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A power generator comprising a thermoelectric device (TED) and a phase change material (PCM) allows energy harvesting from ambient temperature variations, which exist ubiquitously; thus, such a device has received considerable attention as an energy harvester that can operate at any location. We developed a model for estimating the characteristics of a power generator in ambient air, whose temperature is forcibly changed between two temperature values, such as when an air conditioner is turned on and off. We calculated the influence of latent heat and thermal conductivity of the PCM on the characteristics of power generators with various thermal resistances between the TED/PCM interface and ambient air. Latent heat and thermal conductivity of the PCM affect the amount of heat energy (Q) transfer between the ambient air and PCM and the energy conversion efficiency (ηE), respectively, where the amount of electric energy is given by Q × ηE. The increase in Q caused by an increase in the latent heat of the PCM was almost independent of the thermal resistance between the TED/PCM interface and air. However, the increase in ηE caused by an increase in the thermal conductivity of the PCM decreased as the thermal resistance between the TED/PCM interface and air increased. These results indicate that the techniques to improve the power generation characteristics by increasing the thermal conductivity of PCM, which have been frequently investigated in recent years, are effective only when the thermal resistance between the TED/PCM interface and ambient air is small. [ABSTRACT FROM AUTHOR]

When a contact line (CL)—where a liquid–vapor interface meets a substrate—is put into motion, it is well known that the contact angle differs between advancing and receding CLs. Using non-equilibrium molecular dynamics simulations, we reveal another intriguing distinction between advancing and receding CLs: while temperature increases at an advancing CL—as expected from viscous dissipation, we show that temperature can drop at a receding CL. Detailed quantitative analysis based on the macroscopic energy balance around the dynamic CL showed that the internal energy change of the fluid due to the change of the potential field along the pathline out of the solid–liquid interface induced a remarkable temperature drop around the receding CL, in a manner similar to latent heat upon phase changes. This result provides new insights for modeling the dynamic CL, and the framework for heat transport analysis introduced here can be applied to a wide range of nanofluidic systems. [ABSTRACT FROM AUTHOR]

Kinetic theory has long predicted that temperature inversion may happen in the vapor-phase for evaporation and condensation between two parallel plates, i.e., the vapor temperature at the condensation interface is higher than that at the evaporation interface. However, past studies have neglected transport in the liquid phases, which usually determine the evaporation and condensation rates. This disconnect has limited the acceptance of the kinetic theory in practical heat transfer models. In this paper, we combine interfacial conditions for mass and heat fluxes with continuum descriptions in the bulk regions of the vapor and the liquid phases to obtain a complete picture for the classical problem of evaporation and condensation between two parallel plates. The criterion for temperature inversion is rederived analytically. We also prove that the temperature jump at each interface is in the same direction as externally applied temperature difference, i.e., liquid surface is at a higher temperature than its adjacent vapor on the evaporating interface and at a lower temperature than its adjacent vapor on the condensing interface. We explain the interfacial temperature jump and temperature inversion using the interfacial cooling and heating processes, and we predict that this process can lead to a vapor phase temperature much lower than the lowest wall temperatures and much higher than the highest wall temperature imposed. When the latent heat of evaporation is small, we found that evaporation can happen at the low temperature side while condensation occurs at the high temperature side, opposing the temperature gradient. [ABSTRACT FROM AUTHOR]

ABSTRACT The Indo‐Pacific warm pool (IPWP), enclosed by a 28°C isotherm, is vital in controlling atmospheric circulations affecting monsoonal flow. The warming trend of sea surface temperatures (SSTs) over the IPWP has expanded the IPWP region. This study examines the impact of the IPWP warming on the Indian summer monsoon rainfall (ISMR) patterns using ERA5 reanalysis and India Meteorological Department rainfall records based on station data from 1959 to 2021. Analyses based on correlation, regression and composite anomalies show the complex relationship between recent decades of IPWP expansion/warming and monsoon circulation. However, the effects of regional IPWP SST warming changes on the ISMR pattern remain unexplored. Here, we explore the changes in the monsoonal circulation owing to the warming and expansion of IPWP, by comparing two equal periods (1959–1989 and 1990–2021). The responses of monsoons to IPWP warming in these two periods revealed some interesting facts, but the complexity remained. Further, we examined the composite impacts of IPWP SST warming in three categories, that is, very cool, usual and extremely warm, on the dynamics of monsoon circulations. The very cool IPWP is associated with the dry monsoon, while the extremely warm IPWP produces copious rainfall over southern India and dryness over eastern north India. The study confirms the non‐linear relationship between IPWP warming and ISMR, which has been investigated in detail. [ABSTRACT FROM AUTHOR]

Subduction of water masses serves as a critical linkage between the surface and subsurface ocean, playing a crucial role in redistributing heat, carbon, and nutrients in the ocean. This process significantly influences global climate and marine ecosystem dynamics. Analyzing five ocean reanalysis data sets, we reveal a distinctive see‐saw pattern in anomalous subduction rates between western and eastern Subtropical Mode Water (STMW) formation areas. This pattern is predominantly driven by variations in latent heat flux, which modulates the late‐winter mixed layer depth. We demonstrate that late‐winter Aleutian Low (AL) activity induces these anti‐phase variations through its impact on latent heat flux. Notably, the Pacific Decadal Oscillation (PDO) significantly influences this subduction see‐saw pattern. During PDO warm phases, AL southward shift intensifies the anti‐correlated variations. Conversely, during cold phases, AL northward shift weakens its influence on ESTMW area, resulting in a less stable anti‐phase relationship. Plain Language Summary: Subduction is the process where water from the surface sinks into deeper layers of the ocean. This process is crucial because it moves important elements like heat, carbon, and nutrients from the surface to the depths below. Understanding how subduction changes is essential for elucidating climate change and biogeochemical cycles. Subduction rates in the North Pacific reveal a pattern like see‐saw: when the subduction rate increases in western Subtropical Mode Water (STMW) formation area, it often decreases in eastern STMW formation area. This see‐saw pattern is mainly caused by latent heat flux, through modulation of the late‐winter mixed layer depth. The late‐winter Aleutian Low plays an important role in this process. When it shifts in position or changes intensity, it affects latent heat flux, creating this west–east see‐saw pattern in subduction. Furthermore, this subduction see‐saw pattern is stronger during the warm phase of the Pacific Decadal Oscillation compared to the cold phase. Key Points: North Pacific shows a subduction see‐saw pattern between western and eastern STMW areas, driven by mixed layer depth variationsLate‐winter Aleutian Low activity induces anti‐phase subduction variations through its impact on latent heat fluxPacific Decadal Oscillation modulates the strength of the subduction see‐saw pattern, stronger in warm phases, weaker in cold phases [ABSTRACT FROM AUTHOR]

Massive irrigation across eastern China (EC) could reduce extreme heat by altering energy and water budgets. However, the irrigation effect on increasing humidity has often been missed, especially in humid regions, leaving its effect and mechanism on extreme humid heat (EHH) poorly characterized. We analyzed assemblies of observations and performed regional simulations with more detailed irrigation scheme to explore the irrigation impacts and potential mechanisms on EHH. We find that irrigation in EC, despite having a cooling effect of about 0.2–0.6° ${}^{\circ}$C, leads to an increase of about 0.4–0.8° ${}^{\circ}$C in EHH, with a more intense impact on the Middle‐Lower Yangtze Plain (MLYP) by 0.9° ${}^{\circ}$C. Cooling effect induced by increased latent heat fluxes through irrigation contributes to air deposition, which lowers boundary layer height, raises near‐surface moist enthalpy, and ultimately exacerbates the EHH. Results mechanistically emphasized irrigation impacts on EHH and highlighted the necessity of improving irrigation modeling reality. Plain Language Summary: Eastern China (EC) distributes the North China Plain (NCP, semi‐arid climate) and MLYP (humid climate), the first and third largest irrigated areas of China. Large‐scale irrigation mitigates extreme dry heat (EDH) while moistening surface air, which is more dangerous to humans with EDH and high humidity combined. Recently, the advantages of irrigation on summer EDH have been widely explored, whereas the influence of irrigation on compound extreme humid heat (EHH) remains unclear. Hence, we studied the impacts of irrigation on EDH and EHH in EC and its potential driving mechanisms based on in situ observations and simulations of WRF‐Noah model coupled with a subgrid demand‐driven irrigation scheme. The comprehensive analysis supports that although irrigation reduces temperature, it raises the integrated measure of temperature and humidity, exacerbating deadly heat stress. The decline in the height of planetary boundary layer induced by the irrigation cooling effect could have played an important role. We argue that heat wave mitigation measures in MLYP and other regions with dominantly moist climates that ignore the moistening power of irrigation, overestimate irrigation's advantages for EDH but underestimate the risks of tens of millions of outdoor workers in the region experiencing compound EHH. Key Points: Effects of irrigation on summer extreme dry and humid heat stress in eastern China are investigated through observations and simulationsIrrigation decreases summer dry‐bulb temperatures but increases heat index and wet‐bulb temperatures, especially in the Middle‐Lower Yangtze Plain.Reduction in planetary boundary layer height induced by cooling effects of irrigation could contribute to deteriorating humid heat extremes [ABSTRACT FROM AUTHOR]

