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In this research, a novel design stochastic numerical technique is presented to investigate the unsteady form magnetohydrodynamic (MHD) slip flow along the boundary layer to analyze the transportation and heat transfer in a solar collector through nano liquids which is a revolution in the field of neurocomputing. Thermal conductivity in variable form is dependent on temperature and wall slips are assumed over the boundary. For mathematical modeling, the solar collector is assumed in the form of a nonlinear stretching sheet and a quite new artificial neural networks (ANNs) based approach is used to solve the current problem in which inverse multiquadric radial basis (IMRB) kernel is sandwiched between a global search solver named genetic algorithms (GAs) and a highly effective local solver named sequential quadratic programming (SQP) i.e. IMRB-GASQP solver. The governing boundary value problem is altered in the form of a system of nonlinear ordinary differential equations (ODEs) through the utilization of similarity transformation and then the obtained system of ODEs is solved using IMRB-GASQP solver by altering the values of distinguished parameters involved in it to observe the fluctuation in the velocity and temperature profiles of nanofluid. The obtained results are effectively compared with the reference solutions using the Adams numerical technique in graphical and tabulated form. An exhaustive error analysis using performance operators is presented while the efficacy of the designed solver using various statistical operators is also part of this research. [ABSTRACT FROM AUTHOR]

Variable viscosity, activation energy and microgravity effects on Darcy nanofluid for the thermal performance improvement in thermal energy storage systems through stretching flat plate solar collector is the focus of this research. Thermal energy storage (TES) can be improved though solar collectors, phase change materials and photovoltaic cells using nanofluid in the base liquid. To increase the reaction rate in nanoparticles, the activation energy and solar radiations are used for the efficiency of TES. The viscosity of nanofluid improves the heat and mass transmission. Due to solar radiations, nanofluid plays prominent role in TES applications such as heat exchangers, electronic cooling devices and solar power generation through solar plate collector. Solar energy based mathematical model is developed to execute the frequency of oscillating heat transfer in TES numerically. Primitive and Stokes coefficients are used for feasible programming. Finite difference analysis is performed to display oscillatory thermal energy using Gaussian-elimination matrix scheme. Steady velocity, surface temperature and concentrations are plotted and utilized in oscillatory formula to perform oscillatory skin friction, oscillatory heat transfer and oscillatory mass transfer along π⁄4 angle. Fluid velocity enhances but temperature and concentration variation decreases as viscosity decreases. High amplitude in velocity, temperature and concentration is sketched as activation energy and microgravity increases. Steady heat and mass transmission enhances as thermophoretic and Brownian motion enhances. Amplitude and frequency of oscillations in heat transport, skin friction and mass transport enhances as Prandtl and Schmidt component enhances. In validation of results, the 0.00064% percentage error for heat transport and 0.00102% percentage error for mass transmission are deduced. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) with remarkable latent heat storage/release capacity have demonstrated prominent advantages in energy conservation and efficient thermal management. Nevertheless, simultaneously achieving high thermal energy storage capacity, excellent toughness, and flexibility in PCMs is a significant challenge for programmable deformations when used in complex environmental scenarios. A flexible PCM is reported with programmable deformation constructed through a three‐dimensional (3D) dynamic cross‐linked network. This approach has culminated in the development of homogeneously cross‐linked and self‐supporting polyurethane‐based solid‐solid PCM with graphene enhancement, which exhibits exceptional properties of high latent heat storage/release capacity (∆Hm = 105.3 J g−1, ∆Hc = 105.0 J g−1), high toughness (ε = 1543%, σ = 19.2 MPa), excellent flexibility, and shape memory behavior (Rr = 90.3%). Notably, when subjected to photothermal stimulation, it can lift objects weighing more than 2620 times their weight, presenting a working density of 1330 kJ m−3. This flexible PCM, which simultaneously possesses a high latent capacity and photothermal‐driven performance, opens a new pathway for artificial muscles or soft robots with the requirements for energy conservation and thermal management in complex scenarios. [ABSTRACT FROM AUTHOR]

Syntactic foams are lightweight porous composites obtained by the addition of hollow glass microspheres (HGMs) to a polymer matrix. This work experimentally and numerically investigates the thermal behavior of epoxy‐based syntactic foams with enhanced multifunctionality produced by incorporating microencapsulated phase change materials (PCMs) as functional fillers, providing thermal energy storage and temperature stabilization due to its large latent heat of melting. Foams are fabricated using varying ratios of HGMs (0–40 vol%) and PCM (0–40 vol%) to achieve tuned densities and thermal properties with a total filler content of up to 40 vol%. A one‐dimensional numerical heat transfer model based on the enthalpy method is presented to simulate the thermal behavior of these materials. The model accurately incorporates the specific heat and thermal conductivity of the foam components, as well as the latent heat absorption during PCM melting (up to 68 J/g). The model is experimentally validated by demonstrating good agreement with the measurements of transient temperature profiles during heating tests on the foam samples. The validated tool is then leveraged to model the thermal response of the foams under a sinusoidally varying heat source, similar to the possible real applicative scenarios. These results can help optimize foam compositions balancing energy storage density, heat transfer properties, and structural support for lightweight energy storage systems. Potential applications include high‐efficiency thermal management in battery packs, electronic cooling, solar energy storage, and sustainable temperature‐controlled buildings. Highlights: Foams with 0–40 vol% PCM and 0–40 vol% HGM show up to 68 J/g latent heat.1D numerical model accurately captures thermal conductivity and PCM phase change.Validated model simulates thermal response under sinusoidal heat, optimizing foam composition.Foams act as thermal reservoirs, maintaining up to 5°C lower surface temperatures than epoxy. [ABSTRACT FROM AUTHOR]

The article "Microbial growth within porous gravity currents" delves into the effects of microbial activity on buoyancy-driven flow in porous layers, specifically examining how biofilm growth alters rock heterogeneity, porosity, and permeability. Through numerical simulations, the study illustrates the evolution of flow dynamics over time, emphasizing the intricate relationship between microbial growth and fluid migration in porous media. The text also discusses the implications of microbial growth on gravity-driven flows in porous media, particularly in the context of underground hydrogen storage, analyzing different regimes of bioclogging and their respective impacts on fluid migration. Overall, the document compiles various research articles on fluid dynamics in porous media, shedding light on topics such as biofilm growth, hydraulic properties, and the complexities of fluid migration in confined porous layers. [Extracted from the article]

Solar-thermal energy storage (STES) within solid-liquid phase change materials (PCMs) has emerged as an attractive solution to overcome intermittency of renewable energy. However, current storage systems usually suffer from slow charging rates, sacrificed storage capacity, and overheating tendency. Inspired by the thermoregulation behavior of Cyprinid fish, here, we present a quick-responsive, ultrafast, large-capacity, overheating-protective STES strategy. We fabricate a liquid-infused solar-absorbing foam charger that can rapidly advance the receding solid-liquid charging interface to efficiently store solar-thermal energy as latent heat and spontaneously float upward to cease the charging process upon overheating. This bioinspired dynamic charging is adaptable to a variety of PCMs, unlocking the potential for safe and efficient utilization of renewable thermal energy. [ABSTRACT FROM AUTHOR]

Introduction: Solar resources are rich in north China and however, solar thermal energy has little contribution to space heating due to the intermittency and instability as well as the lack of seasonal energy storage technology. Although underground thermal energy storage (UTES) can solve the above problems effectively, the existing UTES systems either have low energy storage density and recovery efficiency or have high construction cost. Methods: Inspired by the enhanced geothermal system (EGS), here a novel scheme of storing high temperature thermal energy into the shallow depth EGS (SDEGS) is proposed. Thermal energy is stored into SDEGS during the non-heating season and is extracted for space heating during the heating season. Results: The results show the thermal performance of SDEGS always remains stable due to continuous thermal energy injection, and its thermal recovery efficiency is always greater than 90% by storing thermal energy into the tight rocks and circumventing the formation of the natural convection. Discussion: SDEGS can be constructed in the shallow buried depth rocks having a low requirement about temperature, largely reducing project cost and risk and widening the application range. [ABSTRACT FROM AUTHOR]

