow interconversion and incomplete reactions caused by agglomeration restrict the cyclic heat storage capability of MgO/Mg(OH)2. In this work, a low-cost efficient Fe-doped MgO was prepared by a simple wet-mixing method and its energy released performance and kinetics in MgO/Mg(OH)2 heat storage progress were examined in a twin fixed-bed reactor and a simultaneous thermal analyzer. Additionally, density functional theory calculations were used to examine the impact of Fe on the mechanisms of MgO/Mg(OH)2 heat storage process. The results shows that when the molar ratio of MgO to Fe is 95:5, the energy released density of Fe-doped MgO is about 400 % higher than that of MgO after 10 heat storage cycles. In preparation process, the existence of Fe leads to the generation of MgFe2O4, which forms layered microstructure with the high specific surface area and pore volume and mitigates agglomeration behavior of MgO. It improves the cyclic stability of MgO and reduces the dehydration temperature of Mg(OH)2, and simultaneously the activation energy of the dehydration stage is reduced by 33.2 %. Fe enhances the interaction of H2O with the MgO surface and promotes the dissociation of H2O on Mg(OH)2 surface. Combined with economic analysis, Fe-doped MgO is a suitable material for MgO/Mg(OH)2 heat storage cycles.

Thermochemical heat storage performance and structural stability of SiO2-coated CaO particles under fluidization in CaO/Ca(OH)2 cycles

The decline in CaO/Ca(OH)2 heat storage performance of CaO-based material with the number of cycles due to its fast expansion and fragmentation is an problem in the fluidized bed reactor. In this paper, a novel SiO2-coated CaO particle was manufactured from limestone and silica sol via wet-mixing method. Exothermic performance (such as exothermic temperature, effective hydration conversion and volumetric energy density) and structural stability of SiO2-coated CaO particles in a fluidized bed reactor were studied. The effects of SiO2 addition and calcination temperature on the exothermic performance and structural stability were analyzed, respectively. The results show that the mass ratio of limestone to silica sol of 1:1 and calcination temperature of 850 °C are recommended for the preparation of SiO2-coated CaO. The SiO2 layer is observed on the surface of the CaO. SiO2-coated CaO particles exhibit superior structural stability than uncoated CaO particles. The SiO2 coating reduces the increase of average particle size during 10 cycles from 33 % to 11 %. After 10 heat storage cycles, SiO2-coated CaO particles achieve a reduction of 45.4 % in expansion rate and 48.5 % in attrition rate compared with uncoated CaO particles, respectively. The volumetric energy density of SiO2-coated CaO particles after 10 cycles is 33.2 % higher than that of uncoated CaO particles. The highest exothermic temperature of SiO2-coated CaO particles after 10 cycles reaches 455.4 °C (steam partial pressure @ 60 kPa). The SiO2-coated CaO seems a promising candidate for the CaO/Ca(OH)2 thermochemical heat storage in the fluidized bed rector.

The thermophysical properties of a promising composite adsorbent based on multi-wall carbon nanotubes for heat storage

AbstractThe use of energy from alternative energy sources as well as the use of waste heat are key elements of an efficient energetics. Adsorption heat storage is a technology that allows solving such problems. For the successful operation of an adsorption heat accumulator, it is necessary to analyze the thermophysical characteristics of the system under the conditions of the operating cycle: heat transfer coefficient adsorbent-metal (α2), overall (U) and global (UA) heat transfer coefficients of heat exchanger. Multi-walled carbon nanotube (MWCNT) composites are very promising for adsorption-based renewable energy storage and conversion technologies. In this work at the stage of heat release, α2 was measured by the large pressure jump (LPJ) method, at the stage of heat storage by large temperature jump method (LTJ), which made it possible to obtain thermophysical characteristics that corresponded to the implementation of the real working cycle as much as possible. The heat transfer coefficients for a pair of adsorbent LiCl/MWCNT—methanol are measured for the first time under the conditions of a daily heat storage cycle both at the sorption stage (α2 = 190 W/m2K) and at the desorption stage (α2 = 170 W/m2K).

