Heat Retention Research Articles

Quantitative typological analysis applied to the morphology of export mugs and their social factors in the Ming and Qing dynasties from the perspective of East–West trade

The relationship between social factors and the formation of exported mug designs is blurred. This study addresses how they influence material design. Based on a quantitative typological analysis, this paper interprets the cultural relationships underlying the evolution of mug designs exported during the Ming and Qing dynasties. The study reveals: (1) the typology and handle styles of mugs can be categorized into six types, with a predominance of Cylindrical bodies and Ear-shaped handles. Notably, artistic emphasis is concentrated on Bulbous cup bodies and Tail outward curved handles; (2) the design of mugs in the eighteenth century exhibited diversity, morphological similarities, and feature continuity, evolving from representational (Ming Dynasty) to abstract and then to minimalistic styles (Qing Dynasty), particularly evident in the three-dimensional modeling of handles for ergonomic comfort (transitioning from a singular Outward curved form to Ear-shaped form, and then to Entwined branch form); (3) the body shape of mugs transformed from Arc-barrel bodies to Bulbous bodies (focusing on heat retention), and eventually to Cylindrical bodies (prioritizing heat retention, practicality, and cost-efficiency).; (4) the volume of mugs steadily increased from the early eighteenth century, generally classified into large volume (≥ 500 ml), medium volume (200-499 ml), and small volume (< 200 ml); (5) considering the extreme range of volume (11090 ml) and height (25 cm), it indicates that these two variables do not necessarily have a direct positive correlation; (6) the low center of gravity in handle design (average width of 3.4 cm against an average height of 9.9 cm for the body) reflects considerations for the distribution of liquid weight and operational convenience. The volume of sample-10 (11127 ml) notably exceeds the typical range for tea-drinking utensils, revealing the mechanism of wealth and status symbolism. Market demand orientation emerged as the primary driver for the evolution of export mug designs during the Ming and Qing Dynasties, with adjustments in the merchant system playing a secondary role. The transformation in mug design reflects the interplay of multiple factors, with the trend toward minimalist design being a response to market demands.

Stable and thermochromic organohydrogels for thermostatically controlled display windows

Thermochromic windows can reduce temperature changes, thereby reducing electricity consumption. Traditional hydrogel-based thermochromic windows suffer from volatilization and freezing, reducing their utility as protective enclosures for display cases. Here, we present a dual-layer organohydrogel system (DG), consisting of thermochromic organohydrogels that provide both heat shielding and heat retention for smart windows. The cononsolvency caused by polyethylene glycol (PEG) is introduced to sharply reduce the thermochromic temperature to below 10 °C for applicability in thermostatically controlled display windows by strengthening hydrogen bonding between mediums and affecting the interaction between copolymer chains and water molecules. PEG imparts antifreeze, liquid retention, and regenerative qualities to DG, enhancing its stability and recyclability. Organohydrogels exhibit over 90 % light transmittance, obstruct 99.17 % of solar heat, and scatter 23.14 % of mid-infrared light. Within 24 h, DG conserves energy at high rates of 37.22 % and 27.13 % in hot and cold settings, respectively. Thus, aims of DG are to maintain a stable temperature within thermostatic display cases and promoting emissions mitigation.

Lab-on-PCB technology for liquid monopropellant microthrusters: Design, fabrication, and performance evaluation

In this study, we introduce an innovative approach to developing microthrusters for nanosatellites using lab-on-printed circuit board (PCB) technology. Focusing on the challenges in nanosatellite propulsion, we design and fabricate microthrusters in horizontal and vertical configurations. These thrusters are constructed utilizing standardized PCB processes, including stencil printing and soldering. Our propulsion tests assess the performance of these microthrusters, focusing on thermal and C* efficiencies, thrust efficiency, and nozzle throat durability. The results demonstrate the effective decomposition of hydrogen peroxide and heat retention in the MnOx/Al2O3-loaded PCB catalyst chambers for both types of thrusters. The lab-on-PCB technology presents potential for scalable, durable, and efficient production of microthruster modules. We also propose a modular assembly approach, allowing for the customization of propulsion systems tailored to specific satellite missions. Future directions include exploring integration with satellite systems and conducting dynamic control performance testing, positioning lab-on-PCB technology as a versatile solution for the evolving requirements of nanosatellite constellations.