Solar dryers present a clean and affordable solution to food wastage which is one of the biggest concerns of the world. The highest contribution of domestic sector to the global food waste and lack of researches on small-scale solar dryers have created a need to develop sustainable and low cost domestic solar dryers. The present research aims to develop and analyse the output behaviour of a beeswax-packed domestic solar dryer (BDSD) for intermittent bitter gourd drying. The drying kinetics of bitter gourd slices and thermal, economic, environmental and exergetic performances of the BDSD have been evaluated with varying sample masses for passive and active drying conditions. The average final moisture content of the bitter gourd slices for passive and active conditions were found to be 3.26 and 3.93 % (wb), respectively. Midilli-Kucuk model exhibited the strongest fit to the bitter gourd drying behaviour under both the drying conditions. The total moisture evaporation, heat transfer coefficients, thermal efficiency, specific moisture extraction rate, savings for dried bitter gourd slices drying, CO2 mitigation, carbon credit earned and exergy efficiency were found to increase while the drying rate, effective moisture diffusivity, specific energy consumption, costs for bitter gourd slices drying, payback period and energy payback time decreased as the sample mass increased under both drying conditions. The performance of the BDSD was found to be a linear function of sample mass under both drying conditions. [ABSTRACT FROM AUTHOR]

This review article provides a comprehensive analysis of the technical advancements and research trends in solar drying technologies for agricultural products. The study encompasses various innovations in energy storage systems, including phase change materials (PCMs) and the use of computational fluid dynamics (CFD) for optimizing the drying process. Through a bibliometric analysis of 126 scientific papers published between 1984 and 2024, five major research clusters were identified: energy generation, heat transfer, thermal storage, simulation modeling, and the integration of hybrid systems. The results demonstrate a marked increase in scientific output over the past decade, emphasizing a growing interest in the sustainable use of solar energy for drying applications. Key findings highlight that while PCM-based storage solutions significantly enhance the thermal stability of dryers, the high implementation costs and technical complexities limit their adoption, especially in small-scale operations. Similarly, CFD models have proven effective in optimizing air and temperature distribution within dryers; however, their performance is hindered by real-world fluctuations in solar radiation and humidity levels. To address these limitations, future research should focus on the development of cost-effective PCM materials and the improvement of CFD models for dynamic environmental conditions. The review concludes by emphasizing the importance of interdisciplinary collaboration in the design and application of these technologies, recommending the inclusion of real-world case studies to better illustrate the practical implications and economic benefits of solar drying technologies for agricultural production. [ABSTRACT FROM AUTHOR]

Naphthalene is a fungicide that can also be a phase-change agent owing to its high crystallization enthalpy at about 80 °C. The relatively rapid evaporation of naphthalene as a fungicide and its shape instability after melting are problems solved in this work by its placement into a cured epoxy matrix. The work's research materials included diglycidyl ether of bisphenol A as an epoxy resin, 4,4′-diaminodiphenyl sulfone as its hardener, and naphthalene as a phase-change agent or a fungicide. Their miscibility was investigated by laser interferometry, the rheological properties of their blends before and during the curing by rotational rheometry, the thermophysical features of the curing process and the resulting phase-change materials by differential scanning calorimetry, and the blends' morphologies by transmission optical and scanning electron microscopies. Naphthalene and epoxy resin were miscible when heated above 80 °C. This fact allowed obtaining highly concentrated mixtures containing up to 60% naphthalene by high-temperature homogeneous curing with 4,4′-diaminodiphenyl sulfone. The initial solubility of naphthalene was only 19% in uncured epoxy resin but increased strongly upon heating, reducing the viscosity of the reaction mixture, delaying its gelation, and slowing cross-linking. At 20–40% mass fraction of naphthalene, it almost entirely retained its dissolved state after cross-linking as a metastable solution, causing plasticization of the cured epoxy polymer and lowering its glass transition temperature. At 60% naphthalene, about half dissolved within the cured polymer, while the other half formed coarse particles capable of crystallization and thermal energy storage. In summary, the resulting phase-change material stored 42.6 J/g of thermal energy within 62–90 °C and had a glass transition temperature of 46.4 °C at a maximum naphthalene mass fraction of 60% within the epoxy matrix. [ABSTRACT FROM AUTHOR]

The space heating in residential buildings during winters account for a considerable amount of conventional or high-grade electrical energy. Therefore, improving the performance of space heating systems with the inclusion of renewable energy sources like solar becomes crucial in order to have better occupant's comfort while reducing energy use. Phase change material (PCM) is one of the best solutions for the storage of renewable thermal energy, especially solar, which are intermittently available. PCM stores energy when surplus energy is available and deliver whenever it is required. It can be integrated with the system for energy storage as well as availing heat at a constant temperature. The present study will try to demonstrate the energy-saving by implementing the local heating with a spiral latent heat thermal energy storage system, when only a particular (local) space heating is of interest. In this work, an experimental, as well as the numerical studies of a dome over a bed were performed. Various heating coil configurations, namely floor coil, roof zig-zag, and roof spiral, were constructed to find the best configuration for the localized space heating. Experiments and simulations with the variable flow rate (0.25, 0.50, and 0.75 m/s) and varying inlet temperatures (55, 60, and 65 °C) of the heat transfer fluid were carried out. It was found that the floor coil heating gives better results as compared with the other two. It was also seen that the effect of mass flow rate and inlet temperature was not that much significant after a limit. A temperature difference of 20 °C was maintained between the space under consideration with the surrounding room. [ABSTRACT FROM AUTHOR]

We compared two methods of partitional calorimetry to calculate heat storage and heat debt during cold air (0°C) exposure causing mild core cooling. Twelve participants performed a 5 min baseline in thermoneutral conditions (∼22.0°C, ∼50% relative humidity) followed by cold air exposure (∼0°C) until rectal temperature was reduced by ∆−0.5°C. Partitional calorimetry was used to calculate avenues of heat exchange (radiative, convective, and evaporative), heat storage, and heat debt continuously throughout cold exposure. We compared deriving these variables using prediction equations based on environmental and participant characteristics (PCALEquation Method) versus using measurement tools such as humidity sensors and heat flux discs (PCALHeat Flux Method). There were significant differences between methods (all p ≤ 0.001) for determining heat exchange, heat storage, and heat debt. At ∆−0.5°C, PCALHeat Flux Method had greater levels of radiative and convective heat exchange (PCALHeat Flux Method: −143.0 ± 16.8 W∙m2 vs PCALEquation Method: −123.0 ± 12.9 W∙m2, p ≤ 0.001), evaporative heat exchange (PCALHeat Flux Method: −9.0 ± 1.7 W∙m2 vs PCALEquation Method: −4.1 ± 0.0 W∙m2, p ≤ 0.001), heat storage (PCALHeat Flux Method: −15.0 ± 31.0 W∙m2 vs PCALEquation Method: +6.0 ± 25.9 W∙m2, p = 0.020), and heat debt (PCALHeat Flux Method: −692.0 ± 315.0 kJ vs PCALEquation Method: −422.0 ± 136.0 kJ, p ≤ 0.001). Overall, this study found the largest discrepancies between the two methods were when the environmental conditions and skin temperature were in high flux, as well as when core temperature was reduced by ∆−0.5°C. The use of PCALHeat Flux Method may be more advantageous to use in the cold to provide a higher resolution measurement of cold strain. [ABSTRACT FROM AUTHOR]

