Search Results (1,603)

Offshore wind turbine blades in cold marine environments are exposed to low-temperature, high-humidity, and saline-droplet conditions, under which the melting behavior, interfacial sliding, and de-icing energy demand of saline ice differ from those of freshwater ice. Existing studies on combined phase-change coating–electrothermal de-icing have mainly focused on freshwater icing. Here, a glass-fiber-reinforced polymer (GFRP) NACA0018 airfoil was tested in a recirculating low-temperature icing wind tunnel to evaluate an n-tetradecane phase-change microcapsule/polyurethane (PCMS-PUR) coating combined with electrothermal heating at a salinity of 3%. Operating parameters, including heat flux density (8, 10, and 12 kW/m²), ambient temperature (−5, −10, and −15 °C), and incoming wind speed (3, 6, and 9 m/s), were systematically varied under a constant water flow rate (60 mL/min) and spray pressure (0.3 MPa) to characterize the evolution of ice morphology, temperature response, and de-icing energy consumption. During electrothermal de-icing, saline ice was more prone to interfacial softening and lubricating meltwater-layer formation, resulting in a dominant whole-block sliding detachment mode rather than gradual local melting. The PCMS-PUR coating further promoted interfacial melting and advanced ice destabilization through latent-heat release and thermal buffering. When the heat flux density increased from 8 to 12 kW/m², the de-icing energy consumption of the uncoated and coated blades decreased by 45.08% and 42.53%, respectively. The maximum energy-saving efficiency of the combined system reached 16.27% at 9 m/s. These findings clarify the de-icing behavior and energy-saving potential of combined phase-change coating–electrothermal systems under saline icing and provide guidance for the design of low-energy de-icing systems for offshore wind turbine blades. Full article

To address the application bottlenecks of organic phase change materials characterized by low thermal conductivity and susceptibility to liquid leakage, this study utilized natural poplar wood as a raw material to construct a three-dimensional carbon/silver heterogeneous porous skeleton via delignification, gradient carbonization, and in situ electroless silver plating. Polyethylene glycol (PEG) was then vacuum-encapsulated within this structure to prepare form-stable composite phase change materials (CPCMs). The regulatory effects of carbonization temperature and metal interface modification on the microscopic morphology and thermophysical properties of the materials were systematically investigated. The results indicate that the skeleton carbonized at 800 °C achieves an optimal balance between pore distribution and skeleton rigidity, ensuring the uniform conformal growth of silver nanoparticles and endowing the material with excellent anti-leakage performance. The thermal conductivity of the optimal sample reaches as high as 0.683 W/(m·K), with the melting latent heat maintained at 133.9 J/g, while also demonstrating an agile and stable photothermal conversion response. Non-equilibrium molecular dynamics (NEMD) simulations further confirm that the silver nanoparticle modification layer smooths the phonon vibration frequency mismatch between the carbon substrate and organic segments, significantly reducing the interfacial thermal resistance. This research provides an important reference for the structural design and microscopic heat transfer mechanism analysis of high-performance phase change energy storage materials. Full article

Thermal regulation of lithium-ion (Li-ion) battery modules is a critical constraint for electric vehicle (EV) safety and durability, particularly during high-C-rate operation. Phase change materials (PCMs) have emerged as promising passive solutions due to their latent heat storage capability; however, current literature is heavily biased toward organic paraffin-based systems and lacks structured benchmarking across PCM categories and integration architectures. This review provides a systematic comparative assessment of PCM-based battery thermal management systems (BTMSs) comprising organic, inorganic, and eutectic materials under EV-relevant discharge conditions. The review is structured according to the conventional classification of PCMs; however, the available literature is predominantly focused on organic materials, particularly paraffin-based PCMs, leading to greater depth of analysis for this category. Thermophysical properties are analyzed in conjunction with discharge rate, module configuration, and hybrid cooling strategies. The results indicate that peak temperature mitigation is weakly correlated with latent heat magnitude when thermal conductivity remains below critical values. Conductivity-enhanced composites incorporating expanded graphite or metal foams significantly improve heat diffusion, reducing hotspot intensity and inter-cell temperature gradients under medium-to-high C-rates. Pure passive PCM systems exhibit thermodynamic limitations during sustained high-power operation due to saturation effects, underscoring the need for hybrid architectures for continuous heat rejection. This work establishes a structured benchmarking framework and demonstrates that effective thermal conductivity, integration strategy, and discharge-dependent design dominate BTMS performance over latent heat alone. The findings also reveal that inorganic and eutectic PCM-based BTMSs remain comparatively less explored in the literature, particularly at the battery module level and under realistic electric vehicle operating conditions, highlighting opportunities for future research. Full article