Efficient simulation of bitter gourd drying in active solar dryer: A state-of-the-art model

Greenhouse drying system is used to dry agricultural products or low-temperature thermal drying using a greenhouse structure. In this paper, an experimental and simulation study is carried out to evaluate the drying performances of an active solar greenhouse dryer using COMSOL Multiphysics. The experimental setup includes a compact thermal storage-based greenhouse dryer (1.5 m × 1.0 m x 0.5 m) equipped with a black gravel-covered Aluminium jacket and 35 kg of paraffin wax for heat retention which is located on the floor of the dryer. The experiments were conducted in Ranchi, India (23.34 °N, 85.30 °E) under clear sky conditions in the month of May. The amount of solar radiation (global solar radiation) varied from (630 W/m2 to 1052 W/m2) with an average of 936 W/m2, ambient air temperature (30.2 °C–38.2 °C), air relative humidity (31.6 %–34.6 %), and wind speed (0.9–1.0 m/s). The inside dryer temperature, humidity, wind speed, and floor temperature were also measured every hour. The average values of these parameters were 59.1 °C, 30.2 %, 0.91 m/s, and 69.1 °C, respectively. The FE (finite element) modelling finds out the maximum temperature in drying products, floor and dryer's outlet is 55.3 °C,72.4 °C and 67.4 °C, respectively at 13:00 h. The proposed dryer costs 19633.50 INR with an embodied energy of 1358.01 kW h. The proposed dryer has a break-even period of 1.87 years, and its lifespan is 35 years. During this time, the net CO2 emission was found to be 21.45 tonnes, and the earned carbon credit varies from 1505.01 to 30030.00 INR. The result shows that the drying efficiency is 42.52 %, reducing the initial moisture content from 88.64 % to 2.28 % within five consecutive hours. The energy and exergy efficiencies of the dryer are found to be 61.84 % and 56 % respectively. The system is a viable, sustainable choice for the large-scale production of bitter gourd flakes.

Computational Fluid Dynamics of Four Stroke In-Cylinder Charge Behavior at Distinct Valve Lift Opening Clearance in Spark Ignition Reciprocating Internal Combustion Renault Engine

In-cylinder flow dynamics in internal combustion Renault engine is complex, expensive and difficult to compute experimentally. The present study attempts to emulate the in-cylinder charge behaviour at distinct valve lift opening clearance in four stroke spark ignition internal combustion engine using computational fluid dynamics. Considering the complexity of the geometry and in-cylinder fluid motion, governing equations for unsteady, three dimensional, compressible turbulent flow were computed with continuity equations (conservation of mass), Navier-Stokes equations (conservation of momentum) and RNG k-ε turbulence model. Assumed to be an inline spark ignition (SI) operating on a four stroke cycle, the engine was modelled with SolidWorks 2019 version while the in-cylinder charge behaviour was simulated using ANSYS Fluent 14.5. Increase in cylinder temperature enhanced the thermal properties of air-fuel mixture during combustion. Increase in valve lift opening clearance led to more charge quantity being ingested through the intake valve opening into the cylinder, thereby causing increase in temperature of in-cylinder charge as well as significant improvement in the volumetric and mechanical efficiency of the cycle. It was also observed that the rate of heat retention in the cylinder may be optimum at lower valve lift which may be characterised by minor or zero loses, while significantly high cylinder charge temperature may be prone to reduction of the intake charge density. Based on Particle Image Velocimetry (PIV), in-cylinder velocity vectors, vorticity magnitudes and distributions of turbulence kinetic energy (TKE) increased with increasing valve lift opening clearance, thereby, improving combustion efficiency, increasing torque and power output for effective engine performance.

Studying the Improvement of Solar Collector Mechanism with Phase Change Materials

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.

Fabrication of high-preformance emulsifier from conjugating maltodextrin onto myofibrillar protein peptide with microwave- ultrasound synergy

In this study, we systematically investigated the emulsifying capabilities of myofibrillar protein (MP)- and MP peptide (MPP)-based conjugates synthesized through intensification techniques: water bath (WB), microwave, ultrasound, and the combined ultrasound-microwave (UM) methods. Compared with WB, microwave, and ultrasound treatments, the combined UM treatment greatly promoted the glycation reaction because ultrasound and microwave mutually reinforced modification effects. The resultant conjugate structure tended to unfold with more flexible conformation and homogeneous morphology. Moreover, the emulsifying properties of conjugates developed with single and combined ultrasound-assisted glycation displayed substantial improvement, and pre-hydrolysis further enhanced these performances, as observed in the Principal Component Analysis as well. Remarkably, MPP grafted by maltodextrin with the assistance of a combined UM field produced the smallest and most uniform emulsion system, positioning it as the most efficient emulsifier among all the fabricated glycoconjugates. Our study highlighted the potential of synergistically applying ultrasound and microwave techniques to develop a well-performance glycation with an ideal conjugate structure, in which they would be associated into a strong film that provided the robust physical barrier, creaming stability, heat retention, and oxidation resistance. These findings offered a basis for better utilizing complex ultrasonic technology to develop novel and improved MP-based food products.

