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Cordierite-mullite composite ceramics were prepared by solid-state method using Panzhihua low-grade Ti-rich clay, talc, and alumina. Influences of cordierite/mullite ratio, sintering temperature, and the chemical composition of clay on the phase composition, microstructure, physical properties, and thermal properties were investigated in detail. The results showed that the impurity oxides inside the Ti-rich clay had a great ability of forming liquid. Above 1300 °C, the reaction between TiO 2 of the clay and Al 2 O 3 produced stable Al 2 TiO 5 , which was conducive to decreasing the coefficient of thermal expansion (CTE). At 1300–1350 °C, the secondary mullitization caused the volumetric expansion, decreasing the bending strength and increasing the CTE. The optimum ratio of cordierite to mullite ranged from 90:10 to 80:20, and the sample fired at 1400 °C exhibited the lowest water absorption and porosity (0.64 % and 1.56 %, respectively), optimal bulk density, and bending strength (2.59 g cm−3 and 87.79 MPa), as well as better CTE, thermal conductivity, and thermal storage density (2.91 × 10−6 °C−1, 4.11 W/(m⋅K) (30 °C), and 1181 kJ kg−1, respectively). Compared with the reported values of cordierite-based thermal storage ceramics prepared by using the high-grade clay or minerals, the obtained samples showed the advantages such as lower costs for raw materials, higher bending strength, higher thermal conductivity (1.63–2 times higher), low CTE, and high thermal storage density. This study demonstrated that the low-grade Ti/Fe-rich clay has excellent cost-effective potential for the preparation of thermal storage ceramics. [ABSTRACT FROM AUTHOR]

An air-rock bed thermal storage system was designed for small-scale powered generation and analyzed with computational fluid dynamics (CFD) using ANSYS-Fluent simulation. An experimental system was constructed to compare and validate the simulation model results. The storage unit is a cylindrical steel container with granite rock pebbles as a storage medium. The CFD simulation used a porous flow model. Transient-state simulations were performed on a 2D axisymmetric model using a pressure-based solver. During charging, heat input that keeps the bottom temperature at 550 °C was applied to raise the storage temperature. Performance analysis was conducted under various porosities, considering natural and forced convection. The natural convection analysis showed insignificant convection contribution after 10 h of charging, as observed in both average air velocity and the temperature profile plots. The temperature distribution profiles at various positions for both convection modes showed good agreement between the simulation and experimental results. Additionally, both cases exhibited similar temperature growth trends, further validating the models. Forced convection reduced the charging time from 60 h to 5 h to store 70 MJ of energy at a porosity of 0.4, compared to natural convection, which stored only 50 MJ in the same time. This extended charging period was attributed to poor natural convective heat transfer, indicating that relying solely on natural convection for thermal energy storage under the given conditions is not practical. Using a small fan to enhance heat transfer, forced convection is a more practical method for charging the system, making it suitable for power generation applications. [ABSTRACT FROM AUTHOR]

Developing materials for efficient energy storage and effective electromagnetic interference (EMI) shielding is crucial in modern technology. This study explores the synthesis and characterization of carbonaceous shape-stabilized octadecane/MWCNT (multi-walled carbon nanotube) composites, utilizing activated carbon, expanded graphite or ceramic carbon foam, as shape stabilizers for phase change materials (PCMs) to enhance thermal energy storage and EMI shielding, for energy-efficient and advanced applications. The integration of octadecane, a phase change material (PCM) with carbonaceous stabilizers ensures the material's stability during phase transitions, while MWCNTs contribute to improved thermal storage properties and EMI shielding capabilities. The research aims to develop novel composites with dual functionality for thermal storage and EMI shielding, emphasizing the role of carbon matrices and their MWCNT composites. SEM and CT microtomography analyses reveal variations in MWCNT incorporation across the matrices, influenced by surface properties and porosity. Leaching tests, infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) confirm the composite's stability and high latent heat storage. The presence of nanotubes enhances the thermal properties of octadecane and ΔH values almost reached their theoretical values. EMI shielding effectiveness measurements indicate that the composites show improved electric properties in the presence of MWCNTs. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of vehicle warm-up performance using phase-change materials (PCMs) and various thermal storage methods. The primary objective is to utilize the thermal energy lost during engine cooling to improve the cold-start performance, thereby reducing fuel consumption and emissions. Thermal storage devices incorporating PCMs were developed and tested by measuring temperature changes and energy transfer over soaking periods of 4, 8, 16, and 24 h. The results show energy transfers of 591, 489, 446, and 315 kJ at 4, 8, 16, and 24 h, respectively. In terms of the warm-up time, the use of thermal storage devices reduced the time required to reach 70 °C by up to 24.45%, with significant reductions observed across all soaking periods. This reduction in the warm-up time directly contributes to faster engine stabilization, leading to proportional improvements in fuel efficiency and a corresponding decrease in exhaust emissions, including CO2. The findings highlight the effectiveness of PCMs in improving the engine warm-up performance and emphasize the importance of optimizing thermal storage systems to balance energy efficiency and practical application considerations. Additionally, the experimental data provide useful benchmark information for computational simulation validation, enabling the further optimization of automotive thermal management systems. Integrating a PCM-based thermal storage device can significantly enhance a vehicle's warm-up performance, leading to reduced fuel consumption and lower emissions. [ABSTRACT FROM AUTHOR]

Australia aims to achieve net zero emissions by 2050, with an interim target of reducing emissions to 43% below 2005 levels by 2030. Electrification of industry processes currently reliant on fossil fuels is a necessary step to achieve these emission reduction goals. This study investigates electrification of steam generation relevant to major industrial operations in the southwest of Western Australia using different renewable energy input levels. The designed system incorporates thermal storage to ensure continuous steam generation. The optimized technology mix, including wind, PV, and concentrated solar thermal (CST) systems for each renewable energy input target, is presented. The optimization process also identifies optimal locations for new renewable energy plants. In summary, the optimization tends towards favouring the development of large CST plants near a demand point. This avoids the use of the transmission network by direct use of the CST system for heating of the storage media, to address the costs and efficiency reductions arising from electrical heating, but the scope of CST use is expected to be limited by site constraints. The levelized cost of heat (LCOH) for the studied renewable energy input targets (i.e., 30–90%) ranges from 15.34 to 36.92 AUD/GJ. This is promising for the 30% renewable energy target, as future natural gas prices in Western Australia are likely to match or exceed the expected LCOH. Cost reductions for renewable generation and storage technologies with further implementation at a large scale in the future may result in more competitive LCOH at higher decarbonization levels, but it is likely that additional technologies will be required for cost competitiveness at very high decarbonization levels. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of determining the optimal capacity of concentrated solar power (CSP) plants, especially in the context of hybrid solar power plants. This work presents an innovative analytical approach to optimizing the capacity of concentrated solar plants. The proposed method is based on the use of additional non-dimensional parameters, in particular, the design factor and the solar multiple factor. This paper presents a mathematical optimization model that focuses on the capacity of concentrated solar power plants where thermal storage plays a key role in the energy source. The analytical approach provides a more complete understanding of the design process for hybrid power plants. In addition, the use of additional factors and the combination of the proposed method with existing numerical methods allows for more refined optimization, which allows for the more accurate selection of the capacity for specific geographical conditions. Importantly, the proposed method significantly increases the speed of computation compared to that of traditional numerical methods. Finally, the authors present the results of the analysis of the proposed system of equations for calculating the levelized cost of electricity (LCOE) for hybrid solar power plants. The nonlinearity of the LCOE on the main calculation parameters is shown. [ABSTRACT FROM AUTHOR]