Calcium-looping thermochemical energy storage and mechanical performance of bio-templated CaO-based pellets under steam-containing environments

The calcium-looping thermochemical heat storage is recognized as a promising technology due to its affordable raw material expense, eco-friendliness, and superior heat storage and release capacity. To investigate the impact of inert support, pore-forming template, and reaction atmosphere on the cyclic thermochemical heat storage capacity and mechanical properties of calcium-based sorbent, spherical CaO-based pellets were prepared using cement as an inert support and microcrystalline cellulose, starch, and sesbania gum as pore-forming templates. The test results demonstrated that the optimal composition ratio for calcium-based particles was 5 wt% cement and 10 wt% pore-forming template. Calcium-based particles containing 5 wt% cement and 10 wt% cellulose demonstrated the highest thermal storage capacity. The steam-containing atmosphere reduced the heat storage ability of the calcium-based particles, but it greatly improved their mechanical characteristics. After undergoing 50 cycles with 10 vol% steam injection during calcination, the calcium-based pellets exhibited a mere 6.09 % reduction in E¯g,N compared to the heat storage cycle without steam addition. In contrast, the average crushing strength experienced a remarkable increase of 42.65 %, while the attrition rate decreased by 30.18 %.

Agglomeration inhibition mechanism of SiO2 in the Ca(OH)2/CaO thermochemical heat storage process: A reactive molecular dynamics study

As a promising thermochemical heat storage material, the Ca(OH)2/CaO can be agglomerated after repeated heat storage cycles, which will affect its performance severely. Experimental evidence indicated that the dopant of SiO2 particles alleviated the agglomeration phenomenon of Ca(OH)2/CaO. However, the mechanisms have not been clarified in theory, including the agglomeration of Ca(OH)2/CaO and the agglomeration inhibition of SiO2. Investigating these mechanisms is important for the broad application of Ca(OH)2/CaO thermochemical heat storage technology. In this paper, reactive molecular dynamics is employed to simulate and quantify the agglomeration of Ca(OH)2 and the inhibition by SiO2 during the heat storage process. Then, the agglomeration phenomena under the two processes are quantitatively described. The mechanisms are analyzed by using the parameters of kinetics and thermodynamics. From the phenomenological analysis, smaller size changes, larger mass center distances, and smaller atomic displacements indicate that SiO2 doping reduces the tendency of nanoparticles to agglomerate into a larger cluster. From the kinetic perspective, the diffusion of pure Ca(OH)2 clusters conforms to viscous flow, while the diffusion of the SiO2-doped clusters is close to surface diffusion. The dopant of SiO2 increases the activation energy of the diffusion process, which would increase the atomic mobility resistance and thus inhibit the agglomeration. From the thermodynamic perspective, cluster agglomeration is mainly caused by the work done by van der Waals forces, which leads to a decrease in potential energy, especially surface potential energy. By doping SiO2, the interatomic van der Waals forces are increased, which lowers the stable potential energy surface of the clusters, thereby obtaining a more stable structure to inhibit agglomeration.

Heat charging and discharging of coupled MgH2–LaNi5 based thermal storage: Cycling stability and hydrogen exchange reactions

Heat charging and discharging performances and cycling stability of the coupled MgH2–LaNi5 thermal storage system are investigated. Heat storage reaction is studied by tracking temperatures and pressures of hydride beds as well as hydrogen mass flow rates exchanging between MgH2 and LaNi5. Upon 20 heat storage cycles, MgH2–LaNi5 pair reveals remarkably cycling stability with the energy densities during heat charging and discharging of 797 ± 37.5 and 680 ± 28 kJ/kg, respectively. The hydrogen content exchange between MgH2 and LaNi5 during heat storage cycles is up to 57 % of theoretical hydrogen capacity. The possibilities to enhance the hydrogen contents participating in the heat storage reaction are discussed. The heat charging and discharging performances at different positions in the hydride beds of MgH2–LaNi5 pair are characterized. Not only thermodynamic compatibility of MgH2 and LaNi5 but also kinetics as well as hydrogen and heat transfer in MgH2 beds considerably influence heat storage performance.

