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It is of great importance to treat a bacterial-infected wound by a smart dressing capable of delivering antibiotics in a smart manner without causing drug resistance. The construction of smart release nanocontainers responsive to near-infrared (NIR) laser irradiation in an on-demand and stepwise way is a promising strategy for avoiding the emergence of multidrug-resistant bacteria. Here, we develop a hydrogel composite made of alginate and nanotubes with an efficient NIR-triggered release of rifampicin and outstanding antibacterial ability. This composite hydrogel is prepared through co-encapsulating antibacterial drug (rifampicin), NIR-absorbing dye (indocyanine green), and phase-change materials (a eutectic mixture of fatty acids) into halloysite nanotubes, followed by incorporation into alginate hydrogels, allowing the in-situ gelation at room temperature and maintaining the integrity of drug-loaded nanotubes. Among them, the eutectic mixture with a melting point of 39 °C serves as the biocompatible phase-change material to facilitate the NIR-triggered drug release. The resultant phase-change material gated-nanotubes exhibit a prominent photothermal efficiency with multistep drug release under laser irradiation. In an in vitro assay, composite hydrogel provides good antibacterial potency against Staphylococcus aureus, one of the most prevalent microorganisms of dangerous gas gangrene. A bacterial-infected rat full-thickness wound model demonstrates that the NIR-responsive composite hydrogel inhibits the bacteria colonization and suppresses the inflammatory response caused by bacteria, promoting angiogenesis and collagen deposition to accelerate wound regeneration. The NIR-responsive composite hydrogel has a great potential as an antibacterial wound dressing functionalized with controlled multistep treatment of the infected sites.

Phase-change materials (PCMs) are commonly employed in building service equipment to regulate indoor temperatures and reduce energy consumption. This study conducted multi-scale finite element modeling to analyze the steady-state and dynamic thermal behavior of a hydronic radiant floor heating system integrated with macro-encapsulated PCMs. It predicted performance values for hydronic floor heating with and without macro-encapsulated PCMs. The study assessed the impact of the PCM volume fraction, heating water temperature, capsule thermal conductivity, and shape on the thermal performance of hydronic floor heating through various finite element models. The predictive capability of the finite element model was validated using experimental data, showing good agreement. Although the inclusion of PCMs lowered the floor temperature, it improved temperature distribution and retained heat when the system was inactive. The PCM volume fraction significantly influenced the performance of the hydronic floor. However, the shape of the macro-encapsulated PCM and thermal conductivity of the shell had minimal effects in the studied case. For instance, increasing the thermal conductivity of the shell of the PCM capsule fifty times from 0.3 to 15 W m−1 K−1 resulted in an increase in surface temperature by 1.2 °C.

Latent thermal energy storage (LTES) devices can efficiently store renewable energy in thermal form and guarantee a stable-temperature thermal energy supply. The gravity-driven motion melting (GDMM) process improves the overall melting rate for packaged phase-change material (PCM) by constructing an enhanced flow field in the liquid phase. However, due to the complex mechanisms involved in fluid–solid coupling and liquid–solid phase transition, numerical simulation studies that demonstrate physical details are necessary. In this study, a simplified numerical model based on the Eulerian method is proposed. We aimed to introduce a fluid deformation yield stress equation to the “solid phase” based on the Bingham fluid assumption. As a result, fluid–solid coupling and liquid–solid phase transition processes become continuously solvable. The proposed model is validated by the referenced experimental measurements. The enhanced performance of liquid-phase convection and the macroscopic settling of the “solid phase” are numerically analyzed. The results indicate that the enhanced liquid-phase fluidity allows for a stronger heat transfer process than natural convection for the pure liquid phase. The gravity-driven pressure difference is directly proportional to the vertical melting rate, which indicates the feasibility of controlling the pressure difference to improve the melting rate.

The helical fins can improve the hampering effect of classical fins on the convection flows of latent heat storage units (LHSU) as an innovative design, but their thermal performance improvement was largely affected by the operational conditions of heat transfer fluid (HTF), especially for fluid temperature and velocity. Based on this, an experimental system was established to measure thermal performance of latent heat storage units with perforated and solid helical fins (PHF-LHSU and SHF-LHSU). Two inlet temperatures were considered as 65 °C and 75 °C in the charge process and 20 °C and 30 °C in the discharge process, while three velocities were employed as 0.5 L/min, 1.0 L/min and 1.5 L/min. Experimental results showed PHF-LHSU exhibited the higher thermal performance than SHF-LHSU, especially in temperature response and average Nusselt number. Increasing HTF temperature from 65 °C to 75 °C increased melting rate, the average heat flux, Nusselt number and thermal efficiency by 25.4%–31.6%, 65.9%–70.6%, 15.9–25.9% and 9.7%–11.6% in the charge process, while reducing HTF temperature from 30 °C to 20 °C lowered the solidifying rate, the average heat flux and thermal efficiency by 39.3%–47.4%, 52.5%–56.6%, and 30.7%–35.3% in the discharge process. The HTF velocity had the certain effects on thermal properties and with the HTF velocity increasing from 0.5 L/min to 1.5 L/min, the thermal efficiency was increased by 3.9%–4.7%.

Multifunctional metalens with tunable focus and intensity is powerfully attractive for compact planar optics. However, the limited degree of freedom in the single-layer metasurface design makes it difficult to satisfy more complicated functionalities, which restricts the application scenarios of metalens. In this paper, a multifunctional metalens with three operating modes is designed at near-infrared wavelength by combining the phase-change material antimony selenide (Sb2Se3) with the bilayer Pancharatnam-Berry (P-B) phase. By reversibly transforming the upper and lower Sb2Se3 nanofins between the crystalline and amorphous states, the metalens can achieve arbitrary switching among dual-focus F1 and F2, single-focus F1, and single-focus F3. Moreover, when the upper Sb2Se3 nanofin is remained in the amorphous state, a bifocal metalens with tunable relative intensity is achieved by controlling the crystallization state of the lower Sb2Se3 nanofin, and the total focusing efficiency of the bifocal metalens is above 86%. Similarly, when the upper Sb2Se3 nanofin is in the crystalline state, a single-focus metalens with adjustable intensity is realized via adjusting the crystallization fraction of the lower Sb2Se3 nanofin. Regardless of whether the metalens operates in bifocal or single focal mode, the simulated focusing efficiency is higher than 53% and the full-width at half-maximum (FWHM) of each focus approaches its diffraction-limited value. The proposed multifunctional metalens can enable wide potential applications in biomedical imaging, optical communication systems, multifunctional devices, and so on.