The combination of electrospinning and hot pressing, namely the electrospinning-hot pressing technique (EHPT), is an efficient and convenient method for preparing nanofibrous composite materials with good energy storage performance. The emerging composite membrane prepared by EHPT, which exhibits the advantages of large surface area, controllable morphology, and compact structure, has attracted immense attention. In this paper, the conduction mechanism of composite membranes in thermal and electrical energy storage and the performance enhancement method based on the fabrication process of EHPT are systematically discussed. Moreover, the state-of-the-art applications of composite membranes in these two fields are introduced. In particular, in the field of thermal energy storage, EHPT-prepared membranes have longitudinal and transverse nanofibers, which generate unique thermal conductivity pathways; also, these nanofibers offer enough space for the filling of functional materials. Moreover, EHPT-prepared membranes are beneficial in thermal management systems, building energy conservation, and electrical energy storage, e.g., improving the electrochemical properties of the separators as well as their mechanical and thermal stability. The application of electrospinning-hot pressing membranes on capacitors, lithium-ion batteries (LIBs), fuel cells, sodium-ion batteries (SIBs), and hydrogen bromine flow batteries (HBFBs) still requires examination. In the future, EHPT is expected to make the field more exciting through its own technological breakthroughs or be combined with other technologies to produce intelligent materials. [ABSTRACT FROM AUTHOR]

Biomass carbon has the advantage of a wide spectral absorption range, which makes it great potential for solar thermal utilization. In this study, porous skeleton support materials of sugarcane-derived carbon were prepared by freeze-drying-high-temperature carbonization method using natural sugarcane as raw material, and the characterization results demonstrate that the porous skeleton of sugarcane-derived carbon has outstanding porous support properties. By combining CuS with sugarcane-derived carbon, a porous material with outstanding photo-thermal conversion performance was synthesized. Four photo-thermal composite phase change materials (CPCMs) were prepared, the maximum loading mass of the support material C600 to the phase change materials (PCMs) reached 79.77 ​%. The C600-CuS-OC had excellent thermal storage properties with an enthalpy of melting of 276.3 ​J/g and a thermal conductivity of 0.61 ​W·m−1·K−1. The photo-thermal conversion efficiency of C600-CuS-OC was 83.2 ​%. Sugarcane carbon-based CPCMs are a low-cost and high-efficiency solar thermal storage material, which has great potential for applications in solar thermal storage, biomass utilization, and thermal management. [ABSTRACT FROM AUTHOR]

The majority of the world's population still cooks using biofuels like wood, agricultural leftovers, and dried animal dung, which lacks the ability to cook efficiently, predictably, safely, and most importantly cleanly. There is an urgent need to develop an alternate, acceptable, hygienic, and low-cost method of cooking, which can be met by Box type Solar Cooker (BSC) due to its compact form and low-cost attributes. But its inability to cook during off-peak hours makes it difficult to adopt as an alternative cooking technique. To address this issue, thermal storage is added to the system to provide heat during off-peak hours which is well addressed in earlier literature. This paper tries to make an overview on box type solar cooking with heat storage unit based on earlier experimental and analytical research studies. This review provides information about the frequently used materials as heat storage, also different technical-economical-social aspects of BSC are discussed to point out the problem associated with its widespread acceptance. [ABSTRACT FROM AUTHOR]

Australia aims to achieve net zero emissions by 2050, with an interim target of reducing emissions to 43% below 2005 levels by 2030. Electrification of industry processes currently reliant on fossil fuels is a necessary step to achieve these emission reduction goals. This study investigates electrification of steam generation relevant to major industrial operations in the southwest of Western Australia using different renewable energy input levels. The designed system incorporates thermal storage to ensure continuous steam generation. The optimized technology mix, including wind, PV, and concentrated solar thermal (CST) systems for each renewable energy input target, is presented. The optimization process also identifies optimal locations for new renewable energy plants. In summary, the optimization tends towards favouring the development of large CST plants near a demand point. This avoids the use of the transmission network by direct use of the CST system for heating of the storage media, to address the costs and efficiency reductions arising from electrical heating, but the scope of CST use is expected to be limited by site constraints. The levelized cost of heat (LCOH) for the studied renewable energy input targets (i.e., 30–90%) ranges from 15.34 to 36.92 AUD/GJ. This is promising for the 30% renewable energy target, as future natural gas prices in Western Australia are likely to match or exceed the expected LCOH. Cost reductions for renewable generation and storage technologies with further implementation at a large scale in the future may result in more competitive LCOH at higher decarbonization levels, but it is likely that additional technologies will be required for cost competitiveness at very high decarbonization levels.

This paper deals with the problem of determining the optimal capacity of concentrated solar power (CSP) plants, especially in the context of hybrid solar power plants. This work presents an innovative analytical approach to optimizing the capacity of concentrated solar plants. The proposed method is based on the use of additional non-dimensional parameters, in particular, the design factor and the solar multiple factor. This paper presents a mathematical optimization model that focuses on the capacity of concentrated solar power plants where thermal storage plays a key role in the energy source. The analytical approach provides a more complete understanding of the design process for hybrid power plants. In addition, the use of additional factors and the combination of the proposed method with existing numerical methods allows for more refined optimization, which allows for the more accurate selection of the capacity for specific geographical conditions. Importantly, the proposed method significantly increases the speed of computation compared to that of traditional numerical methods. Finally, the authors present the results of the analysis of the proposed system of equations for calculating the levelized cost of electricity (LCOE) for hybrid solar power plants. The nonlinearity of the LCOE on the main calculation parameters is shown.