In the present study, a lab-scale for closed thermochemical heat storage reactor design is performed for seasonal thermochemical energy storage using magnesium chloride hexahydrate based on dehydration and hydration processes. Firstly, the closed reactor and plate heat exchanger are studied. Then, reactor layout modifications are examined. The dehydration process is performed under 95°C. During hydration, plates' temperature ranges from 20°C to 30°C. The impact of adding zeolite13X-4A to magnesium chloride hexahydrate is examined. The addition of zeolite13X-4A to magnesium chloride hexahydrate of 1/4 mass ratio improves the hydration process and increases its efficiency. [ABSTRACT FROM AUTHOR]

Using efficient building materials with high thermal inertia maintains indoor thermal comfort while reducing energy demand and energy savings. In this study, we developed and characterized the thermophysical and chemical properties of a novel Biosourced Composite Phase Change Material prepared using the shape-stabilized method for energy storage and improving the energy efficiency of buildings in arid climates. The physico-chemical compatibility between RT28 HC and the selected matrix was verified by Fourier Transform Infrared Spectroscopy and X-Ray Diffraction techniques and observed with Scanning Electron Microscope. The Differential Scanning Calorimeter results indicated that the composite material including 50 wt. % RT28 HC has a melting temperature and latent heat property of 31.5 °C and 128.3 J⋅g−1, respectively. Thermogravimetric measurements confirmed the thermal reliability of the biosourced composite material for building applications. The thermal conductivity of RT28 HC incorporated into the biosourced composite material, including 10 wt. % of graphite, was improved by 305 %. Thermal performance tests the potential of the composite material to improve the thermal performance of walls subjected to the thermal conditions of the arid zone climates were implemented using a trombe wall. Thermal performance results revealed that integrating composite material plates reduced the internal and external faces of the trombe wall temperatures by 7 °C and 14 °C, respectively. Integrating the biosourced composite material into the wall increases its thermal inertia and stabilizes the interior temperature within the comfort temperature range. Thermal performance tests confirm the biosourced composite material's efficacy in improving thermal comfort, as well as its potential application for thermal energy storage in buildings. [ABSTRACT FROM AUTHOR]

Inorganic hydrated salts, noted for their high thermal storage density, excellent thermal conductivity, and non‐toxicity, are suitable candidate material for thermal management, particularly in enhancing human living environments when their phase transition points are near room temperature. Herein, we present an efficient and environmentally friendly microencapsulation method for inorganic hydrated salt through organic phase separation method. Eutectic hydrated salt (EHS) consisted of sodium carbonate decahydrate (SCD) and disodium hydrogen phosphate dodecahydrate (DHPD) was prepared as the core material while the mixture of ethyl cellulose (EC) and acrylonitrile‐butadiene‐styrene (ABS) as composite shell materials. Various characterization techniques were used to evaluate the micromorphology, chemical structure, thermal properties and thermal stability of the microcapsules. The resulting microcapsules exhibited a phase change temperature of 22.6 °C with a remarkable enthalpy of 131.4 J/g. Particularly, the enthalpy remained at 117.7 J/g even after 50 thermal cycles, indicating stable cycling thermal reliability. Furthermore, it was confirmed that the EHS was effectively encapsulated within the composite shell, and the microcapsules had a quasi‐spherical shape and core‐shell structure. More importantly, this method of microencapsulation could potentially be extended to other liquid hydrated salts at room temperature, offering a versatile approach for future applications. [ABSTRACT FROM AUTHOR]

Hydrogen storage technologies are key enablers for the development of low-emission, sustainable energy supply chains, primarily due to the versatility of hydrogen as a clean energy carrier. Hydrogen can be utilized in both stationary and mobile power applications, and as a low-environmental-impact energy source for various industrial sectors, provided it is produced from renewable resources. However, efficient hydrogen storage remains a significant technical challenge. Conventional storage methods, such as compressed and liquefied hydrogen, suffer from energy losses and limited gravimetric and volumetric energy densities, highlighting the need for innovative storage solutions. One promising approach is hydrogen storage in metal hydrides, which offers advantages such as high storage capacities and flexibility in the temperature and pressure conditions required for hydrogen uptake and release, depending on the chosen material. However, these systems necessitate the careful management of the heat generated and absorbed during hydrogen absorption and desorption processes. Thermal energy storage (TES) systems provide a means to enhance the energy efficiency and cost-effectiveness of metal hydride-based storage by effectively coupling thermal management with hydrogen storage processes. This review introduces metal hydride materials for hydrogen storage, focusing on their thermophysical, thermodynamic, and kinetic properties. Additionally, it explores TES materials, including sensible, latent, and thermochemical energy storage options, with emphasis on those that operate at temperatures compatible with widely studied hydride systems. A detailed analysis of notable metal hydride–TES coupled systems from the literature is provided. Finally, the review assesses potential future developments in the field, offering guidance for researchers and engineers in advancing innovative and efficient hydrogen energy systems. [ABSTRACT FROM AUTHOR]

This study investigates innovative solutions for balancing energy supply and demand using long-term thermal energy storage (TES) systems, with a focus on tank thermal energy storage (TTES) for European buildings, which account for approximately 40% of energy consumption in the European Union. Research conducted at the Technical University of Košice explores the potential of TTES systems for efficient and long-term energy storage. The accumulation is carried out in three existing underground tanks of different volumes. Among various outputs, we present the cooling process resulting from covering the water surface and the effect of tank size on cooling. The findings indicate that covering the water surface in the tanks can effectively double the energy retention time, thereby extending the cooling period. A tank with a larger volume cools slower and better ensures the formation of temperature layers. Temperature layering allows for better utilization of the tanks' potential in terms of energy. The overall result is a significant reduction in heat losses and CO₂ emissions. These results demonstrate the critical role of TTES in stabilizing renewable energy sources, especially solar energy, to support sustainable energy solutions in buildings by providing reliable and long-term energy storage. [ABSTRACT FROM AUTHOR]

Aiming at the demand for new energy consumption and mobile portable heat storage, a gravity heat pipe with embedded structure was designed. In order to explore the two-phase heat transfer mechanism of the embedded heat pipe, CFD numerical simulation technology was used to study the internal two-phase flow state and heat transfer process of the embedded heat pipe under different working conditions. The evolution law of the internal working medium of the heat pipe under different working conditions was obtained. With the increase in heating power, it is easier to form large bubbles and large vapor slugs inside the heat pipe. When the heating power increases to a certain extent, the shape of the vapor slugs can no longer be maintained at the bottom of the adiabatic section, and the vapor slugs begin to break and merge, forming local annular flow. When the filling ratio (FR) is relatively low, the bubble is easy to break through the liquid level and rupture, unable to form a vapor slug. With the increase in FR, the possibility of projectile flow and annular flow in the heat pipe increases. Under the same heating power, the temperature uniformity of the heat pipe becomes stronger with the increase in heating time. The velocity distribution in the heat pipe is affected by the FR. The heating power has almost no effect on the distribution of the velocity field inside the heat pipe, but the maximum velocity is different. At an FR of 30%, there are two typical velocity extremes in the tube near positions of 120 mm and 160 mm, respectively, and the velocity in the tube is basically unchanged above a position of 200 mm. There are also multiple velocity extremes at an FR of 70%, with the maximum velocity occurring near 240 mm. [ABSTRACT FROM AUTHOR]

This article reviews selected solar energy systems that utilize solar energy for heat generation and storage. Particular attention is given to research on individual components of these systems, aimed at improving their efficiency and performance. It focuses on an analysis of the literature concerning the design of thermal storage units, with an emphasis on the use of computational fluid dynamics (CFD) as a research tool. Conclusions from scientists' research regarding the impact of tank shape, thermal insulation, flow parameters, and the use of stratification partitions on heat storage efficiency have been presented. The literature review indicates that thermal storage units play a key role in the efficiency of solar systems, and thermal stratification within them can significantly improve their performance. The methodology was based on an analysis of journals, primarily from after 2008, focusing on articles related to the application of CFD methodology in the study of solar systems and heat storage. [ABSTRACT FROM AUTHOR]

