Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffe...Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffer from slow reaction kinetics,poor stability,and low solar absorptance.Here,we successfully realized high power density and highly stable solar thermochemical energy storage/release by synergistically accelerating energy storage/release via binary sulfate and promoting cycle stability,mechanical strength,and solar absorptance via Al–Mn–Fe oxides.The energy storage density of proposed CaCO_(3)pellets is still as high as 1455 kJ kg^(-1)with only a slight decay rate of 4.91%over 100 cycles,which is higher than that of state-of-the-art pellets in the literature,in stark contrast to 69.9%of pure CaCO_(3)pellets over 35 cycles.Compared with pure CaCO_(3),the energy storage power density or decomposition rate is improved by 120%due to lower activation energy and promotion of Ca^(2+)diffusion by binary sulfate.The energy release or carbonation rate rises by 10%because of high O^(2-)transport ability of molten binary sulfate.Benefiting from fast energy storage/release rate and high solar absorptance,thermochemical energy storage efficiency is enhanced by more than 50%under direct solar irradiation.This work paves the way for application of direct solar thermochemical energy storage techniques via achieving fast energy storage/release rate,high energy density,good cyclic stability,and high solar absorptance simultaneously.展开更多
Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawba...Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.展开更多
Ever-increasing CO_(2)emissions and atmospheric concentration mainly due to the burning of traditional fossil fuels have caused severe global warming and climate change problems.Inspired by nature’s carbon cycle,we p...Ever-increasing CO_(2)emissions and atmospheric concentration mainly due to the burning of traditional fossil fuels have caused severe global warming and climate change problems.Inspired by nature’s carbon cycle,we propose a novel dual functional catalyst-sorbent to tackle energy and environmental problems simultaneously via direct capture of CO_(2)from air and in-situ solar-driven conversion into clean fuels.Economically and operationally advantageous,the planned coupling reaction can be carried out in a single reactor without the requirement for an extra trapping device.The great CO_(2)capture and conversion performance in an integrated step is shown by the CO_(2)capacity of up to 0.38 mmol·g^(−1)for adsorption from 500 ppm CO_(2)at 25℃and the CO_(2)conversion rate of up to 95%.Importantly,the catalyst-sorbent is constituted of a nonprecious metal Ni catalyst and an inexpensive commercially available CO_(2)sorbent,viz,zeolite NaA.Furthermore,this designed dual functional material also exhibits outstanding stability performance.This work offers a novel pathway of capturing CO_(2)in the air at room temperature and converting it by CH4 into fuel,contributing to the new era of carbon neutrality.展开更多
A lattice Boltzmann model is developed for investigating the heat conduction process inside the three-dimensional random porous media. Combined with the algorithm for the reconstruction of the three-dimensional porous...A lattice Boltzmann model is developed for investigating the heat conduction process inside the three-dimensional random porous media. Combined with the algorithm for the reconstruction of the three-dimensional porous media, this model is used to investigate the transient heat conduction process inside the porous wick of CPLs/LHPs, which is vital for analyzing the startup stability of a CPL/LHP. The temperature distribution inside the porous wick is obtained and the influence of the porosity and the heat load on the conduction process also is investigated using the present model. The present model is applicable to predicting the effective conductivity of such a complex structure.展开更多
Solar thermoelectric generators （STEGs） are heat engines which can generate electricity from concentrated sunlight. The non-uniform illumination caused by the optical concentrator may affect the performance of solar...Solar thermoelectric generators （STEGs） are heat engines which can generate electricity from concentrated sunlight. The non-uniform illumination caused by the optical concentrator may affect the performance of solar thermoelectric generators. In this paper, a three- dimensional finite element model of solar thermoelectric generators is established. The two-dimensional Gaussian distribution is employed to modify the illumination profiles incident on the thermoelectric generator. Six non-uniformities of solar illumination are investigated while keeping the total energy constant. The influences of non-uniform illumination on the temperature distribution, the voltage distribution, and the maximum output power are respectively discussed. Three thermoelectric generators with 32, 18 and 8 pairs of thermocouples are compared to investigate their capability under non-uniform solar radiation. The result shows that the non-uniformity of the solar illumination has a great effect on the temperature distribution and the voltage distribution. Central thermoelectric legs can achieve a larger temperature difference and generate a larger voltage than peripheral ones. The non-uniform solar illumination will weaken the capability of the TE generator, and the maximum output power decrease by 1.4% among the range of non-uniformity studied in this paper. Reducing the number of the thermoelectric legs for non-uniform solar illumination can greatly increase the performance of the thermoelectric generator.展开更多