Metalenses are emerging as an alternative to digital micromirror devices (DMDs), with the advantages of compactness and flexibility. The exploration of metalenses has ignited enthusiasm among optical engineers, positioning them as the forthcoming frontier in technology. In this paper, we advocate for the implementation of the phase-change material, Sb 2 Se 3 , capable of providing swift, reversible, non-volatile focusing and defocusing within the 1550 nm telecom spectrum. The lens, equipped with a robust ITO microheater, offers unparalleled functionality and constitutes a significant step toward dynamic metalenses that can be integrated with beamforming applications. After a meticulously conducted microfabrication process, we showcase a device capable of rapid tuning (0.1 MHz level) for metalens focusing and defocusing at C band communication, achieved by alternating the PCM state between the amorphous and crystalline states. The findings from the experiment show that the device has a high contrast ratio for switching of 28.7 dB. [ABSTRACT FROM AUTHOR]

In this research, novel, organic, solid-liquid phase-change materials (PCMs) derived from methoxy polyethylene glycol (MPEG) and aromatic acyl chlorides (ACs) were prepared through a condensation reaction. The MPEGs were used as phase-change functional chains with different molecular weights (350, 550, 750, 2000, and 5000 g/mol). The aromatic ACs, terephthaloyl chloride (TPC) and isophthaloyl chloride (IPC), were employed as bulky linker cores. Solubility tests demonstrated that this family of PCMs is soluble in protic polar solvents such as H2O and MeOH, and insoluble in nonpolar solvents such as n-hexane. Fourier-ransform infrared spectroscopy (FT-IR UATR) and nuclear magnetic resonance (1H, 13C, DEPT 135°, COSY, HMQC, and HMBC NMR) were used to confirm the bonding of MPEG chains to ACs. The crystalline morphology of the synthesized materials was examined using polarized optical microscopy (POM), revealing the formation of spherulites with Maltese-cross-extinction patterns. Furthermore, it was confirmed that PCMs with higher molecular weights were crystalline at room temperature and exhibited an increased average spherulite size compared to their precursors. Thermal stability tests conducted through thermogravimetric analysis (TGA) indicated decomposition temperatures close to 400 °C for all PCMs. The phase-change properties were characterized by differential scanning calorimetry (DSC), revealing that the novel PCMs melted and crystallized between −23.7 and 60.2 °C and −39.9 and 45.9 °C, respectively. Moreover, the heat absorbed and released by the PCMs ranged from 57.9 to 198.8 J/g and 48.6 to 195.6 J/g, respectively. Additionally, the PCMs exhibited thermal stability after undergoing thermal cycles of melting-crystallization, indicating that energy absorption and release occurred at nearly constant temperatures. This study presents a new family of high-performance organic PCMs and demonstrates that the orientation of substituent groups in the phenylene ring influences supercooling, transition temperatures, and thermal energy storage capacity depending on the MPEG molecular weight. [ABSTRACT FROM AUTHOR]

Considering the importance of high‐performance composite phase change materials (PCMs) for the realization of efficient thermal energy storage, molecular dynamics simulations were conducted in this study to investigate the thermal properties of graphene/palmitic acid composites and the related interfacial thermal transport. The effects of the interactions between functionalized graphene and fatty acids on the thermal transport properties needs to be investigated further. The addition of functionalized graphene (with epoxy, hydroxyl, and carboxyl groups) increased the phase transition temperature and decreased the specific heat capacity of the PCM, whereas both of these parameters increased with increasing functional group coverage (FGC). Further the effects of the FGC and functional group type on the interfacial thermal resistance (ITR) were investigated by analyzing the interaction energy and vibrational density of states, and the ITR decreased with increasing FGC. Compared to that of pure PA, the phase‐transition temperatures of the PA/pristine graphene composites were higher by ~7 K. The ability of functional groups to decrease the ITR decreased in the order of epoxy < hydroxyl < carboxyl at a constant FGC of 10.12%, with the ITR decreasing by 31.26%, 44.77%, and 56.41%, respectively. The obtained insights are expected to facilitate the design of high‐performance energy storage systems based on composites of fatty acids as PCMs. Highlights: Thermal transport in functionalized graphene/palmitic acid composites is studied.Effects of functional group type/coverage on composite thermal properties are probed.Molecular dynamics simulations are used for thermal property analysis.The obtained insights promote the design of high‐performance phase‐change materials. [ABSTRACT FROM AUTHOR]

Modern technologies of thermal power engineering make it possible to design and build systems using renewable energy sources. Often, energy accumulation and storage require the development and adaptation of appropriate systems, the simplest of which are passive systems based on phase-change materials. In this study, a numerical analysis of heat transfer in a brick wall containing several materials with different melting temperatures is carried out. The unsteady two-dimensional conjugate problem of phase transitions is considered, taking into account natural convection in the melt, which has been solved using the developed in-house finite difference technique. A numerical experiment has been carried out for a brick block with several rectangular inserts filled with PCMs under various external thermal conditions. As a result of the numerical analysis, it has been shown that the relative arrangement of materials with different melting points has a significant impact on the heat transfer and heat exchange between the environment and the room. [ABSTRACT FROM AUTHOR]

In recent years, dynamically tunable structural color has attracted great interest. Here, we introduce the guided-mode resonance (GMR) filter and the phase-change material Sb2S3 to design a reflective optical metasurface to produce tunable structural color, in which the combination of the GMR filter, with narrow resonant wavelength, and the Sb2S3, with a much larger bandgap and higher refractive index, helps to produce high-quality tunable structural color. The simulation results indicate that through the phase transition between the amorphous and crystalline states of Sb2S3, the proposed metasurface can generate tunable structural color that can be perceived by the naked eye. Furthermore, the metasurface can sensitively sense environmental changes through changes in structural color. This work provides a new method for realizing dynamically tunable structural color, and paves the way for the application of controllable structural color in dynamic displays, optical stealth, colorimetric sensing, and other fields. [ABSTRACT FROM AUTHOR]

Tunable structural color has gained significant attention due to its dynamic characteristics. However, conventional devices are usually regulated only in their color capabilities by structural parameters, restricting real-time dynamic applications. In this study, we propose an ultra-thin asymmetric Fabry–Perot cavity patterned with phase-change materials (MPMP). The reversible phase transition of VO2 induces changes in the MPMP's optical performance, enabling color mode switching through temperature control and resulting in rapid color conversion and low-temperature regulation. By adjusting relevant structural parameters of the VO2 layer and nanodiscs, the color performance range can be tailored. Through numerical investigations, we demonstrate that MPMP can produce stable transformation of dynamic structural colors by harnessing the phase-change effect. Our research unveils new possibilities for applications such as anti-counterfeiting, bio/chemical sensing, and temperature sensing. [ABSTRACT FROM AUTHOR]

