Search Results (15)

The smart capsule bubble tile (SCBT) is an innovative flooring solution that combines acupressure-based reflexology with electromagnetic wave stimulation to enhance well-being. Designed for smart buildings and healthcare applications, SCBT integrates traditional construction techniques with advanced healing technologies to create a health-conscious, eco-friendly flooring system. For durability and thermal performance, SCBT tiles are manufactured using conventional concrete methods, enhanced with aluminum oxide (Al₂O₃). Each tile contains multiple pressure point capsules featuring a copper cap that emits electromagnetic waves when exposed to sunlight. This dual-function mechanism stimulates acupressure points on the feet, promoting better blood circulation, reducing stress, and enhancing relaxation. The heat release from the copper caps further improves thermal comfort and energy flow in the body, reinforcing the benefits of reflexology. The performance of SCBT tiles was extensively tested, demonstrating impressive physical and functional properties. They exhibit a flexural strength of 4.6 N/mm², a thermal emissivity of 0.878, a solar reflectance of 0.842, and a water absorption rate of 8.12%. In biomechanical assessments, SCBT showed significant benefits for balance and posture correction. Users experienced a 70.8% reduction in lateral stance ellipse area with eyes open and a 50.5% reduction with eyes closed, indicating improved stability and proprioception. By integrating acupressure and electromagnetic stimulation into flooring design, SCBT promotes a holistic approach to health. This technology supports energy efficiency in smart buildings and contributes to preventive healthcare by enhancing musculoskeletal health and reducing fatigue. SCBT represents a significant step in creating built environments supporting human well-being, merging traditional healing principles with modern material science. Full article

The increasing demand for sustainable energy as a means to combat the impact of climate change is addressed via a novel concept in the present work. Herein presented are developed transferable encapsulated dye-sensitized solar cells, canonically “solar capsules”, for photovoltaic applications on alternative surfaces, such as facades. The solar capsule assembly houses all the components necessary for photovoltaic energy conversion, enclosed within a semiconductor nanotubular array, making them truly unique in their construction. This capsule-style unit enables an easy transfer and draft onto a wide range of materials and surfaces for photovoltaic functionalization and applications. This type of dye-sensitized solar cell typically consists of transferred solar capsules and two additional electrodes. The design and construction of solar capsules means they have a high economic viability as they can seamlessly be up-scaled using commercially established techniques such as anodization and subsequent functionalization. This work demonstrates a working model of such transferable solar capsules by fabricating TiO₂ nanotubes that are functionalized via facile dip- and spin-coating techniques in a wet lab at ambient conditions. These prototypes are characterized in bulk and are thoroughly investigated at the nanoscale for information on the chemical distribution of the constituents, as they may be influenced during the manufacturing process. Full article

Facility agriculture, which involves agricultural production in controlled environments such as greenhouses, indoor farms, and vertical farms, aims to maximize efficiency, yield, and quality while minimizing resource consumption and environmental impact. Energy-saving technologies are essential to the green and low-carbon development of facility agriculture. Recently, phase change heat storage (PCHS) systems using phase change materials (PCMs) have gained significant attention due to their high thermal storage density and excellent thermal regulation performance. These systems are particularly promising for applications in facility agriculture and related buildings, such as solar thermal utilization, greenhouse walls, and soil insulation. However, the low thermal conductivity of PCMs presents a challenge for applications requiring rapid heat transfer. This study aims to provide a comprehensive review of the types, thermophysical properties, and various forms of PCMs, including macro-encapsulated PCMs, shape-stabilized PCMs, and phase change capsules (PCCs), as well as their preparation methods. The research methodology involves an in-depth analysis of these PCMs and their applications in active and passive PCHS systems within facility agriculture and related buildings. The major conclusion of this study highlights the critical role of PCMs in advancing energy-saving technologies in facility agriculture. By enhancing PCM performance, optimizing latent heat storage systems, and integrating intelligent environmental control, this work provides essential guidelines for designing more efficient and sustainable agricultural structures. The article will serve as the fundamental guideline to design more robust structures for facility agriculture and related buildings. Full article