Alloy phase change materials (PCM) are key materials in latent heat storage systems for solar thermal power generation, however, their application is limited by the high corrosion and oxidation problems of alloys. To reduce the erosion problem of alloy PCM, SiC-based ceramic encapsulated flake graphite (EG) modified Al-Cu28-Si6 alloy was used to successfully prepare composite PCM with high compatibility and oxidation resistance. Adopting static erosion test method, the composite PCM was subjected to 50 thermal cycles (25–1000 °C holding time of 10 h was recorded as 1 cycle). The results showed that SiC-based ceramics have excellent corrosion resistance to composite PCM with 10 wt% EG added, which due to the excellent reticulation and encapsulation of EG. Based on the Young-Laplace equation and the contact angle, the erosion resistance mechanism of silicon carbide ceramic alloys has been revealed. SiC-based ceramic-PCM sensible heat-latent heat composite heat storage material was expected to be used for high-temperature heat storage in solar thermal power generation. [ABSTRACT FROM AUTHOR]

The simple wickless structure and strong heat transfer potential of pulsating heat pipes (PHP) have prompted widespread interest in transferring heat from electronic devices. This work proposes a novel single-turn PHP with convergent and divergent shaped additional branches (ABs) (C-PHP and D-PHP) in the evaporator section, which could increase latent heat transfer in the evaporator by minimizing the saturation temperature and improving the unidirectional flow and thermal performance of PHP. Numerical simulations were performed using computational fluid dynamics (CFD) techniques to understand the thermo-hydrodynamics and properties of the proposed novel PHPs. This study provides the outcomes of novel PHPs and a comparison with the performance of traditional PHP (T-PHP) without AB and straight AB PHP (S-PHP). The results demonstrated that the startup time of novel C-PHP and D-PHP were improved by 32.6% and 22.4%, respectively, compared to the T-PHP, "stopovers" and "local flow reversals" are minimized by the use of AB. The average flow velocity of novel C-PHP and D-PHP was improved by 16% when compared to T-PHP and 11.4% compared to S-PHP, the directional component in C-PHP is substantially stronger than S-PHP and D-PHP. [ABSTRACT FROM AUTHOR]

This study examined Baltic Sea Marine Heatwaves (MHWs) using 42 years of satellite-derived sea surface temperature (SST) data. We found that MHWs in warmer months are more intense but shorter compared to MHWs in cooler months. Also, MHWs predominantly affect offshore areas in warmer months, whereas MHWs predominantly impacting coastal seas in cooler months, especially along the eastern coast. Our analysis of interannual variability revealed that, unlike in many other basins worldwide, Baltic MHWs tend to maintain a constant intensity, while their spatial extent has significantly increased over the last few decades. Shortwave radiation notably influences MHW intensity and spatial extent, with additional impacts from longwave radiation in cooler months and latent heat flux in warmer months. Northern Hemisphere teleconnections exhibit stronger correlations with MHWs in the Baltic Sea compared to global-scale climate oscillations, with the Eastern Atlantic pattern having a particularly significant effect on MHW variability in the region. [ABSTRACT FROM AUTHOR]

This work evaluates the use of zinc oxide nanorods as intensifiers of a latent heat thermal energy storage system working with adipic acid as the phase change material (PCM). By virtue of not participating directly in the solid–liquid and liquid–solid phase transition, ZnO-adipic acid composites (ZnO-adipic acid) possessed lower specific heat and latent heat. Our results have shown that the overall heat transfer coefficient during the freezing of PCM through heat transfer to a well-mixed liquid bath is amplified by 61%, when adipic acid is replaced with 2 wt.% ZnO-adipic acid. Heterogenous nucleation due to well-dispersed, ZnO nanorods caused this enhancement. The large enhancement in discharge rate of 2 wt.% ZnO-adipic acid during freezing overweighs higher degree of latent heat loss due to its repeated thermal cycling. The enhancement in overall heat transfer coefficient reported here (61%) is the highest reported so far for any latent heat thermal energy system employing adipic acid or its composites. [ABSTRACT FROM AUTHOR]

Electric vehicles are gradually replacing some of the traditional fuel vehicles because of their characteristics in low pollution, energy-saving and environmental protection. In recent years, concerns over the explosion and combustion of batteries in electric vehicles are rising, and effective battery thermal management has become key point research. Phase change materials (PCM) can absorb or release a large amount of latent heat during the phase change process while maintaining a constant temperature (phase change temperature). In this paper, STAR-CCM+ software is used to carry out three-dimensional simulation of single cell and battery packs with PCM to investigate changing characteristics of battery temperature rise and temperature difference during the cooling and heat preservation process. At the same time, temperature rise and temperature difference of battery are analyzed under different ambient temperatures, convection heat transfer coefficients and phase change latent heats of PCMs. In summer, at an ambient temperature of 30 °C, when using PCM, the battery cell temperature can be reduced by 4 °C in 1800 s, which is about 8.6% lower than that without PCM. In winter, at an ambient temperature of −5 °C, the PCM with a melting point about 20 °C can keep the battery cell temperature drop of no more than 28% within 6700 s at a higher convection coefficient of 5 W/m2·K. Comparing the temperature of the battery pack with that of the battery cell, in the summer with an ambient temperature of 30 °C, the temperature of the battery pack decreased by 13.3 °C in 3600 s, while in the winter with an ambient temperature of −30 °C, the temperature of the battery pack increased by 14.3 °C in 5700 s. The use of phase change materials is conducive for batteries in electric vehicles to dissipate heat in summer and preserve heat in winter. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) offer promising solutions for efficient thermal management in electronic devices, energy storage systems, and renewable energy applications due to their capacity to store and release significant thermal energy during phase transitions. This study investigates the thermal and physical properties of Bi-In-Sn/WO3 composites, specifically for their use as phase change thermal interface materials (PCM-TIMs). The Bi-In-Sn/WO3 composite was synthesized through mechanochemical grinding, which enabled the uniform dispersion of WO3 particles within the Bi-In-Sn alloy matrix. The addition of WO3 particles markedly improved the composite's thermal conductivity and transformed its physical form into a putty-like consistency, addressing leakage issues typically associated with pure Bi-In-Sn alloys. Microstructural analyses demonstrated the existence of a continuous interface between the liquid metal and WO3 phases, with no gaps, ensuring structural stability. Thermal performance tests demonstrated that the Bi-In-Sn/WO3 composite achieved improved thermal conductivity, and reduced volumetric latent heat, and there was a slight increase in thermal contact resistance with higher WO3 content. These findings highlight the potential of Bi-In-Sn/WO3 composites for utilization as advanced PCM-TIMs, offering enhanced heat dissipation, stability, and physical integrity for high-performance electronic and energy systems. [ABSTRACT FROM AUTHOR]