In this study, a novel solar-assisted heat pump (SAHP) system with hybrid thermal energy storage is proposed. The system can address the problems of large space requirements and the unstable heating of solar heating systems and tackle the energy-efficient degradation of air source heat pumps (ASHPs) in winter. This study utilized TRNSYS18 software to establish a dynamic simulation model of the system, including the system's model construction and the control scheme's design. This performance study focused on analyzing the effects of the collector area and thermal energy storage (TES). The results show that with the increase in the collector area, the collector and power generation efficiencies decrease, and the system performance coefficient improves; the rise in the volume of TES leads to the collector and power generation efficiencies first increasing, and then they tend to stabilize, and the performance coefficient shows a trend of firstly increasing, and then decreasing. In terms of parameter optimization, a target optimization scheme and an evaluation model are constructed. The results indicate that the heating demand for a 116-square-meter building in the Tianjin area is met. The equivalent annual cost (EAC) of the system cost is the lowest, which is CNY 3963, when the collector area of the system is 31 square meters, the heat storage tank (HST) volume is 0.4 cubic meters and the phase-change energy storage (PCES) volume is 0.2 cubic meters. The payback period of the system is 10.59 years, which was compared to that of the ASHP. The further comparison of the economic feasibility of the system in the Lhasa, Shenyang, and Tianjin regions shows that the Lhasa region has the lowest EAC and payback period of CNY 1579 and 8.53 years, respectively, while the payback periods of Tianjin and Shenyang are 10.59 and 10.3 years, with EACs of CNY 3963 and CNY 5096, respectively. [ABSTRACT FROM AUTHOR]

A common configuration for transcritical CO2 booster systems in supermarkets involves air conditioning (AC) supplied by cooling a water-glycol circuit. The design capacity of the refrigeration unit must handle all refrigeration loads and the AC load during the hottest summer day, leading to overcapacity and part-load operation for most of the year. A proposed design for implementing cold thermal energy storage (CTES) dedicated to AC demand in a supermarket located in the Oslo region is modeled in the object-oriented language Modelica. Simulation results demonstrate an electricity peak power reduction of up to 32.33%. Even though energy savings are not the primary objective of this project, they are achieved by producing and storing energy when the outdoor temperature is lower, and the coefficient of performance (COP) of the system is higher. The energy savings can reach up to 11.8%. Finally, the economic benefits of the system are assessed under the spot pricing system, revealing potential electricity cost savings of up to 12.56%. [ABSTRACT FROM AUTHOR]

Buildings consume 10% of global energy and 50% of global electricity for heating and cooling. Transitioning to energy-efficient buildings is essential to address the global energy challenge and meet sustainable development goals (SDGs) to limit global temperature rise below 1.5 ° C . The shift from traditional to smart grids has led to the development of micro, milli, and nanogrids, which share energy resources symbiotically and balance heating/cooling demands dealing with acute doldrums (dunkelflaute). This scoping review explores the methods by which phase change materials (PCMs) can be used in residential buildings to form a nanogrid. This review examines the components and concepts that promote the seamless integration of PCMs in residential houses. It also discusses the key challenges (e.g., scalability, stability, and economic feasibility in high summer temperatures), proposing the community-scale network of nanogrids (NoN) and the potential of thermochromic and photochromic materials. The findings of this review highlight the importance of latent heat storage methods and ingenious grid architectures such as nanogrids to construct resilient and sustainable houses in the future and thereby offer practical insights for policymakers and industries in the energy sector. [ABSTRACT FROM AUTHOR]

Nuclear microreactors are a potential technology to provide heat and electricity for remote microgrids. There is potential for the microgrid on the island of El Hierro to use a microreactor, within an integrated energy system (IES), to generate electricity and provide desalinated water. This work proposes a workflow for optimizing and analyzing IESs for microgrids. In this study, an IES incorporating a microreactor, thermal energy storage (TES) system, combined heat and power plant, and a thermal desalination plant was designed, optimized, and analyzed using Idaho National Laboratory's Framework for Optimization of Resources and Economics (FORCE) toolset. The optimization tool, Holistic Energy Resource Optimization Network (HERON), was used to determine the optimal capacity sizes and dispatch for the reactor and thermal energy storage systems to meet demand. The optimized reactor and TES sizes were found to be 11.61 MWth and 58.47 MWhth, respectively, when optimizing the IES to replace 95% of the island's existing diesel generation needs. A dynamic model of the system was created in the Modelica language, using models from the HYBRID repository, to analyze and verify the dispatch from the optimizer. The dynamic model was able to meet the ramp rates while maintaining reactor power with minimal control adjustments. [ABSTRACT FROM AUTHOR]

Thermal systems, including those utilising solar energy and waste heat recovery, often have a mismatch between the energy supply and demand. It is crucial to implement a form of Thermal Energy Storage (TES) to effectively utilise the energy source. This study evaluates the thermal performance of a packed bed Latent Heat Thermal Energy Storage (LHTES) unit that is incorporated with a solar flat plate collector. The results show that the time required to charge the tank is reduced by 7% when the porosity is increased from 0.49 to 0.61, and also when the flow rate is raised from 2 to 4 kg/min, the charging time decreases by 2.5%. Additionally, studies were done to investigate the performances of different kinds of paraffin (RT30, RT28HC, WAX, RT58, and P56-58), and compare the heat capacities of each TES tank which resulted in the RT58 TES tank having the highest heat capacity. Abbreviations: BC: boundary conditions; HTF: heat transfer fluid; LHS: latent heat storage; LHTES: latent heat thermal energy storage; PCM: phase change material; SHS: sensible heat storage; TES: thermal energy storage [ABSTRACT FROM AUTHOR]

Thermal storage systems are needed to overcome solar intermittency and make this energy source more flexible and competitive for concentrated solar power plants. Single-tank sensible heat storage using both fluids and materials is a promising option for reducing storage costs and promoting the development of concentrated solar power. This work is a thorough review on the parameters influencing the performance of a dual-medium thermocline storage system for concentrated solar power plants. Thus, indicators such as efficiency, utilisation rate, thermocline thickness and energy efficiency of the storage system are presented in order to quantify the performance of the system. In addition, the impact of geometric and operating parameters on the performance of the thermocline storage system has been discussed. [ABSTRACT FROM AUTHOR]

In high-temperature mines, miners are exposed to high temperatures for long, increasing body temperature and causing diseases such as heatstroke. Therefore, adjusting the environmental parameters of the working face has become the key to managing thermal stress. Based on the binary method, the predicted thermal strain model (PHS) was transformed into a computer program to determine the zero inflection point of human body heat storage. When workers’ body heat storage reached the zero inflection point, changes in working face temperature, wind speed, and physiological parameters were analyzed under different labor intensities. The results indicate that the higher the labor intensity, the higher the air humidity, and the lower the working face environment temperature that maintains zero heat storage for the human body. A wind speed of 2.5 m/s is optimal for maintaining zero heat storage for the human body. When the wind speed is too high or too low, the working surface environment temperature required to maintain zero heat storage for the human body is relatively low. A thermal stress control method was proposed based on research, providing a reference for adjusting wind speed and refrigeration equipment in high-temperature mining working faces. [ABSTRACT FROM AUTHOR]

This paper addresses the issue of heat accumulation and low heat release efficiency at the bottom of solid thermal storage electric boilers through experimental and simulation studies. A test platform was designed for conducting three sets of comparative experiments. A numerical simulation model was established and solved, and the scientific accuracy of the research was verified through a comparison of experimental data and simulation results. The study shows that as the thermal storage and release processes progress, the temperature of the thermal insulation structure at the bottom of the storage body gradually increases, with significant heat accumulation. Under the experimental scale, the accumulated heat reaches 5.25e5 kJ. Improving ventilation conditions does not enhance the heat utilization of this part. Calculations indicate that the thermal energy in the insulation brick layer is approximately ten times greater than that of other brick layers, playing a dominant role. With three cycles of thermal storage and release, the accumulated heat is substantial, offering considerable potential for improvement. [ABSTRACT FROM AUTHOR]