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 %.

A simplified method for exergy assessment of thermal energy storage tanks: Comparative performance of tanks containing a phase-change material and water

The integration of thermal energy storage (TES) units into thermal systems can be strategic to increase the renewable energy contribution and overall system performance as a result of the greater operational flexibility provided. On the other hand, the integration of a TES unit also involves an intermediary step between the heat source and sink that adds some irreversibility to the system operation for a number of reasons, such as the increased heat losses to surroundings and the pressure drop, the influence of inner heat exchangers (thus, involving a finite temperature difference), or associated fluid mixing. To properly model these complex phenomena, designers should incorporate a Second-Law approach in their designs to assess the exergy losses (degraded useful work) that a TES unit integration entails. This work assesses the entropy generated by four different TES units: three different water tanks (most typical configurations) and an experimentally validated TES tank containing a phase-change material (PCM), when they undergo a complete heat storage and recovery cycle, using a simplified and computationally efficient method in the TRNSYS simulation program to quantify the entropies generated. The TRNSYS simulation results revealed that the greater temperature difference required between the fluid and the PCM, due to its low thermal conductivity, was the main reason for the entropy generation of the PCM tank, while heat losses to the surroundings represented no less than one-half of the total entropy generated by all water tank configurations.

Thermodynamic and techno-economic analysis of a direct thermal oil vaporization solar power system

A unique direct thermal oil vaporization solar power system employing cascade organic-steam Rankine cycle is proposed. The oil is a mixture of biphenyl and diphenyl oxide, and it is used for heat transfer, storage and power cycle fluid in the novel system. Stable electricity output and prolonged storage capacity can be facilitated. In the rated mode, the oil is vaporized at 390 °C in the collectors and drives a top turbine. The exhaust heat is used for preheating and evaporating water of the bottom cycle. Meanwhile, the hot oil in a high-temperature tank (HTT) superheats and reheats the generated steam. When the irradiation is insufficient, the heat released by the oil from the HTT to a low-temperature tank drives the bottom cycle. Fundamentals, thermodynamic performance and techno-economic feasibility are elaborated. The results indicate that, compared with the mainstream dual-tank solar power systems, the proposed system has a higher thermal efficiency with a lower water evaporation temperature (42.90% at 260 °C vs. 38.06% at 310 °C) and a larger temperature drop between the two tanks (121 °C vs. 100 °C). The equivalent payback time with respect to the top oil cycle is less than 3 years.

The Heat Transfer in Plate Fin Heat Exchanger for Adsorption Energy Storage: Theoretical Estimation and Experimental Verification of the Methodology for Heat Accumulation Process

Adsorption energy storage is a promising resource-saving technology that allows the rational use of alternative heat sources. One of the most important parts of the adsorption heat accumulator is the adsorber heat exchanger. The parameters of heat transfer in this unit determine how fast heat from an alternative energy source, such as the Sun, will be stored. For the design of adsorption heat accumulators, plate fin heat exchangers are mainly used. In this paper, the procedure for the estimation of the global heat transfer coefficient for the adsorber heat exchanger depending on its geometry is considered. The heat transfer coefficient for a LiCl/SiO2 sorbent flat layer under conditions of heat storage stage was measured. Based on these data, the global heat transfer coefficients for a number of industrial heat exchangers were theoretically estimated and experimentally measured for the adsorption cycle of daily heat storage. It was shown that theoretically obtained values are in good agreement with the values of the global heat transfer coefficients measured experimentally. Thus, the considered technique makes it possible to determine the most promising geometry of the plate fin heat exchanger for a given adsorption heat storage cycle without complicated experiments.