Surface heat source (SHS) is a crucial factor affecting local weather systems. Particularly SHS on the Tibetan Plateau (TP) significantly influences East Asian atmospheric circulation and global climate. Accurate prediction of summer SHS on the TP is of urgent demand for economic development and local climate change. To evaluate the performance of SHS on the TP, the observed SHS data from the eleven sites on the TP verified against CRA40-land (CRA) is evidenced significantly better than ERA5-land (ERA5), another widely used reanalysis. The predictive capability of the CMA Climate Prediction System Model (CMA-CPS) for SHS on the TP was assessed using multiple scoring methods, including the anomaly correlation coefficient and temporal correlation coefficient, among others. Furthermore, relative variability and trend analysis were conducted. Finally, based on these assessments, the causes of the biases were preliminarily discussed. The CMA-CPS demonstrates a reasonable ability to predict the spatial distribution patterns of SHS, sensible heat (SH), and latent heat (LH) on the TP in summer. Specifically, the prediction results of SHS and LH exhibit an "east-high and west-low" distribution, while the distribution of the predicted SH is opposite. Nevertheless, the predicted values are generally lower than CRA, particularly in interannual variations and trends. Among the predictions, LH exhibits the highest temporal correlation coefficients, consistently above 0.6, followed by SHS, while SH predictions are less accurate. The spatial distribution and skill scores indicate that LH on the TP contributes more significantly to SHS than SH in summer. Furthermore, discrepancies in the predictions of surface temperature gradients, ground wind speed, and humidity on the TP may partly explain the biases in SHS and their components. [ABSTRACT FROM AUTHOR]

The critical role of latent heating (LH) in atmospheric blocking events is well-recognized, yet its influence on the predictability of such events remains underexplored. This study examines the prediction accuracy of winter atmospheric blocking days over the Northern Hemisphere, utilizing 20 years of retrospective forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF). Atmospheric blocking events are categorized into three sectors: Atlantic, Continent, and Pacific. Results indicate substantial variations in the LH contribution among different blocking events. During the first 21 days, the Pacific blockings exhibit the most significant impact on prediction skill under strong LH conditions, followed by the Continent blockings, with the Atlantic blockings being least affected. Interestingly, a consistent pattern emerged across sectors: blocking prediction skill is lower under strong LH than under weak LH. During the first 12 days, the Pacific sector typically exhibit lower prediction skill for blocking onset under strong LH, compared to weak LH. For blocking decay, a consistent pattern is observed: lower prediction skill under strong LH than weak LH. Regarding blocking intensity, the forecasting bias escalates with increasing lead time, particularly for strong LH. This study highlights the need to improve moist process simulations in models, aiming to improve atmospheric blocking forecasting accuracy. [ABSTRACT FROM AUTHOR]

Carbon nanomaterial-based form stable phase change materials (FSPCM) offer significant potential as energy storage materials. However, the timely review respectively summarizing the evolution of each carbon nanomaterial and their differences is still lacking. Herein, a comprehensive and systematic approach to gathering, analyzing, and synthesizing relevant literature is employed to conduct this review paper. Specifically, this review provides an extensive examination of PCM encapsulation techniques employing carbon nanomaterial-based materials, discussing their underlying mechanisms and strategies for improving thermal performance. Additionally, it explores the practical applications of carbon nanomaterial-based FSPCMs and discusses future avenues for research and development in this field. By focusing on advancing encapsulation techniques, improving performance, and expanding application possibities, this review aims to contribute to the ongoing progress in the field of carbon nanomaterial-based FSPCMs. [ABSTRACT FROM AUTHOR]

Understanding tree transpiration variability is vital for assessing ecosystem water‐use efficiency and forest health amid climate change, yet most landscape‐level measurements do not differentiate individual trees. Using canopy temperature data from thermal cameras, we estimated the transpiration rates of individual trees at Harvard Forest and Niwot Ridge. PT‐JPL model was used to derive latent heat flux from thermal images at the canopy‐level, showing strong agreement with tower measurements (R2 = 0.70–0.96 at Niwot, 0.59–0.78 at Harvard at half‐hourly to monthly scales) and daily RMSE of 33.5 W/m2 (Niwot) and 52.8 W/m2 (Harvard). Tree‐level analysis revealed species‐specific responses to drought, with lodgepole pine exhibiting greater tolerance than Engelmann spruce at Niwot and red oak showing heightened resistance than red maple at Harvard. These findings show how ecophysiological differences between species result in varying responses to drought and demonstrate that these responses can be characterized by deriving transpiration from crown temperature measurements. Plain Language Summary: Understanding how forests use water, especially during droughts, is crucial for a changing climate. We developed a method using thermal cameras to estimate individual tree water loss (transpiration), something traditional methods lack. These cameras capture temperature data from the tree crown, which is then used to estimate transpiration rates. Tests in two forests showed this method aligns well with existing water use measurements. The study also revealed fascinating differences in how species handle drought. For instance, lodgepole pine outperformed Engelmann spruce in one forest, while red oak proved more resistant than red maple in the other. This shows that the thermal cameras can help assess how different trees resist drought conditions. This thermal camera technique has the potential to become a valuable tool for monitoring forest health as our climate evolves. Key Points: Canopy‐level evapotranspiration derived from thermal cameras agreed well with eddy covariance measurementsCrown temperature measurements facilitated the estimation of individual‐tree transpiration of co‐occurring species using the same approachThe results show interspecific differences in water use and response to drought that align with species traits [ABSTRACT FROM AUTHOR]

Phase change energy storage microcapsules were synthesized in situ by using melamine-formaldehyde–urea co-condensation resin (MUF) as wall material, n-octadecane (C18) as core material and styryl-maleic anhydride copolymer (SMA) as emulsifier. Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry and thermogravimetric analysis were used to study the effects of emulsifier type, emulsifier dosage, core–wall ratio and pH on the morphology and thermal properties of microcapsules. The results show that the pH of core material and the ratio of core to wall have a great influence on the performance of microcapsules. SMA emulsifiers and MUF are suitable for the encapsulation of C18. When the pH is 4.5 and the core–wall ratio is 2/1, the latent heat and encapsulation efficiency of phase transition reaches 207.3 J g−1 and 84.7%, respectively. The prepared phase-change microcapsules also have good shape stability and thermal stability. [ABSTRACT FROM AUTHOR]

Oxygen atoms have been widely used in porous organic polymers, which has attracted much attention from researchers. Herein, porous organic polymer with high oxygen content is synthesized with oxygen‐rich monomer as construction unit and anhydrous aluminum chloride as catalyst; then phase‐change materials (PCMs) composites are prepared by self‐adsorption method. The pore properties of the oxygen‐rich porous organic polymer are characterized by nitrogen absorption and desorption method. The properties of the PCM composites are characterized by scanning electron microscopy, X‐ray diffraction, Fourier‐transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The results show that the oxygen‐rich porous organic polymer has high Brunauer–Emmett–Teller surface area (465 m2 g−1) and excellent thermal stability. The PCM composites possess high encapsulation rate (50.6 wt%) and latent heat (124.7 kJ g−1). After several thermal cycles, the thermal properties of all PCM composites are almost unchanged, and no leakage phenomenon is found. It can be seen that oxygen‐rich porous polymers have potential applications in PCM adsorption and thermal energy storage. [ABSTRACT FROM AUTHOR]

The < 110 > directional solidification of silicon under varying overall temperature gradients was investigated using an in situ observation system. The growth velocity of an atomically rough interface was found to decrease with increasing temperature gradient. A theoretical model of the thermal field taking undercooling into account was developed to describe this phenomenon and was demonstrated to be valid. The results of this work indicate that the reported linear relationship between growth velocity (V) and undercooling (ΔT), given by V (mm s−1) = 120ΔT (K), is most accurate in the case of a rough interface. In the case that the overall temperature gradient is small, the melting point isotherm moves rapidly such that it becomes more difficult for the interface to keep pace with the isotherm compared with a large temperature gradient. This effect leads to increased undercooling at the interface and consequently a rapid growth velocity. Thermal field calculations confirm that a rapid increase in the ratio of the temperature gradient in the crystal to that in the melt should increase the latent heat release, again providing a more rapid growth velocity. [ABSTRACT FROM AUTHOR]