Thermoresponsive Skin-like Fabric for Personal Comfort and Protection.

Acting as a "second skin", clothing plays an indispensable role in providing comfort and protection in the wide range of environments in which we live. However, comfort and protection are often competing requirements and are difficult to improve simultaneously. By mimicking the exceptional thermoresponsive one-way liquid transport property of human skin, here we developed a scalable and ecofriendly skin-like fabric that has a tunable directional water transport rate while having excellent water repellency. The water transport rate is also temperature-responsive, just like skin. As the temperature increases, the wettability gradient in the spatially distributed channels (acting like "sweat glands") increases, promoting sweat transport and evaporative heat dissipation. As the temperature decreases, on the other hand, the wettability gradient diminishes, reducing liquid transport and evaporative heat loss, thereby promoting heat retention. The fabric is highly suitable for sportswear and functional clothing and can have wider applications, such as oil-water separation, fog harvesting, etc.

Energy Alterations in Patients with Colon-Rectal Cancer

Introduction: Cancer in colon and rectum are the third most common malignancies diagnosed and second most deadly in both sexes. According to traditional Chinese medicine, patients with cancer has energy deficiency and Heat retention. Purpose: to demonstrate that patients with colorectal cancer has in the back ground energy deficiency and formation of internal Heat in the five internal massive organs (Liver, heart, Spleen, Lungs and Kidney) that is predisposing them to have cancer. Methods: through two cases reports of couple who had diagnosis of rectum cancer (in man) and malignancy tumor in the large intestine in the women. Both underwent to surgery, to take out the tumor. They went to my clinic after a year, for another reason and I measured the energy of the internal five massive organs, according to traditional Chinese medicine’s reasoning, by measuring the chakras’ energy centers using a crystal-pendulum through the radiesthesia procedure. Results: what I found was that all the internal massive organs, that corresponds to the chakras’ energy centers were in the lowest level of energy, rated one out of eight with exception of the seventh chakra, that was normal, rated in eight. Conclusion: the conclusion of this study is that patients with colorectum cancer has energy deficiency in the internal five massive organs. This result is important to us to understand how is formed colorectal cancer, in the energy point of view, because treating this condition of energy deficiency state could be one reason to establish preventive measurement for the formation of all types of cancer, in this case, colorectal cancer

Analysis of factors related to the morphological evolution of Lingnan export mugs in the 18th-20th centuries in the context of one belt and one road.

As a significant trade item on the ancient Silk Road, the evolution of mug shapes represents a confluence of Eastern and Western economic history and cultural-artistic exchanges, also reflecting the flourishing export culture of Guangzhou. This paper analyzes the functional and social factors influencing the morphological changes of Lingnan mugs from 1616 to 1949 from the perspective of quantitative typological analysis. The overall design trend of these mugs transitioned from complex to simple, enhancing user comfort, while variations in mug scale reflect the diversity of consumer classes and regional drinking cultures. Among the 30 mugs analyzed, the average capacity was 356ml, with a range of 1588ml. Common shapes included cylindrical bodies and ear-shaped handles. Morphologically, the belly of the mugs transformed from arc-barrel bodies (emphasizing heat retention) to bulbous bodies, and eventually to cylindrical bodies (combining heat retention, practicality, and economy), with handles also showing signs of East-West integration. The analysis of the mug body' s inclination, with handle-side junction angles ranging from 34° to 53° and wall-side junction angles from 50° to 90°, indicates that these features are associated with stability in placement, aesthetic design, and practicality in liquid containment. These morphological evolutions reflect genuine responses to market demands and advancements in production technology, manifesting as products of market orientation and societal needs. By measuring changes in morphology, scale, volume, and external contour curves, this paper addresses how social factors shape material morphology in an academic context.