In recent decades, summer extreme high-temperature (EHT) events in the Sichuan–Chongqing (SC) region of southwestern China have become increasingly frequent under global warming. Carbon dioxide removal (CDR) is considered a key strategy for achieving the temperature targets of the Paris Agreement; however, the response of regional EHT events to CDR remains poorly understood. Based on CN05.1 observations and idealized CO₂ ramp-up and ramp-down experiments from the CMIP6 Carbon Dioxide Removal Model Intercomparison Project (CDRMIP), this study investigates the historical characteristics of summer EHT events over eastern SC and their responses to CDR. The results show that historical EHT events have become more frequent, longer-lasting, and more intense, indicating an overall intensification of regional high-temperature risk. Under idealized CO₂ pathways, regional mean temperature and EHT frequency exhibit pronounced asymmetric and hysteretic responses, with positive anomalies persisting even after CO₂ returns to its initial level. This asymmetric response is closely associated with the enhanced slow oceanic response during the ramp-down period. Stronger El Niño-like and Indian Ocean Dipole-like SST warming intensifies the South Asian High and western Pacific subtropical high, favoring elevated summer temperatures and increased EHT events over eastern SC. Soil moisture also heats the atmosphere by altering the surface latent heat flux in the southwestern part of the study region during ramp-down period. These findings not only improve the understanding of regional extreme event responses in the SC region under carbon neutrality, but also confirm the positive effect of carbon neutrality targets on mitigating regional extreme climate change, thereby highlighting the urgent need to control CO₂ emissions. Full article

Coral reefs support marine biodiversity, fisheries, tourism, and coastal protection, but they are increasingly threatened by environmental stress and bleaching. Satellite-based reef monitoring has mainly relied on thermal metrics, especially Degree Heating Weeks (DHW), to represent bleaching risk. However, thermal exposure alone may not fully describe reef stress in optically complex coastal waters, where light availability, water clarity, and water-quality conditions can modify coral response. This limitation is important in Indonesia, where reefs span diverse coastal environments and many bleaching observations occur under relatively low DHW. In this study, we develop the Coral Reef Environmental Stress Index (CRESI), implemented as CRESI-Mamba, to estimate coral reef stress in Indonesia as a continuous and interpretable satellite-based stress index. CRESI-Mamba uses 26-week sequences of thermal variables from NOAA Coral Reef Watch and ocean-color variables from NASA Visible Infrared Imaging Radiometer Suite (VIIRS). The model decomposes the inferred stress into thermal, optical, and water-quality pathways, and maps the resulting stress index to bleaching probability for event-based evaluation. CRESI-Mamba was trained and evaluated using 8424 reef observations from eight Indonesian regions. In Leave-One-Region-Out cross-validation (LORO-CV), the model achieved a mean area under the receiver operating characteristic curve (AUC) of $0.795\pm 0.087$. In grouped 5-fold cross-validation, it achieved an AUC of $0.802\pm 0.024$, exceeding the DHW-only baseline ($0.627\pm 0.021$) and performing comparably to stronger thermal-only models, while providing a pathway-decomposed stress index. The estimated stress index separated bleached and not-bleached observations, with paired stress differences of $0.299\pm 0.098$ in LORO-CV and $0.281\pm 0.032$ in grouped 5-fold CV. Pathway analysis showed that the dominant stress pathway differed among regions, with optical stress dominant in several low-DHW bleaching cases. These results show that reef stress in Indonesia is better represented as a multi-pathway environmental condition than as thermal exposure alone. CRESI-Mamba provides a framework for interpreting satellite environmental histories as reef stress, while retaining bleaching probability as an evaluation output. Full article

