Heat Storage Applications Research Articles

Revisiting salt hydrate selection for domestic heat storage applications

Revisiting salt hydrate selection for domestic heat storage applications

Combined passive enhancement techniques improve the thermal performance of latent heat storage system: A design anomaly?

Poor heat transfer rate due to low thermal conductivity of phase change material limits the wide application of latent heat storage (LHS) systems. Thermal performance enhancement techniques can be potential methods to address this major limitation of LHS systems. In this context, the present numerical study examines the individual and cumulative impact of two passive heat transfer enhancement techniques (the orientation of the domain and position of the heat transfer fluid (HTF) tube) on the thermal performance of the latent heat storage (LHS) system consisting of high-temperature (HT) phase change medium (PCM). The individual effect of orientation decreases the charging duration of θ = 0° (horizontal configuration) by 10.5 %, 15 %, and 19.04 % than θ = 30°, θ = 60° and θ = 90° (vertical configuration), respectively. However, the discharging duration remains unchanged for all inclinations (11.5–12 h). The individual effect of eccentricity decreases the charging duration of horizontal (θ = 0⁰, ey = −5 mm,-10 mm,-20 mm) system by 6.25 %,12.8 %, and 18.75 % than concentric horizontal (θ = 0°, ex = ey = 0) system. Moreover, the combined effect of orientation and eccentricity (θ = 0⁰,ey = −5 mm,-10 mm,-20 mm) reduces charging duration by 28.75 %, 33.33 %, and 38.1 % than vertical concentric domain (θ = 90°, ex = ey = 0), respectively. However, eccentricity in vertically upward and downward directions increases the discharging duration compared to the concentric domain. Hence, the combined effect results in a design anomaly for HT-LHS system. The charging and discharging performances are observed to be predominantly sensitive to the Rayleigh number than the Reynolds number.

Enhanced radiation heat transfer performance of Alumina-Spinel composite sphere with hollow structure for rapidly ultra-high temperature thermal storage/release process

Heat storage technologies for high temperatures have recently been gaining increasing attention. For heat storage applications at high temperatures, such as industrial regenerative burner systems, the impact of radiant heat transfer on the efficiency of rapid heat storage and release cannot be ignored. Hence, the development of heat storage materials with high infrared radiation absorption is of great significance for energy saving and CO2 emission reduction. Consequently, this study innovatively proposes an advanced composite heat storage material, composited by alumina and a Fe-Co-Mn-Al spinel, with the aim of improving absorptivity. A medium-entropy approach is employed to improve IR absorptivity of alumina. Through the strategic adding of various transition metal oxides, the radiative absorptivity of the alumina material in the 600–1200 °C range increased from an initial 0.2 to an impressive 0.8, provided that doping additives remain below 10 wt%. The high-temperature heat storage material balances cost, heat recovery efficiency and thermal stability. In addition, the heat storage material is prepared as a hollow sphere to further enhance the heat storage density of rapid heat storage/release and reduce cost. Multi-scale numerical simulations are carried out to reveal the heat transfer enhancement mechanisms of modified materials and hollowing. radiative modification can significantly increase the heat storage and release capacity, especially at ultra-high temperatures above 1000 °C. Experimental evaluations using an actual regenerative burner further confirmed the heat recovery performance of this novel heat storage sphere. Comparing with conventional regenerative burner system, heating power remarkably increased by 24.6 %, and the heat storage density of packed bed improved by 16.7 %. This study promises to significantly improve the efficiency of rapid heat recovery at high temperature.

Synthesis, characterization and determination of thermal properties of shape stabilized n-pentadecane based composite phase change materials including graphitic carbon nitride/alumina fillers for latent heat storage applications

Recently, Phase Change Materials (PCMs) has attracted significant interest for thermal energy storage (TES), which is a rational and convenient energy storage method. In the present work, new composite PCMs were prepared by performing easy impregnation process in which n-pentadecane was selected as PCM. For this, emulsion templated porous polymer composites were synthesized and employed as the frameworks to obtain new composite PCMs. To improve the heat transfer characteristics, the support matrices were prepared by loading of 1 wt% thermal conduction enhancer fillers namely, graphitic carbon nitride (g-C3N4), graphitic carbon nitride/alumina (g-C3N4/Al2O3) and alumina (Al2O3). The chemical structure, thermal stability and specific surface area characteristics of the frameworks were examined by Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetry (TG) and Brunauer–Emmet–Teller (BET) surface area analyses. Furthermore, the morphology and distribution of the fillers were explored with Scanning Electron Microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Additionally, improvements in the thermal conduction properties of the composite matrices were determined through the tests performed based on the T-history method. Moreover, the examinations on the thermal properties of the obtained composite PCMs were carried out using Differential Scanning Calorimetry (DSC). It was found that the reductions in supercooling temperatures (ΔT) were observed for the synthesized composite PCMs compared to degree of supercooling of pristine n-pentadecane. According to the obtained results, the synthesized composite PCMs can be employed in the cold thermal energy storage (TES) applications considering their appropriate properties and favorable TES capacities between 79.49 kJ/kg and 121.50 kJ/kg.

