By combining the merits of radiative cooling(RC)and evaporation cooling(EC),radiative coupled evaporative cooling(REC)has attracted considerable attention for sub-ambient cooling purposes.However,for outdoor devices,t...By combining the merits of radiative cooling(RC)and evaporation cooling(EC),radiative coupled evaporative cooling(REC)has attracted considerable attention for sub-ambient cooling purposes.However,for outdoor devices,the interior heating power would increase the working temperature and fire risk,which would suppress their above-ambient heat dissipation capabilities and passive water cycle properties.In this work,we introduced a REC design based on an all-in-one photonic hydrogel for above-ambient heat dissipation and flame retardancy.Unlike conventional design RC film for heat dissipation with limited cooling power and fire risk,REC hydrogel can greatly improve the heat dissipation performance in the daytime with a high workload,indicating a 12.0℃lower temperature than the RC film under the same conditions in the outdoor experiment.In the nighttime with a low workload,RC-assisted adsorption can improve atmospheric water harvesting to ensure EC in the daytime.In addition,our REC hydrogel significantly enhanced flame retardancy by absorbing heat without a corresponding temperature rise,thus mitigating fire risks.Thus,our design shows a promising solution for the thermal management of outdoor devices,delivering outstanding performance in both heat dissipation and flame retardancy.展开更多
Passive daytime radiative cooling(PDRC) is environment-friendly without energy input by enhancing the coating's solar reflectance(R_(solar)) and thermal emittance(ε_(LWIR)) in the atmosphere's long-wave infra...Passive daytime radiative cooling(PDRC) is environment-friendly without energy input by enhancing the coating's solar reflectance(R_(solar)) and thermal emittance(ε_(LWIR)) in the atmosphere's long-wave infrared transmission window.However,high R_(solar) is usually achieved by increasing the coating's thickness,which not only increases materials' cost but also impairs heat transfer.Additionally,the desired high R_(solar) is vulnerable to dust pollution in the outdoors.In this work,a thin paint was designed by mixing hBN plates,PFOTS,and IPA. R_(solar)=0.963 and ε_(LWIR)=0.927 was achieved at a thickness of 150 μm due to the high backscattering ability of scatters.A high through-plane thermal conductivity(~1.82 W m^(-1) K^(-1)) also can be obtained.In addition,the porous structure coupled with the binder PFOTS resulted in a contact angle of 154°,demonstrating excellent durability under dust contamination.Outdoor experiments showed that the thin paint can obtain a 2.3℃ lower temperature for sub-ambient cooling than the reference PDRC coating in the daytime.Furtherly,the above-ambient heat dissipation performance can be enhanced by spraying the thin paint on a 3D heat sink,which was 15.7℃ lower than the reference 1D structure,demonstrating excellent performance for durable and scalable PDRC applications.展开更多
Solar evaporation attracted lots of attention due to its environment-friendly and high efficiency,which is a potential approach to collecting fresh water.Many efforts have been made to improve the evaporation rate in ...Solar evaporation attracted lots of attention due to its environment-friendly and high efficiency,which is a potential approach to collecting fresh water.Many efforts have been made to improve the evaporation rate in the open space.While the actual water collection rate is far less than the evaporation rate,especially in passive water collection,limiting its practical and scalable applications.In this review,we focus on freshwater collection based on solar evaporation.Firstly,heat and mass transfer behaviors on the evaporation side were summarized to improve evaporation performance,including heat transfer processes in thermal radiation,convection,and conduction;mass transfer processes in water supply,evaporation enthalpy,and salt rejection.Sequentially,subcooling,wettability,and geometry of the condensation side were discussed to improve water collection performance,which should be designed collaboratively with the evaporation side in a confined space.Finally,thermal recovery and electricity generation beyond water collection were also introduced,and some challenges still need to improve in the further for scalable and practical applications,including passive water collection rate,integrated system,and long-term issues.展开更多
Solar evaporation has attracted great interest in water collection,gaining considerable attention recently.While many efforts have been made to enhance solar thermal conversion performance from materials design aspect...Solar evaporation has attracted great interest in water collection,gaining considerable attention recently.While many efforts have been made to enhance solar thermal conversion performance from materials design aspects,little attention has been given to the fundamental solar thermal gradient concept,which significantly affects local heating during evaporation.In this work,the polymer sponge evaporator was designed to control the solar thermal gradient by adding copper-carbon core-shell(Cu@C)nanoparticles with similar solar absorptance to understand the effect of solar thermal gradient or local heating on evaporation performance.The optimized solar evaporation can be 2.0 kg·m^(−2)·h^(−1)under 1000 W·m^(−2)(one sun)with a Cu@C mass fraction of 0.5 wt.%,which was higher than that observed in cases with either higher or smaller Cu@C mass fraction.A too-small or large Cu@C mass fraction would enhance heat loss from the bottom or top parts,which was also confirmed by simulation results.Further outdoor water yield experiment showed that the optimized Cu@C mass fraction of 0.5 wt.%achieved the highest water collection(6.67 kg·m^(−2)·d^(−1))compared with the other cases,such as 5.92 kg·m^(−2)·d^(−1)for 0.1 wt.%,5.29 kg·m^(−2)·d^(−1)for 1 wt.%.These results highlighted the impact of local heating on evaporation performance under the solar thermal gradient during the solar evaporation process.展开更多