In the context of increasing energy demands and the integration of renewable energy sources, this review focuses on recent advancements in energy storage control strategies from 2016 to the present, evaluating both experimental and simulation studies at component, system, building, and district scales. Out of 426 papers screened, 147 were assessed for eligibility, with 56 included in the final review. As a first outcome, this work proposes a novel classification and taxonomy update for advanced storage control systems, aiming to bridge the gap between theoretical research and practical implementation. Furthermore, the study emphasizes experimental case studies, moving beyond numerical analyses to provide practical insights. It investigates how the literature on energy storage is enhancing building flexibility and resilience, highlighting the application of advanced algorithms and artificial intelligence methods and their impact on energy and financial savings. By exploring the correlation between control algorithms and the resulting benefits, this review provides a comprehensive analysis of the current state and future perspectives of energy storage control in smart grids and buildings. [ABSTRACT FROM AUTHOR]

In this article, we present some optimised geometries for a thermal storage system previously proposed exploiting Phase-changing materials (PCMs). The optimization has been carried out by using a genetic algorithm. We demonstrate that a simple single-parental, mutation-based, single-objective genetic algorithm can be conveniently employed to optimize the geometry of the proposed PCM thermal energy storage system. Optimization I was the one with the least restrictive conditions and, therefore, with the greatest possibility of variation in the channel geometry. While the one with the worst results is Optimization II because of the most restrictive conditions, primarily constant solid/liquid volume. A metal frame increases the surface area by 6. [ABSTRACT FROM AUTHOR]

Inorganic hydrated salt phase change materials (PCMs) hold promise for improving the energy conversion efficiency of thermal systems and facilitating the exploration of renewable thermal energy. Hydrated salts, however, often suffer from low thermal conductivity, supercooling, phase separation, leakage and poor solar absorptance. In recent years, compounding hydrated salts with functional carbon materials has emerged as a promising way to overcome these shortcomings and meet the application demands. This work reviews the recent progress in preparing carbon-enhanced hydrated salt phase change composites for thermal management applications. The intrinsic properties of hydrated salts and their shortcomings are firstly introduced. Then, the advantages of various carbon materials and general approaches for preparing carbon-enhanced hydrated salt PCM composites are briefly described. By introducing representative PCM composites loaded with carbon nanotubes, carbon fibers, graphene oxide, graphene, expanded graphite, biochar, activated carbon and multifunctional carbon, the ways that one-dimensional, two-dimensional, three-dimensional and hybrid carbon materials enhance the comprehensive thermophysical properties of hydrated salts and affect their phase change behavior is systematically discussed. Through analyzing the enhancement effects of different carbon fillers, the rationale for achieving the optimal performance of the PCM composites, including both thermal conductivity and phase change stability, is summarized. Regarding the applications of carbon-enhanced hydrate salt composites, their use for the thermal management of electronic devices, buildings and the human body is highlighted. Finally, research challenges for further improving the overall thermophysical properties of carbon-enhanced hydrated salt PCMs and pushing towards practical applications and potential research directions are discussed. It is expected that this timely review could provide valuable guidelines for the further development of carbon-enhanced hydrated salt composites and stimulate concerted research efforts from diverse communities to promote the widespread applications of high-performance PCM composites. [ABSTRACT FROM AUTHOR]

Food losses and hunger around the world are majorly attributed to the lack of diverse food processing technologies and standardized methods. Solar energy is a potential solution for drying agricultural products, but traditional solar drying methods are not yet widely used. This study developed a finite element model using COMSOL Multiphysics to assess the performance of a passive greenhouse dryer for drying food products. The proposed model was used to simulate the drying of potato slices, and the results showed that the dryer was able to reduce the moisture content of the potato slices from 1 to 0.005 in 3 h. The drying efficiency was 20.52%, the relative humidity inside the drying chamber was 25.2%, and the energy and exergy efficiencies were 63.46% and 94.01%, respectively. Overall, the results of this study suggest that the passive greenhouse dryer is a suitable drying method for potato chips. The model developed in this study can be used to further optimize the design of the dryer and to evaluate its performance for other food products. [ABSTRACT FROM AUTHOR]

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Solid particle heat storage technology offers a potential solution to the challenges posed by the significant growth of renewable energy sources, particularly in terms of grid security and stability. Consequently, it has the capability to optimize the energy utilization efficiency of the power system. In order to investigate the transport regulation characteristics of solid particles in the thermal storage and release system of a circulating fluidized bed (CFB), a test rig with a capacity of 0.1 MW (th) was established. This rig was utilized to systematically study the transport regulation characteristics of solid particles under the double U-type valve feed structure and U-type valve discharge structure. The experimental findings indicate that the system's design enables efficient and rapid storage and release of solid particles in the CFB. The air distribution mode, specifically the double U-type valve feed structure and the U-type valve discharge structure, significantly influence the feed and discharge characteristics of the ash storage bin. It was observed that the impact of loose air on these characteristics is more substantial than that of the return air, irrespective of the feed structure or the return structure. When adjusting the feed and discharge rate, it is recommended to adopt a scheme that involves coarse adjustment through loose air and fine adjustment through return air. [ABSTRACT FROM AUTHOR]

The use of renewable energy by converting it into heat is an important form of storing energy in a usable form and improving the energy supply flexibility; therefore, the electricity–heating system (EHS) can cope with load fluctuations. However, relevant research is lacking on improving the energy supply limitations by the optimal dispatch of energy flow at the typical EHS, such as the coupled CHP–heat pump–thermal storage system (CCHTS). Based on the study of the energy supply characteristics of the CCHTS for extending the energy supply limitation, this study develops an optimal dispatch method using a heat pump (HP) and the thermal storage (TS) of heating networks to improve the flexibility of the CCHTS and the accommodation capacity of renewable energy. The maximum and minimum energy supply limitation model of the CCHTS and the output power characteristic model are established. Based on the piecewise power supply constraint, the energy flow of the EHS is optimized by using the quadratic programming algorithm. The CCHTS can significantly improve the energy supply flexibility; both coupled combined heat and power (CHP) + HP and coupled CHP + TS can improve the power supply flexibility, but the enhanced effect of CHP + HP is better than that of CHP + TS. An increase of 7.6% in wind power consumption is achieved. The consumption of renewable energy increases by 17.9% in the energy flow optimization results. [ABSTRACT FROM AUTHOR]