Preparation of bio-based heat storage microcapsules of cellulose acetate butyrate/ polymethylmethacrylate composite by micro-suspension polymerization

ABSTRACT Because of environmental concerns, the utilization of bio-based, renewable resource materials has attracted great attention for a wide range of applications. In this research, green cellulose-based microcapsules containing capric acid (CA) as a bio-heat storage material were prepared. Cellulose acetate butyrate (CAB)/methacrylate polymer composite particles were produced by microsuspension iodine transfer polymerization to encapsulate CA. The influences of methacrylate polymer type and amount on microcapsule morphology, encapsulation efficiency (EE) and thermal properties were investigated. Using methyl methacrylate (MMA) monomer, the colloidal stable spherical microcapsules with smooth surfaces and core-shell morphology were obtained. Although high percentages of EE, ≥70%, were obtained at all CAB:MMA weight ratios, the latent heats of the encapsulated CA were lower than those of the original ones which may be due to the incomplete phase separation of the CAB/PMMA shell and CA core. The increase of CA content up to 60% provided stable spherical microcapsules with a maximum loading of 59% and 97% EE. After thermal cycling for 100 cycles, stable microcapsules still remained with stable thermal properties. The obtained bio-based microcapsules would be well applied for heat storage and temperature control applications.

Synthesis and Characterization of Doped Magnesium Hydroxide for Medium Heat Storage Application.

The amount of waste heat generated annually in the UK exceeds the total annual electricity demand. Hence, it is crucial to effectively harness all available sources of waste heat based on their varying temperatures. Through suitable technologies, a substantial portion of this waste heat has the potential to be recovered for reutilization. Thermochemical energy storage (TCES) provides the best opportunities to recover waste heat at various temperatures for long-term storage and application. The potential of TCES with magnesium hydroxide, Mg(OH)2, has been established, but it has a relatively high dehydration temperature, thus limiting its potential for medium-temperature heat storage applications, which account for a vast proportion of industrial waste heat. To this end, samples of doped Mg(OH)2 with varying proportions (5, 10, 15, and 20 wt%) of potassium nitrate (KNO3) have been developed and characterized for evaluation. The results showed that the Mg(OH)2 sample with 5 wt% KNO3 achieved the best outcome and was able to lower the dehydration temperature of the pure Mg(OH)2 from about 317 °C to 293 °C with an increase in the energy storage capacity from 1246 J/g to 1317 J/g. It also showed a monodisperse surface topology and thermal stability in the non-isothermal test conducted on the sample and therefore appears to have the potential for medium heat storage applications ranging from 293 °C to 400 °C.

Bi-salts composites to enhance the hydration kinetics and heat storage capacity

In this study, salt hydrates were deposited on a porous carbon (PC) support to address the challenges associated with maintaining heat capacity and slow hydration kinetics in thermochemical heat storage (THS) systems. Mono-salt (MgSO4) or binary salt (MgSO4-MgCl2) composites on the PC were analyzed by thermogravimetry/differential scanning calorimetry (TG/DSC). The results show that binary salt composites exhibit faster hydration kinetics and higher water adsorption capacity than monosalt composites. The addition of MgCl2 overcomes the kinetic drawbacks caused by the hydrophobic nature of the support and the presence of salt aggregates. The PC_60binary composite achieves a water uptake of 0.75 g/g, exceeding the water uptake of PC_60MgSO4 (0.48 g/g). Furthermore, the heat released by the composites follows a similar trend to water sorption. PC_60MgSO4 produces 52 % (1356 J/g) of the heat released by pure MgSO4, while PC_60binary achieves 70 % (1840 J/g) of the heat released by pure mixed salts. These results suggest that the newly developed binary salt composites are promising for long-term heat storage applications. These experimental results highlight the improved performance of binary salt composites in terms of hydration kinetics, water adsorption and heat release. This study provides valuable pointers for the development of more efficient THS systems.