Herbal myristic acid blended with expanded graphite for thermal regulation in construction materials

This study synthesized modified graphite (EG) through the ultrasonic dispersion method in brewed wine solution with myristic acid (MA) to create conduction of heat mechanism with a greater affinity for saturated fats. The resulting EG made a fatty acid hybrid phase change material (PCM) with excellent overall thermal behaviour. Fourier transform infrared spectroscopy, and X-ray diffraction showed that the synthesis involved physical adsorption rather than a chemical reaction. Differential scanning calorimetry studies showed that adding EG boosted the heat capacity of the hybrid PCM after 1000 heat storage and release cycles. Melting and freezing latent temperatures were 196.99 kJ/kg and 195.33 kJ/kg. Using thermogravimetric analysis (TGA), the thermal stability of MA/EG was evaluated. The SEM findings demonstrate effectively that EG uniformly surrounds the myristic acid's multi-pore structure and that the MA/EG is mostly silky. This revolutionary approach permits the development of hybrid phase-change composites with heat exchange abilities, high conductivity, and excellent thermal stability, which can be applied in a various energy storage technologies.

Study on melting and solidification performances improvement of phase change material using novel branch fin structure

A novel fin structure was proposed to improve the heat transfer characteristics of triple-tube latent heat storage system (TTLHSS). Ansys Fluent software is used for two-dimensional numerical calculation, and the model adopts melting/solidification model. The innovation of this paper is to develop a new type of fin that can simultaneously improve the solidification and melting process of PCM and optimize the structure of the new fin so that it can significantly shorten the time required to complete a heat storage and release cycle. Initially, the melting process of the case without fins and the case with new fins were compared. It was observed that compared with the case without fins, the melting and solidification time was shortened by 67.7 % and 74.8 %, respectively. Then the effects of the thickness, the length ratio, and the angle of the new fins on the melting and solidification process of PCM were studied. The liquid fraction contour of PCM in different cases and the liquid fraction curve of PCM with time were analyzed. The results show that the addition of new fins can significantly improve the heat storage and release rate of PCM in TTLHSS. Compared with rectangular fins, melting time and solidification time are reduced by 32.7 % and 52.9 % respectively. The new fins distribute the fin volume in the central area of the PCM which is difficult to melt, which improves the melting and solidification speed of the PCM and makes the overall rate more uniform. Finally, the geometric parameters of the fins are optimized by the response surface method (RSM), and the fin configuration with the cross fin thickness of 0.8 mm, the fin length ratio of 1, and the fin angle of 63.1° is optimal for shortening the total time. At this time, the time required to complete a heat storage and release cycle is reduced by 84.5 % compared with the case without adding fins. The corresponding regression equation is also obtained, which provides a basis for the design of fins.

Comparison of various heat recovery options for compressed air energy storage system integrated with cascaded heat storage and organic Rankine cycle

Comparison of various heat recovery options for compressed air energy storage system integrated with cascaded heat storage and organic Rankine cycle

Thermal management of catalytic converter with heat pipe embedded in thermal energy storage to reduce cold start emissions

ABSTRACT The Thermal Energy Storage (TES) System aids in improving the cold start efficiency of the catalytic converter (CC). To further improve the TES and CC performance, loop heat pipes embedded into the PCM, TES unit are presented. For evaluation, three cases are considered: Case 1; CC without TES, Case 2; CC with TES, Case 3; CC with a heat pipe embedded in PCM TES. Mg70Zn24.9Al5.1 is used as PCM and paraffin oil as the working fluid for the heat pipe. Three 30 minute transient cycles with idle events in between were run, with the engine soaking for 30 minutes at ambient conditions with varied loads (0 to 100%) at 2000 rpm. Heat storage and release cycles were run for each load condition. Average warm-up HC, NOx and CO conversion efficiency improvement of 45–85% with Case 3, 35–62% with Case 2 compared to Case 1 were observed. Heat storage time was observed to be lower by ~ 35% for Case 3 while the heat retention time was observed to be better for Case 2 by ~44%. System efficiency and effectiveness were found to be better up to 14% and ~0.2 with Case 3 compared to Case 2. Overall Case 3 showed better performance with some penalty on the heat retention time compared Case 2.