We present a sessile droplet manipulation platform that enables the formation and transport of a droplet on a light-absorbing surface via local laser-beam irradiation. The mechanism relies on solutocapillary Marangoni flow arising from a concentration gradient in a binary mixture liquid. Because the mixture is strongly confined in a two-dimensional slit with a spacing of a few micrometers, the wetting film is stably sustained, enabling the rapid formation, deformation, and transport of a sessile droplet. In addition, to sustain the droplet in the absence of laser irradiation, we developed a method to bridge the droplet between the top and bottom walls of the slit. The bridge is stably sustained because of the hydrophilicity of the slit wall. Splitting and merging of the droplet bridges are also demonstrated. [ABSTRACT FROM AUTHOR]

In recent years, the super-oscillation method based on the fine interference of optical fields has been successfully applied to sub-diffraction focusing and super-resolution imaging. However, most previously reported works only describe static super-oscillatory lenses. Super-oscillatory lenses using phase-change materials still have issues regarding dynamic tunability and inflexibility. Therefore, it is vital to develop a flexible and tunable modulation approach for super-oscillatory lenses. In this paper, we propose a super-oscillatory step-zoom lens based on the geometric phase principle, which can switch between two focal lengths within a certain field of view. The designed device consists of nanopillars with high efficiency of up to 80%, and the super-resolution focusing with 0.84 times of diffraction limit is verified by the full-wave simulation. The proposed method bears the potential to become a useful tool for label-free super-resolution microscopic imaging and optical precision machining.

Photonic logic gates have important applications in fast data processing and optical communication. This study aims to design a series of ultra-compact non-volatile and reprogrammable photonic logic gates based on the Sb2Se3 phase-change material. A direct binary search algorithm was adopted for the design, and four types of photonic logic gates (OR, NOT, AND, and XOR) are created using silicon-on-insulator technology. The proposed structures had very small sizes of 2.4 μm × 2.4 μm. Three-dimensional finite-difference time-domain simulation results show that, in the C-band near 1550 nm, the OR, NOT, AND, and XOR gates exhibit good logical contrast of 7.64, 6.1, 3.3, and 18.92 dB, respectively. This series of photonic logic gates can be applied in optoelectronic fusion chip solutions and 6G communication systems. [ABSTRACT FROM AUTHOR]

To address the leakage issue of paraffin phase-change materials in thermal management, a monolithic MTMS-based silica aerogel (MSA) is employed to encapsulate paraffin through a facile impregnation process. We find that the paraffin and MSA form a physical combination, with little interaction occurring between them. The prepared no-leakage paraffin/MSA composites have a density of 0.70 g/cm3 and exhibit good mechanical properties and nice hydrophobicity, with a contact angle of 122°. Furthermore, the average latent heat of the paraffin/MSA composites is found to reach up to 209.3 J/g, about 85% of the pure paraffin's latent heat, which is significantly larger than other paraffin/silica aerogel phase-change composite materials. The thermal conductivity of the paraffin/MSA remains almost the same as that of the pure paraffin (~250 mW/m/K), without any heat transfer interference from the MSA skeletons. All these results indicate that MSA can effectively serve as a carrier material for encapsulating paraffin, which is beneficial for expanding the applications of MSAs in thermal management and energy storage. [ABSTRACT FROM AUTHOR]

The technology of solar air heating systems is one of the branches that is of great importance in capturing and capitalizing on solar energy. This paper presents a summary of the literature on solar air heating systems embedded with materials that have the ability to retain thermal energy, during periods of maximum intensity of solar radiation and its release, when solar energy is reduced or missing for a period of time. It presents the designed and carried out systems by different researchers and the thermal performances obtained in the period of 2017-2021. [ABSTRACT FROM AUTHOR]

The thermal management system of a power battery is crucial to the safety of battery operation; however, for the phase-change material (PCM) thermal management system of a battery, the thermal cycling of phase-change material under large discharge rate conditions will lead to thermal conductivity degradation and thermal stress problems. A method of manufacturing PCM containers with metal fins to package pure phase-change material is put forward to solve the problem. The system temperature under different conditions is studied using numerical and experimental methods. A thermal resistance model is built to analyze the thermal transfer performance of PCM containers with fins. The results show that the PCM container structure can effectively control the battery temperature within the suitable temperature range under the low discharge rate, but the maximum temperature of the battery pack at the high discharge rate of 3 C will exceed the optimum operating temperature range. Adding fins can reduce the maximum temperature and improve the system temperature uniformity. By combining fins with forced-air cooling, the maximum temperature and maximum temperature difference of the battery pack at a high discharge rate can be effectively reduced. [ABSTRACT FROM AUTHOR]

Indirect interactions via shared memory deposited on the field (“field memory”) play an essential role in collective motions. Some motile species, such as ants and bacteria, use attractive pheromones to complete many tasks. Mimicking these kinds of collective behavior at the laboratory scale, we present a pheromone-based autonomous agent system with tunable interactions. In this system, colloidal particles leave phase-change trails reminiscent of the process of pheromone deposition by individual ants, and the trails attract other particles and themselves. To implement this, we combine two physical phenomena: the phase change of a Ge2Sb2Te5 (GST) substrate by self-propelled Janus particles (pheromone deposition) and the AC (alternating current) electroosmotic (ACEO) flow generated by this phase change (pheromone attraction). Laser irradiation causes the GST layer to crystalize locally beneath the Janus particles, owing to the lens heating effect. Under AC field application, the high conductivity of the crystalline trail causes a field concentration and generates ACEO flow, and we introduce this flow as an attractive interaction between the Janus particles and the crystalline trail. By changing the AC frequency and voltage, we can tune the attractive flow, i.e., the sensitivity of the Janus particles to the trail, and the isolated particles undergo diverse states of motion, from self-caging to directional motion. A swarm of Janus particles also shows different states of collective motion, including colony formation and line formation. This tunability enables a reconfigurable system driven by a pheromone-like memory field. [ABSTRACT FROM AUTHOR]

