Maintaining thermal comfort within the human body is crucial for optimal health and overall well-being.By merely broadening the setpoint of indoor temperatures,we could significantly slash energy usage in building hea...Maintaining thermal comfort within the human body is crucial for optimal health and overall well-being.By merely broadening the setpoint of indoor temperatures,we could significantly slash energy usage in building heating,ventilation,and air-conditioning systems.In recent years,there has been a surge in advancements in personal thermal management(PTM),aiming to regulate heat and moisture transfer within our immediate surroundings,clothing,and skin.The advent of PTM is driven by the rapid development in nano/micro-materials and energy science and engineering.An emerging research area in PTM is personal radiative thermal management(PRTM),which demonstrates immense potential with its high radiative heat transfer efficiency and ease of regulation.However,it is less taken into account in traditional textiles,and there currently lies a gap in our knowledge and understanding of PRTM.In this review,we aim to present a thorough analysis of advanced textile materials and technologies for PRTM.Specifically,we will introduce and discuss the underlying radiation heat transfer mechanisms,fabrication methods of textiles,and various indoor/outdoor applications in light of their different regulation functionalities,including radiative cooling,radiative heating,and dual-mode thermoregulation.Furthermore,we will shine a light on the current hurdles,propose potential strategies,and delve into future technology trends for PRTM with an emphasis on functionalities and applications.展开更多
With the increasing attention paid to battery technology,the microscopic reaction mechanism and macroscopic heat transfer process of lithium-ion batteries have been further studied and understood from both academic an...With the increasing attention paid to battery technology,the microscopic reaction mechanism and macroscopic heat transfer process of lithium-ion batteries have been further studied and understood from both academic and industrial perspectives.Temperature,as one of the key parameters in the physical fra mework of batteries,affects the performa nce of the multi-physical fields within the battery,a nd its effective control is crucial.Since the heat generation in the battery is determined by the real-time operating conditions,the battery temperature is essentially controlled by the real-time heat dissipation conditions provided by the battery thermal management system.Conventional battery thermal management systems have basic temperature control capabilities for most conventional application scenarios.However,with the current development of la rge-scale,integrated,and intelligent battery technology,the adva ncement of battery thermal management technology will pay more attention to the effective control of battery temperature under sophisticated situations,such as high power and widely varied operating conditions.In this context,this paper presents the latest advances and representative research related to battery thermal management system.Firstly,starting from battery thermal profile,the mechanism of battery heat generation is discussed in detail.Secondly,the static characteristics of the traditional battery thermal management system are summarized.Then,considering the dynamic requirements of battery heat dissipation under complex operating conditions,the concept of adaptive battery thermal management system is proposed based on specific research cases.Finally,the main challenges for battery thermal management system in practice are identified,and potential future developments to overcome these challenges are presented and discussed.展开更多
Deep penetration into the Earth’s interior and direct monitoring of weak changes in physical fields and their cumulative processes and effects in the deep Earth can enhance the identification of deep Earth targets an...Deep penetration into the Earth’s interior and direct monitoring of weak changes in physical fields and their cumulative processes and effects in the deep Earth can enhance the identification of deep Earth targets and deepen the degree of knowledge of the details of the deep Earth structure and deep processes(Moskvitch,2014),which is important for promoting the development of Earth system science.展开更多
Advanced radiative cooling materials with both heating and cooling mode is of pivotal importance for all-season energy-saving in buildings.In this work,we report the design and fabrication of bacterial cellulose-based...Advanced radiative cooling materials with both heating and cooling mode is of pivotal importance for all-season energy-saving in buildings.In this work,we report the design and fabrication of bacterial cellulose-based Janus films(J-BC)with radiative cooling and solar heating properties,which were developed by two-step vacuum-assisted filtration of modified MXene-doped bacterial cellulose and modified silicon nitride(Si_(3)N_(4))-doped bacterial cellulose,followed by hot-pressing and drying treatments.The as-prepared J-BC films show a unique Janus structure where modified MXene nanosheets and cellulose nanofibers are on the bottom surface,and modified silicon nitride(Si_(3)N_(4))nanoparticles and cellulose nanofibers are on the top surface.The radiative cooling effect of J-BC films is enabled by the Si_(3)N_(4)-doped bacterial cellulose due to the high mid-infrared emissivity of Si_(3)N_(4) nanoparticles,which shows a high solar reflection of~98.1%and high emissivity of~93.6%in the atmospheric transparency window(8-13μm).Thanks to the enhanced photothermal conversion of the modified MXene nanosheets,a reduced solar reflection(6.6%)and relatively low thermal emissivity in the atmospheric window(71.4%)are achieved,making sure the solar heating effect of J-BC films.In the outdoor tests,J-BC films achieve a sub-ambient temperature drop of~3.8°C and an above-ambient temperature rise of~14.2°C.Numerical prediction demonstrated that the J-BC films with dual modes have great potential of all-season energy saving for buildings and a corresponding energy-saving map in China is also created.The work disclosed herein can provide an avenue for the shaping of advanced radiative cooling materials for emerging applications of personal thermal management,sustainable energy-efficient buildings,and beyond.展开更多
