Large Energy Storage Capacity Research Articles

Energy storage device based on a hybrid system of a CO2 heat pump cycle and a CO2 hydrate heat cycle

A new large-capacity energy storage device (with a storage capacity of several megawatt-hours or more) based on a hybrid cycle of a CO2 heat pump cycle and a CO2 hydrate heat cycle is investigated using an experiment-based numerical analysis. In the charging mode of the CO2 heat pump cycle, the work of the compression process is input with surplus electricity from renewable energy sources. Liquid CO2 is stored in a tank after the condensation process. In the discharge (power generation) mode, the liquid CO2 stored in the tank is heated by outside air, and the expanded gas is supplied to the expander, which then operates the generator to obtain electricity from the expansion work. However, if the outside temperature is low, the expansion of liquid CO2 will be insufficient. The abovementioned CO2 hydrate heat cycle is added to the CO2 heat pump cycle. The resulting energy volume density of the proposed system is 80–140 kWh/m3, with a charge–discharge efficiency of 60%–106%, and the equipment costs should be similar to those of pumped storage. At ambient temperatures of <10 °C, the hybrid system with energy storage by gas hydrates is more effective, with a higher energy volume density and charge–discharge efficiency than previous systems.

Study on Energy Storage and Cost Saving Scheme of Traction Substation

Based on the energy-saving and economical operation requirements of high-speed railways, the traction power supply system adopts large-capacity energy storage devices. The paper takes the measured data of a traction substation as an example to compare the energy-saving effects of the two energy storage schemes and give suggestions.

Elaborately designed 3D honeycomb M−Ti3C2Tx@MoS2@C heterostructures as advanced microwave absorbers

Microwave absorption materials with lightweight, high absorption performance, and a broad absorption bandwidth are becoming increasingly popular due to the rapid advancements in wearable devices and portable electronic products. The two-dimensional Ti3C2Tx MXene is a highly promising electromagnetic shielding material thanks to its excellent conductivity, rich functional groups and customizable surface chemistry. However, the low dielectric loss of this material restricts its applications in microwave absorption. Herein, 3D honeycomb M−Ti3C2Tx@MoS2@C heterostructures were synthesized by simple hydrothermal and secondary annealing methods. Vertically assembled MoS2 nanosheets ensured a large electromagnetic energy storage capacity and promoted additional interfacial polarization. The honeycomb surface structure facilitated the electromagnetic wave attenuation through multiple reflections. The carbon coating and M−Ti3C2Tx matrix resulted in high conductive loss in the final products. The three-dimensional honeycomb M−Ti3C2Tx@MoS2@C heterostructures demonstrated exceptional microwave absorption performance. When filler loadings reached 40 wt%, the 3D honeycomb M−Ti3C2Tx@MoS2@C heterostructures delivered a minimum reflection loss of −47.55 dB at a thickness of 4.0 mm, with the added benefit of increasing the effective absorption bandwidth to 4.02 GHz. These findings paved the way for the commercialization of advanced microwave absorbers.

Bidirectional Power Control Strategy for Super Capacitor Energy Storage System based on MMC DC-DC Converter

Abstract: In order to equip more high-energy pulse loads and improve power supply reliability, the vessel integrated power system shows an increasing demand for high-voltage and large-capacity energy storage systems. Based on this background, this paper focuses on a super capacitor energy storage system based on a DC-DC converter. This paper analyzes the different topology of Hybrid Energy Storage System (HESS) and Demand Management System using HESS. Taking into account the shortcomings of the traditional bidirectional power control strategy, this paper proposes a control strategy where the HESS module of each branch independently controls the voltage of the sub-module capacitor. The outputs are validated and verified using MATLAB Simulink platform.

Design and optimization of composite phase change material for cylindrical thermal energy storage