Preservation of perishable food produce is a major concern in the cold chain supply system. Development of an energy-efficient on-farm cold storage facility, hence, becomes essential. Integration of thermal storage into a vapor compression refrigeration (VCR)-driven cold room is a promising technology that can reduce power consumption and act as a thermal backup. However, designing a latent heat energy storage heat exchanger encounters challenges, such as low thermal conductivity of phase change materials (PCMs) and poor heat exchanger efficiencies, leading to ineffective charging–discharging cycles. The current study investigates the effect of the integration of a Phase Change Material (PCM) in terms of the selection of the PCM, the optimal positioning of the PCM heat exchanger, and the selection of heat exchanger encapsulation material. Numerical analysis was undertaken using 3D Experience software (version: 2024x.D31.R426rel.202403212040) by creating a 3D model of a 3.4 m3 micro-cold storage unit to understand the inner temperature distribution profile. Further, the experimental setup was developed, and tests were conducted, during which the energy consumption of 1.1 kWh was recorded for the total compressor run time of 1 h. Results indicated that an improved cooling effect was achieved by positioning the PCM trays on the wall opposite the evaporator. It is seen that a temperature difference in the range of 5 to 7 °C exists between the phase change temperature of PCM and the optimal storage temperature depending on the encapsulation material. Hence, PCM selection for thermal storage applications would have an important bearing on the material and configuration of the PCM encapsulation. [ABSTRACT FROM AUTHOR]

The paper presents the performance evaluation of a modified indirect solar dual collector dryer (MIS2CD) integrated with a thermal storage system for drying myrobalan slices. The design of the solar collector and solar collector with thermal storage was to supply uninterrupted thermal energy to the drying chamber during sunny and sunset hours. To evaluate the dryer performances, one lot (20 kg) of myrobalan was dried in the MIS2CD, and as a result, the thermal efficiency and energy supply period of MIS2CD increased by 12 ± 02% and 41 ± 1.2%, respectively. Drying characteristics of myrobalan slices in MIS2CD, TD, and OSD were studied and compared. A two-term exponential model best explains the drying kinetics of myrobalan slices dried in MIS2CD. The dried sample in MIS2CD results in lesser ΔE* values than TD and OSD methods. The highest exergy efficiency of 78.2% and lower exergy losses were recorded. The energy payback period of the MIS2CD was evaluated as 1.42 years. The CO2 emitted and CO2 reduced reduction are calculated for drying myrobalan in MIS2CD for a lifetime (20 years) of 67.85 kg and 20.65 tons, respectively. The capital cost of the solar dryer design was estimated depending on the economic considerations of the state. The drying hours were increased in MIS2CD against OSD by 59% on the annual sunny days (210 days). The sample drying period MSD and TD to reach the final moisture level of 7% was 9 h and 5 h, respectively. The total economic benefit is 22,622 INR (annually), and the 2.08 benefit–cost ratio for myrobalan dried in MIS2CD compared to TD. The MIS2CD's payback period is nearly 2.18 years, much less than the dryer's lifetime. [ABSTRACT FROM AUTHOR]

The preservation of perishable food items within the cold chain is a critical aspect of modern food logistics. Traditional refrigeration systems consume large amounts of energy, without an optimal temperature distribution, leading to potential food spoilage and economic losses. In recent years, the integration of Phase Change Materials (PCMs) into cold chain systems has emerged as a promising solution to address these challenges. This article presents a comprehensive analysis of the utilization of PCMs for food preservation in a refrigerated truck, focusing on the impact on temperature control, phase change fraction, costs, and energy savings. The effectiveness of PCM-based refrigeration system to maintain the refrigerated truck at a temperature of −18 °C under various scenarios and environmental conditions using a transient model was evaluated. The TRNSYS model includes a representation of a conventional refrigerated van's system, with simulations conducted in a Mediterranean climate (Naples). The model's core components consist of Type 56 for cooling load estimation and Type 1270a for the new PCM component. Results indicate that for guaranteeing −18 °C for 10 h, 96.4 kg and 102.2 kg of E-26 and E-29 PCM are needed, respectively, for scenarios with 10 door openings during transportation and for two different velocities of the truck: 30 and 80 km h−1. Results indicate that the incorporation of PCMs in the refrigerated van leads to significant improvements in temperature stability and uniformity, thereby extending the shelf life of perishable food products and reducing the risk of spoilage. Furthermore, the analysis shows that, using the PCMs, a significant reduction of the energy costs can be obtained (up to a maximum of around 79%). [ABSTRACT FROM AUTHOR]

Concentrated solar power (CSP)—photovoltaic (PV) hybrid power plants allow for the generation of cheap electrical energy with a high capacity factor (CF). A deep integration of both technologies offers synergies, using parts of the PV generated electricity for heating the thermal storage tank of the CSP unit. Such configurations have been previously studied for systems coupled by an electric resistance heater (ERH). In this work, the coupling of a CSP and a PV plant using a heat pump (HP) was analyzed due to the higher efficiency of heat pumps. The heat pump is used as a booster to lift the salt temperature in the storage system from 383 to 565 °C in order to reach higher turbine efficiency. A techno-economic analysis of the system was performed using the levelized cost of electricity (LCOE), the capacity factor and nighttime electricity fraction as variables for the representation. The CSP–PV hybrid with a booster heat pump was compared with other technologies such as a CSP–PV hybrid plant coupled by an electric heater, a standalone parabolic trough plant (PT), a photovoltaic system with battery storage (PV–BESS), and a PV thermal power plant (PVTP) consisting of a PV plant with an electric heater, thermal energy storage (TES) and a power block (PB). [ABSTRACT FROM AUTHOR]

A novel combination of an earth air tunnel (EAT) and a sensible thermal storage-aided solar air heater has been proposed when the sensible storage medium is taken to be rocks filled within the air flow passage. Both time-dependent and steady-state models are reported. The former describes the exact thermal performance of the system for a two-month wintertime for the city of Baghdad, Iraq. The latter describes average performance of the system. The implicit finite difference method and method of separation of variables have been used to solve the pertinent equations in the respective models. Acceptable level of accuracy was obtained between the steady-state numerical and analytical solutions as well as between the numerical and the published data. It is revealed that preheating by a sufficiently long EAT module improves the effective power as well as the output temperature from the rock bed solar air heater by about 35% and 9% respectively for the present set of parameters considered. It is also observed that for the present set of parameters considered, the temperature gradients in the direction normal to air flow in the solar air heater are insignificant and may be ignored. A parametric study is also carried out that assesses the impact of system parameters on the quality as well as quantity of the energy extracted from the system. This work is hence the first to couple an EAT with a sensible thermal storage equipped solar air heater and may pave the way for future studies. [ABSTRACT FROM AUTHOR]

One of the areas for increasing energy efficiency in the production of electrical and thermal energy is the use of cogeneration units (CGU), which is due to an increase in the share of useful heat output to heat supply systems. Large combined heat and power plants (CHPs), as a rule, use steam turbine units, which serve as sources of thermal energy for heating and hot water supply in cities with a high concentration of heat load. In small and medium-sized cities, the main sources of thermal energy are boiler houses. With the advent of modern gas piston and gas turbine units on the market, it is possible to predict the creation of mini-CHPs based on them. To increase their fuel efficiency, it is advisable to use seasonal thermal storage (TS) as part of the municipal energy infrastructure in order to reduce the volume of thermal emissions during the nonheating period. [ABSTRACT FROM AUTHOR]

