Interfacial solar evaporation,which captures solar energy and localizes the absorbed heat for water evaporation,is considered a promising technology for seawater desalination and solar energy conversion.However,it is ...Interfacial solar evaporation,which captures solar energy and localizes the absorbed heat for water evaporation,is considered a promising technology for seawater desalination and solar energy conversion.However,it is currently limited by its low photothermal conversion efficiency,salt accumulation,and poor reliability.Herein,inspired by human intestinal villi structure,we design and fabricate a novel intestinal villi-like nitrogen-doped carbon nanotubes solar steam generator(N-CNTs SSG)consisting of three-dimensional(3D)hierarchical carbon nanotube matrices for ultrahigh solar evaporation efficiency.The 3D matrices with radial direction nitrogen-doped carbon nanotube clusters achieve ultrahigh surface area,photothermal efficiency,and hydrophilicity,which significantly intensifies the whole interfacial solar evaporation process.The new solar evaporation efficiency reaches as high as 96.8%.Furthermore,our ab initio molecular dynamics simulation reveals that N-doped carbon nanotubes exhibit a greater number of electronic states in close proximity to the Fermi level when compared to pristine carbon nanotubes.The outstanding absorptivity in the full solar spectrum and high solar altitude angles of the 3D hierarchical carbon nanotube matrices offer great potential to enable ultrahigh photothermal conversion under all-day and all-season circumstances.展开更多
Evaporation of saline droplets significantly impacts industrial processes such as water and gas treatment.Simulations,with advantages in describing temperature,concentration,and velocity distribution inside the drople...Evaporation of saline droplets significantly impacts industrial processes such as water and gas treatment.Simulations,with advantages in describing temperature,concentration,and velocity distribution inside the droplet,receive increasing attentions.This paper summarized research on numerical simulations of droplet evaporation atmicro-,meso-,and macroscales,emphasizing saline or multicomponent droplets.Accurate description of physics at phase interfaces andwithin proves to be critical for modeling.While recent studies have investigated on interface motion and temperature distribution,the coupling effect of internal concentration and flow distribution is still rarely considered.Among numerical methods,the lattice Boltzmann method is suitable for droplet scale due to its ability to handle non-continuum behavior.Bridging multiscale models remains a challenge,particularly in describing Marangoni and capillary flows.Experimental approaches to the effects of external physical fields(electric,magnetic,convection,and laser)and substrate properties on evaporation were also reviewed.Visualizing evaporation under various conditions can validate macroscopic models,while experiments with different substrates can validate molecular scale simulations,as substrate properties primarily affect evaporation by affecting capillary flow at the droplet bottom.This paper comprehensively reviewed numerical research on droplet evaporation,and analyzed the advantages,limitations,and development directions of various numericalmethods.展开更多
Desiccant regeneration through saline evaporation is critical and major energy consumer in liquid desiccant dehumidification systems(LDDS)for indoor air conditioning.This study investigated the coupled heat and mass t...Desiccant regeneration through saline evaporation is critical and major energy consumer in liquid desiccant dehumidification systems(LDDS)for indoor air conditioning.This study investigated the coupled heat and mass transfer behavior of saline droplet evaporation under forced convection,focusing on the enhancement effects of sweeping air(SA)and Marangoni effect.In-situ measurements and numerical simulations were performed,developing semi-empirical equations correlating evaporation rates with desiccant conditions and SA flowrates.By employing the equations considering SA’s impact on regeneration temperature,EnergyPlus simulation was conducted to evaluate the energy consumption of a typical office building in Guangzhou equipped with a temperature-humidity-independent control system incorporating LDDS.Results showed that SA significantly lowered the