Phase change materials store thermal energy in the form of latent heat, and are often integrated with high thermal conductivity metals to make composites that have both high power density and large energy storage capacity. In this study, we provide a theoretical framework to design and optimize cylindrical composites with three figures of merit – minimization of temperature rise, maximization of the effective volumetric heat capacity and maximization of the effective heat capacity based on mass. We validate the figures of merit experimentally by 3D printing AlSi12 alloy and using octadecane as phase change material for a heat flux of 13.3 Wcm−2 and heating time of 10 s. The metal component volume fractions in the printed structures vary from 15% to 70% for straight fin structures, 10% to 70% for the SC lattice structures, and 20% to 70% for branching fin structures. When minimizing temperature rise, the optimum volume fraction of thermally conductive material is 0.5–0.7. When maximizing the effective volumetric heat capacity, the optimum volume fraction for the high conductivity material is 0.3–0.5. Finally, when maximizing the effective heat capacity by mass in cylindrical composites, the optimum volume fraction for the high conductivity material is 0.2–0.3. Importantly, the optimum values depend on the applied thermal load, which is not captured in existing figures of merit for thermal storage systems. The volumetric and mass based heat capacity values of the optimized composites identified in this study are at least 10x higher when compared to single component PCMs that are widely used for volumetric and mass based thermal storage systems. The figures of merit developed here can assess the performance of most composite PCM systems and help to design future cylindrical composites while accounting for the thermal loads specific to the thermal storage application.

Enhancement in Thermal Properties of Organic Phase Change Material (Paraffin) via TiO2 Foam Doping

Phase change materials (PCM) can absorb or release a huge amount of latent heat in accordance with the increase or decrease of the surrounding temperature. Among all the studied PCMs, organic PCM paraffin has been chosen due to the large energy storage capacity for thermal energy storage (TES). The present work introduces a thermally modified phase change material by TiO2 foam impregnation in paraffin. Three TiO2/paraffin PCM composites TPCM1, TPCM2, and TPCM3 containing 10 wt.%, 15 wt.%, and 20 wt.% of TiO2 foam with paraffin have been successfully synthesized for thermal energy storage. The porous TiO2 foam can provide a high paraffin loading capacity of up to 80 % (TPCM3) due to hollow cavities. TiO2 foam is uniformly distributed over the inner and outer surface of the paraffin as a nano additive to enhance the thermal conductivity (TC) of the composite PCM. The structural, morphological, and thermal study revealed that doping of the supporting material has potentially modified all the criteria of PCM composite for TES. The highest leakage-proof result was obtained for 20 wt.% of TiO2 foam impregnated composite (TPCM3) by analysing mass loss across 500 thermal cycles in an oven at 80°C. The thermal reliability of the TPCM3 composite has also been investigated after 500 thermal cycles. The TPCM3 composite maintains its crystalline nature with homogeneous dispersion and thermal stability without affecting the thermal and chemical properties of the PCM. The latent heat of the TPCM3 composite reached 182.87 J/g, and the thermal conductivity has been calculated at 0.71 W/m-K, which is 3.73 times higher than paraffin. The results concluded that synthesized TPCM3 composite could be a potential candidate for TES due to chemical and physical compatibility, easy synthesis process, good thermal and chemical reliability, and acceptable energy storage capacity with enhanced thermal conductivity.

Synergistic planning of an integrated energy system containing hydrogen storage with the coupled use of electric-thermal energy

Regional integrated energy systems (RIES) can economically and efficiently use regional renewable energy resources, of which energy storage is an important means to solve the uncertainty of renewable energy output, but traditional electrochemical energy storage is only single electrical energy storage, and the energy efficiency level is low. Hydrogen energy storage has the advantages of large energy storage capacity, long storage time, clean and pollution-free, and can realize the synergistic and efficient utilization of electricity and thermal power. Based on this, this paper proposes a synergistic planning method for an integrated energy system with hydrogen storage taking into account the coupled use of electric-thermal energy, which effectively reduces the system carbon emission and improves the comprehensive energy efficiency level. Firstly, this paper constructs an electric-thermal coupling model of the hydrogen energy storage unit and proposes an optimization strategy for the integrated energy system containing hydrogen storage taking into account the utilization of electricity and thermal power. Secondly, a planning optimization model with the lowest economy and carbon emission and the highest comprehensive energy efficiency was constructed. Third, the CSPO-GE optimization algorithm is proposed for solving the problem, which significantly improves the solution efficiency. Finally, a planning optimization simulation of RIES for a residential community W in northern China verifies the effectiveness of the model and method proposed in this paper. The comparative analysis of the three schemes shows that compared with the integrated energy system with conventional electrochemical energy storage and heat storage tank as the main form of energy storage and the integrated energy system with only hydrogen storage, the integrated energy system with hydrogen storage and heat storage tank can reduce carbon emissions by 43.8% and 7.61%, respectively, and improve the integrated energy efficiency level by 337.14% and 14.44%.