To the editor:ATP-citrate lyase(ACLY)is the key enzyme linking glucose catabolism to lipogenesis.Targeting hepatic ACLY for lowering low density lipoprotein-cholesterol(LDL-C)and attenuating atherosclerosis has been v...To the editor:ATP-citrate lyase(ACLY)is the key enzyme linking glucose catabolism to lipogenesis.Targeting hepatic ACLY for lowering low density lipoprotein-cholesterol(LDL-C)and attenuating atherosclerosis has been validated in preclinical animal models and hypercholesterolemic patients1.Bempedoic acid(ETC1002),a first-in-class,potent and orally bioavailable inhibitor of ACLY,has been approved by the US FDA to reduce cardiovascular risk in patients who do not achieve their recommended LDL-C levels through other means.展开更多
As global energy demand continues to rise and climate change accelerates,the need for sustainable and energy-efficient cooling solutions has reached a critical level.Conventional air conditioning systems heavily rely ...As global energy demand continues to rise and climate change accelerates,the need for sustainable and energy-efficient cooling solutions has reached a critical level.Conventional air conditioning systems heavily rely on energy-intensive mechanical cooling,which significantly contributes to both electricity demand and greenhouse gas emissions.Passive cooling strategies,particularly radiative cooling(RC)and evaporative cooling(EC),present an alternative approach by harnessing natural processes for temperature regulation.While standalone RC can be affected by weather conditions and EC relies on water availability,Radiative-coupled EC(REC)offers a versatile and sustainable cooling solution suitable for various applications.Here we summarize an overview of the theoretical foundations and mathematical models of REC,encompassing REC by bulk water(REC-BW),REC by perspiration(REC-P),and REC by sorbed water(REC-SW).Moreover,we explore a range of applications,spanning from industrial processes to personal thermal management,and examine the advantages and challenges associated with each REC approach.The significance of REC lies in its potential to revolutionize cooling technology,reduce energy consumption,and minimize the environmental impact.REC-BW can conserve water resources in industrial cooling processes,while REC-P offers innovative solutions for wearable electronics and textiles.REC-SW’s adaptability makes it suitable for food preservation and future potable cooling devices.By addressing the challenges posed by REC,including water consumption,textile design,and optimization of bilayer structures,we can unlock the transformative potential of REC and contribute to sustainable cooling technologies in a warming world.展开更多
基金financially supported by the Science and Technology Innovation Program of Hunan Province(2024RC3003)the Central South University Innovation-Driven Research Programme(2023CXQD012)the Initiative for Sustainable Energy for its financial support。
文摘By combining the merits of radiative cooling(RC)and evaporation cooling(EC),radiative coupled evaporative cooling(REC)has attracted considerable attention for sub-ambient cooling purposes.However,for outdoor devices,the interior heating power would increase the working temperature and fire risk,which would suppress their above-ambient heat dissipation capabilities and passive water cycle properties.In this work,we introduced a REC design based on an all-in-one photonic hydrogel for above-ambient heat dissipation and flame retardancy.Unlike conventional design RC film for heat dissipation with limited cooling power and fire risk,REC hydrogel can greatly improve the heat dissipation performance in the daytime with a high workload,indicating a 12.0℃lower temperature than the RC film under the same conditions in the outdoor experiment.In the nighttime with a low workload,RC-assisted adsorption can improve atmospheric water harvesting to ensure EC in the daytime.In addition,our REC hydrogel significantly enhanced flame retardancy by absorbing heat without a corresponding temperature rise,thus mitigating fire risks.Thus,our design shows a promising solution for the thermal management of outdoor devices,delivering outstanding performance in both heat dissipation and flame retardancy.
基金financially supported by the Natural Science Foundation of Hunan Province(Grant No.2021JJ40732)the Central South University Innovation-Driven Research Programme(Grant No.2023CXQD012)。
文摘Passive daytime radiative cooling(PDRC) is environment-friendly without energy input by enhancing the coating's solar reflectance(R_(solar)) and thermal emittance(ε_(LWIR)) in the atmosphere's long-wave infrared transmission window.However,high R_(solar) is usually achieved by increasing the coating's thickness,which not only increases materials' cost but also impairs heat transfer.Additionally,the desired high R_(solar) is vulnerable to dust pollution in the outdoors.In this work,a thin paint was designed by mixing hBN plates,PFOTS,and IPA. R_(solar)=0.963 and ε_(LWIR)=0.927 was achieved at a thickness of 150 μm due to the high backscattering ability of scatters.A high through-plane thermal conductivity(~1.82 W m^(-1) K^(-1)) also can be obtained.In addition,the porous structure coupled with the binder PFOTS resulted in a contact angle of 154°,demonstrating excellent durability under dust contamination.Outdoor experiments showed that the thin paint can obtain a 2.3℃ lower temperature for sub-ambient cooling than the reference PDRC coating in the daytime.Furtherly,the above-ambient heat dissipation performance can be enhanced by spraying the thin paint on a 3D heat sink,which was 15.7℃ lower than the reference 1D structure,demonstrating excellent performance for durable and scalable PDRC applications.