Solar driven carbon dioxide(CO_(2))recycling into hydrocarbon fuels using semiconductor photocatalysts offers an ideal energy conversion pathway to solve both the energy crisis and environmental degradation problems.H...Solar driven carbon dioxide(CO_(2))recycling into hydrocarbon fuels using semiconductor photocatalysts offers an ideal energy conversion pathway to solve both the energy crisis and environmental degradation problems.However,the ubiquitous presence of carbonaceous contaminants in photocatalytic CO_(2) reduction system and the inferior yields of hydrocarbon fuels raise serious concerns about the reliability of the reported experimental results.Here in this perspective,we focus on the accurate assessment of the CO_(2) reduction products,systemically discuss the possible sources of errors in the product quantification,elaborate the common mistakes spread in the analysis of reaction products obtained in 13CO_(2) labelling experiments,and further propose reliable protocols for reporting the results of these isotopic tracing experiments.Moreover,the challenges and cautions in the precise measurement of O_(2) evolution rate are also depicted,and the amplification of the concentration of O_(2) in photoreactors well above the limit of detection is still demonstrated to be the most effective solution to this troublesome issue.We hope the viewpoints raised in this paper will help to assessment the reliability of the reported data in future,and also benefit the beginners that intend to dive in the photocatalytic CO_(2) reduction area.展开更多
Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we prop...Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we propose artificial“honeycombhoney”for excellent solar and thermal energy storage capacity based on TiN nanoparticles decorated porous AlN skeletonsPCMs composites.The thermal conductivity of composites achieves 21.58 W/(m·K)at AlN loading of 20 vol.%,superior to the state-of-the-art ceramic-based composites.The charging/discharging time is reduced to about half of pure PCMs with shapestability and thermal reliability well maintained over 500 melting/freezing cycles.The underlying mechanism can be attributed to the combination of single-crystal AlN whiskers with few crystal defects and reduced phonon scattering,as well as vertically arranged three-dimantional(3D)heat conduction channels.A rapid and efficient solar thermal storage is also demonstrated with solar thermal storage efficiency achieving a high value of 92.9%without employing additional spectrum selective coatings.This is benefited from high thermal conductivity and full-spectrum solar absorptance of up to 95%induced by plasmonic resonances of TiN nanoparticles.In addition,by embedding LiNO3-NaCl eutectics,the phase change enthalpy of composites reaches as high as 208 kJ/kg,making high energy storage density and fast energy storage rate compatible.This work offers new routes to achieve rapid,efficient,stable,and compact solar capture and thermal energy storage.展开更多
Tip clearance leakage flow of the turbine bade is an important factor limiting the augment of the high pressure turbine efficiency,which should be suppressed utilizing certain methods.However,the passive control metho...Tip clearance leakage flow of the turbine bade is an important factor limiting the augment of the high pressure turbine efficiency,which should be suppressed utilizing certain methods.However,the passive control method with the traditional structure is more and more difficult to satisfy the suppressing ability of the advanced turbine demand.In the present paper,a synergetic suppressing method by combining the approach of blade shape modification and spontaneous injection is adopted,to construct a novel tip structure.The aerodynamic characteristics of the tip leakage flow(TLF)with different blade tip configurations,such as the squealer,squealer-winglet(SW)and squealer-winglet-spontaneous injection holes(SWS)composite configurations,are numerically investigated.The impacts of several key geometric parameters,such as the winglet width and the space ng of spontaneous injection holes,are also discussed.Due to the adjustment of the winglet,the SW tip configuration can get better suppressing effect on TLF than the squealer tip.The SWS synergetic suppression tip decrease the leakage flow rate and the leakage mixing loss on the basis of the SW tip due to the blocking effect of the spontaneous injection flow.The key geometric parameters study shows that the suppressing effect of the TLF can be improved by reasonably increasing the winglet width and reducing the spacing between spontaneous injection holes.展开更多