Infrared (IR) imaging based comfort appraisal of wool, acrylic, and Thermolite® plaited gloves; Exploring socio-economic materials

Plaited jersey fabrics are always engineered to enhance the thermal conductivity characteristics, providing thermal equilibrium among the wearer and clothing during hot weather. These can also be architected with higher thermal resistance/heat insulation characteristics and is a crucial area of interest; however there isn’t any significant literature reporting this. The study focuses on developing plaited jersey gloves using Thermolite®, acrylic, and wool yarns in alternative main and plaiting configurations for winterwear. Thermal characterizations were conducted to ascertain heat and mass transfer properties, such as fluid transmission and thermal resistance. Infrared (IR) imaging visualized heat retention in terms of temperature gradients. Mechanical characteristics, such as pilling and bursting, were assessed to determine the gloves durability to physical abrasions and stresses. Thermolite® knitted gloves possessed superior heat and mass transfer properties with improved fluid transmission and thermal resistance. Infrared imaging revealed highest body temperature rise of 34.43oC for Thermolite® , and mechanical properties were also found adequate. Fluid transfer (air permeability) was acquired highest for wool samples (1770 mm/sec); however, Thermolite® exhibited 28% lower air permeability than wool, validating its heat retention. Thermolite® knits with the lowest areal density of 226 g/m2 and the smoothest Thermolite® surface had the highest OMMC (overall moisture management capacity) index of 0.46 due to generated capillaries. The statistical analysis of the characterization data indicated the significance ( p-value &lt;0.05) of the main and plating yarns, proving the plaiting a solution to achieve desired heat and mass transfer characteristics.

TWO-DIMENSIONAL CFD ANALYSIS OF A HOT WATER STORAGETANK WITH IMMERSED OBSTACLES

A comprehensive study was conducted to develop a two-dimensional mathematical model for a thermal storage tank containing internal disk-shaped obstacles. This model, incorporating appropriate initial and boundary conditions, was solved using the built-in solvers of the licensed COMSOL Multiphysics 5.6 software. The COMSOL model demonstrated a maximum deviation of 2.2% from experimental results and even smaller discrepancies compared to ANSYS Fluent, validating its accuracy in describing the charging and discharging processes of a sensible heat storage tank with internal obstacles. Using this validated algorithm, numerical studies were performed to analyse temperature distribution and performance indicators for three distinct tank configurations. Among these configurations, the storage tank with a middle disk consistently exhibited superior performance. This tank achieved the highest mixing efficiency, as evidenced by smoother variations in the Richardson number and a more uniform temperature distribution. It also attained the highest capacity ratio (90.12%) and exergy efficiency (81.67%), indicating its effectiveness in heat retention and the quality of stored thermal energy. Furthermore, it demonstrated the highest charging efficiency at 67.51%, highlighting its ability to store incoming heat more effectively. These findings establish the tank with a middle disk as the most efficient configuration for thermal energy storage and uniform temperature distribution.

Effects of Material Composition of Heat Retention Devices on Thermal Characteristics

Effects of Material Composition of Heat Retention Devices on Thermal Characteristics

Influence of honeycomb structures on fluids transmission and heat retention properties; An initiative towards stretchable weaves

The aesthetics and functionality of honeycomb woven assemblies qualifies them for a range of applications expanding across home textiles, fashion, functional apparels, and technical products. Researchers have explored honeycomb assemblies with the focus on shrinkage, sound absorption, thermal conductivity, and heat protection properties analysis via variation in their cell sizes. However, very minimal research is found on analysis of honeycomb woven fabric assemblies’ thermal comfort characteristics by employing different weft insertion sequence and materials (cotton and stretchable yarns). This study reflects the thermal conductivity, dry fluid transmission (air permeability), wet fluid transmission (moisture management), and stiffness attributes of twelve stretchable honeycomb woven assemblies consisting of single ridge, double ridge, and brighton honeycomb weave structures along with different weft sequences of cotton and Type 400 (T-400) stretch yarns. Characterization data showed that single ridge honeycomb structure supports the highest dry fluid transmission property; however, brighton honeycomb offers the highest heat retention property. Double ridge honeycomb highlights the capability of the highest wet fluid transmission property, and brighton honeycomb has immense stiffness. Statistical analysis (ANOVA) also showed that honeycomb structures, weft yarn sequence and material have a statistically significant impact on thermal conductivity and fluid transmission behaviors with p-values less than 0.05.

The effects of a land-based warm-up and accompanying passive heat retention on core body temperature, hormones, and subsequent performance in elite surfers.

