In this article we give an overview of the state of the art of salinity gradient technologies. We first introduce the concept of salinity gradient energy, before describing the current state of development of the most...In this article we give an overview of the state of the art of salinity gradient technologies. We first introduce the concept of salinity gradient energy, before describing the current state of development of the most advanced of these technologies. We conclude with the new trends in the young field of salinity gradient technologies.展开更多
In this study,a novel irreversible cyclic model of a capacitive mixing blue heat engine mainly consisting of super capacitors,charging and discharging circuits,a heat source,as well as two water sources with given sal...In this study,a novel irreversible cyclic model of a capacitive mixing blue heat engine mainly consisting of super capacitors,charging and discharging circuits,a heat source,as well as two water sources with given salt concentrations is established for harvesting salinity gradient energy and waste heat.Additionally,the effects of the charging voltage and ratio of the minimum to maximum surface electric charge density on the thermodynamic efficiency and power output of the cycle are discussed.The maximum power output of the cycle is calculated.The optimized ranges of efficiency and power output as well as the temperatures of two isothermal processes are determined.It is established that during the isoelectric quantity process,there is not only an increase in thermal voltage owing to the temperature difference,but also an increase in concentration voltage owing to the salinity gradient.Consequently,the blue heat engine can obtain higher energy conversion efficiency than a conventional heat engine.When the temperature ratio of the heat source to the heat sink is 1.233,the maximum efficiency can reach approximately36%.The results obtained can promote the application of capacitive mixing technology in real life,reducing the consumption of fossil fuels.展开更多
Coupling low-grade heat(LGH)with salinity gradient is an effective approach to increase the efficiency of the nanofluidic-membrane-based power generator.However,it is a challenge to fabricate membranes with high charg...Coupling low-grade heat(LGH)with salinity gradient is an effective approach to increase the efficiency of the nanofluidic-membrane-based power generator.However,it is a challenge to fabricate membranes with high charge density that ensures ion permselectivity,while maintaining chemical and mechanical stability in this composite environment.Here,we develop a bis[2-(methacryloyloxy)ethyl]phosphate(BMAP)hydrogel membrane with good thermal stability and anti-swelling property through self-crosslinking of the selected monomer.By taking advantage of negative space charge and three-dimensional(3D)interconnected nanochannels,salinity gradient energy conversion efficiency is substantially enhanced by temperature difference.Theoretical and experimental results verify that LGH can largely weaken the concentration polarization,promoting transmembrane ion transport.As a result,such a hydrogel membrane delivers high-performance energy conversion with a power density of 11.53 W·m^(−2)under a negative temperature difference(NTD),showing a 193%increase compared with that without NTD.展开更多
Membrane fouling inevitably occurs during nanofluidic reverse electrodialysis.Herein,the impact of multi-fouling on the energy conversion performance of negatively charged conical nanochannels under asymmetrical confi...Membrane fouling inevitably occurs during nanofluidic reverse electrodialysis.Herein,the impact of multi-fouling on the energy conversion performance of negatively charged conical nanochannels under asymmetrical configurations is systematically investigated.The results reveal that in Configuration I,where a high-concentration solution is applied at the tip side,at small concentration ratios,multiple foulings reduce the electric power.In Configuration II,where a low-concentration solution is applied at the tip side,multiple foulings near the base side contribute to the electric power.Any fouling that formed near the lowconcentration entrance diminished the electric power and energy conversion efficiency.Multi-fouling lowered the electrical power consumption by 69.27%and 99.94%in Configurations I and II,respectively.In Configuration I,the electric power first increased with increasing fouling surface charge density,reached its maximum value,and thereafter decreased.In Configuration II,the electric power first decreased with increasing fouling surface charge density,reached its minimum value,and thereafter increased.Large negative or positive charge densities of fouling contribute to the electric power and energy conversion efficiency.展开更多