With the global ambition of moving towards carbon neutrality,this sets to increase significantly with most of the energy sources from renewables.As a result,cost-effective and resource efficient energy conversion and ...With the global ambition of moving towards carbon neutrality,this sets to increase significantly with most of the energy sources from renewables.As a result,cost-effective and resource efficient energy conversion and storage will have a great role to play in energy decarbonization.This review focuses on the most recent developments of one of the most promising energy conversion and storage technologies-the calcium-looping.It includes the basics and barriers of calcium-looping beyond CO_(2) capture and storage(CCS)and technological solutions to address the associated challenges from material to system.Specifically,this paper discusses the flexibility of calcium-looping in the context of CO_(2) capture,combined with the use of H_(2)-rich fuel gas conversion and thermochemical heat storage.To take advantage of calcium-looping based energy integrated utilization of CCS(EIUCCS)in carbon neutral power generation,multiple-scale process innovations will be required,starting from the material level and extending to the system level.展开更多
基金supported by the National Natural Science Foundation of China[No.51820105010 and 51888103]support from Jiangsu Province(No.BK20202008,BE2022024,BE2022602,BK20220001,BK20220009,and BK20220077).
文摘Solar thermochemical energy storage based on calcium looping(CaL)process is a promising technology for next-generation concentrated solar power(CSP)systems.However,conventional calcium carbonate(CaCO_(3))pellets suffer from slow reaction kinetics,poor stability,and low solar absorptance.Here,we successfully realized high power density and highly stable solar thermochemical energy storage/release by synergistically accelerating energy storage/release via binary sulfate and promoting cycle stability,mechanical strength,and solar absorptance via Al–Mn–Fe oxides.The energy storage density of proposed CaCO_(3)pellets is still as high as 1455 kJ kg^(-1)with only a slight decay rate of 4.91%over 100 cycles,which is higher than that of state-of-the-art pellets in the literature,in stark contrast to 69.9%of pure CaCO_(3)pellets over 35 cycles.Compared with pure CaCO_(3),the energy storage power density or decomposition rate is improved by 120%due to lower activation energy and promotion of Ca^(2+)diffusion by binary sulfate.The energy release or carbonation rate rises by 10%because of high O^(2-)transport ability of molten binary sulfate.Benefiting from fast energy storage/release rate and high solar absorptance,thermochemical energy storage efficiency is enhanced by more than 50%under direct solar irradiation.This work paves the way for application of direct solar thermochemical energy storage techniques via achieving fast energy storage/release rate,high energy density,good cyclic stability,and high solar absorptance simultaneously.
基金This work was financially supported by the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(51888103)the National Key R&D Program of China(2021YFF0500700)Jiangsu Natural Science Foundation Project(BE2022024 and BK20202008).
文摘Solar-driven CO_(2)-to-fuel conversion assisted by another major greenhouse gas CH_(4)is promising to concurrently tackle energy shortage and global warming problems.However,current techniques still suffer from drawbacks of low efficiency,poor stability,and low selectivity.Here,a novel nanocomposite composed of interconnected Ni/MgAlOx nanoflakes grown on SiO_(2)particles with excellent spatial confinement of active sites is proposed for direct solar-driven CO_(2)-to-fuel conversion.An ultrahigh light-to-fuel efficiency up to 35.7%,high production rates of H_(2)(136.6 mmol min^(-1)g^(-1))and CO(148.2 mmol min^(-1)g^(-1)),excellent selectivity(H_(2)/CO ratio of 0.92),and good stability are reported simultaneously.These outstanding performances are attributed to strong metal-support interactions,improved CO_(2)absorption and activation,and decreased apparent activation energy under direct light illumination.MgAlO_(x)@SiO_(2)support helps to lower the activation energy of CH^(*) oxidation to CHO^(*) and improve the dissociation of CH_(4)to CH_(3)^(*) as confirmed by DFT calculations.Moreover,the lattice oxygen of MgAlO_(x) participates in the reaction and contributes to the removal of carbon deposition.This work provides promising routes for the conversion of greenhouse gasses into industrially valuable syngas with high efficiency,high selectivity,and benign sustainability.