Domestic water heating accounts for 15% to 27% of the total energy consumption in buildings in Australia. Over the past two decades, the latent heat thermal energy storage (LHTES) system has been widely investigated as a way to reduce fossil fuel consumption and increase the share of renewable energy in solar water heating. However, the research has concentrated on the geometric optimisation of the LHTES heat exchanger for the past few years, and this might not be sufficient for commercialisation. Moreover, recent review papers mainly discussed the development of a particular heat-transfer improvement technique. This paper presents perspectives on various solar hot water systems using LHTES to shift focus to on-demand performance studies, as well as structure optimisation studies for faster commercialisation. Future challenges are also discussed. Since the topic is an active area of research, this paper focuses on references that showcase the overall performance of LHTES-assisted solar hot water systems and cannot include all published work in the discussion. This perspective paper provides directional insights to researchers for developing an energy-efficient solar hot water system using LHTES. [ABSTRACT FROM AUTHOR]

All-dielectric metasurfaces are a blooming field with a wide range of new applications spanning from enhanced imaging to structural color, holography, planar sensors, and directionality scattering. These devices are nanopatterned structures of sub-wavelength dimensions whose optical behavior (absorption, reflection, and transmission) is determined by the dielectric composition, dimensions, and environment. However, the functionality of these metasurfaces is fixed at the fabrication step by the geometry and optical properties of the dielectric materials, limiting their potential as active reconfigurable devices. Herein, a reconfigurable all-dielectric metasurface based on two high refractive index (HRI) materials like silicon (Si) and the phase-change chalcogenide antimony triselenide (Sb2Se3) for the control of scattered light is proposed. It consists of a 2D array of Si–Sb2Se3–Si sandwich disks embedded in a SiO2 matrix. The tunability of the device is provided through the amorphous-to-crystalline transition of Sb2Se3. We demonstrate that in the Sb2Se3 amorphous state, all the light can be transmitted, as it is verified using the zero-backward condition, while in the crystalline phase most of the light is reflected due to a resonance whose origin is the contribution of the electric (ED) and magnetic (MD) dipoles and the anapole (AP) of the nanodisks. By this configuration, a contrast in transmission (ΔT) of 0.81 at a wavelength of 980 nm by governing the phase of Sb2Se3 can be achieved. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive review of the thermal management strategies employed in cylindrical lithium-ion battery packs, with a focus on enhancing performance, safety, and lifespan. Effective thermal management is critical to retain battery cycle life and mitigate safety issues such as thermal runaway. This review covers four major thermal management techniques: air cooling, liquid cooling, phase-change materials (PCM), and hybrid methods. Air-cooling strategies are analyzed for their simplicity and cost-effectiveness, while liquid-cooling systems are explored for their superior heat dissipation capabilities. Phase-change materials, with their latent heat absorption and release properties, are evaluated as potential passive cooling solutions. Additionally, hybrid methods, such as combining two or more strategies, are discussed for their synergistic effects in achieving optimal thermal management. Each strategy is assessed in terms of its thermal performance, energy efficiency, cost implications, and applicability to cylindrical lithium-ion battery packs. The paper provides valuable insights into the strengths and limitations of each technique, offering a comprehensive guide for researchers, engineers, and policymakers in the field of energy storage. The findings contribute to the ongoing efforts to develop efficient and sustainable thermal management solutions for cylindrical lithium-ion battery packs in various applications.

Solid–liquid organic phase-change micro/nanocapsules are potential candidates for energy storage. Recently, significant progress has been made regarding phase-change micro/nanocapsules in terms of their synthesis, properties, and applications. Extensive research has been conducted to enhance their thermal properties, such as thermal storage capacity, thermal conductivity, and thermal reliability. However, factors that influence the thermal properties of micro/nanocapsules have received little attention. This study presents a comprehensive review of phase-change micro/nanocapsules focusing on their thermal properties and their influencing factors. In addition, the thermal properties of the major solid–liquid organic pure phase-change materials are summarized. Furthermore, common micro/nanoencapsulation methods and their influence on the thermal properties were analyzed. Finally, the potential applications of these phase-change micro/nanocapsules were also investigated. This study was devoted to enhancing the thermal properties of micro/nanocapsules, which play a crucial role in their practical applications.

Based on the research status of phase-change material (PCM) energy piles, this paper proposes a new type of PCM energy pile-spiral tube-encapsulated PCM energy pile. In order to study the related properties of the energy pile, this study designed and processed the relevant test equipment and built an indoor scale model experimental system. The thermodynamic performance of the spiral tube-encapsulated phase-change energy pile under summer conditions was studied by the test system. Through the indoor scale model test, it is found that compared with the traditional energy pile, the spiral tube-encapsulated PCM energy pile improves the heat exchange capacity of the unit pile body in the early and middle stages of operation, and reduces the surface temperature of the pile body and the heating rate of the surface temperature of the pile body. The upward displacement of the energy pile top is reduced. The heat exchange capacity of the unit pile depth is increased by 6.52 W/m, the maximum pile surface temperature difference is 0.62 °C, and the maximum pile top displacement difference is 0.005 mm. In addition, the total heat transfer of the spiral tube-encapsulated PCM energy pile during the whole operation period is 3.38% higher than that of the traditional energy pile. However, during the whole operation period, the surface stress value of the spiral tube encapsulated PCM energy pile is higher than that of the traditional energy pile. The maximum difference between the two is 9.84 kPa and the maximum difference is 10.8%. The difference between the two is finally stabilized at 1.4 kPa with an increase in time, and the final difference is only 8.8%.

Glass curtain walls (GCWs) have become prevalent in office buildings, owing to their lightweight and modular characteristics. However, their lower thermal resistance, compared to opaque walls, results in increased energy consumption. Incorporating phase-change materials (PCMs) provides a viable solution through which to address the susceptibility of GCWs to external conditions, thus enhancing thermal performance and mitigating energy concerns. This study delves into the influences of the glazing solar heat gain coefficient (SHGC), the glazing heat transfer coefficient (U-value), and PCM thickness on the energy performance of buildings. Using Design Builder (DB) software version 6.1.0.006, a multi-story office building was simulated in different climatic zones in China, covering the climatic characteristics of severe cold, cold, hot summer and warm winter, cold summer and winter, and mild regions. The simulation results quantitatively elucidated the effects of the glazing parameters and the number of PCMs on thermal regulation and energy consumption. A sensitivity analysis identified the glazing SHGC as the most influential factor in energy consumption. Additionally, by employing Response Surface Methodology (RSM), the researchers aimed to achieve a balance between minimal building energy consumption and economic cost, ultimately determining an optimal design solution. The results demonstrated significant energy savings, ranging from 20.16% to 81.18%, accompanied by economic savings, ranging from 15.78% to 79.54%, across distinct climate zones in China.