Characterization of silica-PEG-CaCl2 composite sorbents in an open thermochemical heat storage reactor

Composite sorbents based on silica, polyethylene glycol (PEG) and containing calcium chloride were successfully synthetized using the sol-gel method. Their heat storage performance was investigated in a lab-scale open fixed-bed reactor. The silica/PEG matrix managed to stabilize hydrated calcium chloride when the salt content was equal to 32 wt% despite partial salt deliquescence. The presence of a crystallized phase CaCl2/PEG resulting from the complexation of the salt by the polymer may indeed prevent salt leakage, which was observed only when the salt content was increased to 42 wt%. Comparative experiments with a PEG-free control sample confirmed that the polymer enhances material stability. With a regeneration temperature of 130 °C, the best performing composite sorbent exhibited an average water sorption capacity of 0.37 gH2O g−1 of dehydrated material and an energy density of 782 kJ kg−1 over four successive sorption cycles at 30 °C and 42 % relative humidity. The dispersion and accessibility of the salt was enhanced after its first dissolution in the reactor. Compared to zeolite 13X, the sorption kinetics of the composite is much slower, resulting in a halved generated power. Still, the mass energy density of the composite is 70 % higher than that of zeolite, which makes it a promising material for heat storage applications with moderate required power outputs.

Recycling of aluminium scrap into phase change materials for high-temperature storage applications: Thermophysical properties and microstructural characterisation

Metal scrap is often generated during conventional production processes and at the end-of-life of metallic components finding use as a recycled metal source. However, the impurities introduced in the recycling process can deteriorate the mechanical properties of the final product leading to down-cycling from structural applications or requiring great effort to make the material viable again.Metallic phase change materials (mPCMs) are promising materials due to their high energy storage density and high thermal conductivity relative to common inorganic and organic thermal storage materials. Metals used for thermal applications, such as mPCMs do not have strict mechanical requirements, and could potentially be made from recycled sources unsuitable for structural significant applications. Thermal storage offers an alternative use for scrap sources, especially aluminium alloys which according to the International Energy Agency are among the metals with the highest recovery rates.AlSi cast alloys are widely used in different applications, especially the automotive industry. In this work, the eutectic composition Al-12.6 wt% Si has been proposed as thermal storage material due to the great potential and excellent storage properties in the temperature range 500–600 °C. Thermophysical properties including melting temperature, heat of fusion, heat capacity and thermal diffusivity were experimentally determined via Differential Scanning Calorimetry (DSC) and Light Flash Analysis (LFA) in order quantify the impact of impurities typically present in commercial aluminium alloys such the 2000 and 3000 series.Four different AlSi alloys with different impurity levels from scrap-equivalent compositions were investigated as candidate materials for latent heat storage applications and their potential contribution in the circular economy.

Probing Water Diffusion Inside Crystals of AlPO‐5 by PFG NMR and IRM for Heat Storage Applications

AbstractDiffusion of water in the aluminophosphates AlPO‐5 is studied using a combination of pulsed field gradient NMR and IR microimaging. The concentration profiles measured by the latter allowed to visualize the process of water sorption and propagation into the crystals of AlPO‐5. The self‐diffusion coefficients obtained by NMR were one order of magnitude higher values compared to corrected ones from the IR microimaging study. The concentration profiles allowed to visualize the process of water sorption and propagation into the crystals of AlPO‐5. The obtained results are compared with experimental and simulation data for the water/AlPO‐5 system for the literature and discussed in the context of its potential use for heat storage applications.

Evaluation of rhyolite rock as thermocline storage material for medium and high temperature applications