基金financially supported by the Central South University Innovation-Driven Research Programme(2023CXQD012).
文摘Solar evaporation attracted lots of attention due to its environment-friendly and high efficiency,which is a potential approach to collecting fresh water.Many efforts have been made to improve the evaporation rate in the open space.While the actual water collection rate is far less than the evaporation rate,especially in passive water collection,limiting its practical and scalable applications.In this review,we focus on freshwater collection based on solar evaporation.Firstly,heat and mass transfer behaviors on the evaporation side were summarized to improve evaporation performance,including heat transfer processes in thermal radiation,convection,and conduction;mass transfer processes in water supply,evaporation enthalpy,and salt rejection.Sequentially,subcooling,wettability,and geometry of the condensation side were discussed to improve water collection performance,which should be designed collaboratively with the evaporation side in a confined space.Finally,thermal recovery and electricity generation beyond water collection were also introduced,and some challenges still need to improve in the further for scalable and practical applications,including passive water collection rate,integrated system,and long-term issues.
基金supported by the Science and Technology Innovation Program of Hunan Province(No.2024RC3003)the Central South University Innovation-Driven Research Programme(No.2023CXQD012).
文摘Solar evaporation has attracted great interest in water collection,gaining considerable attention recently.While many efforts have been made to enhance solar thermal conversion performance from materials design aspects,little attention has been given to the fundamental solar thermal gradient concept,which significantly affects local heating during evaporation.In this work,the polymer sponge evaporator was designed to control the solar thermal gradient by adding copper-carbon core-shell(Cu@C)nanoparticles with similar solar absorptance to understand the effect of solar thermal gradient or local heating on evaporation performance.The optimized solar evaporation can be 2.0 kg·m^(−2)·h^(−1)under 1000 W·m^(−2)(one sun)with a Cu@C mass fraction of 0.5 wt.%,which was higher than that observed in cases with either higher or smaller Cu@C mass fraction.A too-small or large Cu@C mass fraction would enhance heat loss from the bottom or top parts,which was also confirmed by simulation results.Further outdoor water yield experiment showed that the optimized Cu@C mass fraction of 0.5 wt.%achieved the highest water collection(6.67 kg·m^(−2)·d^(−1))compared with the other cases,such as 5.92 kg·m^(−2)·d^(−1)for 0.1 wt.%,5.29 kg·m^(−2)·d^(−1)for 1 wt.%.These results highlighted the impact of local heating on evaporation performance under the solar thermal gradient during the solar evaporation process.
基金supported by grants from the National Key R&D Program of China(Grant No.2021YFC2500500)the National Natural Science Foundation of China(Grant Nos.82370444,82070464,12411530127)+1 种基金supported by the Program for Innovative Research Team of The First Affiliated Hospital of USTC(CXGG02,China)Anhui Provincial Natural Science Foundation(Grant No.2208085J08,China).
文摘To the editor:ATP-citrate lyase(ACLY)is the key enzyme linking glucose catabolism to lipogenesis.Targeting hepatic ACLY for lowering low density lipoprotein-cholesterol(LDL-C)and attenuating atherosclerosis has been validated in preclinical animal models and hypercholesterolemic patients1.Bempedoic acid(ETC1002),a first-in-class,potent and orally bioavailable inhibitor of ACLY,has been approved by the US FDA to reduce cardiovascular risk in patients who do not achieve their recommended LDL-C levels through other means.
基金the Natural Science Foundation of Hunan Province(No.2021JJ40732)the Central South University Innovation-Driven Research Program(No.2023CXQD012).
文摘As global energy demand continues to rise and climate change accelerates,the need for sustainable and energy-efficient cooling solutions has reached a critical level.Conventional air conditioning systems heavily rely on energy-intensive mechanical cooling,which significantly contributes to both electricity demand and greenhouse gas emissions.Passive cooling strategies,particularly radiative cooling(RC)and evaporative cooling(EC),present an alternative approach by harnessing natural processes for temperature regulation.While standalone RC can be affected by weather conditions and EC relies on water availability,Radiative-coupled EC(REC)offers a versatile and sustainable cooling solution suitable for various applications.Here we summarize an overview of the theoretical foundations and mathematical models of REC,encompassing REC by bulk water(REC-BW),REC by perspiration(REC-P),and REC by sorbed water(REC-SW).Moreover,we explore a range of applications,spanning from industrial processes to personal thermal management,and examine the advantages and challenges associated with each REC approach.The significance of REC lies in its potential to revolutionize cooling technology,reduce energy consumption,and minimize the environmental impact.REC-BW can conserve water resources in industrial cooling processes,while REC-P offers innovative solutions for wearable electronics and textiles.REC-SW’s adaptability makes it suitable for food preservation and future potable cooling devices.By addressing the challenges posed by REC,including water consumption,textile design,and optimization of bilayer structures,we can unlock the transformative potential of REC and contribute to sustainable cooling technologies in a warming world.