The thermal performance of a lithium-ion battery module comprising three cells contained within a casing was investigated at discharge rates of 3C and 5C with three different cooling strategies: forced air, phase-change material (PCM), and a hybrid system using a combination of forced air and the PCM. Three levels of fan speed (5000 rpm; 7000 rpm; and 9000 rpm) for cooling air flow were considered. A numerical simulation of heat transfer was performed using the ANSYS Fluent software. The electrochemical modelling of a battery was developed based on the NTGK approach, and the phase-change phenomenon was treated as an enthesis–porosity problem. The composite PCM, aluminum metal foam embedded in n-octadecane, had better heat dissipation performance than forced air convection. The PCM is significantly more effective at heat dissipation than forced air. Interestingly, when using a hybrid cooling system that combines forced air and a PCM, although it meets the operational requirements for Li-ion batteries in regard to maximum temperature and temperature uniformity at a 3C discharge rate, the airflow appears to have a negligible effect on thermal management and yields an indiscernible change in temperature. This can be attributed to a complex flow pattern that developed in a casing as a result of the suboptimal design of the inlet and outlet. Further studies will be required for the optimal positioning of the inlet and outlet, as well as the effectiveness of combining liquid cooling methods.

In this study, we developed a thermal storage medium comprising porous activated carbon filled with organic phase-change materials (PCMs) that utilizes the latent heat of phase-change to absorb heat during heating and release heat during cooling. For the activated carbon, we used both charcoal-based powdered activated carbon (250–350 mesh) and granular activated carbon. The organic phase-change materials used in the experiments were dodecane, tridecane, tetradecane, and pentadecane. Material properties such as thermal conductivity, latent heat, and melting temperature range were evaluated experimentally and theoretically, with the results observed to be consistent. The cyclic thermal performance of the proposed medium was also evaluated. Notably, filling the activated carbon with a mixture of organic PCMs resulted in the highest temperature-moderating effect. The procedure and results presented in this study are expected to aid in further improvement in the performance of thermal storage media containing PCM where stable temperatures are required, including building heating and cooling.

Modern energy batteries are mainly used in pure electric vehicles. The stability of battery operation relies heavily on thermal management systems for which phase-change batteries have become an effective solution. In this study, we designed a battery thermal management system divided into two parts: a shaped phase-change material (PCM) module and a battery module. In the qualitative PCM module, polyethylene glycol was used to absorb heat, expanded graphite (EG) was used as the thermally conductive agent, and copper foam formed the support skeleton. The battery module comprised an 18650 lithium-ion battery with an enthalpy of 155 J/g. In our experiments, we applied PCMs to the battery modules and demonstrated the effectiveness of composite PCM (CPCM) in effectively lowering the temperature of both battery packs and minimizing the temperature discrepancies among individual batteries. At a gradually increasing discharge rate (1C/2C/3C), the battery’s Tmax could be lowered and the temperature could be de creased at various positions. It was evident that the battery temperature could be effectively preserved using CPCM. The findings of this study lay a foundation for future research on battery thermal management. Finally, the copper foam and EG contributed significantly to the prevention of leakage.

Phase-change materials have various applications across industries from thermal energy storage through automotive battery temperature management systems to thermal stabilisation. Many of these applications are shell and tube structures with different shell shapes. However, it is not yet known how the shape of the shell affects the melting, solidification times, and heat transport processes in such structures. To fill this research gap, seventeen shell shapes/orientations were compared using a simulation study. The well-known and validated enthalpy porosity algorithm implemented in the Fluent 2021R2 software was used. The numerical calculations were preceded by the measurement of thermal conductivity, phase change enthalpy, and specific heat during melting and solidification of the phase-change material. The shortest melting time was achieved for a semi-circular shell shape in the downward position, which was 44% shorter than the reference circular case. The shortest solidification times were recorded for an isosceles trapezium in an upward orientation relative to the reference circular case. Therefore, it is possible to significantly reduce the melting time in shell-and-tube systems as a result of the appropriate selection of the shell shape.

Latent thermal energy storage, employing phase-change materials, has been traditionally researched in several areas such solar energy, refrigeration, and electronic cooling, but less conventional applications, e.g. cancer therapy, are also emerging. In this review, theoretical studies categorized in a wide range of subjects are critically discussed. Some topics commonly found in the literature are analyzed, including (not limited to) intensification techniques of heat transfer and numerical methods. Nevertheless, less reported matters are also discussed, such the development of correlations and the utilization of non-conventional techniques to enhance heat transfer. Besides, this work is arranged in a timeline, so that the origins of each topic are tracked and followed along the years to better identify the incremental and disruptive contributions. As an example, first attempts to compare different algorithms to solve phase-change problems, were identified in the 1990′s. To cite more significant advancements, the 2000′s was marked by the first use of artificial neural networks and by the birth of nano-enhanced phase-change materials. Lastly, research gaps and prominent research fields are pointed out as the consequence of mapping the state of the art. A sample of identified gaps are the: (i) investigation on the Newtonian behavior of nano-enhanced phase-change materials in the liquid state, (ii) better investigation on the porosity constant values, for the same phase-change material under different conditions. On the other hand, some promising fields revealed were the development of correlations to predict several parameters and the investigation of non-conventional techniques, e.g. magnetic fields and ultrasound. Latent thermal energy storage was found to possess some well understood behaviors for a ready implementation in commercial scales, but also presents a wide range of areas for continuous research and development. [ABSTRACT FROM AUTHOR]

Phase change materials (PCM) are very effective in improving the thermal performance of walls with their superb heat storage and release capacity. However, the effectiveness of PCM in different thermal environments is restricted by their inherent phase-transition temperatures, especially in summer and winter. In this study, the influence laws and effectiveness of different kinds/configurations of PCM on the thermal performance of lightweight building walls (LBW) in summer and winter were evaluated by using a validated numerical model, and the suitable PCM configurations were proposed to maximize the application potential of PCM. The results show that: (1) Although a single-layer of PCM performs prominently in one season (summer or winter), a double-layer of PCM is the best choice from a year-round perspective under the same total thickness; (2) The effectiveness of double-layer PCM is closely related to the temperature difference between indoor and outdoor (comprehensive outdoor temperature), which is better in summer than in winter; (3) The narrower the phase-transition temperatures range (ΔT), the higher the PCM utilization under other suitable parameters, but the optimum value exists from the application effectiveness, the double-layer PCM is ΔT = 6 °C (27–33 °C, 12–18 °C). Meanwhile, the effectiveness of PCM reaches saturation when thickness and latent heat exceed 10 mm (5 mm+5 mm) and 125 kJ/kg, respectively; (4) The optimized PCM kinds/configurations are applied in local summer/winter can reduce the attenuation rate by 84.6%/84.3%, the delay time is added to 5 h/4.86h, the peak and average heat flux are decreased by 58.2%/36.4% and 22.1%/19.4%, respectively compared with reference wall (no PCM). The findings of this study can provide data support and theoretical reference for the application of PCM in LBW to maximize economic benefits. [ABSTRACT FROM AUTHOR]