The development of novel materials with ion-selective nanochannels has introduced a new technology for harvesting salinity gradient(blue)energy,namely nanopore power generators(NPGs).In this study,we perform a compreh...The development of novel materials with ion-selective nanochannels has introduced a new technology for harvesting salinity gradient(blue)energy,namely nanopore power generators(NPGs).In this study,we perform a comprehensive analysis of the practical performance of NPG in both coupon-size and module-scale operations.We show that although NPG membrane coupons can theoretically generate ultrahigh power density under ideal conditions,the resulting power density in practical operations at a coupon scale can hardly reach 10 W·m^(-2) due to concentration polarization effects.For module-scale NPG operation,we estimate both the power density and specific extractable energy(i.e.,extractable energy normalized by the total volume of the working solutions),and elucidate the impact of operating conditions on these two metrics based on the interplay between concentration polarization and extent of mixing of the high-and low-concentration solutions.Further,we develop a modeling framework to assess the viability of an NPG system.Our results demonstrate that,for NPG systems working with seawater and river water,the gross specific extractable energy by the NPG system is very low(~0.1 kW?h?m?3)and is further compromised by the parasitic energy consumptions in the system(notably,pumping of the seawater and river water solutions and their pretreatment).Overall,NPG systems produce very low net specific extractable energy(<0.025 kW?h?m?3)and net power density(<0.1 W?m?2).Our study highlights the significant practical limitations in NPG operations,casting doubt on the viability of NPG as a technology for blue energy harvesting.展开更多
Based on the rapid advancements in nanomaterials and nanotechnology,the Nanofluidic Reverse Electrodialysis(NRED)has attracted significant attention as an innovative and promising energy conversion strategy for extrac...Based on the rapid advancements in nanomaterials and nanotechnology,the Nanofluidic Reverse Electrodialysis(NRED)has attracted significant attention as an innovative and promising energy conversion strategy for extracting sustainable and clean energy fromthe salinity gradient energy.However,the scarcity of research investigating the intricate multi-factor coupling effects on the energy conversion performance,especially the trade-offs between ion selectivity and mass transfer in nanochannels,of NRED poses a great challenge to achieving breakthroughs in energy conversion processes.This numerical study innovatively investigates the multi-factor coupling effect of three critical operational factors,including the nanochannel configuration,the temperature field,and the concentration difference,on the energy conversion processes of NRED.In this work,a dimensionless amplitude parameter s is introduced to emulate the randomly varied wall configuration of nanochannels that inherently occur in practical applications,thereby enhancing the realism and applicability of our analysis.Numerical results reveal that the application of a temperature gradient,which is oriented in opposition to the concentration gradient,enhances the ion transportation and selectivity simultaneously,leading to an enhancement in both output power and energy conversion efficiency.Additionally,the increased fluctuation of the nanochannel wall from s=0 to s=0.08 improves ion selectivity yet raises ion transport resistance,resulting in an enhancement in output power and energy conversion efficiency but a slight reduction in current.Furthermore,with increasing the concentration ratio cH/cL from 10 to 1000,either within a fixed temperature field or at a constant dimensionless amplitude,the maximumpower consistently attains its optimal value at a concentration ratio of 100 but the cation transfer number experiences amonotonic decrease across this entire range of concentration ratios.Finally,uponmodifying the operational parameters fromthe baseline condition of s=0,c_(H)/c_(L)=10,andΔT=0 K to the targetedconditionof s=0.08,c_(H)/c_(L)=50,andΔT=25 K,there is a concerted improvement observed in the open-circuit potential,short-circuit current,andmaximumpower,with respective increments of 8.86%,204.97%,and 232.01%,but a reduction in cation transfer number with a notable decrease of 15.37%.展开更多
Based on a general review of marine renewable energy in China, an assessment of the development status and amount of various marine renewable energy resources, including tidal energy, tidal current energy, wave energy...Based on a general review of marine renewable energy in China, an assessment of the development status and amount of various marine renewable energy resources, including tidal energy, tidal current energy, wave energy, ocean thermal energy, and salinity gradient energy in China＇s coastal seas, such as the Bohai Sea, the Yellow Sea, the East China Sea, and the South China Sea, is presented. We have found that these kinds of marine renewable energy resources will play an important role in meeting China＇s future energy needs. Additionally, considering the uneven distribution of China＇s marine renewable energy and the influences of its exploitation on the environment, we have suggested several sites with great potential for each kind of marine energy. Furthermore, perspectives on and challenges related with marine renewable energy in China are addressed.展开更多