Surfing is a high participation sport, yet little sport science research exists regarding competitive performance in surfing. Given surfing's inclusion as an Olympic sport from the 2020 Tokyo Olympics onwards, an examination of performance would seem useful. In numerous land-based sports, and in swimming, the importance of a warm-up and muscle heat is well documented. However, surfing is a unique sport in that it is undertaken both above and below water. Therefore, the aim of this study was to explore the effectiveness of a warm-up in terms of readiness to perform in surfing. We discuss this in the context of thermal regulation, hormone profile change, and the subsequent expression of "power" on waves-a key criteria that surfers are scored for. Nineteen advanced level surfers (i.e., competitive at just below national level in Australia; n = 15 males and n = 4 females) with mean (±SD) age, height, and weight of 24.5 ± 11.6 years, 174.7 ± 9.1 cm, and 67.7 ± 10.2 kg, respectively, were recruited. We adopted a repeated measures pre- and post-design whereby participants engaged in several simulated surfing competitions in an artificial wave pool; once after an active warm-up combined with a passive heat retention strategy (i.e., wrapping themselves in survival blankets-treatment), and once after no warm-up (control). Saliva samples were collected pre- and post-active warm-up, or at equivalent times under control conditions, for the measurement of testosterone and cortisol. Increases in these hormones have previously been associated with an enhanced readiness to compete. Our results demonstrate a clear thermoregulatory benefit from the treatment, with the participants' core body temperatures typically higher from the end of the warm-up to the end of the surf session following treatment (p ≤ 0.03), and a magnitude of increase in core body temperature once in the water that is greater following treatment (p = 0.01). A small magnitude upward change in testosterone (p = 0.01) and cortisol (p ≤ 0.001) following warm-up was also observed. Finally, warm-up was associated with an improved wave performance compared with the control, with a 20% increase in the performance score typically observed (p ≤ 0.01). We argue that the improved thermal profile may have influenced power and, as such, surfing performance was enhanced.

Direct numerical simulation of contaminant removal in presence of underfloor air distribution system

Indoor contaminant removal over 0.5 ≤ FrT ≤ 5.0, 0.5 ≤ N ≤ 5.0, and 50 ≤ Re ≤ 500 was investigated numerically, wherein FrT refers to the Froude number, N refers to the buoyancy ratio, and Re refers to the Reynolds number. As demonstrated, the ventilation effectiveness increased with increasing contaminant source intensity and air supply intensity at a constant air temperature, indicating that increase the fresh air can effectively eliminate contaminants in this case. At high air supply temperatures, the heat retention time and contaminant transport was extremely short, and the fresh air induced by strong natural convection floating lift was rapidly discharged. Additioanlly, the air supply intensity had significant effects on contaminant removal. Quantification of the ventilation effectiveness under the combined effects of air supply intensity, air supply temperature and contaminant source intensity was determined based on the results of direct numerical simulations.

Cellulose nanocrystal stabilized copper nanoparticles for grafting phase change materials with high thermal conductivity

Phase change materials (PCMs) have recently garnered significant attention for thermal energy storage applications. However, widely used PCMs, such as polyethylene glycol (PEG), suffer from low heat conductivity, poor thermal stability, and a tendency to leak, limiting their practical use. Therefore, the objective of this study is to develop a highly thermally conductive composite PCM using PEG and a thermally conductive nanomaterial, specifically cellulose nanocrystals supported by copper nanoparticles (CNC@Cu-NPs). The CNC@Cu-NPs nanocomposite material was used as a matrix to support polyethylene glycol (PEG), resulting in a shape-stable phase change material termed PEG/CNC@Cu-NPs. The obtained PEG/CNC@Cu-NPs were characterized using various analytical techniques. Fourier transform infrared spectroscopy (FTIR) analysis revealed the chemical linkages between PEG and cellulose nanocrystals through a radical polymerization reaction. Polarizing optical microscopy (POM) images of PEG/CNC@Cu-NPs exhibited spherocrystal morphology with smaller sizes compared to pure PEG, suggesting that CNC inhibited PEG side-chain mobility. According to differential scanning calorimetry, the suggested PEG/CNC@Cu-NPs demonstrated a temperature transition between 0.51 °C to 24.5 °C with enthalpies of fusion and crystallization measured at 92.19 and 98.54 J/g, respectively, while also exhibiting excellent cycling stability after 60 heating/cooling cycles. The addition of a modest amount of copper nanoparticles resulted in a remarkable improvement (>50 %) in the thermal conductivity of the PCM. Thermal imaging using an infrared camera showed that PEG/CNC@Cu-NPs exhibited a delay of 10 min in heating compared to pure CNC, confirming the good heat retention capacity of the developed composite material. Based on the aforementioned findings, the proposed PEG/CNC@Cu-NPs PCM offers promising application possibilities in the field of thermal energy storage.