Nowadays, the packed bed filled with aggregates, which replaces a large part of the used fluid and prevents convective mixing in the storage liquid, has a better cost/storage time ratio. It is easily integrated with some types of renewable energy. Besides, it is cheap and more efficient without environmental impact. As a result, it was crucial to check some criteria to select the storage materials. In this regard, this paper aims to examine the properties of the rhyolite rock as a candidate for heat storage. It was collected from Oued Tensift near Marrakech, Morocco. The optimal temperature range for this rock was defined. Chemical and structural composition and thermo-physical properties of the rock are carried out by using XRF, EDX, DRX and TGA-DTA. Experimental heating and cooling tests were also performed at two different temperatures 300 °C and 600 °C to determine the effect of thermal cycling on the mineralogical structure of rhyolite rock. The found results indicate that this material can be used to store thermal energy for medium temperature (100–300 °C) as well as for high-temperature applications (below 650 °C) such as CSP plants.Rhyolite is a good candidate for heat storage as it exhibits structural stability even after undergoing thermal cycling. This stability means that the thermophysical and chemical properties required for heat storage can be maintained. When heated to 1000 °C, rhyolite undergoes minimal mass loss, which doesn’t exceed 1.5 %. This characteristic confirms its suitability for heat storage applications. Rhyolite has an almost constant bulk density (decrease around 0.18 kg/ m3) over a temperature of 600 °C, rhyolite's average capacity and thermal conductivity values are 1.92 MJ/m3. °C and 2.16 W/m.°C, respectively, when heated from ambient temperature to 400 °C. These values indicate the rock's ability to store and release heat efficiently.

Experimental and numerical investigation of a rectangular finned-tube latent heat storage unit for Carnot battery

Latent heat storage technology has a great potential in Carnot battery systems, and its thermal performance directly affects the system performance. In this paper, a rectangular phase change heat storage unit with finned-tube structure is designed and manufactured, and polyethylene wax/expanded graphite is adopted as the composite phase change material. The thermophysical properties of the polyethylene wax are characterized by experiments first, and then the heat transfer performance of the unit is investigated through varying inlet mass flow rates and inlet temperature on the test rig. Meanwhile, the detailed evolution of the phase change process is visualized and obtained by corresponding numerical simulations. Furthermore, the effects and selection principle of fin number, thickness, and material on the melting process are clarified by numerical simulations. Results shows that the influence of the inlet temperature is more significant than the mass flow rate on the melting/solidification time, however, changing the inlet temperature and mass flow rate has little effect on melting/solidifying the last 10 % of PCM. Heat conduction dominated the heat transfer process due to the high viscosity of polyethylene wax, inducing little stratification of the temperature distribution in the regions bounded by fins. The regions close to the corners and sidewalls are the primary factors delaying melting/solidification rate. Increasing fin number and thickness can effectively decrease the melting/solidification time at the expense of the heat storage capacity. Compared to selecting only high thermal conductivity fin materials, adopting fins with high thermal conductivity, low density, and low specific heat is a better approach for achieving higher heat storage capacity and shorter melting time. The present study explores candidate materials for medium-low temperature latent heat storage and potential applications of traditional finned-tube heat exchangers in medium-low temperature latent heat storage.

Solid state sensible heat storage technology for industrial applications – A review

Cost effective methods of storing heat can be an enabling technology to promote utilization of solar thermal and heat recovery systems for industrial applications. The technology can reduce the use of conventional heat sources like coal and gas by offering a competent option of producing industrial process heat. Solid state sensible thermal energy storage (TES) systems have emerged as a viable method of heat storage especially with the prospect of using natural stones as heat storage media which are cheap, locally available, and harmless to the environmental. This study reviews research work on solid state sensible heat storage systems focusing on the solid materials being used for heat storage applications. Also, the review covers numerical and experimental investigations that have been done to evaluate different design parameters and thermal performance of solid-state TES systems. In addition, the environmental impact of adopting this heat storage technology is also discussed. The study has revealed that, there are areas that still need further research, and these include, experimental characterization of thermal properties of natural solid materials with potential for heat storage purposes, investigations on improving thermal performance as well as durability of solid-state sensible TES systems.

High-power-density packed-bed thermal energy storage using form-stable expanded graphite-based phase change composite

Thermal energy storage is highlighted as a crucial strategy for energy saving and utilization, in which domain, latent heat storage using phase change materials has gained great potential for efficient heat storage and thermal management applications. A strategy for developing high energy-storage-density and power-density latent heat storage units, through the compression-induced assembly of expanded graphite based stearic acid composites and the macro encapsulation method by using polyethylene shells, is demonstrated. The fabricated composite shows a satisfactory phase change enthalpy of 161.24 ± 0.5 J g−1, and enhances thermal conductivity to 13.4 ± 0.8 W m−1 K−1. The resulting heat storage unit also exhibits form-stable, leakage-proof, good homogeneity, and high-power-density behaviors. A 0.462 kWh proof-of-concept prototype of the packed-bed latent-heat-storage system by using 492 heat storage units has demonstrated its feasibility in fast heat charging/discharging operations. The outlet air temperature in the discharging process can maintain above 30 °C for over 1.74 h with a heat storage utilization efficiency of 90.3 ± 6.1% and an effective discharging efficiency of 93.5 ± 9.4%, under a volumetric flow rate of 30 m3 h−1 and heat storage temperature of 27–86 °C. The maximum and average power density, and effective energy density are obtained as 20.7 ± 1.6 kW m−3, 14.2 ± 0.9 kW m−3, 24.8 ± 2.5 kWh m−3, respectively, with a discharging threshold temperature of 30 °C. This high-power-density apparatus using form-stable heat storage units has realized hourly rapid heat charging-discharging processes, showing its prospective potential of low-temperature heat storage and thermal management.