Intensive duck production is shifting from greenhouse/curtain-sided houses toward closed, mechanically ventilated systems, yet low-carbon environmental control for moisture-dominated houses remains insufficiently synthesized. Using the preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews (PRISMA-ScR) framework, this review aimed to identify low-carbon environmental-control pathways by integrating evidence on envelope design, ventilation, heat pump, and moisture management. Scopus, Web of Science, and PubMed were searched for English-language articles published during 2018–2025. Direct duck house evidence was separated from transferable poultry, livestock-building, and building-energy evidence. Synthesis shows that water access, wet litter, stocking density, and climate make houses latent-load-dominated systems, affecting relative humidity (RH), ammonia (NH₃), particulates, heat stress, welfare, and energy demand. Greenhouse-type houses have low energy use but weak environmental stability, whereas closed/windowless houses improve control and biosecurity but increase dependence on electricity, dehumidification, and backup systems. Low-carbon housing requires staged integration of moisture-source control, drainage, litter management, roof solar-load reduction, controlled ventilation, heat recovery, climate-suitable heat pumps, renewable electricity, sensor-based control, and resilience planning. Low-carbon environmental-control packages should be selected according to house type, climate, and management conditions. Future validation should report standardized energy, carbon, air quality, litter condition, welfare, productivity, cost, and outage-resilience metrics. Full article

Achieving sustainability in the manufacturing sector calls for systemic reductions in energy consumption and carbon emissions without compromising productivity. In the global energy consumption landscape, the manufacturing sector accounts for a significant proportion and is a major source of carbon emissions, with manufacturing systems and HVAC (Heating, Ventilation, and Air Conditioning) systems being the principal energy consumers. Existing research typically optimizes these two systems independently, neglecting their dynamic coupling; production scheduling determines equipment power and heat dissipation, which alters building thermal loads and consequently affects HVAC energy consumption. To address this problem and advance sustainable manufacturing practices, this study proposes an energy-aware scheduling framework integrating manufacturing and HVAC control. A WOA-XGBoost energy consumption prediction model is constructed, employing the Whale Optimization Algorithm to tune XGBoost hyperparameters, achieving a prediction accuracy of R² = 0.937 on the Shanghai typical meteorological year dataset. The HVAC decision variables are defined as five operational control variables—supply air flow rate, fan total pressure, ERV sensible/latent heat recovery effectiveness, and ventilation air flow rate—ensuring the physical realizability of scheduling solutions. An integrated scheduling-and-control model incorporating production capacity constraints and electricity demand response is then formulated and solved using a hybrid Particle Swarm Optimization algorithm. Validation on a five-machine, four-buffer flow shop demonstrates that the proposed framework reduces total electricity cost by 8.85% and total energy consumption by 14.88% in summer compared with a physics-based coupling baseline, with all metrics exhibiting coefficients of variation below 4% across ten independent runs. These results demonstrate that the proposed data-driven framework provides a practical and scalable pathway toward sustainable manufacturing by jointly reducing energy use and associated carbon emissions while maintaining full production throughput. Full article