基金This work was financially supported by the National Key R&D Program of China(No.2021YFF0500700)the Natural Science Foundation of Jiangsu Province(No.BK20202008)+1 种基金the Basic Science Center Program for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103)X.L.L.also wants to thank the support from the Natural Science Foundation of Jiangsu Province(Nos.BE2022024,BK20220001,and BE2022602).
文摘Ever-increasing CO_(2)emissions and atmospheric concentration mainly due to the burning of traditional fossil fuels have caused severe global warming and climate change problems.Inspired by nature’s carbon cycle,we propose a novel dual functional catalyst-sorbent to tackle energy and environmental problems simultaneously via direct capture of CO_(2)from air and in-situ solar-driven conversion into clean fuels.Economically and operationally advantageous,the planned coupling reaction can be carried out in a single reactor without the requirement for an extra trapping device.The great CO_(2)capture and conversion performance in an integrated step is shown by the CO_(2)capacity of up to 0.38 mmol·g^(−1)for adsorption from 500 ppm CO_(2)at 25℃and the CO_(2)conversion rate of up to 95%.Importantly,the catalyst-sorbent is constituted of a nonprecious metal Ni catalyst and an inexpensive commercially available CO_(2)sorbent,viz,zeolite NaA.Furthermore,this designed dual functional material also exhibits outstanding stability performance.This work offers a novel pathway of capturing CO_(2)in the air at room temperature and converting it by CH4 into fuel,contributing to the new era of carbon neutrality.
基金Supported by the National Natural Science Foundation of China (Grant No. 50576038)Program for New Century Excellent Talents in University
文摘A lattice Boltzmann model is developed for investigating the heat conduction process inside the three-dimensional random porous media. Combined with the algorithm for the reconstruction of the three-dimensional porous media, this model is used to investigate the transient heat conduction process inside the porous wick of CPLs/LHPs, which is vital for analyzing the startup stability of a CPL/LHP. The temperature distribution inside the porous wick is obtained and the influence of the porosity and the heat load on the conduction process also is investigated using the present model. The present model is applicable to predicting the effective conductivity of such a complex structure.
基金This work was supported by the National Natural Science Foundation of China （Grant No.51590903）.
文摘Solar thermoelectric generators （STEGs） are heat engines which can generate electricity from concentrated sunlight. The non-uniform illumination caused by the optical concentrator may affect the performance of solar thermoelectric generators. In this paper, a three- dimensional finite element model of solar thermoelectric generators is established. The two-dimensional Gaussian distribution is employed to modify the illumination profiles incident on the thermoelectric generator. Six non-uniformities of solar illumination are investigated while keeping the total energy constant. The influences of non-uniform illumination on the temperature distribution, the voltage distribution, and the maximum output power are respectively discussed. Three thermoelectric generators with 32, 18 and 8 pairs of thermocouples are compared to investigate their capability under non-uniform solar radiation. The result shows that the non-uniformity of the solar illumination has a great effect on the temperature distribution and the voltage distribution. Central thermoelectric legs can achieve a larger temperature difference and generate a larger voltage than peripheral ones. The non-uniform solar illumination will weaken the capability of the TE generator, and the maximum output power decrease by 1.4% among the range of non-uniformity studied in this paper. Reducing the number of the thermoelectric legs for non-uniform solar illumination can greatly increase the performance of the thermoelectric generator.
基金the Basic Science Center Project for Ordered Energy Conversion of the National Natural Science Foundation of China(No.51888103).
文摘Solar driven carbon dioxide(CO_(2))recycling into hydrocarbon fuels using semiconductor photocatalysts offers an ideal energy conversion pathway to solve both the energy crisis and environmental degradation problems.However,the ubiquitous presence of carbonaceous contaminants in photocatalytic CO_(2) reduction system and the inferior yields of hydrocarbon fuels raise serious concerns about the reliability of the reported experimental results.Here in this perspective,we focus on the accurate assessment of the CO_(2) reduction products,systemically discuss the possible sources of errors in the product quantification,elaborate the common mistakes spread in the analysis of reaction products obtained in 13CO_(2) labelling experiments,and further propose reliable protocols for reporting the results of these isotopic tracing experiments.Moreover,the challenges and cautions in the precise measurement of O_(2) evolution rate are also depicted,and the amplification of the concentration of O_(2) in photoreactors well above the limit of detection is still demonstrated to be the most effective solution to this troublesome issue.We hope the viewpoints raised in this paper will help to assessment the reliability of the reported data in future,and also benefit the beginners that intend to dive in the photocatalytic CO_(2) reduction area.