Fluidic microencapsulation of calcium chloride hexahydrate phase change material in resorcinol formaldehyde shell

Phase change material, encapsulated in micro-particles are required extensively in temperature control and heat storage applications. The encapsulation through random mixing and chemical emulsification does not allow use of inorganic salt as PCM that is otherwise known to be safe and effective. Microencapsulation of an inorganic phase change material in resorcinol resin shell is demonstrated here by co-flowing the two phases in a fluidic device, and inducing instability driven disintegration of core-sheath filament. Highly unimodal sized microcapsules with diameter of 978 µm ± 75 µm and uniform coating thickness were evident from the optical microscope as well as scanning electron microscope images. The heat absorption and release characteristics of microcapsules with varied shell thickness of 1.57 µm, 4.05 µm and 12.8 µm were studied by differential scanning calorimetry. The integrity of the shell was evaluated through sustained dipping of microcapsules in water, and measuring the electrical conductivity. The fractional release was restricted to about 10% of in-place PCM after 30 days. The results serve as proof of concept for the fluidic microencapsulation in general, and inorganic material in particular, which in spite of possessing many favourable aspects has not been studied till date for thermal control and energy harvesting applications.

Macroencapsulated carbonate eutectic salt phase change material with high durability for high temperature heat storage

Carbonate eutectic salt is a kind of promising phase change material (PCM) for high temperature thermal storage application, which unfortunately constrained by its significant corrosiveness and low thermal conductivity. The encapsulation of salt PCM with stable inorganic shell to make capsules of millimeter to centimeter size can solve these problems, which is unfortunately technologically difficult to be prepared. In this work, a double shell strategy was proposed to coat the salt macrospheres with inner expanded graphite (EG) layer and outer ceramic kaolin layer. All raw materials were powders, which were shaped to spheres and capsules with the help of organic binder, pressed by isostatic pressing and finally sintered at high temperature for capsule formation. In a comparative case, the single kaolin shell coated capsules leaked when they were heated over the melting point of salt since that the relatively porous kaolin shell could be infiltrated with liquid salt because of their good wettability. However, the double shells coated capsules could prevent the leakage of salt since that the inner EG layer was repellent to liquid salt. The double shells coated macrocapsules showed good stability and high durability for long-term use, as confirmed by a cycling test over 300 cycles. The eutectic salt (Na2CO3/Li2CO3 = 57/43 in weight) core PCM presented a high latent heat of 313 J/g and melting point of around 498 °C. The macrocapsules with a size of 10@1.5@3 showed a high heat storage capability of 380 J/g in a temperature range of 400–600 °C. The macroencapulated carbonate eutectic salt with good heat storage capability and good thermal cycling durability can be extensively used for high-temperature heat storage applications in solar thermal power plant and industrial waste heat recovery.

Thermodynamic assessment of binary chloride salt material for heat transfer and storage applications in CSP system

Molten chloride salt is recognized as a promising heat transfer fluid and thermal energy storage material (TES) in concentrating solar power (CSP) in recent years, and its phase diagram as key data for material design still need further research. In this work, the phase equilibrium characteristics of solid-liquid equilibrium and vapor-liquid equilibrium for binary chloride salt system (Na/K–Ca/Mg) are investigated respectively. Based on Wilson model, the activity coefficient and non-ideal behavior of liquid salts are predicted effectively, and then the solid-liquid phase diagrams of binary salts are calculated, and the predicted eutectic temperature and component agree well with experimental data. Vapor-liquid phase diagrams of binary salts are also calculated, and azeotropic temperature can only be found in the MgCl2 based mixed salts. As the system pressure rises, the azeotropic temperature increases, while azeotropic component slightly changes. According to the variation of vapor pressure for eutectic salts, the correlations for vapor pressure with temperature and composition are developed. Thermal stability of eutectic salts is experimentally studied by Thermo-gravimetric analyzer (TGA) and operating temperature ranges of these mixed salts are revealed. It can be found that the mass loss rate at different temperature is directly proportional to the vapor pressure. In general, present binary chloride salts show wide operating temperature range and high heat storage density, and eutectic NaCl–MgCl2 with advantage of heat storage density and azeotropic point existence is recommended as TES in the CSP plant.