Self-assembly of MXene-decorated stearic acid/ionic liquid phase change material emulsion for effective photo-thermal conversion and storage

As a typical latent functionally thermal fluid with large energy storage capacity and good liquidity, phase change material emulsion (PCME) plays a broad and important role in solar energy utilization. However, the high-temperature instability and supercooling problems of PCME limit its practical application. The ionic liquid (IL)-based PCME allows for the possibility of being used as a heat transfer fluid (HTF) under more extreme temperature conditions. In this work, stearic acid (SA)/IL PCME, prepared by one-step self-assembly of MXene nanosheets at the SA/IL interface, can effectively absorb and convert solar energy into thermal energy. Furthermore, MXene-decorated SA/IL PCMEs have good high-temperature stability, little supercooling degree (0.9–3.1 °C), and large energy storage capacity. The maximum apparent specific heat capacity and average absorbance of the MXene-decorated SA/IL PCME are 4.5 and 303.1 times higher than those of IL, respectively. Under 2 sun irradiation, the 0.05–20 wt% MXene-decorated SA/IL PCME achieves high photo-thermal conversion efficiencies (91.3% at 68.9 °C, 39.4% at 115.1 °C) due to its large energy storage capacity and excellent optical absorption property. The simple interfacial self-assembly provides a promising strategy to prepare high-performance SA/IL PCME used as a novel HTF for medium-temperature solar energy utilization systems.

Effect of Capacity Variation in Series-Connected Batteries on Aging

Batteries are used in various combinations in various fields. Research on single-cell batteries is well underway and is approaching a stabilization phase. However, problems caused by battery combinations are still insufficiently studied. The purpose of this study was to investigate the cause of fires due to gradual damage in a large-capacity energy storage system (ESS). In the paper Energy Storage System Safety Operation Plan by Preventing Overcharge During Relaxation Time, which was based on the fact that most fires in large-capacity energy storage devices occurred during the diastolic period, it was proven that the inflow of compensation current due to a voltage imbalance in the cell was the cause. The total amount of compensation current is determined by the voltage deviation of the battery. Batteries connected in series have different rates of aging due to differences in their capacities. Thus, with use, the total amount of compensating current continues to increase until a fire occurs. In this study, by analyzing the effect of battery-capacity deviation on the aging of individual cells, it was confirmed that the capacity deviation increased as the battery was used, resulting in an increase in the total amount of compensation current. In addition, if a solution to the problem is presented and the proposed solution is applied, the allowable range of battery-capacity deviation will be widened. We used Matlab 2009a, assuming a real environment. Using Simulink, problems were identified through simulation, improvement measures were suggested, and the proposed method was verified via simulation.

CdO nanocubes decorated on rGO sheets as novel high conductivity positive electrode material for hybrid supercapacitor

Hybrid supercapacitor devices (HSs) are critical in developing electrochemical energy storage systems with large energy storage capacity and low operating costs. Here, we present the development of novel CdO-rGO nanocomposites, with changing rGO concentrations, as positive electrodes exhibiting outstanding energy storage performance. The nanocomposites were synthesized using a controlled and cost-effective hydrothermal technique. Interestingly, the composite with 25% optimal concentration (from now on referred to as CdO-25%rGO) demonstrated excellent specific capacitance (1195 F g−1 at 1 A g−1) with superior rate performance due to the addition of conductive rGO, allowing quick charge transfer kinetics. Inspired by the outstanding performance, we built CdO-25%rGO//AC HSC that expanded the voltage frame to 2 V when tested in a 3 M KOH alkaline electrolyte. Notably, the fabricated CdO-25%rGO//AC HSC delivered a high specific capacitance of 55 F g−1 at 1 A g−1 and displayed a large energy density of 30 Wh kg−1 at a maximum power density of 5000 W kg−1 coupled with excellent stability (12% capacity fade after 7000 cycles). These findings provide a helpful, logical direction for developing materials with unique compositional properties and electrochemical performance for energy storage applications.

The effect of electric vehicle energy storage on the transition to renewable energy

The most viable path to alleviate the Global Climate Change is the substitution of fossil fuel power plants for electricity generation with renewable energy units. This substitution requires the development of very large energy storage capacity, with the inherent thermodynamic irreversibility of the storage-recovery process. Currently, the world experiences a significant growth in the numbers of electric vehicles with large batteries. A fleet of electric vehicles is equivalent to an efficient storage capacity system to supplement the energy storage system of the electricity grid. Calculations based on the hourly demand-supply data of ERCOT, a very large electricity grid, show that a fleet of electric vehicles cannot provide all the needed capacity and the remaining capacity must be met by hydrogen. Even though the storage capacity of the batteries is close to 1–2% of the needed storage capacity of the grid, the superior round-trip storage efficiency of batteries reduces the energy dissipation associated with the storage and recovery processes by up to 38% and the total hydrogen storage capacity by up to 50%. The study also shows that anticipated improvements in the round-trip efficiencies of batteries are almost three times more effective than improvements in hydrogen storage systems.