This study delves into the integration of phase change materials (PCM) in solar thermal collector systems to address this challenge. By incorporating nano encapsulated PCMs, researchers have mitigated concerns surrounding PCM leakage, revolutionizing the potential of solar collector systems to elevate energy efficiency, diminish carbon emissions, and yield manifold benefits. This article comprehensively investigates the design and utilization of solar phase change energy storage devices and examines the transformative impact of employing nano-coated phase change materials (Nano capsules) to augment solar collector performance. The integration of paraffin-based PCM and the insulation of the collector system have been crucial in optimizing heat retention and operational efficacy. The composition of the PCM involves a balanced blend of octadecane phase-change particles and water as the base fluid, designed to maximize thermal performance. Analysis of the experimental findings demonstrates the dynamic thermal behavior of the nano encapsulated phase change material, revealing distinctive temperature profiles about fluid dynamics and absorbent characteristics. Notably, the study emphasizes the nuanced trade-offs associated with the conductivity and melting temperature of the Nano encapsulated PCM, yielding valuable insights into energy storage capacity limitations and thermal performance variations throughout diurnal cycles. Central to the investigation, the optimal nanoparticle proportion is elucidated, shedding light on its pivotal role in modulating PCM performance. Furthermore, findings underscore the complex interplay between nanoparticle volume fraction and thermal fluid temperature, providing critical perspectives on optimizing PCM-enhanced solar collector systems. Full article

Hyperloop technology is a transport mode designed to move passengers anywhere in the world, using electric propulsion to carry passengers through a vacuum/near-vacuum tube for a maximum speed of 1200 km/h. Given this, governments, engineers, researchers, and billionaires have been racing over the past years to obtain the first operational system in the world off the ground and bring it from concept to reality. The paper aimed to maximize the capacity of the Hyperloop’s capsule and identify a suitable design of Hyperloop technology based on the different capacities and speeds of the capsules as well as the assumptions of the initial annual demand. Additionally, significant attention will be paid to the interior design of the capsules in which people travel to make the journey more comfortable and enjoyable. The design will be conducted in AutoCAD and Autodesk Revit models based on the allocation of different components such as capacity, compressor fan, batteries, compressor motor, etc. The Hyperloop is powered by solar panels located on the top of the tube, which will allow the capsule to generate more energy based on its capacity than it needs to run. The optimizing cost of each design of the Hyperloop’s capsule will be considered using an MS Excel sheet. As a result, the Hyperloop capsule with a lower capacity (28 seats) has the highest value of optimizing cost due to the number of acquired capsules (38) compared to 25 capsules and 16 capsules for medium- and high-capacity capsules, respectively. The total annual cost of the Hyperloop’s capsules with different capacities of 28, 40, and 50 seats is EUR 5.6 million, EUR 5.5 million, and EUR 6.2 million, respectively, which is determined through the sum of the purchasing cost, operating cost and maintenance cost of capsules. Full article

A numerical investigation of a phase change material (PCM) energy storage tank working with carbon nanotube (CNT)–water nanofluid is performed. The study was conducted under actual climatic conditions of the Ha’il region (Saudi Arabia). Two configurations related to the absence or presence of conductive baffles are studied. The tank is filled by encapsulated paraffin wax as the PCM, and CNT–water nanofluid flows through the capsules. The main goal is to increase the temperature of the PCM to 70 °C in order to store the thermal energy, which can then be used during the night and cloudy weather. Numerical computations are made using the finite element method (FEM) based on actual measured weather conditions. Climate conditions were collected from a weather station located on the roof of the engineering college’s building at the University of Ha’il. The collected data served as input to the numerical model, and the simulations were performed for three months (December, March, and July). The solid CNT volume fraction range was (0 ≤ ϕ ≤ 0.05) and the nanofluid volume flow rate ranged was (0.5 L/min ≤ V ≤ 3 L/min). For both considered cases (with and without baffles), it was found that the use of CNT–nanofluid led to a reduction in the charging time and enhanced its performance. An increase in the volumetric flow rate was found to accelerate the melting process. The best performances of the storage tank occurred during July due to the highest solar irradiation. Furthermore, it was found that the use of baffles had no beneficial effects on the melting process. Full article

Recently, radiation-absorbing phase change material (PCM) for thermal storage that can discharge thermal energy on demand when no radiation is present has been developed and tested indoors. Organic materials with limited thermal conductivity slow down the thermal response processes when charging and discharging. For various industrial applications, much research is devoted to the introduction of solar collectors with the best possible integration of solar thermal collector and PCM in terms of both shape and material. In this study, the performance of a solar collector is examined in relation to the additive effects of aluminum particles in spherical capsules. For the transfer fluid temperature with the behavior of the heat storage, a mathematical model of the solar collector was created. The integrated system consists of two primary steps: a first phase that involves an isolated duct covered in glass, and a second step that involves an array of spherical capsules used as storage. The solar air collector is 1.32 m in width and 2.450 m in length. The PCM unit has a 7.7 cm diameter, 0.15 cm thickness, and is filled with a paraffin wax with concentrations between 0.1 and 0.5 weight of nanoparticle aluminum powder. The air mass flow rate varies from 0.03 kg/s up to 0.09 kg/s, while the temperature varied from 30 to 35 °C. The results obtained from experiments agreed with the predicted results. The reduction in charging time was approximately 70% as the cooling rate increased. The improvement of efficiency of thermal storage reached 76.8% and 71%, at mass flow rates 0.07 kg/s and 0.05 kg/s for pure paraffin wax. The overall thermal storage performance for the system was enhanced from 21.7% to 78.9%. Full article