This study numerically investigates the thermo-energetic behaviour of partitioned cavity walls integrating hypothetical phase change material (PCM) arrangements with single and staggered transition temperatures under cyclic thermal excitation representative of building-envelope operating conditions. The investigated configurations included single-PCM cases with transition temperatures of $20 °\mathrm{C}$, $22 °\mathrm{C}$, and $24 °\mathrm{C}$, as well as two staggered multi-PCM arrangements, namely $(20,22,24 °\mathrm{C})$ and $(24,22,20 °\mathrm{C})$. A two-dimensional transient numerical model based on the enthalpy–porosity approach was developed and validated against previously published numerical and experimental studies available in the literature. Several thermo-energetic indicators were introduced, including temperature amplitude reduction, damping factor, heat-flux attenuation, thermal time lag, cumulative transmitted thermal energy, and liquid-fraction evolution. A normalized multi-objective thermo-energetic assessment was additionally performed to identify the most balanced PCM arrangement. The results demonstrated that the $20 °\mathrm{C}$ PCM provided the strongest indoor-side thermal attenuation, reducing the temperature amplitude and heat-flux amplitude at facet $x8$ by $66.34\%$ and $62.20\%$, respectively, while increasing the thermal time lag to approximately $7.41\mathrm{h}$. The liquid-fraction analysis further revealed that latent heat activation remained strongly localized and spatially selective within the partitioned cavity structure. The staggered multi-PCM arrangements generated broader and spatially redistributed latent heat activation patterns, promoting more progressive thermal regulation over time. In particular, the $(20,22,24 °\mathrm{C})$ arrangement produced the highest partial latent activation, with a maximum liquid fraction approaching $0.1596$, corresponding to the highest latent activation ratio observed in the present study (≈15.96%), whereas the reversed arrangement $(24,22,20 °\mathrm{C})$ provided enhanced indoor-side stabilization associated with delayed and spatially redistributed latent heat activation. The combined thermo-energetic assessment further revealed important trade-offs between peak thermal damping, delayed thermal response, and distributed latent heat activation. Overall, the obtained findings demonstrate that both PCM transition temperature and spatial ordering strongly influence the transient thermal behaviour of partitioned cavity walls and should therefore be carefully considered in the design of adaptive PCM-integrated building envelopes. Full article

Understanding the dynamics of the urban atmospheric boundary layer is critical for accurate meteorological and air quality modeling. Utilizing one year of continuous Doppler wind lidar observations, this study investigates the seasonal and diurnal variability of wind fields, low-level jets (LLJs), and mixing-layer height (MLH) at an urban site in Beijing. Results show that horizontal winds are strongest in winter and spring and weaker in summer, with northwesterly flow dominating in winter and more diverse patterns in summer, while the corrected vertical-velocity distributions show seasonally varying structures and are interpreted cautiously as frequency-distribution characteristics. A distinct diurnal phase reversal in wind speed is identified near 0.3 km. LLJs occur predominantly at night, with core heights descending from 1.2–1.6 km in winter to 0.6–0.8 km in summer, and are associated with enhanced vertical shear. MLH reaches its deepest development in spring, with clear-sky peaks exceeding 1.5 km, while summer growth is comparatively limited and is associated with stronger latent heat partitioning. These findings indicate that wind fields, LLJs, and MLH exhibit coherent seasonal and diurnal covariations, while their direct causal relationships require further process-oriented analysis. This study provides a year-long observational basis for evaluating urban ABL parameterizations. Full article

Hybrid nanofluids combining thermally conductive nanoparticles with latent heat-storing nanocapsules have attracted growing interest for near-ambient liquid-based thermal management, yet direct comparisons between mono and hybrid phase-change-material-containing systems on a common experimental basis remain scarce. In this work, water-based mono Al₂O₃, mono polyurethane-nanoencapsulated n-nonadecane (PU-NEPCM), and Al₂O₃/PU-NEPCM hybrid nanofluids were prepared under identical surfactant, sonication, and dispersion conditions, and their thermal conductivity, dynamic viscosity, and Day-1 colloidal stability were characterized over 298–313 K at total volume fractions of 0.1, 0.3, and 0.5 vol.%, with the hybrids prepared at a 50:50 volumetric ratio. At 0.5 vol.% and 313 K, the hybrid (NFH3) exhibited the highest thermal conductivity enhancement (+8.27%), exceeding the corresponding mono Al₂O₃ and mono PU-NEPCM nanofluids by 4.6 and 5.2 percentage points, respectively, while maintaining a moderate viscosity penalty. The hybrid formulations also achieved |ζ| = 32–37 mV, exceeding the conventional electrostatic-stabilization threshold and outperforming both mono families. A two-factor analysis of variance (ANOVA) identified particle concentration as the dominant factor governing both properties (p < 0.001), with temperature becoming statistically significant only for the hybrid viscosity (p = 0.043). The synergy index varied between 0.85 and 1.43 across the tested conditions—reaching values of 1.20–1.43 for the lowest-loaded hybrid (NFH1)—while the performance index remained close to unity (0.97–1.01). These results identify low-loaded Al₂O₃/PU-NEPCM hybrid nanofluids as a balanced and stable candidate for near-ambient liquid-based thermal management applications. Full article