The equatorward contraction of tropical precipitation, commonly referred to as the "deep‐tropical contraction", is witnessed in the paleoclimate simulations of the early Eocene. However, the mechanism driving this contraction is still unclear. Based on the energetics framework of the Intertropical Convergence Zone (ITCZ) and the decomposition method of the latent heat flux along with the simulations of a climate system model, CESM1.2, we proposed a novel mechanism responsible for the "deep‐tropical contraction" in the early Eocene. The greenhouse gases‐induced sea surface warming amplifies the sensitivity of evaporation to surface wind speed changes through Clausius‐Clapeyron scaling, leading to an interhemispheric asymmetric enhancement of the latent heat flux. To maintain hemispheric energy balance, the cross‐equatorial atmospheric energy transport must be reduced during the solstice seasons. As a result, the solstitial location of the ITCZ shifts equatorward, causing the "deep‐tropical contraction" in the early Eocene. Plain Language Summary: The early Eocene is the warmest epoch in the last 65 million years, with a global mean temperature 9°C–23°C higher than the preindustrial period. According to state‐of‐the‐art climate models, the tropical rainfall contracted toward the equator during this extremely warm period. However, the physical mechanism causing this phenomenon remains unclear. In this study, we examined the hemispheric energy balance in the early Eocene that causes the equatorward contraction of tropical precipitation. A novel mechanism underlying this phenomenon is revealed. Based on the climate modeling of CESM1.2, we show that the GHG‐induced warmth enhances the sensitivity of evaporation to surface wind speed changes in the early Eocene. Thus, the stronger tropical trade wind in the winter hemisphere will drive out stronger latent heat flux than in the summer hemisphere. This interhemispheric asymmetric response reduces the interhemispheric heating contrast in the solstice seasons. As a result, the ascending motion in the tropical atmosphere migrates toward the equator, finally decreases the width of tropical precipitation in the early Eocene. Key Points: The "deep tropical contraction" in the early Eocene is caused by the equatorward migration of the seasonal ITCZThe equatorward migration of the solstitial ITCZ location in the early Eocene is due to decreased cross‐equatorial energy transportThe enhanced wind‐evaporation effect in the early Eocene reduces the cross‐equatorial atmospheric energy transport in the solstitial seasons [ABSTRACT FROM AUTHOR]

[Display omitted] Phase change materials (PCMs) can store and release latent heat under the designed phased change temperature and have received substantial interest for energy conservation and thermal control purposes. The use of PCMs in the construction of constant temperature buildings can improve the comfortable environment and save more energy. However, the leakage of PCMs during phase change process limits the application of PCMs. In this paper, a series of PCMs microcapsules with controllable core numbers is synthesized with paraffin (37 ℃) as the core and cross-linked chitosan as the wall. The single-core phase-change microcapsules (S−PCM) and multicore phase-change microcapsules (M−PCM) were prepared by adjusting the preparation condition. The latent heat of S−PCM and M−PCM are 61.4 mJ mg−1 and 50.1 mJ mg−1, respectively. The S-PCM and M−PCM display good stability without paraffin leakage. In addition, the composite blocks of gypsum and S−PCM (GSCM) and M−PCM (GMCM) were prepared and the thermoregulatory effection was investigated, where the surface temperature of GSCM was 5–10 ℃ lower than that of pure gypsum block. PCMs may also have broad application space in electronics, cold chain, and other industries. [ABSTRACT FROM AUTHOR]

Among metal‐based phase change materials (PCMs), Al and its alloys have garnered significant attention due to their high latent heat and high thermal conductivity. However, challenges such as leakage, corrosion, and oxidation have limited their widespread application. Numerous researches have demonstrated that encapsulating Al and its alloy PCMs is one effective way to address these problems. This review provides a comprehensive overview of the characteristics, encapsulation strategies, and applications of Al and its alloy PCMs. First, the advantages and thermal properties of Al and its alloy PCMs are introduced, and their problems are then discussed. Subsequently, various encapsulation strategies that are expected to solve the above problems are summarized and compared. Additionally, the applications of Al and its alloy PCMs in solar thermal energy storage, catalysis, and electric vehicles are reviewed. Finally, current challenges, potential solutions, and the key direct of future study are presented. [ABSTRACT FROM AUTHOR]

The extractive distillation process using propylene glycol (IUPAC name: 1,2 propanediol) as an extractive agent for the separation of the isopropanol–water system was investigated in this work. A systematic procedure was set out to obtain the optimal design and process conditions for extractive distillation and solvent recovery columns using the PRO/II process simulator. Four thermally integrated flowsheets were proposed, implying the recovery of the sensible heat and latent heat from the hot streams in the process. To establish the economic feasibility of the proposed process, we calculated the total annual cost for all the simulated versions, and the proposed fully thermally integrated flowsheets could save up to 43.13% in terms of the utility costs and up to 15.57% in terms of the TAC compared to the conventional design. Thus, propylene glycol (PG) is found to be suitable as a new solvent for isopropanol dehydration, being comparable with other classical solvents used for the dehydration of alcohols. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) have emerged as an intriguing option for the storage of thermal energy because of their remarkable capacity to store latent heat. However, the practical application of these materials is hindered by their low thermal conductivity and limited photo-absorbance. For this investigation, graphene nanoplatelets (GNP) and multiwall carbon nanotubes (MWCNT) hybrid nanoparticles were disseminated in RT-54HC organic PCMs at different weight fractions. The nanoparticles were incorporated into the base PCMs using a melt blending technique. Based on the findings, one combination of GNP to MWCNT in a 0.25:0.75 ratio has shown the highest thermal conductivity, with an increase of 40% (0.28 Wm−1 K−1) compared to other hybrid combinations. This breakthrough could potentially open new avenues in the field of thermal energy storage. The chemical stability of the hybrid nanoparticle dispersed composites was assessed through FTIR analysis. In addition, the composites exhibited excellent thermal stability, maintaining their structural integrity even at temperatures as high as 300 ℃. The melting temperature of the composites also showed minimal variation. Based on the evaluation of latent heat enthalpy, the organic PCM known as base RT-54HC demonstrated a heat storage capacity of 230 J/g. However, the composites exhibited a slight decrease in latent heat with increasing nanoparticle weight fraction. In addition, the composite with added hybrid nanoparticles demonstrated an increase in optical absorbance, accompanied by a decrease in transmissibility. Therefore, the hybrid nano-enhanced composites have demonstrated enhanced thermo-physical properties, making them not only suitable but also highly promising for use in applications with mid-range melting temperatures. [ABSTRACT FROM AUTHOR]

An unprecedented heavy rainfall event in China ("21.7" extreme rainfall event) was simulated using the global variable‐resolution model (MPAS‐Atmosphere) across the scales (4, 8, 16 and 50 km). Although almost all experiments at different resolutions reproduce the spatiotemporal characteristics of precipitation, the simulated precipitation intensity from high to low is 16, 8, 50, and 4 km, with the 16 km simulation being closest to the observations. Precipitation magnitude is prominently influenced by the difference in simulated large‐scale circulation across a range of grid spacings. Further analysis revealed that the differences in latent heating across scales affect the geopotential height and wind field by altering temperature. The latent heating in 4 km simulation is the minimum while the 16 km simulation is maximum. More latent heating release leads to the low‐level pressure depression, amplifies the water vapor flux convergence, produces stronger upward motion and more clouds, and ultimately results in stronger precipitation. The sensitivity experiments for turning off latent heating tendencies during the event showed that the latent heat release has positive feedback on the "21.7" heavy rainfall event. This study highlights the importance of scale‐awareness of latent heat at different resolutions and suggests that the difference in simulated latent heat release during the event is the main reason for simulated different atmospheric circulation and precipitation across scales. Plain Language Summary: Due to the advancements in the numerical computing power, numerical weather prediction models (NWP) are operating at horizontal grid spacing ranging from 1 to 10 km. This study evaluates the simulation performance of the global variable‐resolution model MPAS‐A for a heavy precipitation event and investigates the influence of scale‐aware convective parameterizations on modeling rainfall at horizontal resolutions across the scales (4, 8, 16 and 50 km). The results show that 4 km simulation exhibits the weakest precipitation while the simulated precipitation at 16 km is the strongest. The difference in precipitation simulated by four experiments across scales derives from the variations in large‐scale circulation simulated with different refined resolutions. Further analysis revealed that the differences in latent heat at different resolutions ultimately lead to the changes in geopotential height and large‐scale wind field by altering temperature. 4 km experiment simulates less latent heat than other lower‐resolution experiments. Owing to the positive feedback of the latent heat release on precipitation, 4 km experiment simulates the minimum precipitation. This work highlights that latent heat plays a vital role in simulation of synoptic condition and precipitation. Key Points: Precipitation is influenced by the difference in simulated atmospheric circulation across a range of grid spacingsThe differences in simulated latent heat release across scales affect the geopotential height and wind field by altering temperatureThe latent heat release has positive feedback impact on the "21.7" heavy precipitation event [ABSTRACT FROM AUTHOR]