The practical application of semiconductor-based high-efficiency white-light sources, also known as light-emitting diodes, or LEDs, is a recent development of Japanese engineering. This development could be a game-cha...The practical application of semiconductor-based high-efficiency white-light sources, also known as light-emitting diodes, or LEDs, is a recent development of Japanese engineering. This development could be a game-changer for lighting worldwide, given that current power consumption for lighting accounts for 16% of the total electricity consumption in Japan.展开更多
Two-thirds of the world’s population has limited access to potable water.As we continue to use up our freshwater resources,new and improved techniques for potable water production are warranted.Here,we present a gene...Two-thirds of the world’s population has limited access to potable water.As we continue to use up our freshwater resources,new and improved techniques for potable water production are warranted.Here,we present a general concept called“salinity exchange”that transfers salts from seawater or brackish water to treated wastewater until their salinity values approximately switch,thus producing wastewater with an increased salinity for discharge and desalinated seawater as the potable water source.We have demonstrated this process using electrodialysis.Salinity exchange has been successfully achieved between influents of different salinities under various operating conditions.Laboratory-scale salinity exchange electrodialysis(SEE)systems can produce high-quality desalinated water at~1 mL/min with an energy consumption less than 1 kWh/m3.SEE has also been operated using real water,and the challenges of its implementation at a larger scale are evaluated.展开更多
Multi-stage reverse electrodialysis(MSRED)offers a promising way for efficient salinity gradient energy harvesting.Here,an improved model of the MSRED system under serial control strategy is proposed.The technical–ec...Multi-stage reverse electrodialysis(MSRED)offers a promising way for efficient salinity gradient energy harvesting.Here,an improved model of the MSRED system under serial control strategy is proposed.The technical–economic analysis is conducted with considering discount,depreciation and different regional tax and electricity price lev-els under the maximum net power output conditions.Results reveal that net power output and energy efficiency both increase first with increasing stage numbers,reach their maximum values,and then decrease.For 5 M/0.05 M solutions,the optimal net power output of 4.98 kW is obtained at the stage number n=12.The optimal stage number corresponding to the maximum net power increases with increasing feed solution concentrations.Due to the com-promise between net power generation and capital cost,there exist optimal stage numbers leading to the lowest LCOE and largest NPV,respectively.Higher feed solution concentration can significantly decrease the system LCOE and increase the NPV.The optimal stage number corresponding to the maximum NPV increases with increasing feed solution concentrations.In Germany,for 5 M/0.05 M solutions,the lowest LCOE of 0.061€·kWh^(-1) is achieved at n=3 while the highest NPV over the system lifecycle of 52,005€is obtained at n=8.Lower tax,higher electricity price,appropriate membrane price and stage numbers,and high salinity gradient sources can significantly accelerate the commercial completeness of the MSRED systems.展开更多
文摘In this article we give an overview of the state of the art of salinity gradient technologies. We first introduce the concept of salinity gradient energy, before describing the current state of development of the most advanced of these technologies. We conclude with the new trends in the young field of salinity gradient technologies.
基金supported by the National Natural Science Foundation of China(Grant No.51876181)。
文摘In this study,a novel irreversible cyclic model of a capacitive mixing blue heat engine mainly consisting of super capacitors,charging and discharging circuits,a heat source,as well as two water sources with given salt concentrations is established for harvesting salinity gradient energy and waste heat.Additionally,the effects of the charging voltage and ratio of the minimum to maximum surface electric charge density on the thermodynamic efficiency and power output of the cycle are discussed.The maximum power output of the cycle is calculated.The optimized ranges of efficiency and power output as well as the temperatures of two isothermal processes are determined.It is established that during the isoelectric quantity process,there is not only an increase in thermal voltage owing to the temperature difference,but also an increase in concentration voltage owing to the salinity gradient.Consequently,the blue heat engine can obtain higher energy conversion efficiency than a conventional heat engine.When the temperature ratio of the heat source to the heat sink is 1.233,the maximum efficiency can reach approximately36%.The results obtained can promote the application of capacitive mixing technology in real life,reducing the consumption of fossil fuels.