To address heat accumulation, localized hot spots, and non-uniform temperature distribution in large-capacity lithium iron phosphate energy storage battery modules under high ambient temperature and high-rate charge/discharge conditions, this study proposes a fin-enhanced phase change material (PCM)-air hybrid thermal management structure for a 100 Ah prismatic lithium iron phosphate battery and a 2P18S energy storage battery module. First, the battery thermal model is validated using single-cell experimental data reported in the literature. Subsequently, a three-dimensional transient fluid–solid coupled heat transfer model is established by considering transient battery heat generation, PCM solid–liquid phase change, air-side flow and heat transfer, and temperature-dependent thermophysical properties. User-defined functions are employed to implement the transient heat source and temperature-dependent material properties. Under identical boundary conditions, the thermal management performances of three configurations, namely Fin-Air, PCM-Air, and Fin-PCM-Air, are compared. The effects of ambient temperature (20 °C, 25 °C, and 30 °C) and inlet air velocity (1 m/s, 2 m/s, and 3 m/s) on the maximum module temperature, temperature uniformity, PCM liquid fraction evolution, and flow field distribution are quantitatively analyzed. The results show that, compared with the Fin–Air system without PCM and the PCM-Air system without fins, the Fin-PCM-Air configuration reduces the maximum module temperature by 1.57% and 0.25%, respectively, at an ambient temperature of 30 °C and an inlet air velocity of 3 m/s. After four charge–discharge cycles, the peak maximum temperature of the module is approximately 38.56 °C, and the peak maximum temperature difference remains below 3.6 K, indicating good temperature uniformity and latent heat buffering capability. In addition, the air velocity trade-off analysis indicates that increasing the inlet air velocity can improve cooling performance but also increases the air-channel pressure drop and fan power consumption. Therefore, the Fin-PCM-Air structure is more suitable for high-thermal-load conditions, and its practical application should comprehensively consider cooling benefits, additional mass, manufacturing cost, and long-term reliability. This study provides a reference for the design and engineering application of hybrid thermal management structures for large-capacity energy storage battery modules. Full article

Power batteries used in electric-powered vessels, new-energy tractors or construction machinery typically require prolonged, continuous operation at high power levels, which can lead to significant heat buildup and pose serious threats to battery safety, cycle life, and operational stability. Traditional air-cooled and liquid-cooled systems struggle to meet the requirements for efficient heat dissipation under heavy loads. Phase change materials (PCMs) are ideal for passive battery thermal management due to their high latent heat but are severely limited by low thermal conductivity and liquid leakage. In this study, nitrogen-doped carbon nanotubes@SiO₂ (PNT@SiO₂) were synthesized and further fabricated into oriented porous aerogels by directional freeze-drying using cellulose-based materials as the skeleton. Polyethylene glycol-8000 (PEG-8000) was loaded via vacuum impregnation to obtain the PSAP composite PCM. The optimized composite exhibits a thermal conductivity of 0.93 W/m·K, 3.2 times that of pure PEG, with 96% PEG loading and a phase change enthalpy of 158 J/g. Battery thermal management tests demonstrate its excellent temperature control and heat suppression performance. This study provides a high-performance and feasible thermal management solution for power batteries used in relevant fields. Full article