基金the National Key Research and Development Program of China(No.2018YFA0702300)the National Natural Science Foundation of China(Nos.51820105010 and 52076106).
文摘Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we propose artificial“honeycombhoney”for excellent solar and thermal energy storage capacity based on TiN nanoparticles decorated porous AlN skeletonsPCMs composites.The thermal conductivity of composites achieves 21.58 W/(m·K)at AlN loading of 20 vol.%,superior to the state-of-the-art ceramic-based composites.The charging/discharging time is reduced to about half of pure PCMs with shapestability and thermal reliability well maintained over 500 melting/freezing cycles.The underlying mechanism can be attributed to the combination of single-crystal AlN whiskers with few crystal defects and reduced phonon scattering,as well as vertically arranged three-dimantional(3D)heat conduction channels.A rapid and efficient solar thermal storage is also demonstrated with solar thermal storage efficiency achieving a high value of 92.9%without employing additional spectrum selective coatings.This is benefited from high thermal conductivity and full-spectrum solar absorptance of up to 95%induced by plasmonic resonances of TiN nanoparticles.In addition,by embedding LiNO3-NaCl eutectics,the phase change enthalpy of composites reaches as high as 208 kJ/kg,making high energy storage density and fast energy storage rate compatible.This work offers new routes to achieve rapid,efficient,stable,and compact solar capture and thermal energy storage.
基金supported by the National Science and Technology Major Project(2017-III-0010-0036).
文摘Tip clearance leakage flow of the turbine bade is an important factor limiting the augment of the high pressure turbine efficiency,which should be suppressed utilizing certain methods.However,the passive control method with the traditional structure is more and more difficult to satisfy the suppressing ability of the advanced turbine demand.In the present paper,a synergetic suppressing method by combining the approach of blade shape modification and spontaneous injection is adopted,to construct a novel tip structure.The aerodynamic characteristics of the tip leakage flow(TLF)with different blade tip configurations,such as the squealer,squealer-winglet(SW)and squealer-winglet-spontaneous injection holes(SWS)composite configurations,are numerically investigated.The impacts of several key geometric parameters,such as the winglet width and the space ng of spontaneous injection holes,are also discussed.Due to the adjustment of the winglet,the SW tip configuration can get better suppressing effect on TLF than the squealer tip.The SWS synergetic suppression tip decrease the leakage flow rate and the leakage mixing loss on the basis of the SW tip due to the blocking effect of the spontaneous injection flow.The key geometric parameters study shows that the suppressing effect of the TLF can be improved by reasonably increasing the winglet width and reducing the spacing between spontaneous injection holes.
基金supported by the National Science Fund for Distinguished Young Scholars[51925604]the National Natural Science Foundation of China[52176210,51820105010]+1 种基金the Bureau of International Cooperation of Chinese Academy of Sciences[182211KYSB20170029]the Cooperation Foundation of Dalian National Laboratory for Clean Energy[DNL202017].
文摘With the global ambition of moving towards carbon neutrality,this sets to increase significantly with most of the energy sources from renewables.As a result,cost-effective and resource efficient energy conversion and storage will have a great role to play in energy decarbonization.This review focuses on the most recent developments of one of the most promising energy conversion and storage technologies-the calcium-looping.It includes the basics and barriers of calcium-looping beyond CO_(2) capture and storage(CCS)and technological solutions to address the associated challenges from material to system.Specifically,this paper discusses the flexibility of calcium-looping in the context of CO_(2) capture,combined with the use of H_(2)-rich fuel gas conversion and thermochemical heat storage.To take advantage of calcium-looping based energy integrated utilization of CCS(EIUCCS)in carbon neutral power generation,multiple-scale process innovations will be required,starting from the material level and extending to the system level.