Street Design Strategies Based on Spatial Configurations and Building External Envelopes in Relation to Outdoor Thermal Comfort in Arid Climates

Climate change patterns and expected extreme weather conditions drive urban design practices toward more effective adaptation strategies for the built environment. Biskra City, one of the largest urban areas in the Algerian Sahara territory, has suffered from unprecedented extreme weather patterns, specifically during the summer. This paper examined outdoor thermal comfort in the arid climates of Biskra, Algeria, during summer extreme conditions by investigating the impact of the height-to-width (H/W) ratio aspect and the north–south (N-S) and east–west (E-W) street orientations on pedestrian thermal comfort with the parameterization of external building envelopes using brick, concrete, adobe, and limestone materials. This study was conducted with ENVI-met 5.1.1 software, based on 24 parametric scenarios, to identify the most effective composition for outdoor thermal stress mitigation using the physiological equivalent temperature (PET) thermal index. Across all scenarios, the PET index values fluctuated between PETmin = 32.2 °C and PETmax = 60.6 °C at different hours. The coupling between the H/W ratio and street orientation as geometry factors and building envelope characteristics reveals six distinct categories of building materials, each with an impact on outdoor thermal comfort: (1) high cooling (60–100%), (2) medium cooling (40–60%), (3) low cooling (&lt;40%), (4) high heating (60–100%), (5) medium heating (40–60%), and (6) low heating material (&lt;40%). Therefore, in the N-S orientation, limestone walls can provide a cooling efficiency range from 85% to 100% throughout deep and shallow canyons. Contrary to this, brick walls can cause a heat retention range varying from 70% to 93% within the same canyons. When considering extreme summer conditions in arid climates, the results show that the most effective bioclimatic passive strategy that could be achieved is the E-W orientation, within H/W &lt; 1, characterized by a high albedo building material.

Preparation of thermal energy storage microcapsule with double-layer ceramic shell possessing sponge effect to improve the thermal cycling performance

In present study, thermal energy storage microcapsules with double-layer ceramic shell were fabricated and thermal cycling test was conducted. Thermal cycling test results showed that when ceramic shell constituted of dense inner layer and loose outer layer, the microcapsule had excellent thermal stability. After 3000 thermal cycles, latent heat retention ratio of the microcapsule was more than 90 % and almost no leakage of molten core. This super durability and stability attributed to “sponge effect” of loose outer layer which offered volume buffer for microcapsule core and inhibited molten core overflow during phase change. According to the Mass Conservation Law, criterion Г for describing “sponge effect” was deduced. Г was defined as a quarter of the product of the specific surface area of the microcapsule and criterion Г was derived as Г≥1ρL−1ρS. The criterion shows that when the value of Г is larger than or equal to the difference between the specific volumes of liquid and solid phase change material, microcapsule core is not overflow during phase change. Criterion Г provides theoretical guidance for the preparation of thermal energy storage microcapsules with excellent thermal cycling performance.

Designing surface microstructure for improving energy efficiency of SiO2 glass window by infrared emission

Windows are among the least energy-efficient components of buildings, accounting for about 44 % of building energy consumptions. Improving the energy efficiency of windows is crucial for sustainable and eco-friendly building design. In this work, we introduce a novel glass design featuring specialized surface structures on the front side and Indium Tin Oxide (ITO) coatings on the rear side. Through meticulous structural engineering, the front side achieves a high emissivity of approximately 0.97, ideal for efficient heat dissipation during the summer. Notably, our study reveals a myriad of possible configurations, offering great flexibility that is expected to ease the future fabrication process. Meanwhile, the back side exhibits a low emissivity of about 0.06 due to the ITO coatings, enabling heat retention in the winter. These innovative designs are expected to reduce the average energy consumption by more than 100 MJ/m2 per year. Our approach highlights the potential of mid-infrared emissions to enhance the energy efficiency of windows, thereby advancing the development of smart windows and optimizing their energy-saving capabilities.