Mini-channel heatsinks are one of the most effective thermal management methods for high heatflux devices due to the high performance of convective heat transfer.In recent years,various techniques have been innovated t...Mini-channel heatsinks are one of the most effective thermal management methods for high heatflux devices due to the high performance of convective heat transfer.In recent years,various techniques have been innovated to improve the thermal proficiency of the mini-channel heatsinks.Some of these are taking advantage offins’structural designs and ar-rangements of inlets and outlets.The zigzagfins and channels were considered in the previous works in heatsinks,and researchers analyzed their cooling enhancement effects.However,in the present work,a combined cooling technique,considering new-type zigzagfins’geometrical parameters(arrangement,length,and height)causes turbulenceflow and higher convective heat transfer along with different positionings offlow inlet and outlets resulting in superior temper-ature uniformity,is proposed to evaluate their impacts on the cooling proficiency of the heat sink versus different Reynolds numbers.To assess the thermal and hydraulic performance of the proposed heatsink,different parameters,including temperature contours,Nusselt numbers,thermal resistance,and entropy generation are investigated.As a result,it is observed that in the case demonstrating the best thermal performance,the Nusselt number,pressure drop,thermal resistance,and entropy generation are respectively 37.13,4586.46 Pa,0.000078 m^(2)·K/W,and 0.1078 W/K in the best header.As well,it is found that by changing the arrangements of inlets and outlets,the Nusselt number,and thermal resistance are improved by 12%and 13%,respectively.Accordingly,the proposed mini-channel heat sink could be used as a high-performance thermal management system for electronic devices in different industries,including energy,solar,and medical sectors.展开更多
基金support from the Research Grants Council of the Hong Kong Special Administrative Region,China(PolyU152052/21E)Green Tech Fund of Hong Kong(Project No.:GTF202220106)+1 种基金Innovation and Technology Fund of the Hong Kong Special Administrative Region,China(ITP/018/21TP)PolyU Endowed Young Scholars Scheme(Project No.:84CC).
文摘Maintaining thermal comfort within the human body is crucial for optimal health and overall well-being.By merely broadening the setpoint of indoor temperatures,we could significantly slash energy usage in building heating,ventilation,and air-conditioning systems.In recent years,there has been a surge in advancements in personal thermal management(PTM),aiming to regulate heat and moisture transfer within our immediate surroundings,clothing,and skin.The advent of PTM is driven by the rapid development in nano/micro-materials and energy science and engineering.An emerging research area in PTM is personal radiative thermal management(PRTM),which demonstrates immense potential with its high radiative heat transfer efficiency and ease of regulation.However,it is less taken into account in traditional textiles,and there currently lies a gap in our knowledge and understanding of PRTM.In this review,we aim to present a thorough analysis of advanced textile materials and technologies for PRTM.Specifically,we will introduce and discuss the underlying radiation heat transfer mechanisms,fabrication methods of textiles,and various indoor/outdoor applications in light of their different regulation functionalities,including radiative cooling,radiative heating,and dual-mode thermoregulation.Furthermore,we will shine a light on the current hurdles,propose potential strategies,and delve into future technology trends for PRTM with an emphasis on functionalities and applications.
基金supported by the National Natural Science Foundation of China (No.62373224,62333013,and U23A20327)。
文摘With the increasing attention paid to battery technology,the microscopic reaction mechanism and macroscopic heat transfer process of lithium-ion batteries have been further studied and understood from both academic and industrial perspectives.Temperature,as one of the key parameters in the physical fra mework of batteries,affects the performa nce of the multi-physical fields within the battery,a nd its effective control is crucial.Since the heat generation in the battery is determined by the real-time operating conditions,the battery temperature is essentially controlled by the real-time heat dissipation conditions provided by the battery thermal management system.Conventional battery thermal management systems have basic temperature control capabilities for most conventional application scenarios.However,with the current development of la rge-scale,integrated,and intelligent battery technology,the adva ncement of battery thermal management technology will pay more attention to the effective control of battery temperature under sophisticated situations,such as high power and widely varied operating conditions.In this context,this paper presents the latest advances and representative research related to battery thermal management system.Firstly,starting from battery thermal profile,the mechanism of battery heat generation is discussed in detail.Secondly,the static characteristics of the traditional battery thermal management system are summarized.Then,considering the dynamic requirements of battery heat dissipation under complex operating conditions,the concept of adaptive battery thermal management system is proposed based on specific research cases.Finally,the main challenges for battery thermal management system in practice are identified,and potential future developments to overcome these challenges are presented and discussed.