Thermochemical heat storage performance of CaO particles under fluidization in coupled CaO/Ca(OH)2 cycles and CaO/CaCO3 cycles

The sintering of CaO in CaO/CaCO3 heat storage cycles and the agglomeration of CaO in CaO/Ca(OH)2 heat storage cycles are the main reasons for the decay in heat storage performance of CaO-based materials, respectively. In this work, a novel CaO/Ca(OH)2/CaCO3 coupling process using limestone under fluidization was proposed to realize the sequential CaO/Ca(OH)2 heat storage and CaO/CaCO3 heat storage. The exothermic performance of CaO particles under fluidization in the CaO/Ca(OH)2/CaCO3 coupling heat storage process were investigated. Two coupling modes were compared according to the different feeding methods of fresh CaO particles. The maximum exothermic temperature of CaO particles in the optimal coupling mode reaches 456.9 °C in the first CaO/Ca(OH)2 cycle and 783.8 °C in the first CaO/CaCO3 cycle, respectively. The interaction mechanism between CaO/CaCO3 heat storage cycles and CaO/Ca(OH)2 heat storage cycles was determined. The volume shrinkage caused by the sintering of CaO in CaO/CaCO3 cycles improves the volumetric energy density of CaO particles in CaO/Ca(OH)2 cycles. After introducing 10 CaO/CaCO3 cycles in the first coupling step, the energy density of CaO particles in CaO/Ca(OH)2 cycles is improved by 190 %. The CaO/Ca(OH)2 cycles reactivate carbonation activity of CaO particles in CaO/CaCO3 cycles by increasing porosity of CaO. Therefore, after introducing 10 CaO/Ca(OH)2 cycles in the first coupling step, the carbonation conversion of CaO particles increases by 64.7 %. This work provides a novel and promising heat storage process by integrating efficient CaO/Ca(OH)2 and CaO/CaCO3 cycles under the fluidization.

Influence of minerals with different porous structures on thermochemical heat storage performance of CaCl2-based composite sorbents

Thermochemical heat storage has been successfully employed as a reliable solution for enhancing the utilisation of renewable energy. In this paper, we report novel composite sorbents fabricated by impregnating CaCl2 into porous minerals with different structural properties. Sepiolite (SP), diatomite (DT), and expanded perlite (EP) were chosen as the mesoporous, macroporous, and foamed macroporous matrices, respectively. The pore structure of the matrix exerts a vital influence on the loading of salt hydrates and the performance of the composite material. EP/Ca had the highest energy storage density of 2166 J/g with a water exchange amount of 1.20 g/g, while the energy storage densities of SP/Ca and DT/Ca were 1026 J/g and 1520 J/g, respectively. The foamed macropores of EP provided more space for salt hydrate loading, whereas DT and SP only possessed mesoporous pores with limited pore volumes, thus contributing to lower salt hydrate content. Moreover, EP/Ca exhibited good structural stability during heat storage cycles because of the foamed macroporous structure. In contrast, the restrictive effect of the holes of DT on the salt solution was low, thus causing DT/Ca leakage and caking. Therefore, EP was chosen as the most suitable matrix for supporting salt hydrates. Moreover, this work presents an excellent perspective for exploring new sorption heat-storage materials with low cost, mass production, and high performance.

Experimental study of the thermal properties of a fatty acid-modified graphite composite phase change material dispersion system

In this study, modified graphite (MEG) with a strong affinity for fatty acids was synthesized via the ultrasonic dispersion method in myristic acid ethanol solution and used as a heat conduction additive. A fatty acid composite phase change material (PCM) with excellent comprehensive thermal performance was prepared with the resultant MEG. Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction showed that the synthesis of MEG and composite PCM was due to the physical adsorption and no chemical reaction was involved. The results of thermal conductivity and differential scanning calorimetry measurements showed that the thermal conductivity of the composite PCM increased by 139.3 % after adding 2 wt% MEG. Interestingly, the latent heat of the synthesized composite was between 182.6 and 187.1 J/g after 200 heat storage and release cycles, which is comparable to that of the pure fatty acid eutectic. Thermal cycling, thermogravimetric analysis, and the thermal conductivity changes of the upper and lower layers of the composite PCM demonstrate that the composite has good dispersion stability and thermal cycling stability. Moreover, these results may provide feasible strategies for successfully synthesizing new high-performance composite PCMs and further improving energy storage efficiency.