Polybenzimidazole Membrane for Vanadium Flow Battery Applications

The vanadium redox flow battery (VRFB) is one of the most promising secondary batteries as a large-capacity energy storage device for storing renewable energy.1 Perfluorinated-based ion exchange membranes such as Nafion are the most widely used membranes in VRFB due to their high proton conductivity. However, the extremely high cost and low ion selectivity of Nafion have limited their further application in VRFB. Among the aromatic hydrocarbon-based membranes that combine both high ion selectivity and high proton conductivity, polybenzimidazole- based membranes have served as one of the most promising alternatives to Nafion due to their excellent chemical and mechanical stability and low cost.2 In the present work m-PBI membranes of varying thickness and modified PBI were prepared, and their properties and VRFB performances were compared. The voltage efficiency (VE) increased with decreasing membrane thickness because of the decreasing ohmic resistance. The excellent current efficiency (CE) of VRFBs using meta-PBI based membranes is attributed to the negligible vanadium crossover observed in ex-situ permeability tests.The stability of the membranes after long term cycling is one of the most challenging problems in large-scale VRB applications. The durability of PBI membrane in VRFB cell testing and the capacity decay was measured by operating the cells for 100 cycles under a high current density of 200 mA cm−2. Fig 1: Flow battery efficiencies using electrodes: 2.5 mm SGL, CR = 20%, membrane: PBI 7 µm at current density of 200 mA/cm2, the electrolyte solution V(IV):V(III) (50:50) in 2.0 M H2SO4 and 0.05 M H3PO4 . The chemical stability of PBI membranes was analyzed after immersion of the PBI samples in various highly oxidizing and reducing sulfuric acid based vanadium and cerium solutions. The membranes stayed unchanged for more than 4 months. This result suggests that the PBI membranes demonstrate excellent ex-situ chemical stability in the harsh acid, oxidizing and reducing conditions.

Characterization and optimization of energy sharing performances in energy-sharing communities in Sweden, Canada and Germany

Peer-to-peer (P2P) renewable power sharing within a building community is a promising solution to enhance the community’s self-sufficiency and relieve the grid stress posed by the increased deployment of distributed renewable power. Existing studies have pointed out that the energy sharing potentials of a building community are affected by various factors including location, community scale, renewable energy system (RES) capacity, energy system type, storage integration, etc. However, the impacts of these factors on the energy sharing potentials in a building community are not fully studied. Being unaware of those factors’ impacts could lead to reduced energy sharing potentials and thus limit the associated improvement in energy and economic performances. Thus, this study conducts a comprehensive analysis of various factors’ impacts on the energy sharing performances in building communities. Two performance indicators are first proposed to quantify the energy sharing performances: total amount of energy sharing and energy sharing ratio (ESR). Then, parametric studies are conducted based on real electricity demand data in three countries to reveal how these factors affect the proposed indictors and improvements in self-sufficiency, electricity costs, and energy exchanges with the power grid. Next, a genetic algorithm based design method is developed to optimize the influential parameters to maximize the energy sharing potentials in a community. The study results show that the main influential factors are RES capacity ratio, PV capacity ratio, and energy storage system capacity. A large energy storage capacity can enhance the ESR. To achieve the maximized ESR, the optimal RES capacity ratio should be around 0.4 ∼ 1.1. The maximum energy sharing ratio is usually smaller in high latitude districts such as Sweden. This study characterizes the energy sharing performances and provides a novel perspective to optimize the design of energy systems in energy sharing communities. It can pave the way for the large integration of distributed renewable power in the future.