Evaporative fraction (EF) is a useful measure for quantifying land surface energy partitioning processes and determining evaporative regimes; however, its influencing factors remain highly uncertain. Here, global data sets were compiled to disentangle the effects of environmental variables on EF variations along climate and land surface gradients. We found that (a) at annual timescales, ecosystem‐level EF could be expressed as a power law function of aridity index. The relationships of mean annual soil water content (SWC) and leaf area index (LAI) with mean annual EF resembled the traditional evaporative regime theory; (b) at daily timescales, the boosted regression tree method quantitatively revealed that the impacts of environmental variables (including meteorological variables) on EF showed equal importance, especially at humid sites, primarily due to the different response direction and magnitude of latent heat (LE) and sensible heat (H) fluxes to environmental changes. Particularly, the contrasting responses of LE (positive) and H (negative) to SWC, LAI, and relative humidity enhanced the positive effects of those influencing variables on EF; whereas, the correlations between EF and energy‐related factors (i.e., net radiation‐Rn and air temperature‐Ta) deteriorated as both LE and H showed positive response patterns to those variables; (c) meteorological factors were also found to have nonlinear effects on daily EF, further modified by climatic conditions. Rn near 150 W/m2 and Ta near 15°C appeared to be important energy‐partitioning thresholds at drier and humid sites, respectively. Moreover, changing interactions among environmental variables with climates were demonstrated to be important for better explaining EF variations. Plain Language Summary: Evaporative fraction (EF; defined as latent heat flux‐LE divided by the sum of LE and sensible heat flux‐H) can vary under different climatic and land surface conditions, but its influencing factors remain poorly understood. To this end, we explored the effects of environmental variables on annual and daily EF variations at different sites around the globe. We found that mean annual EF decreased with increasing aridity index and increased with mean annual soil water content and leaf area index. By comparison, the boosted regression tree method quantitatively showed that environmental variables exerted equally important roles in regulating daily EF, especially at humid sites. The complex interplays of daily EF with environmental variables were mainly due to the different responses of LE and H to surrounding environments and the strong nonlinear and interactive effects of environmental variables. These results are important for understanding the driving mechanisms of EF and land surface energy partitioning processes along climate and land surface gradients. Key Points: Environmental variables exerted equally important roles in regulating daily evaporative fraction, especially at humid sitesSynchronous responses of latent and sensible heat to surroundings determined how environmental variables affected evaporative fractionEnvironmental factors had strong nonlinear and interactive effects on daily evaporative fraction, which was further modified by climates [ABSTRACT FROM AUTHOR]

Persistent positive sea surface temperature anomalies (SSTAs) in the mid‐latitude Northeast Pacific (NEP), also known as "warm blob" or "marine heatwave," have substantial ecological and climate effects. This study delves into the spatiotemporal connection between Arctic Oscillation (AO) and SSTAs in the NEP. First, we conduct the lead‐lag correlation and maximum covariance analyses to disentangle the closest temporal relationship between October AO and wintertime SSTAs in the NEP. Then, we categorize the years in positive AO (pAO) phase into two groups: positive AO with warm anomaly (pAO&Blob) group and positive AO without warm anomaly (pAO&noBlob) group based on the October AO index and wintertime blob index. Results show that the positive phase of AO in October strongly influences the wintertime warm SSTAs in the NEP through local and remote pathways. The local pathway is contingent upon the longitudinal positioning of AO‐related high‐pressure anomaly (i.e., anomalous ridge) in the North Pacific. When easterly anomalies prevail at the southern flank of the anomalous ridge over the NEP, they foster warm SSTAs in the NEP. However, different locations of the high‐pressure anomalies may impede the NEP warming. Remote pathways indicate the teleconnections triggered by AO‐related precipitation increase in Greenland and decrease in East Asia, sustaining the high‐pressure anomaly and promoting the anomalous NEP warming. Hence, this study presents new evidence on polar and mid‐latitude climate connections, which may provide potential predictability for the warm SSTAs in the NEP. Plain Language Summary: Under rapid climate change, long‐lasting warm sea surface temperature anomalies (SSTAs) in the mid‐latitude Northeast Pacific (NEP) have attracted wide attention due to their substantial ecological and climate effects. Arctic Oscillation (AO) is the dominant mode of atmospheric circulation variability in mid‐to‐high latitudes of the Northern Hemisphere. Its positive phase is featured by a low‐pressure center in the Arctic region and high‐pressure centers in the mid‐latitude regions. Our results reveal a robust connection between the positive phase of AO in October and warm SSTAs in the NEP during winter. We identify two primary pathways through which the October AO influences the wintertime sea surface temperature (SST) warming in the NEP. Locally, a high‐pressure anomaly over the NEP is associated with easterly wind anomalies to its southern flank, which diminish oceanic latent heat loss to the atmosphere, thus fostering the SST warming in the NEP. However, other locations of the high‐pressure anomaly related to AO may not be favorable for the warming of the NEP. From a remote view, AO can impact the NEP SST through teleconnections due to increased precipitation in Greenland and decreased precipitation in East Asia, sustaining the high‐pressure anomaly over the NEP and further bolstering the NEP warming. Key Points: Temporally, Arctic Oscillation (AO) in October is closely linked to wintertime sea surface temperature (SST) anomalies in the mid‐latitude Northeast Pacific (NEP)The AO‐related anomalous ridge located over the NEP is favorable for the warming of SST locallyRemotely, enhanced rainfall in Greenland and decreased rainfall near East Asia sustain the anomalous ridge over the NEP via teleconnection [ABSTRACT FROM AUTHOR]

El Niño typically induces cooling in the Southwest Pacific Ocean during austral summers, usually leading to decreased marine heatwave frequency and severity. However, the 2016 extreme El Niño unexpectedly coincided with the longest and most extensive marine heatwave ever recorded in the region. This heatwave, spanning over 1.7 million square kilometers, persisting for 24 days with a peak intensity of 1.5°C, resulted in massive coral bleaching and fish mortality. This exceptional warming resulted from anomalously strong shortwave radiation and reduced heat loss via latent heat fluxes, owing to low wind speed and increased air humidity. These anomalies are attributed to a rare combined event "Madden-Julian Oscillation and extreme El Niño." Following 10 February, the rapid dissipation of this marine heatwave results from the most intense cyclone ever recorded in the South Pacific. The hazardous ecological impacts of this extreme event highlight the needs for improving our understanding of marine heatwave-driving mechanisms that may result in better seasonal predictions. [ABSTRACT FROM AUTHOR]

The evolution of Storm Ciarán was different from what is commonly attributed to windstorms affecting northwest Europe. Ciarán initially developed as a diabatic Rossby wave, driven by low‐level latent heat release and with negligible upper tropospheric forcing. It then crossed the jet stream, intensifying explosively while developing a low‐level warm seclusion and producing extreme near‐surface winds, including sting jets. Ciarán is an example of an extreme windstorm following this pathway and highlights the need of a systematic assessment of its relevance in our warming climate. [ABSTRACT FROM AUTHOR]

The Mechanical properties of concrete significantly deteriorate when exposed to fire, with explosive spalling posing a major threat to structural integrity. This highlights the need for effective insulation systems to protect concrete structures in fire conditions. However, current insulation solutions are typically installed externally, requiring additional labour and materials. This review explores the potential of incorporating Phase Change Materials (PCMs) directly into concrete as an embedded insulation system. As a latent heat storage material, PCM offers promising fire-resistant properties, reducing the need for external insulation while improving the fire performance of concrete. This paper presents a bibliometric analysis and a systematic review of recent publications on the use of PCMs in concrete and their fire performance applications. One thousand two hundred and four publications retrieved from Scopus© and Web of Science databases were passed through the PRISMA flowchart to obtain a database of recent literature on the study area. The current trend of research shows a shift towards inorganic PCMs in concrete. There is a significant lack of studies on using inorganic and eutectic PCM in concrete for fire applications and existing studies show inorganic PCM can be a viable solution. Commercial availability and lack of synthesised encapsulated PCM were found to be barriers to research. [ABSTRACT FROM AUTHOR]