Carnot batteries (or Power-to-Heat-to-Power systems) are capable of increasing the use of electricity from photovoltaic or wind power plants to achieve decarbonisation of the electricity sector. To decouple electricity production from demand, these renewable power plants can be connected to the thermal energy storage system of a concentrated solar thermal power plant via electric heaters. As an alternative to electric heaters, microwaves are studied as a volumetric and selective heating method, avoiding the limitations of the Joule effect conventional heating when having solar salt (non-eutectic mixture of 60 wt % NaNO3 and 40 wt % KNO3), which is a storage medium with low thermal conductivity, working at a temperature very close to its affordable maximum temperature without degradation. In this work, the two heating methods are compared both experimentally and numerically. At experimental level, a microwave oven and a muffle furnace are used to record energy consumption and time for a common objective. Additionally, different crucible materials were used to test their suitability with microwaves. Only quartz glass was validated for microwave heating, while the porcelain and alumina based materials (Corundum and Alsint 99.7) failed while exposed to microwaves. Compared to conventional heating, heating solar salt with microwaves saved fifty minutes of time and ninety percent of consumption. These experiments were validated by numerical simulations, showing a different distribution in each experiment.

The objective of this study is to improve the thermal characteristics of gypsum ceiling boards intended for building envelope applications, focusing on enhancing energy efficiency by integrating graphite-infused phase change material (PCM). The investigation examines PCM incorporation with graphite powder (PCMGP) at 10 % and 20 % mass ratios using differential scanning calorimetry (DSC) analysis. The results indicate that the melting points of PCM, PCMGP – 10 %, and PCMGP – 20 % are approximately 59.6 °C, 59.6 °C, and 59.8 °C, respectively. Notably, the PCMGP-10 % composite displays a narrower melting temperature range, signifying superior thermal characteristics. The PCMGP-10 % composite layer significantly reduces the average room temperature by up to 3.79 % compared to non-PCM gypsum ceiling boards, up to 2.11 % compared to PCM layers without infused graphite, and up to 1.41 % compared to the PCMGP-20 % composite layer under controlled temperature conditions when applied to gypsum ceiling boards. The optimized PCMGP composite enhances thermal performance and thermal energy storage efficiency, leading to significant electrical energy savings by reducing cooling requirements within the building envelope. The implications of this study are crucial for sustainable construction materials and energy conservation strategies. Incorporating PCMGP composites in building envelopes has the potential to enhance energy efficiency and thermal comfort, thus supporting sustainable and energy-efficient construction practices.

The increasing desire for comfort and healthy indoor environment, as well as improvements in energy standards in recent years, have stressed the need to make an active use of the building mass to achieve the maximum energy saving This is why the application of ventilated hollow-core slab systems (VHCS) can be considered as one of the innovative approaches. These systems have precast concrete slabs with tubular voids directing ventilation air on its length. In the present study Solving this system numerically using the ANSYS fluent program to study the temperature distribution and air flow in the 3-D test model of the present study to determine the feasibility of applying this system in an arid climate especially in Iraq by checking the inlet velocity and temperature and to predict the impact of these operating parameters on human comfort and energy savings. The study aimed to provide a numerical analysis of a conditioned zone's temperature distribution using VHCS. The investigation was carried out on a scale model room of size (1 m × 1.2 m × 1 m) with a scale factor of ¼. Four distinct scenarios were examined: the first two cases occurred during a no-load time in the night when there were no internal or external loads and examined the effects of changes in inlet temperatures and air velocities. The remaining two scenarios were conducted during an occupied period with internal heat gain of 630 W/m2 and external heat gain of 800 W/m2 based on the SHGC for the summer season of Iraq. As previously demonstrated, setting the inlet velocity to 1 m/s resulted in an optimal temperature and velocity distribution in the main flow, irrespective of changes in the external and internal loads and temperatures of the supply core. The findings shown that input air velocity and temperature affect heat remove efficiency. In addition, numerical outcomes have also illustrated that the Thermal Active VHCS System, while used in combination with ventilation strategies, could indeed regulate the space conditions by cooling down the building's ceiling, thus eradicating stored heat. All investigations found VHCS systems suitable for air conditioning in dry and hot locations. The systems are known for their ease of use, simplicity, high performance, comfort, and energy savings. They can also reduce peak loads to boost structural energy efficiency.

Solar power is currently a widely recognized energy source that has gained significant attention from numerous countries. Over time, two predominant solar technologies have emerged internationally: solar photovoltaics and solar thermal power. In the case of solar photovoltaics, sunlight is directly converted into electricity. However, despite advancements in thin-film solar photovoltaics, they still exhibit lower electricity output due to the uncontrollable and highly variable nature of rapidly changing weather conditions. Solar thermal power, on the other hand, harnesses solar heat in power plants to generate electricity. However, this type of power generation faces similar challenges. The lack of high-capacity thermal storage contributes to its inherent unpredictability and variability. In the coming years, the solar thermal power industry in Uzbekistan should prioritize harnessing the unique advantages offered by the combination of hybridization and thermal energy storage. With decreasing costs and the increasing adoption of renewable energies, solar thermal power plants have the capability to provide dispatchable power, making them highly suitable for a pivotal role in a future energy grid primarily powered by renewable sources.

Thermal storage has not yet been classified in a unified way. By analyzing the factors of thermal storage and the interactions of fluids, spaces, and solids, this study proposes a three-level classification scheme based on fluid–space–solid thermal storage and dissects the main thermal storage types in the Eryuan, Midu, and Lancang areas of Yunnan Province. The results show that the hydrothermal-karst-carbonate reservoirs of the lower Devonian Kanglang Formation, Carboniferous, and Lower Permian are the main reservoirs in the Eryuan area, the hydrothermal-fracture-carbonate reservoirs are Carboniferous and Lower Permian in the Midu area, and the hydrothermal-fracture-metamorphic reservoirs of the Manlai and Huimin formations are the main reservoirs in the Lancang area. These reservoirs are characterized by high porosity and permeability, high thermal conductivity, high thermal diffusivity, and high specific heat capacity. The classification scheme is systematic, comprehensive, and unified, is capable of conveying multiple information points, and provides a new method for geological exploration personnel to analyze the thermal storage characteristics.

As building electrification is recognised as an important opportunity to reduce greenhouse gas emissions, the integration of solar energy and heat pump represents a promising solution towards net-zero carbon buildings. This paper presents a hybrid multifunctional solar-assisted heat pump (SAHP) system that can provide space heating, space cooling, domestic hot water, and onsite electricity generation. Photovoltaic-thermal collectors are used for electricity generation, heat collection, and radiative cooling. The system design and controls support fourteen operational modes involving different components. TRNSYS software is used to model and simulate the multifunctional SAHP system. With a 2-m3 storage tank and 30-m2 PVT collectors, the multifunctional SAHP system has a seasonal performance factor of 2.7 in Baltimore and 3.7 in Las Vegas. The onsite electricity generation can cover 53% of the building’s electricity needs in Baltimore and 83% in Las Vegas.