Sodium vanadium oxides: From nanostructured design to high-performance energy storage materials

· Be the first to have an overview of NVO materials family, which is a promising materials category for energy storage systems. · Summarize with an insight into crystal structures, morphologies, mechanisms and the electrochemical energy storage performances. · Discuss the electrochemical behaviors, which provide further insight into metal-ion storage mechanisms in NVO materials family. Developing high-capacity and low-cost cathode materials for metal-ion rechargeable batteries is the mainstream trend and is also the key to providing breakthroughs in making high-energy rechargeable batteries. Vanadium has a variety of valence states and can form a variety of vanadate structures. As a typical positive electrode material, vanadate has abundant ion adsorption sites, a unique “pillar” framework, and a typical layered structure. Therefore, it has the advantages of high specific capacity and excellent rate performance, possessing the prospect of being a large-capacity energy storage material. In this review, we focus on applications of sodium vanadium oxides (NVO) in electrical energy storage (EES) devices and summarize sodium vanadate materials from three aspects, including crystal structure, electrochemical performance, and energy storage mechanism. The recent progress of NVO-based high-performance energy storage materials along with nanostructured design strategies was provided and discussed as well. This review is intended to serve as general guidance for researchers to develop desirable sodium vanadate materials.

Boron Nitride-Doped Inorganic Hydrated Salt Gels Demonstrating Superior Thermal Energy Storage and Wearability Toward High-Performance Personal Thermal Management

Realizing the person thermal management (PTM) toward human body and its local environment is emerging as a research hotspot. Sodium sulfate decahydrate (SSD) possessing reversible thermal energy absorption, storage, and release around the human body temperature provides a promising solution for PTM and thermal comfort. However, developing SSD-based functional materials with superior thermophysical properties and wearability to enable efficient PTM still remains a huge challenge. Herein, a strategy of ionic cross-linking, chemical cross-linking, and boron nitride (BN) doping is developed to manufacture the high-performance hybrid SSD gels. The supercooling degree of the BN@SSD gels can be reduced to 0 °C. The thermal conductivity (1.2668 W m–1 K–1) of the BN@SSD gels can be increased by 63.14%. The BN@SSD gels present a large thermal energy storage capacity of 132.52 J g–1. The BN@SSD gels demonstrate excellent form stability to confine the liquid SSD and high cyclic stability of 200 cycles. Furthermore, The BN@SSD gels also possess superior wearability in terms of high flexibility, high self-repairing efficiency, and high cost effectiveness (5.53 × 10–3 ¥ g–1). Owing to the various merits of the synergistic enhancement effect, the BN@SSD gels are effectively utilized in wearable PTM to generate thermal comfort for the human body. The multifunctional thermal energy storage gels offer a promising route to the highly efficient application of PCMs in next-generation PTM.

An evaluation of domestic electric water heaters for frequency control

Maintaining the frequency of a power system close to its nominal value (50 Hz or 60 Hz) is critical, which comes mainly from generators and flexible loads in traditional power systems. Direct load control (DLC) is a method to control controllable loads for power system optimization. In general, it is used to reduce or shave peak demand. Nonetheless, DLC also can be used to provide frequency control services. Domestic electric water heater (DEWH) is an important kind of controllable load, which takes a high percentage of domestic electric power consumption and has a large thermal energy storage capacity. Hence, DEWH can be a prime candidate for DLC. This study proposes a framework to provide frequency control service with DEWHs. A virtual battery pack system (VBPS) is introduced to be equivalent to the capacity of DEWHs, and a series of measurable indicators are proposed to show the capacity of the VBPS when providing frequency control services. An adaptive criterion is applied to classify controllable DEWHs, which helps to maintain end-user comfort. The performances of the proposed frequency control method during normal and contingency conditions are verified through case studies in CYME.

A novel efficient electrocatalyst for oxygen reduction and oxygen evolution reaction in Li-O2 batteries: Co/CoSe embedded N, Se co-doped carbon

The research of highly efficient and large-capacity energy storage systems is the focus of the research community and the market. Lithium-oxygen (Li-O2) batteries have shown great potential as next generation secondary batteries since their energy density is comparable to that of gasoline. Herein, we report a three dimensional (3D) self-supporting Co-CoSe@NSeC/bioC cathode fabricated through growing cobalt based metal organic framework (ZIF-67) on biomass and subsequent high-temperature selenization. The as synthesized Co-CoSe@NSeC/bioC cathode, benefiting from the 3D porous structure, the active defects derived from the doping of N, Se heteroatoms in carbon skeleton, and the highly-active of Co/CoSe heterojunction, shows excellent oxygen reduction reaction/oxygen evolution reaction (ORR/OER) electrocatalytic activity. It delivers a high specific capacity of 9.1 mAh·cm−2 at a current density of 0.05 mA·cm−2 and maintains 78 stable cycles. The good performance of Co-CoSe@NSeC/bioC proves its potential as cathode for Li-O2 batteries.