This article presents an analytical model for the diurnal cycle of slope‐normal profiles of potential temperature and wind speed characterizing thermally driven slope winds, generated by a daily‐periodic surface energy budget. The model extends the solution proposed by Zardi and Serafin, originally formulated for a pure sinusoidal surface forcing temperature. To account for the asymmetric features characterizing the daytime and nighttime phases, a full Fourier series expansion is derived, the coefficients and phases of which are prescribed from the surface energy budget driven by the daily‐periodic radiation model described in Part 1 of the present work. The model is applicable for any slope angle (0∘≤α≤90∘$$ {0}^{\circ}\le \alpha \le {90}^{\circ } $$) and orientation, at any latitude and elevation (up to 2500 m), and for all seasons. Despite some inherent limitations, the most remarkable being the absence of moist processes and latent heat fluxes, the model captures most key features of daily‐periodic slope wind systems, in particular the asymmetry between daytime and nighttime phases. Moreover, it allows exploration of the sensitivity of these flows to the various factors concurring in their development, and offers a basis for more realistic analytical solutions for slope winds. [ABSTRACT FROM AUTHOR]

This paper investigates acoustic wave propagation in wet rigid-frame porous media accounting for evaporation and condensation. At equilibrium, the solid walls are covered by a thin water film, and water vapor in the air is at its temperature-dependent saturation pressure. Small acoustic perturbations cause water to vaporize or condense, which together with the reversibility of the phase change, lead to a linear problem where the usual local poro-acoustics physics is enriched with the (i) Clapeyron relation linking liquid-wall temperature, vapor pressure, and latent heat of vaporization, (ii) latent heat transfer in the solid frame, (iii) diffusion equation for water vapor in air, and (iv) water vapor's equation of state. The equilibrium temperature highly influences the vapor concentration and the physical parameters of saturated moist air. Using the two-scale asymptotic homogenization method, it is shown that the dynamic permeability is determined similarly to classical porous media, while the effective compressibility is modified by evaporation/condensation and the equilibrium temperature. This modification is influenced by vapor mass and heat flows associated with phase changes through a local fully coupled heat transfer and water vapor diffusion problem, with specific boundary conditions at the gas–water interface. The analysis identifies dimensionless parameters and characteristic frequencies defining the upscaled model's features. Depending on equilibrium temperature, the theory qualitatively and quantitatively determines the characteristics of acoustic waves propagating through the media. The results are illustrated and discussed with analytically developed models. [ABSTRACT FROM AUTHOR]

This study investigated the application of nanophase change material emulsions (NPCMEs) for thermal management in high-capacity ternary lithium-ion batteries. We formulated an NPCME of n-octadecane (n-OD) and n-eicosane (n-E) with a mass fraction of 10%, whose phase change temperatures are 25.5 °C and 32.5 °C, respectively, with specific heat capacities 2.1 and 2.4 times greater than water. Experiments were conducted to evaluate the thermal control performance and latent heat utilization efficiency of these NPCMEs. The NPCMEs with an n-OD mass fraction of 10% (NPCME-n-OD), particularly reduced the battery pack's maximum temperature and temperature difference to 41.6 °C and 3.72 °C under a 2 C discharge rate, lower than the water-cooled group by 1.3 °C and 0.3 °C. This suggests that nano emulsions with phase change temperatures close to ambient temperatures exhibit superior cooling performance. Increased flow rates from 50 mL/min to 75 mL/min significantly lowered temperatures, resulting in temperature reductions of 2.73 °C for the NPCME-n-OD group and 3.37 °C for the NPCME-n-E group. However, the latent heat utilization efficiency of the nano emulsions decreased, leading to increased system energy consumption. Also, it was found that the inlet temperature of the NPCMEs was very important for good thermal management. The right inlet temperatures make it easier to use phase change latent heat, while excessively high temperatures may make thermal management less effective. [ABSTRACT FROM AUTHOR]

Phase change material (PCM)‐based heat storage systems utilize the absorption or release of latent heat during a phase change of the storage material to store thermal energy. Nevertheless, the effectiveness of these systems is restricted by the shape and structure of their confinement, as well as the heat conductivity of the storage material. This work investigates a novel method to enhance the effectiveness of PCM systems by concurrently utilizing two techniques: the inclusion of nanoparticles and the alteration of the system's geometry. Introducing nanoparticles enhances the thermal conductivity of the storage medium while altering the shape, which improves heat transfer efficiency by adjusting the surface area available for heat exchange. RT‐35 was tested for use in latent heat thermal energy storage systems for space heating and cooling. With a melting point of 35°C, RT‐35 was chosen to moderate building temperatures by storing and releasing thermal energy for space heating and cooling. The results indicate that using nanoparticles and adjusting shape can greatly enhance the effectiveness of PCM systems. By incorporating Al2O3 nanoparticles, the melting time of the PCM was reduced by 20% compared to the pure PCM, and it is more efficient than the best case of shape modification. These findings indicate that including nanoparticles and modifying the shape are effective methods to improve the performance of heat storage devices. This technology's potential surpasses this study's limits and can be utilized in diverse applications, including solar thermal energy storage, district heating and cooling, and industrial process heat. [ABSTRACT FROM AUTHOR]

The present study numerically investigates the energy and exergy analysis of solidification of phase change materials within a double tube and triple tube latent heat storage unit using ANSYS Fluent. Double tube and triple tube thermal energy storage system's thermal characteristics are examined using MXene nano‐enhanced phase change material to determine system efficiency, discharged energy, heat transfer rate, exergy destruction, entropy generation number, exergetic efficiency, liquid fraction, solidification temperature contours. The result revealed that the double tube thermal energy storage with pure cetyl alcohol PCM has 14.76% lower discharge exergy than MXene‐based nano‐enhanced phase change material in pure solidification. In a triple tube thermal energy storage system, the solidification time for MXene‐based nano‐enhanced phase change material is impressively reduced by 54.76% compared to a double tube system using pure phase change material. At a Fourier number of 0.00672, MXene nano‐enhanced phase change material exhibits an 11.69% higher Stefan number (St) than cetyl alcohol phase change material in a double tube thermal energy storage system. At 2400 s, pure phase change material and MXene nano‐enhanced phase change material generated 3.14% and 4.88% less entropy than pure cetyl alcohol in the triple tube thermal energy storage system. During the pure solidification process in a double tube thermal energy storage system, pure cetyl alcohol experiences 7.60% higher exergy destruction compared to MXene nano‐enhanced phase change material at a solidification time of 2400 s. In a triple tube thermal energy storage system, the discharging temperature for pure cetyl alcohol phase change material is 2.92% lower than that in a double tube system. Double tube thermal energy storage with pure cetyl alcohol discharged more efficiently over 2400 s. The triple tube thermal energy storage system solidified cetyl alcohol PCM 20.83% faster than pure phase change material due to MXene nanoparticles' better thermophysical properties. Thus, MXene‐based nano‐enhanced cetyl alcohol phase change material solidifies faster per volume in a triple tube thermal energy storage latent heat system. [ABSTRACT FROM AUTHOR]

Melting and solidification of a phase change material (PCM) is investigated experimentally by applying a partial filling strategy to the hybrid enhancement of heat pipe–metal foam (HP‐MF) in a vertical cylinder. HP‐MF enhancement can improve the heat transfer capacity of the PCM system as it combines HP's efficient heat transfer capacity with MF's highly effective thermal conductivity capability. The experimental results demonstrate that the partial filling strategy in the melting and solidification of HP‐MF PCM can be optimized for effective MF utilization in the HP‐MF PCM system. A filling ratio of 83% of MF in HP‐MF PCM shows almost identical total melting and solidification along with a temperature distribution to that of an HP‐MF PCM (95% porosity, 20 pore density [PPI]). It is plausible to conclude that the removal of 33% or less mass had no significant effect on the overall melting process of HP‐MF PCM. It should be noted that the HP‐MF PCM system's HP heat transfer efficiency significantly decreased during the melting process when the MF filling ratio was 37.5% and 12.5%. [ABSTRACT FROM AUTHOR]