Nearly zero-emission buildings (nZEBs) are increasingly being constructed in Europe. There are also incentives to refurbish older buildings and transform them into nZEBs. However, permission is not always granted for their connection to the grid to infuse surplus photovoltaic electricity due to the grid being overloaded with a large number of renewables. In this study, the case of a refurbished school building in Central Greece is examined. After refurbishing it, a significant amount of photovoltaic electricity surplus is observed during the summer and neutral months, which cannot be exported to the grid. The absence of an adequate battery storage capacity resulted in the rejection of an application for exporting the school's surplus to the network and the photovoltaic installation staying idle. An alternative approach is proposed in this work, involving a shift in the export of the photovoltaic electricity surplus to the evening hours, in order for the school to be granted permission to export it to the network. To this end, an optimal battery storage size is sought by employing a building energy system simulation. The mode of operation of the battery designed for this application is set to discharge daily, in order to export the electricity surplus in the afternoon hours to the evening hours, when it is favorable for the network. Additionally, the optimal size of the thermal energy storage of the heating system is studied to further improve its energy efficiency. Our battery and storage tank size optimization study shows that a significant battery capacity is required, with 12 kWh/kWp photovoltaic panels being recommended for installation. The ever-decreasing cost of battery installations results in the net present value (NPV) of the additional investment for the battery installation becoming positive. The solution proposed forms an alternative path to further increase the penetration of renewables in saturated networks in Greece by optimizing battery storage capacity. [ABSTRACT FROM AUTHOR]

This article presents an analytical solution for the evaluation of the thermal performance of packed bed sensible heat storage. The numerical model developed was tested for four different solid storage mediums. The thermal energy equation is solved numerically by deploying the finite difference method. The presented analytical solution is based on a novel mathematical approach. The numerical model was validated using the computer simulation package Comsol Multiphysics v5.3. Our numerical model results are in good agreement with the published experimental data, with an overall difference of ~10%. Hence, the numerical model is an efficient way of evaluating the thermal performance of packed bed thermal energy storage systems compared to other numerical strategies or computer simulation techniques. This proves that the novel analytical model has shown to be a reliable and broadly accurate approach to acquire the thermal performance of sensible heat storage. [ABSTRACT FROM AUTHOR]

In this paper, a thermal storage system based on a phase change material is proposed and investigated. The system is composed of several tubes that cross a phase change material mass. A fluid flowing in the tubes charges and discharges the heat storage system. A mathematical model of the system has been developed, which provides the time and space distribution of velocity, temperature, and liquid phase-changing material concentration in a non-stationary regime. A hybrid solution method based on finite volumes and finite differences techniques has been employed for the model equations in the MATLAB environment. To the tubes, a rectangular cross section has been assigned. The performance of the system in terms of accumulated energy density and accumulated power density has been investigated by varying some geometric parameters. The considered geometric parameters influence the number of tubes per unit of system width, the tube hydraulic resistance, the amount of phase change material around each tube, the heat transfer surface of the tube, and the heat storage velocity. In the parametric analysis, peaks have been evidenced in the investigated performance parameters at different instants after the beginning of the heat storage. [ABSTRACT FROM AUTHOR]

In this paper, the experimental results of the thermal sub-system of a reliable and cost-effective polygeneration solar system are presented. This polygeneration system produces heating, cooling, and electricity from solar energy, which is used in an existing test building. Heat is generated in four evacuated tube solar collectors (ETCs). The heat may be used for space cooling through a variable geometry ejector (VGE) heat pump. In order to reduce the mismatches between generation and consumption, two thermal storage tanks were added. The performance of a new thermal storage, with 400 L, able to store both sensible and latent heat, was tested. The heating performances of the test building were assessed. Ejector cycle tests were also performed, and the variation of the cooling coefficient of performance (COP) was calculated for different flow rates. For heating, the results showed that the heat storage was capable of heating the test building for 8 h, with temperatures between 22 °C and 26 °C. All results showed that this polygeneration prototype could be capable of meeting the heating and cooling needs when applied to a real building. [ABSTRACT FROM AUTHOR]

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The demand for the power grid system's capacity to undergo peak-shaving is increasing as the proportion of renewable energy rises. In China, nuclear power units usually only provide a base load operation in the view of safety and economic considerations, but they do not provide load adjustment services, which undoubtedly increases the pressure of grid load adjustment. In this paper, a novel flexibility load adjustment strategy of the CHP nuclear unit is studied, which is achieved by introducing the thermal storage tank (TST) into the Rankine cycle without changing the output of the nuclear reactor. The AP1000 pressurized water reactor nuclear power unit for combined heat and power is taken as an example, and the thermodynamic model is established through the water vapor equation. Furthermore, the reference system is simulated for the goal of minimizing the imbalance between power supply and demand, and the flexibility–environment–economy benefits are evaluated. The results show that the heat storage/release of the TST may achieve power output flexible adjustment of the nuclear unit, and the power imbalance of the reference energy system is reduced from 1107.99 MWh to 457.24 MWh, a reduction of 58.73%. The introduction of a 600 MWh TST can enable the reference unit to contribute 335 MWh of peak electricity within the reference day. From the perspective of replacing the power generation output increment of coal-fired power units with equal amounts, it can achieve a reduction of 106.09 tons of coal consumption in the case day, which means that 277.73 tons of CO2 emissions can be reduced. The profit of the reference unit can be improved by CHY 70,125 via participating in load adjustment in the case day if following the time-of-use electricity price. [ABSTRACT FROM AUTHOR]

In order to understand the multi-objective particle swarm optimization algorithm for data collection and system characteristics research of heat pump water heaters, the author proposes a multi-objective particle swarm optimization algorithm for data collection and system characteristics research of phase change thermal storage heat pump water heaters. The author first introduced the working principle of the phase change heat storage heat pump water heater, and then conducted a comparative experimental study on the performance of two types of heat pump water heater systems using pure paraffin phase change heat storage and water storage. They compared and analyzed the heat storage process, condensation heat recovery rate of the heat storage box, and comprehensive energy efficiency coefficient of the system under the refrigeration and heat recovery mode of the two types of heat pump water heater systems, on this basis, measures were proposed to improve the performance of pure paraffin phase change thermal storage hot water systems. At long last, the examination of exploratory information shows that the Rx of the water warm capacity framework is around 6% higher than that of the stage change warm capacity framework, and the framework COPt is likewise 20% higher than that of the stage change warm capacity framework, from this, it tends to be seen that the stage change heat capacity box has unfortunate intensity move proficiency, prompting a lessening in the presentation of the intensity siphon water radiator framework. Contrasted and customary water stockpiling heat siphon boiling water frameworks, unadulterated paraffin stage change capacity heat siphon high temp water frameworks lessen the volume of the intensity stockpiling tank, and the framework works somewhat flawlessly during the intensity stockpiling process. However, the system's overall energy efficiency is impacted by the heat storage tank's poor heat exchange effect and relatively low condensation heat recovery rate. The intensity move of the intensity stockpiling box can be upgraded by finning the winding curls in the intensity stockpiling box, embedding aluminum foil, adding extended graphite, and different measures to further develop the buildup heat recuperation rate, subsequently working on the general execution of the framework. [ABSTRACT FROM AUTHOR]