To transport a spacecraft to distances far beyond the solar heliosphere and around the planets of other stars will require advanced space propulsion systems that go beyond the existing technological state of the art. The release of fusion energy from the interaction of two low mass atomic nuclei that are able to overcome the Coulomb barrier offers the potential for ∼10¹¹J/g specific energy release and implies that robotic missions to the nearby stars to distances of ∼5–10 ly may be possible in trip durations of the order of ∼50–100 years, travelling at cruise speeds of the order of ∼0.05–0.15 c. Such missions would be characterised with ∼kN-MN thrust levels, ∼GW-TW jet powers, ∼kW/kg-MW/kg specific powers. One of the innovative methods by which fusion reactions can be ignited is via the impingement of laser beams onto an inertial confinement fusion capsule, imploding it to a thermonuclear state. This paper gives an overview of the physics of inertial confinement fusion and the interaction of a laser beam with a capsule to include the simulation of a 1D particle-in-cell code calculation to illustrate the effects. In the application to deep space missions, various spacecraft concepts from the literature are discussed, and the range of values assumed for the pulse frequency, burn fraction and areal density appropriate for the mission are presented. It is concluded that advanced space propulsion via inertial confinement fusion is a plausible part of our future, provided that experimental validation of ignition is on the horizon and numerical models for feasibility concepts are developed to high fidelity and on a consistent basis. Full article

This paper presents the results of comprehensive numerical analyses in the performance of a packed-bed latent heat storage (PBLHS) system in terms of key performance indicators, namely charging time, charging rate, charging capacity, and charging efficiency. Numerical simulations are performed for the packed bed region using a transient two-dimensional axisymmetric model based on the local thermal non-equilibrium (LTNE) approach. The model considers the variation in the inlet temperature of the system as these storage systems are typically integrated with solar collectors that operate with intermittent solar radiation intensity. The model results are validated using the experimental data for temperature distribution throughout the bed. The simulations are carried out while changing the operating parameters such as the capsule diameter, bed porosity, inlet velocity, and the height-to-diameter aspect ratio to investigate their impact on the performance indicators. Observations indicate that low porosity, large-sized capsules, low inlet velocity, and a low height-to-diameter aspect ratio increase the charging time. In terms of achieving a high charging rate, a bed with low porosity, small-sized capsules, a high inflow velocity, and a high height-to-diameter aspect ratio is deemed advantageous. It is shown that raising the flow velocity and the height-to-diameter aspect ratio can improve the charging efficiency. These findings provide recommendations for optimizing the design and operating conditions of the system within the practical constraints. Full article

Molten salts eutectics are promising candidates as phase change materials (PCMs) for thermal storage applications, especially considering the possibility to store and release heat at high temperatures. Although many compounds have been proposed for this purpose in the scientific literature, very few data are available regarding actual applications. In particular, there is a lack of information concerning thermal storage at temperatures around 600 °C, necessary for the coupling with a highly efficient Rankine cycle powered by concentrated solar power (CSP) plants. In this contest, the present work deals with a thermophysical behavior investigation of a storage heat exchanger containing a cost-effective and safe ternary eutectic, consisting of sodium chloride, potassium chloride, and sodium carbonate. This material was preliminarily and properly selected and characterized to comply with the necessary melting temperature and latent enthalpy. Then, an indirect heat exchanger was considered for the simulation, assuming aluminum capsules to confine the PCM, thus obtaining the maximum possible heat exchange surface and air at 5 bar as heat transfer fluid (HTF). The modelling was carried out setting the inlet and outlet air temperatures at, respectively, 290 °C and 550 °C, obtaining a realistic storage efficiency of around 0.6. Finally, a conservative investment cost was estimated for the storage system, demonstrating a real possible economic benefit in using these types of materials and heat exchange geometries, with the results varying, according to possible manufacturing prices, in a range from 25 to 40 EUR/kWh. Full article

A horizontally aligned GaAs p–i–n nanowire array solar cell is proposed and studied via coupled three-dimensional optoelectronic simulations. Benefiting from light-concentrating and light-trapping properties, the horizontal nanowire array yields a remarkable efficiency of 10.8% with a radius of 90 nm and a period of 5 radius, more than twice that of its thin-film counterpart with the same thickness. To further enhance the absorption, the nanowire array is placed on a low-refractive-index MgF₂ substrate and capsulated in SiO₂, which enables multiple reflection and reabsorption of light due to the refractive index difference between air/SiO₂ and SiO₂/MgF₂. The absorption-enhancement structure increases the absorption over a broad wavelength range, resulting in a maximum conversion efficiency of 18%, 3.7 times higher than that of the thin-film counterpart, which is 3 times larger in GaAs material volume. This work may pave the way for the development of ultra-thin high-efficiency solar cells with very low material cost. Full article