基金supported by Major International(Regional)Joint Research Project of the National Natural Science Foundation of China(61320106011)National High Technology Research and Development Program of China(863 Program)(2014AA052802)National Natural Science Foundation of China(61573224)
基金funded by the National Key Research and Development Program subject(Grant No.2018YFC1503903)
文摘Deep penetration into the Earth’s interior and direct monitoring of weak changes in physical fields and their cumulative processes and effects in the deep Earth can enhance the identification of deep Earth targets and deepen the degree of knowledge of the details of the deep Earth structure and deep processes(Moskvitch,2014),which is important for promoting the development of Earth system science.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52173181 and 51973155)Natural Science Foundation of Tianjin City(20JCYBJC00810)+1 种基金Key Program of National Natural Science Foundation of China(No.52130303)National KeyR&D Program of China(2022YFB3805702).
文摘Advanced radiative cooling materials with both heating and cooling mode is of pivotal importance for all-season energy-saving in buildings.In this work,we report the design and fabrication of bacterial cellulose-based Janus films(J-BC)with radiative cooling and solar heating properties,which were developed by two-step vacuum-assisted filtration of modified MXene-doped bacterial cellulose and modified silicon nitride(Si_(3)N_(4))-doped bacterial cellulose,followed by hot-pressing and drying treatments.The as-prepared J-BC films show a unique Janus structure where modified MXene nanosheets and cellulose nanofibers are on the bottom surface,and modified silicon nitride(Si_(3)N_(4))nanoparticles and cellulose nanofibers are on the top surface.The radiative cooling effect of J-BC films is enabled by the Si_(3)N_(4)-doped bacterial cellulose due to the high mid-infrared emissivity of Si_(3)N_(4) nanoparticles,which shows a high solar reflection of~98.1%and high emissivity of~93.6%in the atmospheric transparency window(8-13μm).Thanks to the enhanced photothermal conversion of the modified MXene nanosheets,a reduced solar reflection(6.6%)and relatively low thermal emissivity in the atmospheric window(71.4%)are achieved,making sure the solar heating effect of J-BC films.In the outdoor tests,J-BC films achieve a sub-ambient temperature drop of~3.8°C and an above-ambient temperature rise of~14.2°C.Numerical prediction demonstrated that the J-BC films with dual modes have great potential of all-season energy saving for buildings and a corresponding energy-saving map in China is also created.The work disclosed herein can provide an avenue for the shaping of advanced radiative cooling materials for emerging applications of personal thermal management,sustainable energy-efficient buildings,and beyond.
文摘Mini-channel heatsinks are one of the most effective thermal management methods for high heatflux devices due to the high performance of convective heat transfer.In recent years,various techniques have been innovated to improve the thermal proficiency of the mini-channel heatsinks.Some of these are taking advantage offins’structural designs and ar-rangements of inlets and outlets.The zigzagfins and channels were considered in the previous works in heatsinks,and researchers analyzed their cooling enhancement effects.However,in the present work,a combined cooling technique,considering new-type zigzagfins’geometrical parameters(arrangement,length,and height)causes turbulenceflow and higher convective heat transfer along with different positionings offlow inlet and outlets resulting in superior temper-ature uniformity,is proposed to evaluate their impacts on the cooling proficiency of the heat sink versus different Reynolds numbers.To assess the thermal and hydraulic performance of the proposed heatsink,different parameters,including temperature contours,Nusselt numbers,thermal resistance,and entropy generation are investigated.As a result,it is observed that in the case demonstrating the best thermal performance,the Nusselt number,pressure drop,thermal resistance,and entropy generation are respectively 37.13,4586.46 Pa,0.000078 m^(2)·K/W,and 0.1078 W/K in the best header.As well,it is found that by changing the arrangements of inlets and outlets,the Nusselt number,and thermal resistance are improved by 12%and 13%,respectively.Accordingly,the proposed mini-channel heat sink could be used as a high-performance thermal management system for electronic devices in different industries,including energy,solar,and medical sectors.