Design of economical and effective solar ponds which are useful thermal energy storage devices, remains a huge challenge. The present work aims at investigating the thermal performance of low cost mini salt gradient solar pond. The portable pond was fabricated as a rectangular configuration having a volume of 0.5m³. Polystyrene and high density polyethylene sheets were employed for insulating the walls. The top of the pond was covered with a slender glass so that the dust accumulation could be prevented without affecting the absorption of solar radiation. Sodium chloride salt was used as the medium and the three salt gradient regions namely lower convective, non-convective, and upper convective regions were established through injection filling technique. The temperature and salt gradient data were observed experimentally for a period of 20 days at Coimbatore, India. The pond could absorb significant amount of available radiation (around 65%) and the maximum temperature of the pond was observed to be 49 °C. Frequent washing of the water surface is necessary to maintain stable salt gradient. Nevertheless, portable pond fabricated with low cost materials exhibited good potential of storing solar energy for solar thermal applications. [ABSTRACT FROM AUTHOR]

This study presents the application of a comprehensive risk assessment and risk management framework on a grid‐independent and renewable energy‐based electric vehicle charging station with multiple energy storage techniques including hydrogen and ammonia. The design comprises complex subsystems such as concentrated photovoltaic thermal, wind turbine, biomass standby generator, hydrogen storage, fuel cell, Ammonia storage and fuel cell, Lithium‐ion battery storage, Salt‐hydrate thermal storage, lithium‐bromide absorption cooling, and fast charging units. Systematic risk‐based approaches compromising multiple phases and qualitative and quantitative risk assessment techniques are applied to identify the causes and consequences of potentially critical events associated with the incorporated subsystems and components. The results show that out of 15 identified technical, economic, environmental, and health and safety risks, three health and safety risks were found unacceptable with risk values above 14. In contrast, three technical, three environmental, two health and safety, and one economic risks were found undesirable with risk values between 8 and 12. Appropriate preventive and protective measures are applied to lessen the high‐risk levels to acceptable safe limits below 6. Proper safety barriers and distances are considered while recommending the associated subsystems and components' optimal physical site distribution plan. [ABSTRACT FROM AUTHOR]

Given the growing share of nuclear power plants in the energy systems of the European part of Russia and the shortage of flexible generating capacities, there is a need to attract nuclear power plants to participate in covering the variable part of the electrical load schedule. The use of storage units, such as latent heat thermal energy storages (LHTES), capable of storing thermal energy received from nuclear power plant reactor units during off-peak hours in the power system and using it during peak load hours to generate electricity will improve the system efficiency of nuclear power plants. Based on the analysis, promising phase change materials (PCM) were identified for operation in thermal storage systems at temperatures from 200 to 300°C, which is determined by the characteristics of the steam turbine plant of a nuclear power plant, including the parameters of feed water and main steam. For the adopted process circuit of an installation with an LHTES with an increase in the temperature of the feed water after the high-pressure heaters of an indirest steam cycle nuclear power plant, the methodological basis for choosing design solutions for the storage system with lithium nitrate as a phase change material has been developed. Using the finite element method in a computer software package, modeling of unsteady heat transfer between this material and water for finned and unfinned pipes was carried out in relation to the LHTES elementary section. Based on the calculation results, graphs of the dependence of the thermal power of the section on the LHTES discharge duration were constructed. Methods are proposed for calculating the duration of LHTES discharge and the mass of the required phase change material when reducing thermal power. For a process circuit with an additional steam turbine unit with a capacity of 12 MW (for NPP power units with VVER-1200), the main characteristics of the latent heat thermal energy storage and the effectiveness of the proposed solution for different LHTES discharge durations are determined. [ABSTRACT FROM AUTHOR]

The development of energy storage systems has become crucial to reduce negative environmental impacts and overcome the mismatch between the required and produced energy. Thermal energy storage systems (TESS) have become highly relevant, and one of the most promising TESS systems is the latent heat thermal energy storage system (LHTESS) based on phase change materials (PCMs). However, the low thermal conductivity and poor heat transfer capabilities of PCMs limit their performance. The use of metal foams as porous media in LHTESS can enhance the low thermal conductivity of PCM and exploit its high energy density. The study performs a simulation on a vertical shell and convergent tube geometry composed of metal foam filled with pure paraffin wax as the PCM considering external heat losses and using the Darcy-Forchheimer model and the enthalpy-porosity theory to analyze the thermal behavior of the system. The numerical results show that the combination of metal foam with PCM significantly improves heat transfer, resulting in a much faster phase change process and reduced melting time. The study can also be expanded further to simulate other types of metal foam and PCMs. [ABSTRACT FROM AUTHOR]

In this paper, the present status of energy storage implementation and research in Arab countries (ACs) is investigated. The different technologies of energy storage are reviewed then projects and capacities of installed or planned energy storage systems in the ACs are summarized based on published literature. In ACs, the installed and planned capacity of pumped hydro storage is 4365 MW, while for battery storage it is 5597 MW. No compressed energy storage projects are installed or planned in the near future. Green hydrogen as a fuel is planned in Egypt, Algeria, and Morocco. Renewable energy as a main employer of energy storage is predicted for the next 30 years; similarly, energy storage capacity is forecasted for the next 30 years. To enhance energy storage implementation it is recommended to include energy storage in all new commercial renewable energy projects. In addition to creating a regulatory framework that encourages the development of energy storage schemes. To advance research in the energy storage, modeling and simulation of energy storage systems in residential, commercial, and industrial sectors are recommended. In addition, cold energy storage for cooling and air‐conditioning using phase change material to be investigated. [ABSTRACT FROM AUTHOR]

Exterior insulation finishing systems (EIFSs) can efficiently promote energy efficiency of buildings. In this study, an EIFS with high thermal efficiency is presented to improve the insulation behavior of building enclosure. Based on heat transfer analysis results, energy simulations of buildings with fire spread prevention structures were performed. Results revealed that heat flow through the wall increased by 10.3 % when using a metal rail to fix the insulation; in contrast, using non-combustible phenolic foam reduces heat flow by 37.4 %, satisfying the requirement for fire spread prevention structures. Additionally, the energy consumption decreased by 8.8 % when both mineral wool and phenolic foam were applied. Fire spread prevention structures are essential to improve the fire safety performance of buildings. This external insulation system efficiently promote energy saving in building; additionally, leveraging a phase change material to improve the thermal storage performance of the building can reduce energy consumption by up to 11.9 %.