The performance of solar-thermal conversion systems can be improved by incorporation of encapsulated phase change materials. In this study, for the first time, Crodatherm^TM 60 as a phase change material (PCM) was successfully encapsulated within polyurea as the shell supporting material. While preparing the slurry samples, graphite nanoplatelet (GNP) sheets were also incorporated to enhance the thermal and photothermal properties of the prepared materials. The morphology and chemical properties of these capsules were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectrum, respectively. The results show the spherical-like and core-shell structure of capsules with an average diameter size of 3.34 μm. No chemical interaction was observed between the core and the supporting materials. The thermal characteristics of the microencapsulated PCMs (MEPCMs), analyzed by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), indicate that the prepared samples with 0.1 weight percentage of GNP possess the latent heat of 95.5 J/g at the phase transition temperature of about 64 °C. Analyzing the rheological properties of the prepared slurry with 16 wt % of MEPCMs proves that the prepared material meet the requirements given by the heat transfer applications. The thermal storage capacity, good thermal stability, and improved photothermal performance of the prepared material make it a potential candidate for using in direct absorption solar thermal applications. Full article

Recent advances in Convolutional Neural Networks (CNNs) have attracted great attention in remote sensing due to their high capability to model high-level semantic content of Remote Sensing (RS) images. However, CNNs do not explicitly retain the relative position of objects in an image and, thus, the effectiveness of the obtained features is limited in the framework of the complex object detection problems. To address this problem, in this paper we introduce Capsule Networks (CapsNets) for object detection in Unmanned Aerial Vehicle-acquired images. Unlike CNNs, CapsNets extract and exploit the information content about objects’ relative position across several layers, which enables parsing crowded scenes with overlapping objects. Experimental results obtained on two datasets for car and solar panel detection problems show that CapsNets provide similar object detection accuracies when compared to state-of-the-art deep models with significantly reduced computational time. This is due to the fact that CapsNets emphasize dynamic routine instead of the depth. Full article

Organic phase change materials (PCMs) represent an effective solution to manage intermittent energy sources as the solar thermal energy. This work aims at encapsulating docosane in organosilica shells and at dispersing the produced capsules in epoxy/carbon laminates to manufacture multifunctional structural composites for thermal energy storage (TES). Microcapsules of different sizes were prepared by hydrolysis-condensation of methyltriethoxysilane (MTES) in an oil-in-water emulsion. X-ray diffraction (XRD) highlighted the difference in the crystalline structure of pristine and microencapsulated docosane, and ¹³C solid-state nuclear magnetic resonance (NMR) evidenced the influence of microcapsules size on the shifts of the representative docosane signals, as a consequence of confinement effects, i.e., reduced chain mobility and interaction with the inner shell walls. A phase change enthalpy up to 143 J/g was determined via differential scanning calorimetry (DSC) on microcapsules, and tests at low scanning speed emphasized the differences in the crystallization behavior and allowed the calculation of the phase change activation energy of docosane, which increased upon encapsulation. Then, the possibility of embedding the microcapsules in an epoxy resin and in an epoxy/carbon laminate to produce a structural TES composite was investigated. The presence of microcapsules agglomerates and the poor capsule-epoxy adhesion, both evidenced by scanning electron microscopy (SEM), led to a decrease in the mechanical properties, as confirmed by three-point bending tests. Dynamic mechanical analysis (DMA) highlighted that the storage modulus decreased by 15% after docosane melting and that the glass transition temperature of the epoxy resin was not influenced by the PCM. The heat storage/release properties of the obtained laminates were proved through DSC and thermal camera imaging tests. Full article

The paper presents the theoretical and experimental studies undertaken for the realization of an intelligent composite material with phase shift that has optimal characteristics in the thermal energy storage process and an experimental method for integrating the material with phase change in a possible efficient system to be used in the construction of a dwelling. It analyzes the main factors in designing such systems (the temperature limits between which the system must operate, the melting/solidification temperature of the Phase Change Material (PCM), the latent heat of the PCM, the degree of thermal loading, the bed configuration of PCM capsules and a PCM-RB01 material is set. A micro-encapsulation method was chosen and a “solar wall” is made where the incident solar radiation is absorbed by the PCM embedded in the wall, so the stored heat is used for heating and ventilation of a home. Experimental research has shown that developed PCM allows a maximum room temperature reduction of about 4 °C during the day and can reduce the night-time heating load. Also, despite the lower thermal energy absorption capacity, the developed PCM-RB01 material provides a superior physical stability compared to the classical types of integration. Full article