Increasing the operational aspect of heat storage system (HSS) contributes to significant positive influence on thermal system. As one fast-developing storage technology, modification of the material HSS (MHSS) has become crucial, specifically for organicbased MHSS. The drawbacks of poor phase transformation during energy intake and release (charging/discharging) of MHSS make undesirable performance for heat exchange and effective operation. To solve the problem, this work proposes modification of pure octadecanoic acid (POA) as MHSS by forming polymeric-embedded OA (PEOA). Evaluation is taken for the heating/cooling cycle operation of the HSS, showing positive contribution of the proposed method. The PEOA reduces the preheating duration by 14.8%, meaning the charging ratio can be improved effectively for the HSS. The effective energy ratio for PEOA is obtained with maximum value of 83.9%, which is higher than the POA with 74.8%. It is accounted for the application of PEOA since it allows a suitable solidification process on the heat release, making the maximum total heat loss drop to 17.9%. The profile observation using microscope electron demonstrates the stable formation of PEOA as a direct result of the presence of polymer structure of the composite. The result demonstrates the improvement in the operation of HSS unit, which is linked to the stabilized material, achieving a favorable energy ratio that potentially promotes better operation and control of HSS unit. Moreover, a consecutive discharge cycle for the heat storage tank (HST) using PEOA also brings positive outcomes and improves the heat discharge stage. [ABSTRACT FROM AUTHOR]

District energy networks (DENs) are recognized crucial to contribute to the carbon neutrality target by 2050, thanks to the possibility to integrate renewables at the local level in the heating and cooling sector beyond the electricity one. Thermal energy storage (TES) allows DENs to be more flexible by managing the temporal gap between supply and demand. The identification of the TES size in a DEN is challenging, depending on several variables as energy loads and prices, the coupling of energy processes within the DEN, and the different economic or sustainability priorities. The contribution of this paper is to present an optimization model for sizing TES under the eco-exergetic operation optimization of DENs. The model is based on mixed-integer linear programming and aims to determine the optimal operation strategies of the DEN and the optimal TES capacity with the goal to maximize the economic/exergetic performance of the network. As case study, a real DEN located in Torino is considered. From the comparison with the results obtained with the current case in the absence of the TES, it emerges that the optimization tool brings valuable economic and exergetic benefits to the DEN, thanks to the identification of the optimal TES capacity. [ABSTRACT FROM AUTHOR]

This study emphasizes the significance of understanding groundwater flow behavior for effective contaminant transport and heat storage. Aquifers, with their irregular shapes and variable permeability, exhibit anisotropic flow resistances that affect mass and heat transfer, posing challenges for modeling. The dual-porosity model is used as a numerical approach to calculate macroscopic heat transfer without explicitly resolving the structure. By solving equations for mobile and immobile phases and coupling relevant equations for heat conservation, this model was applied to transient numerical experiments simulating heat transfer and storage in a desktop model filled with glass beads. Results indicate alignment with experimental and numerical models resolving porous structures on the microstructure scale. This methodology offers a comprehensive digital toolbox for solving large-scale heat storage problems in aquifers, contributing to digital and sustainability transformations with reasonable computational demands. [ABSTRACT FROM AUTHOR]

The current research work involves the design and performance assessment of a solar still, which is a conventional single‐slope basin‐type solar still (CSSBTSS) and a modified single‐slope basin‐type solar still (MSSBTSS) under the meteorological conditions of Solan city, Himachal Pradesh, India (30.90° N, 77.09° E). The individual and the combined effect of different sample quantities of sensible Himalayan Rambaan fibers (HRFs) and mass of latent paraffin wax (PW) A48 on the performance of MSSBTSS is evaluated and compared with CSSBTSS. The use of HRF material enhanced the evaporation rate significantly and improved the daytime distillates. Besides, different masses of latent PW filled inside the aluminum tubes improved the nocturnal distillates. For the analysis, three cases have been considered which are, namely: Case 1, solar still with sensible HRFs (MSSBTSS‐HRF); Case 2, solar still with latent PW A48 (MSSBTSS‐PW); and Case 3, solar still with sensible and latent material (MSSBTSS‐HRF‐PW). The results showed that the maximum thermal efficiency for Cases 1 and 2 was improved by 30.02% and 42.41% with five sample quantities of HRF material and 5000 g of PW. For Case 3, the maximum energy efficiency was 90.71% with a gain of 45.16% over CSSBTSS. The economic analysis concluded that the cost per liter of distillate yield produced using MSSBTSS‐HRF‐PW and CSSBTSS is ₹1.5 and ₹1.6, respectively. These outcomes showed the great potential of MSSBTSS‐HRF‐PW approach towards enhancing the overall performance and cost‐effectiveness of solar still. [ABSTRACT FROM AUTHOR]

This study introduces a new analytical framework that employs the image‐well method to simulate the spatial and temporal temperature distribution in vertical borehole thermal energy storage (BTES) systems. The model accommodates complex boundary shapes and conditions, including insulation, convection, and constant temperature, without requiring iterative solutions at each time step. The model's accuracy and utility are demonstrated through an application to a borehole heat exchanger cluster arranged in an octagonal shape with insulating boundaries, based on a BTES site in Drake Landing (Canada). Model predictions are validated against a finite element model, showing a root‐mean‐square error of 0.012°C. A global sensitivity analysis highlights the influence of thermal parameters on system performance, identifying the heat flux of the borehole heat exchanger as the most sensitive parameter. Overall, this approach combines the advantages of analytical and numerical techniques to provide a clear and efficient tool for evaluating BTES systems, offering significant potential for advancing sustainable energy solutions. [ABSTRACT FROM AUTHOR]

• Environmental responsible new materials. • Utilization of agricultural residues for refrigeration applications. • Computational simulation of avocado seed oil as a phase change material. • Performance analysis of the avocado seed oil as a phase change material. Bio-based phase change materials (BPCMs) derived from agro-industrial residues represent an ecofriendly alternative for refrigeration applications. In this work, a BPCM was obtained by steam extraction from avocado seed and studied as a suitable cold thermal energy storage system. First, differential scanning calorimetry was used to determine that the solid-liquid phase transition occurred from -27°C to 15°C. This temperature range is of interest for the conservation different food products. The study aimed to determine the best distribution of the material, which was stored in plastic packaging bags, and placed in an insulated polystyrene thermal container. Two configurations were evaluated: (i) four bags of 75 mL, (ii) two bags of 75 mL and one of 150 mL. The temperatures of the avocado seed oil, and of the air inside the container, were measured during 6 to 8 h. It was concluded that, despite working with the same amount of avocado seed oil (300 mL) in different experiments, there was a better performance when the same volume of material was distributed in each wall. Furthermore, the utilization of avocado seed oil allowed to maintain low temperatures, suitable for food preservation during two additional hours. In the same way, in a yogurt storage experimentation of 8 h, the utilization of the avocado oil enhanced the temperature preservation by 6°C on the phase change range from 4°C to 14°C. While compared to water, the temperature difference was evaluated showing a good performance of the BPCM and an important stability on the temperature heating rate. [ABSTRACT FROM AUTHOR]

• ⋅The adsorbent is regenerated in <30 min with humid air preheated to 200 °C. • ⋅Regeneration time depends less on the dew point as humid air temperature increases. • ⋅A heat source at 200 °C is obtained even with humid air unavailable latent heat. • ⋅Maximum temperature of generated humid air theoretically estimated exceeded 220 °C. To reuse low-temperature wasted heat as a thermal resource for high temperature, a direct-contact adsorption thermal storage was focused using humid air and zeolite 13X particles as the working fluid and adsorbent, respectively. Only a few previous studies have chosen the working fluid in gaseous form because it is unavailable for latent heat in generating heat sources. Recovering waste heat in humid air to generate hotter steam is unique and becomes an originality of our present work. The time required to regenerate zeolite particles and the maximum temperature of the generated steam were investigated assuming a warm-up device for a vehicle. The time required to regenerate zeolite was investigated by changing the dew point, temperature, and superficial velocity of the inlet humid air. It was mainly affected by the temperature of the inlet air. The absorbent was regenerated within 30 min when the humid air preheated to 200 °C was supplied. On the other hand, the maximum steam temperature was investigated by changing the superficial velocity and temperature of saturated inlet humid air. As one of the significant and novel finding in this work, the steam of >200 °C was obtained as a high-temperature heat source even with saturated humid air unavailable latent heat. Moreover, as theoretical knowledge, it was revealed that the maximum temperature of the heat source can be estimated by the relationship between the heat balance on the packed bed and adsorption equilibrium. [ABSTRACT FROM AUTHOR]