temperature required for high evaporation rates.At desiccant temperature of above 70℃,a strong thermal Marangoni effect resulted in enhanced evaporation,which increased with SA flowrates.At lower temperatures,forced convection still facilitates evaporation,though to a lesser extent,while also helping to prevent desiccant crystallization.EnergyPlus simulations revealed that if SA was incorporated into regeneration,substantial annual energy savings of up to 18.30%for LDDS can be achieved,with hourly savings ranging from 7.83 to 8.40 kW,peaking in August.Optimizing the SA flowrate is crucial,with ideal rates of around 3.5 m/s in high-humidity and 2.5 m/s in low-humidity conditions.This study deepens the understanding of non-isothermal droplet evaporation under forced convection,and establishes a significant bridge between saline evaporation and LDDS energy consumption assessment in practical buildings.展开更多
Hydrogels are soft,highly absorbent and water-retaining polymers that are widely used in energy utilization.Molecular dynamics(MD)simulation is powerful in exploring micro/nano mechanisms and can assist material regul...Hydrogels are soft,highly absorbent and water-retaining polymers that are widely used in energy utilization.Molecular dynamics(MD)simulation is powerful in exploring micro/nano mechanisms and can assist material regulation and experimental design.This review summarizes recent MD simulations on the composition and structure characteristics of physically and chemically crosslinked hydrogels,focusing on the functionalities such as mechanical properties,heat transfer performance,hygroscopic properties and photocatalytic applications required in the energy conversion process.The fundamentals of MD simulations are also introduced,along with common modeling procedures for hydrogels.Literature review showed that MD simulations can visually display molecular-scale changes during cross-linking and absorption processes,thereby predicting changes in intermolecular interactions and associated microstructural change.Challenges for future research include constructing hydrogel networks that can be experimentally verified,and developing appropriate molecular force fields under various operating conditions.Incorporating quantum mechanics or coarse-graining methods in MD simulations further broaden its application into electronic or mesoscopic problems.Combining with machine learning,finite element or lattice Boltzmann methods may be also promising as it can be used to reveal the influence of 3D pores within hydrogels.This study aims to promote the use of MD simulations in exploring characteristics and mechanisms of hydrogel and other polymer materials in energy utilization.展开更多
基金Funding information National Natural Science Foundation of China,Grant/Award Numbers:52476072,51936005Young Talent Support Project of Guangzhou Association for Science and Technology+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2024A1515030035)Guangdong Pro vincial University Innovation Team Project(No.2023KCXTD038)。
文摘Interfacial solar evaporation,which captures solar energy and localizes the absorbed heat for water evaporation,is considered a promising technology for seawater desalination and solar energy conversion.However,it is currently limited by its low photothermal conversion efficiency,salt accumulation,and poor reliability.Herein,inspired by human intestinal villi structure,we design and fabricate a novel intestinal villi-like nitrogen-doped carbon nanotubes solar steam generator(N-CNTs SSG)consisting of three-dimensional(3D)hierarchical carbon nanotube matrices for ultrahigh solar evaporation efficiency.The 3D matrices with radial direction nitrogen-doped carbon nanotube clusters achieve ultrahigh surface area,photothermal efficiency,and hydrophilicity,which significantly intensifies the whole interfacial solar evaporation process.The new solar evaporation efficiency reaches as high as 96.8%.Furthermore,our ab initio molecular dynamics simulation reveals that N-doped carbon nanotubes exhibit a greater number of electronic states in close proximity to the Fermi level when compared to pristine carbon nanotubes.The outstanding absorptivity in the full solar spectrum and high solar altitude angles of the 3D hierarchical carbon nanotube matrices offer great potential to enable ultrahigh photothermal conversion under all-day and all-season circumstances.