Accelerating the theoretical study of Li-polysulfide adsorption on single-atom catalysts via machine learning approaches.

Li–S batteries are a promising alternative to Li‐ion batteries, offering large energy storage capacity and wide operating temperature range. However, their performance is heavily affected by the Li‐polysulfide (LiPS) shuttling. Computational screening of LiPS adsorption on single‐atom catalyst (SAC) substrates is of great aid to the design of Li–S batteries which are robust against the LiPS shuttling from the cathode to the anode and the electrolyte. To facilitate this process, we develop a machine learning (ML) protocol to accelerate the systematic mapping of dominant local energy minima found with calculations based on the density functional theory (DFT), and, in turn, fast screening of LiPS adsorption properties on SACs. We first validate the approach by probing the potential energy surface for LiPS adsorbed on graphene decorated with a Fe–N4–C SAC. We identify minima whose binding energies are better or on par with the one previously reported in the literature. We then move to analyze the adsorption trends on Zn–N4–C SAC and observe similar adsorption strength and behavior with the Fe–N4–C SAC, highlighting the good predictive power of our protocol. Our approach offers a comprehensive and computationally efficient alternative to conventional approaches studying LiPS adsorption.

Fabrication and Thermal Performance of 3D Copper-Mesh-Sintered Foam/Paraffin Phase Change Materials for Solar Thermal Energy Storage

Due to its large latent heat and high energy storage capacity, paraffin as one of the phase change materials (PCMs) has been widely applied in many energy-related applications in recent years. The current applications of paraffin, however, are limited by the low thermal conductivity and the leakage problem. To address these issues, we designed and fabricated form-stable composite PCMs by impregnating organic paraffin within graphite-coated copper foams. The graphite-coated copper foam was prepared by sintering multilayer copper meshes, and graphite nanoparticles were deposited on the surface of the porous copper foam. Graphite nanoparticles could directly absorb and convert solar energy into thermal energy, and the converted thermal energy was stored in the paraffin PCMs through phase change heat transfer. The graphite-coated copper foam not only effectively enhanced the thermal conductivity of paraffin PCMs, but also its porous structure and superhydrophobic surface prevented the paraffin leakage during the charging process. The experimental results showed that the composite PCMs had a thermal conductivity of 2.97 W/(m·K), and no leakage occurred during the charging and discharging process. Finally, we demonstrated the composite PCMs can be readily integrated with solar thermoelectric systems to serve as the energy sources for generating electricity by using abundant clean solar-thermal energy.

Production of thermoregulating slurries constituted by nanocapsules from melamine-formaldehyde containing n-octadecane

The development of novel thermal fluids having large thermal energy storage (TES) capacity represents a research field of growing interest nowadays. One of the most explored alternatives is the employment of slurries containing encapsulated Phase Change Materials (PCM) at nano-scale range to avoid pumping problems. Slurries constituted by capsules from melamine-formaldehyde (MF) polymer containing n-octadecane (C18) have been synthesized by varying the paraffin/polymer (C18/MF) mass ratio within 1.50–4.00, in one single reaction step process, without waste generation and non-requiring additional purification treatments. All synthesized products presented high fluidity (viscosity around 4 mPa·s); Zeta-potential (ζ) values lower than −45 mV and pH values comprised between 5.5 and 6.0. Nevertheless, the thermal and physical properties of the slurries were function of the 18/MF mass ratio. While above a C18/MF mass ratio of 3.00 the slurry presented an undesirable large amount of non-encapsulated PCM, those ones produced with a C18/MF mass ratio bellow 3 exhibited high encapsulation yield and monodisperse particle size distribution (PSD). The slurries produced with C18/MF mass ratios larger than 2.33 satisfied the European Commission and ISO/TS 80004–1 classification as nanomaterials. Therefore, the highest encapsulation yield (98.7%), the dn0.5 of 63.7 ± 10.2 nm and the spherical shape and smooth morphology of nanocapsules allowed to select the slurry synthesized with C18/MF mass ratio of 2.33 as the optimal nano encapsulated PCM slurry (NPCS). This nanoslurry exhibited a latent heat of ~23 J/g, being constituted by 14.44 wt% of nanocapsules having a latent heat of 125.85 J/g. Finally, the properties of this NPCS are better than the reported in literature for this type of slurries, being suitable to be applied as thermal fluid in thermal energy storage active systems.