• Four common latent heat functional fluids are described and compared. • Summarizes the current methods for determining the stability of PCMEs. • The mechanism and solution to the stability of PCMEs are analyzed. • The mechanism, inhibition method and research on PCME supercooling are concluded. • An overview of the latest research progress of PCMEs in various fields. As the global environment continues to deteriorate and temperatures gradually rise, it has been realized that the utilization of renewable energy is one of the most effective measures to mitigate global warming. Thermal energy storage plays a crucial role in the energy mix, and phase change materials are among the most significant and effective methods of thermal energy utilization. Phase change material emulsions, as fluid-phase phase change materials, play a significant role in thermal energy storage and heat transfer. However, issues related to stability and supercooling hinder the practical application of phase change material emulsions. Consequently, this paper explores the current research status of stability and supercooling mechanisms and technologies. Firstly, this paper provides a brief overview of the fundamental concepts of phase change material emulsions. Then, it addresses the challenges related to controlling the stability of phase change material emulsions and the issue of significant supercooling. The paper elaborates on relevant research findings in detail, mechanisms, evaluation criteria, and potential solutions. Finally, the paper outlines the research progress of phase change material emulsions in the fields of solar energy, construction, and thermal management, demonstrating their potential to advance renewable energy and various industrial sectors. [ABSTRACT FROM AUTHOR]

• Utilizing LNG by air separation, ORC, wastewater ice-making, and cold warehouse. • Two-stage freezing and pre-desalination system for desulfurization wastewater. • Optimization: exergy efficiency=70.34% output power=2.96*1011 kW LCOE=0.0623 $/kWh. • 4E analysis and improved energy efficiency=42.52% reduced CO 2 =1.234*1015kg. Against the backdrop of escalating resource depletion and the urgent quest for alternative sources, liquefied natural gas (LNG) is increasingly gaining prominence as a sustainable solution, particularly in refrigeration applications. However, its underutilization results in wasted resources. To efficiently harness the released cold energy from LNG gasification, this study proposes an integrated system comprising air separation, power generation, refrigeration, and ice thermal storage. The system undergoes optimization using the non-dominated sorting genetic algorithm II (NSGA-II) to determine the optimal operating parameters. The optimized system is comprehensively analyzed from energy, exergy, economic, and environmental perspectives. Results show that the system, with a 70t/h LNG capacity, achieves an energy efficiency of 42.52% and an exergy efficiency of 48.09%. Economically, the system incurs a cost of approximately 0.0711 $/kWh and can mitigate over 1.4504*107kg of CO 2 emissions. Compared to traditional LNG utilization systems, the integrated system demonstrates a 22.32% improvement in energy efficiency, a 7.69% enhancement in exergy efficiency, and a cost reduction of 0.0049 $/kWh. In summary, this technologically advanced and economically viable system offers a significant alternative to optimize LNG cold energy utilization. [ABSTRACT FROM AUTHOR]

Wet bulb globe temperature (WBGT) is a commonly used measure to predict heat strain in workers. Different combinations of environmental conditions can create equivalent WBGT, yet it remains unknown whether biophysical, physiological, and perceptual responses vary when working in different but equivalent hot conditions. The purpose of the study was to compare body heat storage and physiological and perceptual strain during walking in hot-dry and warm-wet conditions of the same WBGT. Twelve subjects (age: 22 ± 2 y) walked for 90 min at 60% maximum heart rate in a 27.8°C WBGT environment of hot-dry (HD: 40°C, 19% relative humidity) or warm-wet (WW: 30°C, 77% relative humidity) conditions. Partitional calorimetry was used to estimate heat storage. Core temperature at 90 min (HD: 38.5 ± 0.5°C; WW: 38.4 ± 0.3°C, p = 0.244) and cumulative heat storage (HD: 115 ± 531 Kj; WW: 333 ± 269 Kj, p = 0.242) were not different. At 90 min, heart rate was not different (HD: 160 ± 19 bpm; WW: 154 ± 15 bpm, p = 0.149) but skin temperature (HD: 36.6 ± 0.9°C; WW: 34.7 ± 0.6°C, p < 0.001), thirst (HD: 6.8 a.u.; WW: 5.3 a.u. p = 0.043), and sweat rate (HD: 15.1 ± 4.4 g·min−1; WW: 10.0 ± 4.1 g·min−1, p < 0.001) were greater in HD compared to WW. Hot environments of equivalent 27.8°C WBGT created equivalent core temperature despite differences in physiological strain during exercise, including earlier onset of cardiovascular strain, greater sweat rate, and higher skin temperature compared to a WW environment. ClinicalTrials.gov ID NCT04624919. [ABSTRACT FROM AUTHOR]

Although Aquifer Thermal Energy Storage (ATES) systems are widely researched, Fractured Thermal Energy Storage (FTES) systems are comparatively underexplored. This study presents a detailed numerical model of a fractured granitic reservoir at the Bedretto underground laboratory in Switzerland, developed using COMSOL Multiphysics. Energy efficiency was evaluated across different flow rates and well configurations, including single-well and doublet systems, as well as for two different temperatures, namely 60 °C and 120 °C. The doublet configuration at an injection temperature of 60 °C with a flow rate of 2 kg/s demonstrated the highest energy efficiency among the cases studied. Potential applications for the stored heat are discussed, with scenarios including district heating for the nearby village and greenhouse heating. The results show that although FTES is associated with unique challenges, it has significant potential as a reliable thermal energy storage method, particularly in regions without suitable aquifers. It can also be considered as a cost-effective and competitive approach for climate mitigation (assuming the system is solely powered by solar-PV). This study provides insights into the viability and optimization of FTES systems and highlights the role of fracture/fault properties in enhancing energy efficiency. [ABSTRACT FROM AUTHOR]

Organic phase change materials (O-PCMs) such as alkanes, fatty acids, and polyols have recently attracted enormous attention for thermal energy storage (TES) due to availability in a wide range of temperatures and high latent heat values. However, low thermal conductivity and leakage problems during the phase transition of O-PCMs are of great concern. To overcome the long-standing drawbacks of O-PCMs, we critically discussed the preparation techniques of macro encapsulation phase change (MaPCM), microencapsulation phase change materials (MPCM), shape stabilized phase change materials (SSPCM), eutectic phase change materials (EPCM), nano-enhanced phase change materials (NePCM) along with the morphological insights, thermal property enhancements & molecular dynamics (MD) simulation of the prepared composite PCMs. The article also discusses fundamental thermal property increments in phonon interaction, Van der Waals forces of attraction, aspect ratio, thermal conductive path, temperature agglomeration, surfactant effect, and thermal resistance of O-PCMs. The current ongoing review manuscript consolidates the variation in thermal properties with different concentrations of nanoparticles, considering the variety of references to provide valuable insight to the researchers. Carbon-based nanoparticles dispersed with the O-PCMs are the best way to reduce the low thermal conductivity problem. The π-π stack interaction between the O-PCMs and the nanoparticles decreased the leakage problems of O-PCMs during encapsulation and shape stabilization. The authors observed that the highest increment in the thermal conductivity and the latent heat of the OPCMs is 1008.33% and 60%, respectively. Finally, the present review provides a new vision and draws more attention to the material reliability of O-PCMs-based applications in the future, particularly regarding TES. [ABSTRACT FROM AUTHOR]