New geometry with rectangular inner cylinder containing cold flow has been simulated in this article. Freezing phenomenon has been simulated and NEPCM was mixture of CuO and water. Time-dependent solid fraction term was added to energy equation. Software based on FEM with adaptive grid was implemented for modeling the problem. Diameter of nanomaterial and amplitude of outer wall were assumed as variable. To reach the reliability of assumption of neglecting buoyancy term, comparison with experimental data was illustrated. Providing greater value of A makes the freezing time to reduce about 5.82% which is associated with existence of more NEPCM near the rectangular cylinder when A = 0.3. Influence of A on Tave has no sensible impact for t < 70 s and t > 320 s. Increasing diameter of nano-powder can augment the conductivity but experimental observation shows that there is optimum value for this factor. As dp augments from 30 to 50 nm and 40 nm, the time of solidification alters from 186.57 s to 222.77 s and 149.37 s. With rise of dp, at first, the time declines about 19.98% then time augments about 49.16%. When A = 0.3 and dp = 40 nm, the quickest process takes place and it takes 149.37 s to reach full freezing. [ABSTRACT FROM AUTHOR]

Based on the phase-change material Ge2Sb2Te5 (GST), achromatic metasurface optical device in the longer-infrared wavelength is designed. With the combination of the linear phase gradient GST nanopillar and the adjustment of the crystalline fraction m value of GST, the polarization insensitive achromic metalenses and beam deflector metasurface within the longer-infrared wavelength 9.5 μm to 13 μm are realized. The design results show that the achromatic metalenses can be focused on the same focal plane within the working waveband. The simulation calculation results show that the full-width at half-maximum (FWHM) of the focusing spot reaches the diffraction limit at each wavelength. In addition, the same method is also used to design a broadband achromatic beam deflector metasurface with the same deflection angle of 19°. The method proposed in this article not only provides new ideas for the design of achromatic metasurfaces, but also provides new possibilities for the integration of optical imaging, optical coding and other related optical systems. [ABSTRACT FROM AUTHOR]

Oral squamous cell carcinoma represents 90% of all oral cancers. Recurrence prevention remains an important prognostic factor in patients with oral squamous cell carcinoma, and the recovery of the oral epithelium post-surgery is still a challenge. Thus, there is an urgent need to develop a smart carrier material to realize the spatiotemporally controlled release of anticancer drugs, instead of multiple oral administrations, for recurrence prevention and promoting the reconstruction of injured epithelial tissues. Here, we developed a multi-layered nanofiber patch capable of the photothermal-triggered release of low-molecular-weight fucoidan (LMWF) from the sandwiched layer, together with electrospun fibers as the backing and top layers. The sandwiched layer was made of phase-change materials loaded with indocyanine green, a photosensitive dye, for the localized release of LMWF in response to near-infrared irradiation. We showed that the on-demand release of LMWF was able to kill oral cancer cells effectively. Furthermore, adding acellular dermal matrix to the top nanofiber layer improved the proliferation of human oral keratinocytes, while the hydrophobic back layer served as a barrier to prevent loss of the drug. Taken together, this study provides a feasible and smart material system for killing oral squamous cancer cells together with the recovery of oral epithelium. [ABSTRACT FROM AUTHOR]

Based on the phase-change material Ge2Sb2Te5 (GST), achromatic metasurface optical device in the longer-infrared wavelength is designed. With the combination of the linear phase gradient GST nanopillar and the adjustment of the crystalline fraction m value of GST, the polarization insensitive achromic metalenses and beam deflector metasurface within the longer-infrared wavelength 9.5 μm to 13 μm are realized. The design results show that the achromatic metalenses can be focused on the same focal plane within the working waveband. The simulation calculation results show that the full-width at half-maximum (FWHM) of the focusing spot reaches the diffraction limit at each wavelength. In addition, the same method is also used to design a broadband achromatic beam deflector metasurface with the same deflection angle of 19°. The method proposed in this article not only provides new ideas for the design of achromatic metasurfaces, but also provides new possibilities for the integration of optical imaging, optical coding and other related optical systems. [ABSTRACT FROM AUTHOR]

A one-phase Stefan problem for a semi-infinite material is studied for special functional forms of the thermal conductivity and specific heat depending on the temperature of the phase-change material. Using the similarity transformation technique, an exact solution for these situations are shown. The mathematical analysis is made for two different kinds of heat source terms, and the existence and uniqueness of the solutions are proved. [ABSTRACT FROM AUTHOR]

The demand for high-performance and compact electronic devices has been increasing day by day. Due to their compactness, excessive heat is generated, causing a decrease in efficiency and life. Thermal management of electronic components is crucial for maintaining excessive heat within the limit. This experimental research focuses on the combined effect of nano-enhanced phase-change material (NePCM) with different configurations of heat sinks for cooling electronic devices. Multi-walled carbon nanotubes (MWCNTs) are used as nanoparticles with concentrations of 3 wt% and 6 wt%, RT-42 as the phase-change material (PCM), and aluminum as the pin fin heat sink material. Different configurations of the heat sink, such as circular, square, and triangular pin fins, are used against the fixed volume fraction of the fins. It is found that the square configuration has the highest heat transfer with and without PCM. A maximum base temperature reduction of 24.01% was observed in square pin fins with RT-42 as PCM. At 6 wt% of NePCM, the maximum base temperature lessened by 25.83% in the case of a circular pin fin. It is concluded from the results that a circular pin fin with NePCM is effective for base temperature reduction, and all fin configurations with NePCM collectively reduce the heat sink base temperature. [ABSTRACT FROM AUTHOR]

Optical characteristics of germanium telluride (GeTe) thin films in multilayer structures are calculated. A model of a multilayer optical coating with a four-level transmission coefficient is developed. Based on the calculated data, thickness values are determined at which the transmittance change is greatest for 1550-nm modulated optical radiation. Experimental samples coated with antireflection GeTe films are synthesized and their optical transmission characteristics are investigated. Combinations of parameters of the multilayer structures for the implementation of contrast transmittance levels are determined. The results of the study represent the implementation of a multilevel artificial optical synapse for neuromorphic processors.