On the Use of Water and Methanol with Zeolites for Heat Transfer.

Reducing carbon dioxide emissions has become a must in society, making it crucial to find alternatives to supply the energy demand. Adsorption-based cooling and heating technologies are receiving attention for thermal energy storage applications. In this paper, we study the adsorption of polar working fluids in hydrophobic and hydrophilic zeolites by means of experimental quasi-equilibrated temperature-programmed desorption and adsorption combined with Monte Carlo simulations. We measured and computed water and methanol adsorption isobars in high-silica HS-FAU, NaY, and NaX zeolites. We use the experimental adsorption isobars to develop a set of parameters to model the interaction between methanol and the zeolite and cations. Once we have the adsorption of these polar molecules, we use a mathematical model based on the adsorption potential theory of Dubinin-Polanyi to assess the performance of the adsorbate-working fluids for heat storage applications. We found that molecular simulations are an excellent tool for investigating energy storage applications since we can reproduce, complement, and extend experimental observations. Our results highlight the importance of controlling the hydrophilic/hydrophobic nature of the zeolites by changing the Al content to maximize the working conditions of the heat storage device.

Ionic Liquids as Working Fluids for Heat Storage Applications: Decomposition Behavior of N-Butyl-N-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate.

Ionic liquids (ILs) represent promising working fluids to be used in thermal energy storage (TES) technologies thanks to their peculiar properties, such as low volatility, high chemical stability, and high heat capacity. Here, we studied the thermal stability of the IL N-butyl-N-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate ([BmPyrr]FAP), a potential working fluid for TES applications. The IL was heated at 200 °C for up to 168 h either in the absence or in contact with steel, copper, and brass plates to simulate the conditions used in TES plants. High-resolution magic angle spinning nuclear magnetic resonance spectroscopy was found to be useful for the identification of the degradation products of both the cation and the anion, thanks to the acquisition of 1H, 13C, 31P, and 19F-based experiments. In addition, elemental analysis was performed on the thermally degraded samples by inductively coupled plasma optical emission spectroscopy and energy dispersive X-ray spectroscopy. Our analysis shows a significant degradation of the FAP anion upon heating for more than 4 h, even in the absence of the metal/alloy plates; on the other hand, the [BmPyrr] cation displays a remarkable stability also when heated in contact with steel and brass.

Experimental investigation on thermal properties and fire performance of lauric acid/diphenyl phosphate/expanded perlite as a flame retardant phase change material for latent heat storage applications

The form-stable composite energy storage developed in this study was produced by integrating a novel flame retardant phase change material formed of 90 wt% lauric acid (LA) as a phase change material and 10 wt% resorcinol bis(diphenyl phosphate) (RDP) as a flame retardant into a supporting material of expanded perlite (EP) without leakage. A differential scanning calorimeter (DSC) test is employed to characterize the mass ratio of LA_RDP, and a filter paper is used to assess the leakage test of LA_RDP/EP. Results from scanning electron microscopy (SEM) show that the flame retardant phase change material of LA_RDP has been successfully embedded into EP’s porous structure. Moreover, chemical compatibility of composites is analyzed by fourier transform-infrared spectrometer (FT-IR). According to the DSC test, the flame retardant phase change material developed of LA_RDP/EP has an appropriate phase transition temperature of ∼ 40–45 °C and fusion latent heat range of ∼ 86.02–88.29 J/g for thermal control in buildings. After 50 thermal cycles, the thermal cycling test depicted that the composite PCM possess outstanding thermal reliability. By incorporating 5 wt% expanded graphite (EG), the thermal conductivity of the LA_RDP/EP composite is enhanced by about 41.6%. In accordance with the thermogravimetric analysis (TGA) test, the produced flame retardant and EP reduces the mass loss of LA. Cone calorimetry is also utilized to examine the flame retardant phase change material composite’s flammability characteristics. LA_RDP/EP demonstrates valued thermal properties while lowering the flammability of LA. The findings demonstrated that the formed LA_RDP/EP composite might be assessed as a suitable material in thermal applications for effective and sustainable energy use.