This work proposes new approach for recycling plastic to form stabilized-hexadecanoic acid (SHA) as material thermal storage technology (TST). Surface profile of SHA shows the plastic is embedded effectively, maintaining the chemical and phase structural of SHA remains identic with HA. The synthesized SHA indicates a lower supercooling (2.2 °C) and high latent heat capacity above 135 J/g. Also, SHA has a higher specific rating charge around 61.35 % than HA. The finding demonstrates a feasible consideration to recycle plastic as energy storage material, which can be used as fundamental basis for designing specialized TST system and production method of SHA.

Phase change materials are well employed in thermal energy storage systems due to their high thermal storage capacity; however, the problem with phase change materials lies in their low thermal conductivity. The experimental work presented here investigates the effect of adding Alumina (Al2O3) nanoparticles to paraffin wax (Bio-PCM). The resultant nanofluids contain nanoparticles with 1 % and 3 % volume fractions, with corresponding mass fractions of 4 % and 11 %, respectively. It was found that the thermal properties of the prepared nanofluids under investigation exhibit a nonlinear increase in the thermal conductivity with the volume fraction of nanoparticles. A reduction in the latent heat of paraffin wax-based nanofluids was also observed as the volume fraction of nanofluids increased. The results also show the dependence of thermal conductivity on the temperature, where more significant enhancement was observed as the temperature increased. The optimal volume fraction of nanoparticles suspended in the wax was determined to be at 1 % VF with a thermal conductivity value of 0.307 W/m.K at room temperature and latent heat of 207.43 J/g with a melting temperature of 33.63 °C. Furthermore, a stability test was performed to test the thermal conductivity of the mixture under continuous melting and solidification cycles.

An air-rock bed thermal storage system was designed for small-scale powered generation and analyzed with computational fluid dynamics (CFD) using ANSYS-Fluent simulation. An experimental system was constructed to compare and validate the simulation model results. The storage unit is a cylindrical steel container with granite rock pebbles as a storage medium. The CFD simulation used a porous flow model. Transient-state simulations were performed on a 2D axisymmetric model using a pressure-based solver. During charging, heat input that keeps the bottom temperature at 550 °C was applied to raise the storage temperature. Performance analysis was conducted under various porosities, considering natural and forced convection. The natural convection analysis showed insignificant convection contribution after 10 h of charging, as observed in both average air velocity and the temperature profile plots. The temperature distribution profiles at various positions for both convection modes showed good agreement between the simulation and experimental results. Additionally, both cases exhibited similar temperature growth trends, further validating the models. Forced convection reduced the charging time from 60 h to 5 h to store 70 MJ of energy at a porosity of 0.4, compared to natural convection, which stored only 50 MJ in the same time. This extended charging period was attributed to poor natural convective heat transfer, indicating that relying solely on natural convection for thermal energy storage under the given conditions is not practical. Using a small fan to enhance heat transfer, forced convection is a more practical method for charging the system, making it suitable for power generation applications.

This study investigates the enhancement of vehicle warm-up performance using phase-change materials (PCMs) and various thermal storage methods. The primary objective is to utilize the thermal energy lost during engine cooling to improve the cold-start performance, thereby reducing fuel consumption and emissions. Thermal storage devices incorporating PCMs were developed and tested by measuring temperature changes and energy transfer over soaking periods of 4, 8, 16, and 24 h. The results show energy transfers of 591, 489, 446, and 315 kJ at 4, 8, 16, and 24 h, respectively. In terms of the warm-up time, the use of thermal storage devices reduced the time required to reach 70 °C by up to 24.45%, with significant reductions observed across all soaking periods. This reduction in the warm-up time directly contributes to faster engine stabilization, leading to proportional improvements in fuel efficiency and a corresponding decrease in exhaust emissions, including CO2. The findings highlight the effectiveness of PCMs in improving the engine warm-up performance and emphasize the importance of optimizing thermal storage systems to balance energy efficiency and practical application considerations. Additionally, the experimental data provide useful benchmark information for computational simulation validation, enabling the further optimization of automotive thermal management systems. Integrating a PCM-based thermal storage device can significantly enhance a vehicle’s warm-up performance, leading to reduced fuel consumption and lower emissions.

Based on the continuous heat extraction from the heat storage by the buried tube heat exchanger in the middle and deep layers, the temperature field of the heat storage in the middle and deep layers shows different attenuation degrees at the end of the nonheating season. A comparative analysis was mainly conducted on the temperature field changes in two different recovery scenarios: natural recovery of thermal storage around buried pipes in the non heating season and human intervention thermal storage recovery after operating for one heating season. A heat transfer model was established using ANSYS Fluent, and solved using the finite volume method. The model was compared and verified with actual project data. Through comparative analysis of the two different recovery modes at the end of the non-heating season, the results show that when the deep heat storage through natural recovery in the middle of the non-heating season, the lowest heat recovery rate of heat storage temperature is 96. 81% . At the end of the non-heating season, the maximum recovery rate of heat storage temperature can reach 158. 09% . The temperature difference reaches 10. 09 ℃ at the end of non-heating season, and the temperature difference decreases with the increase of depth and radial distance. [ABSTRACT FROM AUTHOR]

An innovative solar-powered tiffin warmer with built-in thermal storage is suggested in this research. Storing food for long periods of time is difficult in many areas of the world due to a lack of electricity, particularly in developing regions. People that depend on pre-packaged meals, such employees, students, and tourists, are especially affected by this problem. sun tiffin warmers, which use sun energy to keep food at a constant temperature, are one answer to this problem. An efficient heating element, thermal storage, a solar reflecting mirror, a phase change material (PCM), and a small, portable tiffin make up the system. In order to maintain a constant temperature regardless of the weather, the system makes use of thermal storage materials to store any surplus heat energy generated during the sun's peak hours. This creative method not only helps the environment by reducing our dependence on traditional energy sources, but it also offers a long-term solution for keeping food warm. The goal of this project is to provide a green, efficient, and cost-effective way to heat meals when traditional energy sources are unavailable. Solar tiffin warmers with thermal storage could help people in off-grid locations live better lives while also decreasing their environmental impact and boosting sustainability. [ABSTRACT FROM AUTHOR]