Phase-change materials (PCMs) excel in storing significant thermal energy through the latent heat of fusion during phase changes. However, they often suffer from low thermal conductivity, requiring the incorporation of materials with higher thermal conductivity to overcome this limitation. In this study, we employ the level-set method to topologically optimize the distribution of both PCM and high thermal conductivity materials within heat sinks. The heat transfer process is modeled as an unsteady diffusion problem, with PCM integrated using the apparent heat capacity method. The finite element method, implemented using FEniCS, is utilized to compute the temperature distribution at each time step. The optimization problem is solved using ParaLeSTO, a modular topology optimization software written in C++, seamlessly interfacing with FEniCS through its Python interface. To compute boundary point sensitivities for level-set topology optimization, the discrete adjoint method is employed, combining a perturbation scheme with automatic differentiation. The proposed methodology is first applied to a two-dimensional example of temperature oscillation minimization with a heat flux boundary condition, drawn from existing literature. Subsequently, a two-dimensional example with multiple volumetric heat sources is studied, followed by an extension to a three-dimensional design domain. Comparisons with optimized designs without PCM, serving as a reference, highlight the superior thermal performance of heat sink designs with PCM. The results showcase a maximum temperature reduction of up to 42%, a mean temperature reduction of up to 42%, and a temperature variance reduction of up to 94%. This research contributes to heat sink design by offering discrete solutions that significantly improve thermal performance as compared to designs without PCM. Its impact extends to addressing crucial challenges in thermal management across various applications, including automotive cooling systems, aerospace components, and consumer electronics. • Introducing level-set topology optimization for heat sinks with phase-change materials. • Comparative analysis between designs with and without phase-change materials. • Demonstrating method versatility with examples in two- and three-dimensions. [ABSTRACT FROM AUTHOR]

Unreasonable filling positions of phase-change materials (PCMs) significantly reduce the heat storage capacity, heat release time, output temperature difference, heat collection efficiency, and heat peak migration capacity of PCM-based solar–air collectors in building heating systems, thereby affecting the comprehensive heating requirements of building users. To solve this problem and obtain the optimal filling position of the PCM, four PCM filling schemes were designed in this experiment: Type I was a solar air collector with the PCM filled in the upper portion, Type II was filled in the middle portion, Type III was filled on both sides, and Type IV was filled in the bottom portion. Subsequently, the four models were compared. A comparative analysis of the thermal performance evaluation index showed that compared with the other three types of collectors, the heat storage layer of Type I stored 1.505 × 106 J of heat in 1.42 h , indicating that the Type I solar–air collector had the best heat storage speed rate. When the solar energy supply was terminated, the continuous heat release time of the Type I collector was 13.92 h , and the ratio of the heat release time to the non-solar time was 96 %. The Type I collector had the lowest output temperature and the slightest temperature fluctuation, which could increase indoor thermal comfort. The average daily heat collection efficiency of the Type I collector was the lowest, at only 38.11 %, indicating that the Type I collector has the strongest "peak cutting and valley filling" ability, which allows for transferring more heat for nighttime release. Therefore, filling the upper portion is the optimal filling scheme that can provide technical benefits for the application and development of collectors. [ABSTRACT FROM AUTHOR]

[Display omitted] • An investigation of ventilated PCM roof in a mono-zone building was performed. • Roof configurations were evaluated experimentally and numerically in a Bsh climate. • Ventilation stabilized the time the PCM remained in each melting–solidification phase. • PCM roof reduced indoor temperature fluctuations between 1.94 and 10.4 %. • PCM reduced the thermal loads by up to 92.9 % with small ducts open 24 h/day. The effect of incorporating phase change material (PCM) into roofing systems combined with natural ventilation is numerically and experimentally investigated. Four roof configurations, including ventilated and unventilated options with and without an air gap between the PCM and the insulation material, are subjected to experimental research during the winter season in a semi-arid climate using two fully instrumented modules. A sensitivity analysis is conducted through annual transient simulations for different air gap dimensions and schedule openings. The experimental campaign demonstrates a decrease in the maximum peak indoor air temperature of between 1.9 and 4.4 % when the PCM is employed. Additionally, an increase in the minimum indoor air temperature between 4.4 and 10.4 % is achieved. Similarly, an improvement in the thermal performance of the PCM is observed when natural ventilation occurs, and it positively influences the interior surface temperature of the roof. Furthermore, the numerical results show almost zero annual thermal balance in the scenario where natural ventilation is allowed in the combination of 12 and 24 h per day through ducts with a diameter of 15 and 20 cm, respectively. Finally, this demonstrates that PCM roofs enhanced with natural ventilation could be an energy-efficient alternative for semi-arid climates under well-configured ventilation schedules and roof layers. [ABSTRACT FROM AUTHOR]

• Phase-change microcapsules with GO were synthesized via suspension polymerization. • Incorporation of GO nanosheets improved the thermophysical properties. • Microcapsules with GO had the functions of photothermal conversion and storage. • GO-doped microcapsules achieved a 67.88% photothermal conversion efficiency. Solar energy is a green but intermittent energy source that has triggered widespread interest in phase-change materials (PCMs) for energy storage. Graphene oxide (GO)-doped styrene–divinylbenzene copolymer (SDB) microcapsules with n-Octadecane (ODE) were synthesized as composite PCMs by suspension polymerization. Emphasis was placed on how GO nanosheets affect heat storage, photothermal conversion, and heat transfer of the microcapsules. The microcapsules are spherical and well-dispersible when viewed under a scanning electron microscope. Thermal analysis techniques were employed to describe the thermophysical characteristics of the microcapsules. The results show that microcapsules with a 1.0 wt% GO concentration (MEPCM@GO-1.0) have the best performance. The melting enthalpy of MEPCM@GO-1.0 microcapsules is 120.7 ± 0.4 J·g−1, the crystallization enthalpy is 113.3 ± 0.3 J·g−1, and the encapsulation rate is 53.3 ± 0.5 %. Doping GO nanosheets enhances the thermal stability of microcapsules. In the photothermal conversion test, the MEPCM@GO-1.0 microcapsules achieved 67.88 % photothermal conversion efficiency. In the thermal cycle test and photothermal conversion cycle test, the microcapsules showed good repeatability and stability. The GO-doped microcapsules have potential application prospects in heat storage systems, heat dissipation of electronic devices, and solar energy utilization, which are conducive to the development of sustainable energy. [ABSTRACT FROM AUTHOR]