Numerical simulation of urban heat islands – Evaluation of simulation results by thermal measurements Urban development, including urban surfaces, vegetation, and water bodies, influence the urban climate in various ways. In addition to the geometric features of the built environment, material properties such as thermal storage capacity and the radiative behavior of roofs, façades, and transportation infrastructure significantly impact the local climate and the formation of heat islands. To predict these effects, urban climate simulations are increasingly used and are now scientifically established. However, the question of the accuracy of these results frequently arises. This paper focuses on the evaluation of simulation results through thermal measurements, including temperature, wind speed, and thermography, conducted both at ground level and using drones. By comparing simulation outputs with measured data, input parameters for the simulations can be refined. This enables the development of reliable forecasts regarding the effectiveness of green infrastructure, such as green roofs and façades, in mitigating urban heat island effects. These insights form the basis for designing appropriate adaptation strategies to enhance urban resilience against increasingly intense heat events. [ABSTRACT FROM AUTHOR]

This study presents a comparative numerical analysis of an active magnetic regenerative (AMR) system using Al2O3 nanofluids, multi-walled carbon nanotube (MWCNT) nanofluids, and hybrid nanofluids composed of a 50–50 % mixture of Al2O3 and MWCNT, with volume concentrations ranging from 0–1 %. In the hybrid nanofluid, the concentration of each component (Al2O3 and MWCNT) is equal and ranges from 0–0.5 % to make up the total concentration. Results indicate that nanofluid density increases with nanoparticle concentration, enhancing mass and fluid dynamics, while specific heat capacity decreases, impacting heat storage. Thermal conductivity improves with higher nanoparticle concentration, benefiting heat transfer, but viscosity increases, affecting fluid resistance and pumping power. MWCNT nanofluids, particularly at 1.0 %, exhibit superior cooling performance, achieving the lowest temperatures and enhancing cooling efficiency by about 42.4 % compared to water. They also show the best improvement in temperature span (5.2 %) and the highest increase in cooling capacity (51.3 %) and COP (37.0 %). Hybrid Al2O3+MWCNT nanofluids also show considerable improvements, highlighting their potential for advanced thermal management. These findings underscore the potential of MWCNT nanofluids to significantly enhance AMR system performance. [ABSTRACT FROM AUTHOR]

In this work, two types of chemical vapor deposition (CVD)-derived porous supporting materials consisting of CNTs–decorated diatomite (CNT/DE) and CNT sponges (CNS) were developed to prepare novel form-stable phase-change material (PCM) composites by impregnation, using polyethylene glycol (PEG) as the PCM. The CNT/DE support matrix showed highly entangled nanotubes (the weight ratio of CNTs to DE was 0.16) over and inside the porous structure of diatomite, giving the hybrid matrix an electrical response. The CNS that resulted was mainly composed of bent and interconnected CNTs forming a three-dimensional highly porous structure. XPS and FTIR results revealed that CNTs in both the supporting materials have a moderate amount of oxygen-containing functional groups. Both hosts allow for high PEG loading (about 75 wt%) without showing any PCM leakage during melting. Both form-stable PCM composites showed high thermal reliability upon a hundred melting–solidification DSC cycles (PEG/CNT/DE latent heat is 86 ± 4 J/g and PEG/CNS latent heat is 100 ± 2 J/g; melting temperature 34 °C). An analytical model was used to evaluate the passive cooling performance of the systems, simulating the thermal behaviour of a building wall containing the confined PCM in the hosts, resulting in a reduction in required cooling power of about 10%. The overall results suggest that the developed form-stable PCM composites could be considered promising additive materials for the production of building envelopes with thermal energy storage capability. [ABSTRACT FROM AUTHOR]

This study proposes enhanced thermal stability and excellent electrochemical and photocatalytic performance of hierarchical structure of zinc-phthalocyanine (ZnPc) samples prepared through eco-friendly enhanced microwave (MW) synthesis over 5 min at T = 200 °C. The structure and morphology of the obtained ZnPc were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (TEM), and Atomic Force Microscope (AFM). At the same time, thermal stability was analyzed using thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The obtained ZnPc with high crystallinity, pure crystalline phases and reflection peaks related to the β-form of ZnPc. The average crystallite size (D) of 74 nm was determined using the Debye-Scherrer equation for a peak at 2θ = 9.30°. AFM image presented ZnPc material as a distinguished multilayered crystal with a rhombus-shaped crystal structure that seems very smooth on its surface, while TEM images showed a hierarchical structure of synthesized ZnPc self-organized assembles from the needle-like morphology which are aligned at different orientations having length up to approximately 500 nm and with 20 nm in diameter. TGA and DTA showed that the decomposition process occurred at a high temperature of 649 °C, for a heating rate of 15 °C/min, indicating good thermal stability of the investigated ZnPc. The photocatalytic activity of the hierarchically structured ZnPc was evaluated using different initial concentrations of Reactive Blue 19 (RB-19), pH value, and catalyst dose. Additionally, the electrochemical performance of ZnPc as electrode material was investigated. This study indicates facile, low-cost, and green MW method can be used for the preparation of the needle-like form of ZnPc as a promising multifunctional material for the potential applications: in thermal energy storage in future solar power technologies, as electrode material exhibiting superior voltammetric response, with cathodic and anodic current values and as photocatalyst for degradation of RB-19 and other organic dye-pollutants. [Display omitted] • Needle-like form of ZnPc were acquired through microwave-аssisted synthesis. • Thermal stability of ZnPc at high-temperature decomposition, at around 640 °C. • An electrochemical and photocatalytic properties of ZnPc were investigated. • Effects of RB-19 concentration and pH value on the decolorization rate were studied. [ABSTRACT FROM AUTHOR]

A dual-phase change material (DPCM) containing polyethylene glycol (PEG) 400/expanded graphite (EG) and PEG1500/EG with both high and low-temperature regulation capacities was prepared. It was added as an additive to the NovaChip-Type C asphalt mixtures. Laboratory and field temperature regulation tests were designed. The images taken by SEM showed that PEG was fully adsorbed by EG and the structure of DPCM was stable. The test results showed the DPCM has good durability in the cyclic phase change process. The modified asphalt binders with different DPCM content showed different heat storage capacity. The results of temperature regulation tests showed that the addition of DPCM effectively reduced the temperature change rate of asphalt mixtures. With 1.88% DPCM, the extremum of high temperature of asphalt mixtures reduced by 2.3°C while the extremum of low temperature increased by 2.0°C. In terms of road performance, the cracking resistance at low temperature of asphalt mixtures gradually improved with the increase of DPCM content. Meanwhile, the rutting resistance at high temperature and water damage resistance still met the requirements of the specification. The DPCM had a good effect on restraining the occurrence of road diseases caused by temperature and prolonging the service life of the road. [ABSTRACT FROM AUTHOR]

Crumb rubber (CR)-modified asphalt shows positive effects on engineering performance and environmental conservation. However, its limited compatibility with asphalt due to unstable interactions poses challenges for its application. The incorporation of polyurethane precursor-based reactive modifier (PRM) facilitates the establishment of a three-dimensional crosslinked network structure within the asphalt, thereby enhancing pavement performance and compatibility. In this study, a novel compound-modified asphalt (CPMA) was prepared with CR and PRM. The performance of CPMA was assessed using the Dynamic Shear Rheometer (DSR), Blend Beam Rheology (BBR) and storage stability tests. Microstructure and modification mechanism were revealed by Atomic Force Microscopy (AFM) and Fluorescence Microscopy (FM) analyses. The results show that CPMA produced using an optimized process has better high-temperature performance and fatigue life than CR-modified asphalt (CRMA) and PRM-modified asphalt (PMA). Polar molecules, such as asphaltenes and resins, are crosslinked by the PRM to form a three-dimensional network, which enhances the thermal storage stability of CPMA. Furthermore, the flexibility and resilience of CR mitigated the low-temperature hardening of PMA. Physicochemical compound modifications provide significant advantages in terms of performance enhancement and system stability and demonstrate the potential of CR and PRM to complement and enhance their respective applications. [ABSTRACT FROM AUTHOR]