Urban Land Surface Models (ULSMs) simulate energy and water exchanges between the urban surface and atmosphere. However, earlier systematic ULSM comparison projects assessed the energy balance but ignored the water balance, which is coupled to the energy balance. Here, we analyze the water balance representation in 19 ULSMs participating in the Urban‐PLUMBER project using results for 20 sites spread across a range of climates and urban form characteristics. As observations for most water fluxes are unavailable, we examine the water balance closure, flux timing, and magnitude with a score derived from seven indicators expecting better scoring models to capture the latent heat flux more accurately. We find that the water budget is only closed in 57% of the model‐site combinations assuming closure when annual total incoming fluxes (precipitation and irrigation) fluxes are within 3% of the outgoing (all other) fluxes. Results show the timing is better captured than magnitude. No ULSM has passed all water balance indicators for any site. Models passing more indicators do not capture the latent heat flux more accurately refuting our hypothesis. While output reporting inconsistencies may have negatively affected model performance, our results indicate models could be improved by explicitly verifying water balance closure and revising runoff parameterizations. By expanding ULSM evaluation to the water balance and related to latent heat flux performance, we demonstrate the benefits of evaluating processes with direct feedback mechanisms to the processes of interest. Plain Language Summary: Urban environments have their own local climates including typically higher nocturnal temperatures compared with rural areas. Ideally, modeling cities should capture their influences on the atmosphere above them. As the energy and water balances are linked by evaporation, a good water balance representation will support a good energy balance simulation. Focusing on the water balance, we find the water balance in models could be improved by paying attention to closure and runoff. Key Points: We evaluate the water balance in 19 urban land surface models (ULSM) from the Urban‐PLUMBER projectULSMs capture the timing of water fluxes more accurately than their magnitudeThe water balance appears unclosed in 43% of the model runs (19 models at 20 sites) [ABSTRACT FROM AUTHOR]

Sea-effect snow (SES) is a meteorological phenomenon resulting from cold air moving over warmer waters. Accurate prediction of SES is vital for emergency management, transportation, and water resource planning. A thundersnow event in Istanbul from 17–19 February 2015 caused significant disruptions, with traffic and flights affected, highways temporarily closed, and trees falling due to heavy snowfall. This study investigates the influence of different parameterization schemes in the Weather Research and Forecasting (WRF) model on SES simulations. Six distinct PBL parameterization schemes were used in a series of WRF simulations. In addition, the following factors pivotal to SES event have also been investigated: 1000–500 hPa thickness, total and latent heat fluxes, radar and satellite analyses, temperature gradients, wind shear, inversion levels, and atmospheric stability indices. Additionally, the formation of SES during the cold front transition further contributed to these elements in the Black Sea region. The simulations displayed notably high total heat flux and latent heat flux values, particularly following the passage of the cold front. Furthermore, the northeast-southwest oriented SES cloud, distinguished by its banded structure, was successfully validated using radar and satellite imagery. However, it's worth noting that the model positioned it farther west than its actual location. This study highlights the challenges in precise prediction and analysis of such convective activities. In this thundersnow event, the local closure schemes, particularly MYNN in first place and second MYJ, demonstrated superior performance compared to non-local schemes within the parameterization options. [ABSTRACT FROM AUTHOR]

Solar energy is a primary form of renewable energy, and photothermal conversion is a direct conversion process with tunable conversion efficiency. Among various kinds of photothermal conversion materials, porous organic polymers (POP) are widely investigated owing to their controllable molecular design, tailored porous structures, good absorption of solar light, and low thermal conductivity. A variety of POP, such as conjugated microporous polymers (CMP), covalent organic frameworks (COF), hyper‐crosslinked porous polymers (HCP), polymers of intrinsic microporosity (PIM), porous ionic polymers (PIP), are developed and applied in photothermal conversion applications of seawater desalination, latent energy storage, and biomedical fields. In this review, a comprehensive overview of the recent advances in POP for photothermal conversion is provided. The micro molecular structure characteristics and macro morphology of POP are designed for applications such as seawater desalination, latent heat energy storage, phototherapy and photodynamic therapy, and drug delivery. Besides, a probe into the underlying mechanism of structural design for constructing POP with excellent photothermal conversion performance is methodicalized. Finally, the remaining challenges and prospective opportunities for the future development of POP for solar energy‐driven photothermal conversion applications are elucidated. [ABSTRACT FROM AUTHOR]

The increasing global population has intensified the demand for energy and food, leading to significant greenhouse gas (GHG) emissions from both sectors. To mitigate these impacts and achieve Sustainable Development Goals (SDGs), passive thermal storage methods, particularly using phase change materials (PCMs), have become crucial for enhancing energy efficiency and reducing GHG emissions across various industries. This paper discusses the state of the art of bio-based phase change materials (bio-PCMs), derived from animal fats and plant oils as sustainable alternatives to traditional paraffin-based PCMs, while addressing the challenges of developing bio-PCMs with suitable phase change properties for practical applications. A comprehensive process is proposed to convert bacon fats to bio-PCMs, which offer advantages such as non-toxicity, availability, cost-effectiveness, and stability, aligning with multiple SDGs. The synthesis process involves hydrolysis to break down fat molecules obtained from the extracted lipid, followed by three additional independent processes to further tune the phase change properties of PCMs. The esterification significantly decreases the phase transition temperatures while slightly improving latent heat; the UV-crosslinking moderately raises both the phase transition temperature and latent heat; the crystallization remarkably increases the both. The future research and guidelines are discussed to develop the large scale manufacturing with cost effectiveness, to optimize synthesis process by multiscale modeling, and to improve thermal conductivity and latent heat capacities at the same time. [ABSTRACT FROM AUTHOR]

In order to explore the influence of laser power on the evolution of molten pool and convective heat transfer of laser cladding Incoloy 926 on stainless steel surface, a three-dimensional thermal fluid multi-field coupled laser cladding numerical model was established in this paper. The variation of latent heat during solid-liquid phase transformation was treated by apparent heat capacity method. The change in the gas–liquid interface was tracked using the mesh growth method in real time. The instantaneous evolution of temperature field and velocity flow field of laser cladding Incoloy 926 on a stainless steel surface under different laser power was discussed. The solidification characteristic parameters of the cladding layer were calculated based on the temperature-time variation curves at different nodes. The mechanism of the impact of laser power on the microstructure of the cladding layer was revealed. The experiment of laser cladding Incoloy 926 on 316L surface was carried out under different laser power. Combined with the numerical simulation results, the effects of laser power on the geometrical morphology, microstructure and element distribution of the cladding layer were compared and analyzed. The results show that with the increase in laser power, the peak temperature and flow velocity of the molten pool surface both increase significantly. The thermal influence of the molten pool center on the edge is enhanced. The temperature gradient, solidification rate, and cooling rate increased gradually. The microstructure parameters (G/R) are relatively small when the laser power is 1000 W. In the experimental range, the dilution rate and wetting angle of the cladding layer both increase with the increase in laser power. When the laser power is 1000 W, the alloying elements of the cladding layer are more evenly distributed and the microstructure is finer. The experimental results are in good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

Landfast sea ice plays a crucial role in the Antarctic coastal ecosystem and iceberg dynamics. This study employs a single-column thermodynamic model to simulate landfst sea ice near Zhongshan Station from 2016 to 2017. Forcing variables, including wind, temperature, specific humidity, and radiation, were obtained from in-situ automatic weather stations (AWS) and reanalysis atmospheric data (ERA5 and JRA55). Although there was alignment with observations, reanalysis data consistently overestimated precipitation, with a correlation coefficient of less than 0.8. Sensitivity experiments were conducted by varying precipitation inputs. In Group 1, the simulated sea ice thickness showed minimal biases of 6.3 cm and 5.3 cm when using AWS and ERA5 data, respectively. Additionally, the sea ice temperature simulations in Group 1 were within 0.3 ℃ of the observed values. The minimum bias in simulated sea ice thickness using JRA55 across all experiments was 10.9 cm. Overestimated snow depth, particularly with JRA55 data, resulted in thicker snow ice. Excessive precipitation led to overestimated snow depth, which revealed the dual impact of snow. Excessive snow depth led to greater snow ice formation, while reduced snow depth resulted in colder inner sea ice temperatures, promoting more bottom sea ice growth. Bottom melt primarily reduced sea ice thickness, while lateral melt reduced sea ice fraction, with latent heat flux dominating energy loss during melting. This study underscores the significance of snow depth, largely influenced by precipitation, in understanding the ablation process of landfast sea ice. Despite the discrepancies between simulations and observations, which indicate a need for refinement, this study highlights the potential of reanalysis data in sea ice thermodynamic simulations. [ABSTRACT FROM AUTHOR]