Using phase-change materials in thermal energy storage systems for concentrating solar thermal plants can significantly reduce the volume of storage media and, therefore, the cost of the system. However, this approach introduces new material compatibility issues between the thermal energy storage material and the containment vessel in the form of corrosion and thermal transients, which are inherent in these systems. Rods and sheet coupons of stainless steel 316L were corroded for up to 768 h in 59.4/40.6 wt% Na 2 CO 3 /NaCl eutectic salt under isothermal (650 °C) and cycled conditions (between 600 and 650 °C). The testing methodologies correspond to actual service conditions, as isothermal degradation may not represent material loss under typical solar thermal cycling conditions. Mass losses were calculated via the Dynamic Gravimetric Analysis technique while Scanning Electron Microscopy utilizing Energy Dispersive Spectroscopy was used to analyze the corrosion layers. Isothermal mass loss plateaued at 75 mg/cm2 at 96 h with no further measurable loss after this time, while cycled samples had a fast initial mass loss rate of 60 mg/cm2 in the first 96 h and lost 0.0331 mg/cm2 every hour thereafter. The results indicate that isothermal samples corrode more slowly than the predominant industry cases of thermal cycling. Spalling is responsible for the degradation in both sets; the continual temperature changes in the cycled samples lead to additional stresses, exacerbating the effect. • Molten salt media must be tested to ensure storage material compatibility. • Corrosion rates estimate lifing of thermal energy storage containment vessels. • Isothermal samples build a semi-protective porous oxide layer. • Cycled samples spall the oxide layer and have overall higher corrosion rates. • Thermal cycling dramatically reduces the life of storage containers. [ABSTRACT FROM AUTHOR]

Radial assembly of graphene nanoplates in PCM, which delivers excellent thermal cycling stability, remarkable latent heat storage capacity, together with leak-proof properties. [Display omitted] • Radial assembly of graphene nanosheets based on ice template method. • Multidirectional conduction pathways for microscopically thermal transport. • Enhanced thermal conductivity by incorporating mere 6 vol% of GNP. • Remarkable latent heat storage capacity exceeding 175 J/g. • Superior solar-to-thermal efficiency upon to 85.8% Phase change material (PCM) with the capacity to store and release substantial thermal energy, has drawn significant attention. However, its large-scale application is still hindered by inadequate thermal management capacity and unsatisfactory thermal conductivity. In this study, graphene nanoplates were assembled into a 3D thermally conductive scaffold using a specialized ice template method. By virtue of the unique growth of ice crystals in radial pattern, a series of multidirectional thermal conduction pathways were successfully constructed within PCM, which has provided microscopically interconnected pathways for thermal transport. Consequently, a remarkable 5.2-fold increment in thermal conductivity (1.365 W m−1 K−1) in comparison to pure paraffin was achieved by incorporating a mere 6 vol% of GNP, which therefore enables excellent thermal cycling stability, remarkable latent heat storage capacity exceeding 175 J/g, together with leak-proof properties even under extended high-temperature conditions. Moreover, the solar-to-thermal energy storage efficiency is up to 85.8 % due to its efficient photothermal effect. This work presents an innovative approach to design PCMs with enhanced thermal conductivity and photothermal efficiency, offering promising applications in advanced thermal storage. [ABSTRACT FROM AUTHOR]

The paper chronologically describes the results of research on the flow of micro-encapsulated PCM (mPCM) and nano-encapsulated PCM (nPCM) slurry in heat-transfer systems. The focus is on three thematic groups: mPCM (nPCM) slurry flow pressure drop; the friction factor in the laminar, transient, and turbulent flow of slurry in the channels; and the assessment of the effectiveness of using the mPCM (nPCM) slurry in the context of improving heat-transfer coefficients but with increased pumping power. It was found that the number of publications devoted to the above-mentioned topics is very limited compared to the research on the thermal and rheological properties of the mPCM (nPCM) slurry, which has resulted in the lack of systematized knowledge about the influence of slurry concentration, particle size, materials, etc., for example, on the friction factor. It was found that the use of the mPCM (nPCM) slurry in heat-transfer systems may be proper, provided that an appropriate and sufficiently high flow rate is ensured.

Thermal heat storage is becoming important in systems with renewable energy sources. Their largest benefit is smoothing the intermittent production and reduction in the site peak demand. The advantages of thermal energy storage with phase-change material are storing energy at a lower temperature for reduction in thermal losses, and enabling energy transfer at a constant temperature, which reduces the risk of equipment damage. In this paper, a low-order model of latent thermal energy storage, derived in a state-space form by using the mixed logical dynamical approach, is proposed. The model is compared to a stratified model and shows significant improvements of physical accuracy and execution time. Finally, a model predictive control algorithm suited for the real case study is designed, implemented and compared to classical rule-based control. The obtained results show significant energy savings of 8.43%, and improvements in user comfort and equipment duration.

This article presents the use of phase-change material (PCM) thermal storage within the Horizon 2020 HEART project (Holistic Energy and Architectural Retrofit Toolkit), aimed at decarbonising the European building sector through the retrofitting of existing structures into energy-efficient smart buildings. These buildings not only reduce energy consumption, but also incorporate advanced technologies for harnessing green energy, thereby promoting environmental sustainability. The HEART project employs state-of-the-art technologies for electricity production/dispatching and heat generation/storage, managed by a cloud-based platform for the real-time monitoring of parameters and optimising energy utilisation, enabling users to control their environmental comfort. The article provides a detailed examination of one of the project’s demonstration sites in Italy, focusing on various components such as heat pumps, photovoltaic systems (PV), controllers, and particularly emphasising the significance of storage tanks. The study involved the measurement and analysis of three heat storage tanks, each with a total volume of 3000 L. These tanks utilised PCM modules for latent heat storage, significantly enhancing overall heat accumulation. Water served as the heat transfer fluid within the tanks. Through meticulous calculations, the article quantifies the accumulated heat and presents a comparative evaluation between PCM-based storage tanks and conventional water tanks, showcasing the advantages of PCM technology in terms of increased heat retention and efficiency.

The wide application of lithium-ion batteries (LIBs) brings along with it various safety problems, such as fire and explosion accidents. Aiming at the thermal runaway (TR) and fire problems of LIBs, we reviewed the evolution of TR within LIB and the release of TR gases and their hazards, as well as the research progress in recent years in the area of fire separation of LIBs. To begin with, physical, electrical, and thermal abuse are the three main factors leading to TR and the thermal stability of aging batteries significantly deteriorates. Furthermore, the decomposition of the electrolyte and the reaction between the active materials generates CO, CO2, H2, HF, and a variety of hydrocarbons. These TR gases have serious toxic and explosive hazards. In addition, fire separation can effectively delay the occurrence and propagation of TR within LIB modules. As a good heat-absorbing material, phase-change materials are widely used in the thermal management system and have a great prospect of wide applications in the fire separation of LIBs. Finally, the research on the TR gases’ hazards of aging LIB and safer and more effective fire separation are prospected.