The La Mancha region (a semi-arid area of southeast Spain) hosts the world’s highest concentration of vineyards and is also one of the regions with the largest areas devoted to almond tree cultivation. Viticulture and nut fruit trees (mainly almonds) are one of the region’s principal sources of economic revenue. The Two-Source Energy Balance (TSEB) model can assist management of water resources. A simplified version of the TSEB approach (STSEB) was previously tested in a vineyard and almonds to estimate sensible heat (H) and latent heat (LE) fluxes using a parallel scheme method based on the Monin–Obukov similarity theory (MOST). This study introduces a method based on Surface Renewal (SR) theory to partition the sensible heat flux using low-frequency measurements as input. The latter was friendlier than the parallel MOST method under unstable conditions and than the series SR and MOST methods. The objective was to compare the MOST and SR models within a parallel scheme method. During the 2014 and 2015 growing season, measurements were collected in a 4 ha row crop drip-irrigated Tempranillo vineyard. Hourly sensible heat flux measured by an eddy covariance (EC) system and evapotranspiration (ET) registered by a 9 m² monolithic large weighting lysimeter were used as a reference. ET estimates were obtained as a residual of the energy balance equation (known as the residual method) using three methods for estimating sensible heat flux, H_SR, H_MOST and H_EC, yielding ET_SR-RE, ET_MOST-RE and ET_EC-RE, respectively. For sensible heat flux, the index of agreement (IA expressed in %) for 2014 and 2015 was 93% and 83%, respectively, using SR, and 84% and 78%, respectively, for MOST. This represents a 6–10% improvement using SR. For evapotranspiration, the ET_SR-RE and ET_MOST-RE IA showed similar performance in both years (around 88%), while ET_EC-RE yielded the best results (92% and 89% for 2014 and 2015, respectively). In addition, half-hourly EC fluxes, during the growing season of 2017, were used as a reference in an almond orchard. The SR sensible heat flux performed better (IA = 93%) than MOST (IA = 86%) in this case, whereas for the latent heat flux, the residual method performed the best, resulting in an IA of 81% for SR and of 78% for MOST. Overall, SR performed better than MOST, particularly under unstable conditions with wind speeds above 1 ms⁻¹. Full article

Phase change materials (PCMs) are increasingly incorporated into façades and wall systems to enhance passive thermal regulation; however, their fire safety remains poorly understood. While PCMs effectively reduce cooling loads, limited data exist on their behaviour under real fire exposure. In this study, the thermal response of PCM-integrated concrete panels was investigated through two-dimensional finite element modelling using an apparent heat-capacity formulation that accounts for phase change, latent-heat absorption, and encapsulation softening. Simulations were performed under the ISO 834 standard fire curve and constant furnace exposures between 200 °C and 800 °C for 60 min to evaluate insulation performance and encapsulation stability. Results show that PCM melting at approximately 31 °C provides a 20–25 min delay in rear-face temperature rise under moderate fire exposure (≤400 °C), maintaining the rear-face temperature increase below 180 °C for one hour. Beyond 500 °C, the acrylonitrile butadiene styrene (ABS) encapsulation softens near 95 °C, suppressing latent-heat storage and leading to rear-face temperatures between 260 °C and 360 °C. Comparative analyses indicate that organic PCMs lose effectiveness rapidly unless protected by at least a 25 mm concrete cover, whereas inorganic PCMs exhibit superior stability owing to their non-combustibility and endothermic dehydration behaviour. The results identify performance trends, thermal limitations, and design considerations for the investigated PCM–ABS–concrete assembly under the studied fire exposure conditions. The validated experimental–numerical framework provides insight into the thermal response of PCM-integrated concrete assemblies and supports future development of fire-resilient building-envelope components. Full article

Phase change materials (PCMs) have been widely investigated for latent thermal energy storage in building envelopes; however, conventional single-melting-point PCMs often exhibit limited adaptability under dynamically varying thermal conditions. This study investigates the thermodynamic feasibility of hybrid-melting-point PCMs to improve transient thermal regulation in multilayer building wall systems. A transient numerical model was developed to evaluate wall assemblies incorporating single and hybrid PCM configurations under structured dynamic thermal loading conditions representing mild, hot, and cold regimes. To isolate the influence of melting-point distribution, hybrid systems containing multiple phase-transition temperatures were compared against conventional single-transition PCM systems with identical total latent heat capacities. The results demonstrate that distributing melting thresholds broadens the effective activation temperature range and enhances attenuation of indoor temperature fluctuations under varying thermal loads. Compared with the conventional single-melting-point system, the proposed hybrid configuration reduced peak indoor temperature by up to 18.5% and increased the minimum indoor temperature by up to 51.9%. Additional material-level simulations revealed that staged phase transitions promote sequential latent heat activation and prolong thermal buffering behavior. The findings suggest that hybrid-melting-point PCMs can improve the transient thermal adaptability of PCM-integrated building envelopes without increasing total latent heat storage capacity. The present study is intended as an exploratory thermodynamic feasibility assessment rather than a climate-specific annual building-energy prediction framework. Full article