Before establishment of the Asian summer monsoon, the spring diabatic heating over the Tibetan Plateau (TP) is regarded as an essential factor to modulate rainfall in the surrounding and downstream regions of the TP, but its intraseasonal variability (ISV) has not been paid enough attention to. Based on the observation and ERA5 reanalysis data, the first two leading modes of the spring ISV of the surface sensible heat (SH) and the latent heat of condensation (LH) over the eastern TP have been identified, which both exhibit a north–south dipole and uniform pattern with dominant ~ 40-day and 10–20-day periods, respectively. The ISV of LH is strongly negatively correlated to that of SH, which is determined by variations of ground-air temperature difference. The north–south dipole patterns for the 40-day period are induced by the synergistic effect of northward-propagating circulation anomalies from the tropical Indian Ocean and a southeastward-propagating wave train in the middle-to-high latitudes, whereas the uniform patterns can be attributed to an eastward-propagating zonal wave train in the mid-latitude. Accompanied with the ISV of SH and LH, the anomalous moisture convergence/divergence and thus rainfall anomalies occur in the Yangtze River Basin. These results suggest that the spring diabatic heating over the eastern TP has great potentials as a predictability source of anomalous precipitation in its downstream regions on intraseasonal timescale. [ABSTRACT FROM AUTHOR]

The impacts of hydrometeor-related processes on the development and evolution of the "21·7" extremely heavy rainfall in Zhengzhou were investigated using WRF simulations. Surface precipitation was determined by the hydrometeor microphysical processes (all microphysical source sink terms of hydrometeors) and macrophysical processes (local change and flux convergence of hydrometeors). The contribution of hydrometeor macrophysical processes was commonly less than 10%, but could reach 30%–50% in the early stage of precipitation, which was largely dependent on the size of the study area. The macrophysical processes of liquid-phase hydrometeors always presented a promotional effect on rainfall, while the ice-phase hydrometeors played a negative role in the middle and later stages of precipitation. The distributions of microphysical latent heat corresponded well with those of buoyancy and vertical velocity (tendency), indicating that the phase-change heating was the major driver for convective development. Reasonable diagnostic buoyancy was obtained by choosing an area close to the convective size for getting the reference state of air. In addition, a new dynamic equilibrium involving hydrometeors with a tilted airflow was formed during the heavy precipitation period (updraft was not the strongest). The heaviest instantaneous precipitation was mainly produced by the warm-rain processes. Sensitivity experiments further pointed out that the uncertainty of latent heat parameterization (±20%) did not significantly affect the convective rainfall. While when the phase-change heating only altered the temperature tendency, its impact on precipitation was remarkable. The results of this study help to deepen our understanding of heavy rainfall mechanisms from the perspective of hydrometeor processes. [ABSTRACT FROM AUTHOR]

This study aimed to determine a method to suppress thermal runaway in electric vehicles by passing water directly inside the battery case. A scaled-down model experiment was conducted using a lithium-ion battery pack consisting of six 18650 cells, which is equal to about one-thousandth of an electric vehicle's charging capacity. The heat generation rate, heat transfer coefficient, and time constant for cooling were measured using a simple model for the cooling methods, thermal runaway stages, and state of charge. When thermal runaway occurred during natural cooling, the battery temperature rose to 630 °C at a rate of 116 °C/s. Through water injection, the thermal runaway was quickly suppressed with a time constant of about 3 s and a heat transfer coefficient of 3400 W/m2·K. The water effectively prevented chain explosions and kept harmful gases emitted from the batteries. It was found that it is difficult to completely suppress thermal runaway using the latent heat of the stagnant water in the spaces between cylindrical batteries. If the experimental results of this study were to be applied to an actual vehicle, it is expected that thermal runaway could be suppressed with a time constant of about 170 s and 1 ton of water. [ABSTRACT FROM AUTHOR]

The earthquake (EQ) precursors from satellites data portray an image of the energy propagation from the lithosphere to atmosphere and then to the ionosphere. Previous studies have often presented detailed discussion on different precursors at various altitudes. However, this study aimed to investigate the anomalies at various altitudes associated with the Hotan China EQ (hypocentral depth: 10 km, latitude 35.5°N, longitude 82.4°E). The goal was to identify pre-and post-seismic anomalies statistically in the conjunction with the wavelet transformation. We observed possible precursors in the atmosphere such as variations in aerosol optical depth, tropopause pressure, relative humidity, latent heat flux, and outgoing longwave radiation in a window of 5–10 days before the seismic event. Moreover, the total electron content had precursors during quiet geomagnetic storm conditions (−20 < Dst ≤ − 40 nT, Kp ≤ 3) beyond the bound within 5–10 days. These findings highlight the potential of using atmospheric and ionospheric parameters to detect seismic anomalies as EQ precursors for improved EQ early warning systems. [ABSTRACT FROM AUTHOR]

Heat storage is an emerging field of research, and, therefore, new materials with enhanced properties are being developed. Examples of phase change materials that provide high heat storage are inorganic salts and salt mixtures. They are commonly used for industrial applications due to their high operational temperature and latent heat. These parameters can be modified by combining different types of salts. This paper presents the experimental study of the impact of the composition of binary salts on their thermophysical properties. Unlike the literature data, this article provides a detailed analysis of the phase change process in both directions: solid–liquid and liquid–solid. The results indicate that the highest latent heat was observed for a 70% NaNO3 content in the NaNO3–KNO3 mixture. Therefore, when this salt is used for heat storage, the most favorable choice is a 70:30 ratio, which provides the highest heat storage density and the lowest phase transition temperature. In the case of the NaNO3–NaNO2 mixture, the highest value of latent heat occurs for a ratio of 80:20, resulting in phase transition temperatures of 267.0 °C for the solid–liquid transition, and 253.5 °C for the liquid–solid transition. For heat storage applications, it is recommended to use pure NaNO2 salt instead of the NaNO3–NaNO2 mixture. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of heat transfer in Latent Heat Thermal Energy Storage (LHTES) systems by using internal fins within a rectangular enclosure. Using lauric acid as the Phase Change Material (PCM), the impact of different fin configurations on the melting process is examined. A numerical model, incorporating the enthalpy-porosity method, is developed to simulate the phase change within the PCM. The model considers the effects of fin geometry, including variations in fin length and positioning. Results indicate that strategically placed fins significantly improve heat transfer efficiency, reducing complete melting time by more than 50% compared to a configuration of uniform-length fins. This enhancement is attributed to increased convective heat transfer facilitated by the longer fin in the lower zone of the enclosure. [ABSTRACT FROM AUTHOR]

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Flash droughts, characterised by their rapid onset and significant impacts on local communities and agriculture, pose challenges for monitoring and mitigation efforts due to their unpredictable nature. Therefore, this study aims to investigate the occurrence, characteristics and influencing factors of flash droughts in the Ganga River Basin (GRB) for the period 1981–2020. Flash droughts are identified using the pentad averaged root zone soil moisture (PRZSM). The Mann‐Kendall trend test is used to determine the spatial and temporal pattern of flash drought characteristics. Furthermore, a multivariate flash drought index (MFDI) is developed to account for the combined effects of flash drought characteristics. Finally, wavelet coherence analysis evaluates the relationship between climatic oscillations and MFDI at the sub‐basin scale. Utilising a revised flash drought identification approach incorporating non‐stationary cumulative distribution functions (CDFs), the study identifies flash droughts in the GRB, particularly emphasising higher occurrences in the Chambal and Upper Yamuna Sub‐basins. Analysis of flash drought characteristics under stationary and non‐stationary conditions reveals increased frequency, severity and decline rates, highlighting the impact of evaporation and latent heat flux. Furthermore, the Upper Ganga Sub‐basin demonstrates coherence with the DMI at shorter time scales (1 to 4‐year time scales), while the Lower Ganga Sub‐basin displays a pronounced association with the NINO3.4 index (5.65‐year time scale), indicating the impact of climate oscillations on flash drought dynamics in these regions. These findings provide valuable insights for drought monitoring, prediction and management strategies in a changing climate, emphasising the need for integrated approaches to address the complex interplay between climate variability and flash drought occurrences in the GRB. [ABSTRACT FROM AUTHOR]