基金National Natural Science Foundation of China,Grant/Award Numbers:52122605,51936005Guangzhou Science and Technology Plan Project,Grant/Award Number:202201010112Fundamental Research Funds for the Central Universities,Grant/Award Number:2023ZYGXZR027。
文摘Evaporation of saline droplets significantly impacts industrial processes such as water and gas treatment.Simulations,with advantages in describing temperature,concentration,and velocity distribution inside the droplet,receive increasing attentions.This paper summarized research on numerical simulations of droplet evaporation atmicro-,meso-,and macroscales,emphasizing saline or multicomponent droplets.Accurate description of physics at phase interfaces andwithin proves to be critical for modeling.While recent studies have investigated on interface motion and temperature distribution,the coupling effect of internal concentration and flow distribution is still rarely considered.Among numerical methods,the lattice Boltzmann method is suitable for droplet scale due to its ability to handle non-continuum behavior.Bridging multiscale models remains a challenge,particularly in describing Marangoni and capillary flows.Experimental approaches to the effects of external physical fields(electric,magnetic,convection,and laser)and substrate properties on evaporation were also reviewed.Visualizing evaporation under various conditions can validate macroscopic models,while experiments with different substrates can validate molecular scale simulations,as substrate properties primarily affect evaporation by affecting capillary flow at the droplet bottom.This paper comprehensively reviewed numerical research on droplet evaporation,and analyzed the advantages,limitations,and development directions of various numericalmethods.
基金supported by National Natural Science Foundation of China(52122605,51936005)supported by the Fundamental Research Funds for the Central Universities(2023ZYGXZR027).
文摘Desiccant regeneration through saline evaporation is critical and major energy consumer in liquid desiccant dehumidification systems(LDDS)for indoor air conditioning.This study investigated the coupled heat and mass transfer behavior of saline droplet evaporation under forced convection,focusing on the enhancement effects of sweeping air(SA)and Marangoni effect.In-situ measurements and numerical simulations were performed,developing semi-empirical equations correlating evaporation rates with desiccant conditions and SA flowrates.By employing the equations considering SA’s impact on regeneration temperature,EnergyPlus simulation was conducted to evaluate the energy consumption of a typical office building in Guangzhou equipped with a temperature-humidity-independent control system incorporating LDDS.Results showed that SA significantly lowered the temperature required for high evaporation rates.At desiccant temperature of above 70℃,a strong thermal Marangoni effect resulted in enhanced evaporation,which increased with SA flowrates.At lower temperatures,forced convection still facilitates evaporation,though to a lesser extent,while also helping to prevent desiccant crystallization.EnergyPlus simulations revealed that if SA was incorporated into regeneration,substantial annual energy savings of up to 18.30%for LDDS can be achieved,with hourly savings ranging from 7.83 to 8.40 kW,peaking in August.Optimizing the SA flowrate is crucial,with ideal rates of around 3.5 m/s in high-humidity and 2.5 m/s in low-humidity conditions.This study deepens the understanding of non-isothermal droplet evaporation under forced convection,and establishes a significant bridge between saline evaporation and LDDS energy consumption assessment in practical buildings.
基金supported by National Natural Science Foundation of China(52122605,51936005)Guangzhou Science and Technology Plan Project(202201010112)supported by the Fundamental Research Funds for the Central Universities(2023ZYGXZR027).
文摘Hydrogels are soft,highly absorbent and water-retaining polymers that are widely used in energy utilization.Molecular dynamics(MD)simulation is powerful in exploring micro/nano mechanisms and can assist material regulation and experimental design.This review summarizes recent MD simulations on the composition and structure characteristics of physically and chemically crosslinked hydrogels,focusing on the functionalities such as mechanical properties,heat transfer performance,hygroscopic properties and photocatalytic applications required in the energy conversion process.The fundamentals of MD simulations are also introduced,along with common modeling procedures for hydrogels.Literature review showed that MD simulations can visually display molecular-scale changes during cross-linking and absorption processes,thereby predicting changes in intermolecular interactions and associated microstructural change.Challenges for future research include constructing hydrogel networks that can be experimentally verified,and developing appropriate molecular force fields under various operating conditions.Incorporating quantum mechanics or coarse-graining methods in MD simulations further broaden its application into electronic or mesoscopic problems.Combining with machine learning,finite element or lattice Boltzmann methods may be also promising as it can be used to reveal the influence of 3D pores within hydrogels.This study aims to promote the use of MD simulations in exploring characteristics and mechanisms of hydrogel and other polymer materials in energy utilization.