Composite modification has proven to be an effective strategy in addressing the insufficient performance associated with single-modified bituminous mixture. This research aims to thoroughly investigate the performance of the compound-modified bituminous mixture incorporation phenol–formaldehyde resin (PF) and organic montmorillonite (OMMT). The performance investigations of the bituminous mixture were conducted through the Marshall stability test, dynamic stability test, indirect tensile test, immersion Marshall test, freeze–thaw splitting test, indirect tensile fatigue test and long-term aging test. The test results indicated that OMMT plays a crucial role in advancing thermal storage stability and compatibility between PF and bitumen. Importantly, the optimal dosage of OMMT was determined not to exceed 5%. The 3%PF+5%OMMT bituminous mixture demonstrated excellent rutting and cracking resistance, superior water stability and anti-fatigue capabilities. Furthermore, the 2%PF+5%OMMT and 3%PF+5%OMMT bituminous mixtures exhibited superior anti-aging abilities. In consideration of laboratory performance and bitumen compatibility, the combination of 3%PF+5%OMMT can be utilised to enhance the bituminous mixture performance. The results of single-factor analysis of variance indicated that PF and OMMT had significantly impact on the bituminous mixture performance. Notably, the influence of PF/OMMT dosage on the cracking resistance, water stability and anti-aging ability requiring attention when considering them as bitumen modifiers. [ABSTRACT FROM AUTHOR]

This study aims to optimize the phase change material (PCM) and fin structure, in order to improve the heat storage efficiency of the casing unit. Paraffin, lauric acid, and stearic acid were mixed with three organic PCMs. Once the total volume was constant, the volume fraction of the three PCMs was adjusted to prepare the mixed organic PCMs. An optimal combination was selected with the highest thermal conductivity. Then, Al2O3, Fe2O3, Fe, and Cu nanoparticles with different mass fractions were doped into the organic PCMs, in order to prepare a variety of composite phase change heat storage materials. The results show that four types of nano-Cu with different weight fractions (0.5%, 1%, 1.5%, and 2%) were selected as the additives to improve the thermal conductivity of the original PCM samples of 0.2% SDBS. The thermal conductivity values were 0.371, 0.373, 0.374, and 0.370 W/(m·K), respectively, which were 13.46%, 14.07%, 14.37%, and 13.15% higher than that of the sample without Cu nanoparticles, respectively. The composite PCM with 1.5% Cu nanoparticles shared the highest thermal conductivity of 0.374 W/(m·K), which was 14.37% higher than that of the sample without Cu nanoparticles. The typical fin structure of casing was summarized into four shapes: triangular, parallelogram, rectangular, and fan-shaped. The heat transfer performance of the four shapes was numerically simulated, according to the same working conditions: the volume ratio of the fin to the heat storage material, and the heat exchange edge length. It was found that the arc-shaped and straight fin were combined to achieve the high melting rate of the fan-shaped structure. The three-dimensional numerical simulation was carried out on the heat storage device of the fin structure using FLUENT software. Once the Ste number changed from 0.3 to 0.7, the melting time was reduced from 7 207 to 904 s, where the whole melting time was shortened by 6 303 s. Once the Ste number was 0.7, there was the maximum temperature difference between HTF and PCM. The natural convection was particularly intense to further accelerate the melting process of the heat storage unit. The relationship between melting time and Ste number was fitted by dimensionless quantity. The heat flux corresponded to the different Ste numbers. Once the Ste number was 0.3, the peak value of heat flux reached 155 W at the beginning of melting and then decreased gradually. The reason was that the HTF with the temperature difference between the initial and PCM entered the inner tube for heat exchange, and then the heat flux rate increased rapidly to the peak, due to the superior thermal conductivity of the steel pipe, while the HTF was continued to transfer the heat into the steel pipe, finally the heat loss occurred in the flow process, resulting in the heat flow rate gradually decreasing until the end of melting. The peak heat flow reached 436 W at a Ste number of 0.7, due to the large temperature difference between the HTF inlet temperature and the PCM. The findings can also provide a strong reference to improve the heat storage efficiency of phase change heat storage units. [ABSTRACT FROM AUTHOR]

This study aimed to devise a novel fermentation unit for yogurt production utilizing phase change materials (PCM) and primarily powered by solar energy. The unit comprises a solar flat plate collector (FPC), PCM cells, and a fermentation cabinet equipped with trays. High-density polyethylene (HDPE) cylindrical cells were employed to contain paraffin wax for thermal energy storage. The performance of the integrated solar system for the fermentation process was assessed across different air velocities (1.2 to 1.8 m/s), with the most rapid temperature rise observed at 1.8 m/s. The PCM-based thermal storage exhibited an impressive capability of releasing heat autonomously for 6 hours without sunlight, eliminating the need for external energy sources. PCM's capacity to store and release thermal energy ensures fermentation stability, even without solar radiation. This innovative approach offers a compelling environmentally friendly solution with significant implications for sustainable yogurt production, paving the way for industrial integration. [ABSTRACT FROM AUTHOR]

During test operation of a geological latent heat storage system as a potential option in the context of heat supply for heating and cooling demand, part of a shallow Quaternary glacial aquifer was frozen at the TestUM test site. In order to evaluate the current thermal state in the subsurface, the dimension of the frozen volume has to be known. As the target is too deep for high-resolution imaging from the surface, the use of borehole ground-penetrating radar (GPR) is being investigated. For imaging and monitoring of a vertical freeze–thaw boundary, crosshole zero-offset and reflection borehole GPR measurements are applied. The freezing can be imaged in the zero-offset profiles (ZOPs), but the determination of ice body size is ambiguous because of the lack of velocity information in the frozen sediment. Reflection borehole GPR measurements are able to accurately image the position of the freezing boundary through repeated measurements of ±0.1 m, relying on the velocity information from ZOPs. We have found that the complementary use of ZOPs and reflection measurements provides a fast and simple method to image freezing in geological latent heat storage systems. The presence of superimposed reflections from other observation wells and the low signal-to-noise ratio are problematic. The use in multiple observation wells allows an estimation of ice body size. A velocity model derived from multiple ZOPs enabled us to extrapolate geological information from direct-push-based logging and sediment cores to a refined subsurface model. [ABSTRACT FROM AUTHOR]

Phase change materials have been studied for many applications aiming at enhancing energy efficiency and economy. Nevertheless, in order to select the right phase change material (PCM) to meet the required standards, a trade-off between competing quantitative and qualitative criteria (also referred to as attributes) is usually required. The PCM selection literature analysis reveals that researchers employed many multi-attribute decision-making (MADM) methods. However, these MADM methods have their merits as well as demerits. Hence, this study offers a simple and efficient MADM method named"Best Holistic Adaptable Ranking of Attributes Technique (BHARAT)" to select the optimal PCM for various energy storage applications. The BHARAT method is illustrated with three case studies. In the first case study, the best PCM for a thermal energy storage unit with a solar box cooker is chosen by considering 5 PCMs and 8 attributes; in the second case study, the best PCM for a ground source heat pump integrated with a phase change thermal storage system is chosen by considering 8 PCMs and 13 attributes; In the third case study, 20 PCMs and 5 attributes are considered in order to determine which PCM is optimal for energy storage and thermal comfort in a vehicle. Comparisons are made between the results of the BHARAT method and those of other popular MADM methods. The BHARAT method's potential has been thoroughly proved and validated by the results of the three PCM selection case studies. It has been demonstrated that the BHARAT methodis straightforward, simple to implement, free of fuzzy logic requirements, provides a logical method for assigning attributes' weights, and is adaptable to PCM selection problems in various scenarios. [ABSTRACT FROM AUTHOR]