基金supported by the National Key R&D Program of China(Nos.2022YFB3805904,2022YFB3805900,and 2020YFA0710401)the National Natural Science Foundation of China(Nos.22122207,21988102,and 52075138)+2 种基金CAS Key Laboratory of Bio-inspired Materials and Interfacial Science,Technical Institute of Physics and Chemistry(No.BMIS202102)China Postdoctoral Science Foundation(Nos.2022TQ0345,2022M723229,and 2022M713226)Postdoctoral International Exchange Talent-Introducing Program(No.YJ20220199).
文摘Coupling low-grade heat(LGH)with salinity gradient is an effective approach to increase the efficiency of the nanofluidic-membrane-based power generator.However,it is a challenge to fabricate membranes with high charge density that ensures ion permselectivity,while maintaining chemical and mechanical stability in this composite environment.Here,we develop a bis[2-(methacryloyloxy)ethyl]phosphate(BMAP)hydrogel membrane with good thermal stability and anti-swelling property through self-crosslinking of the selected monomer.By taking advantage of negative space charge and three-dimensional(3D)interconnected nanochannels,salinity gradient energy conversion efficiency is substantially enhanced by temperature difference.Theoretical and experimental results verify that LGH can largely weaken the concentration polarization,promoting transmembrane ion transport.As a result,such a hydrogel membrane delivers high-performance energy conversion with a power density of 11.53 W·m^(−2)under a negative temperature difference(NTD),showing a 193%increase compared with that without NTD.
基金supported by the National Natural Science Foundation of China(Grant No.52176070)。
文摘Membrane fouling inevitably occurs during nanofluidic reverse electrodialysis.Herein,the impact of multi-fouling on the energy conversion performance of negatively charged conical nanochannels under asymmetrical configurations is systematically investigated.The results reveal that in Configuration I,where a high-concentration solution is applied at the tip side,at small concentration ratios,multiple foulings reduce the electric power.In Configuration II,where a low-concentration solution is applied at the tip side,multiple foulings near the base side contribute to the electric power.Any fouling that formed near the lowconcentration entrance diminished the electric power and energy conversion efficiency.Multi-fouling lowered the electrical power consumption by 69.27%and 99.94%in Configurations I and II,respectively.In Configuration I,the electric power first increased with increasing fouling surface charge density,reached its maximum value,and thereafter decreased.In Configuration II,the electric power first decreased with increasing fouling surface charge density,reached its minimum value,and thereafter increased.Large negative or positive charge densities of fouling contribute to the electric power and energy conversion efficiency.
基金financial support from the Center for Enhanced Nanofluidic Transport (CENT),an Energy Frontier Research Center funded by the US Department of Energy,Office of Science,Basic Energy Sciences through Award No.DESC0019112
文摘The development of novel materials with ion-selective nanochannels has introduced a new technology for harvesting salinity gradient(blue)energy,namely nanopore power generators(NPGs).In this study,we perform a comprehensive analysis of the practical performance of NPG in both coupon-size and module-scale operations.We show that although NPG membrane coupons can theoretically generate ultrahigh power density under ideal conditions,the resulting power density in practical operations at a coupon scale can hardly reach 10 W·m^(-2) due to concentration polarization effects.For module-scale NPG operation,we estimate both the power density and specific extractable energy(i.e.,extractable energy normalized by the total volume of the working solutions),and elucidate the impact of operating conditions on these two metrics based on the interplay between concentration polarization and extent of mixing of the high-and low-concentration solutions.Further,we develop a modeling framework to assess the viability of an NPG system.Our results demonstrate that,for NPG systems working with seawater and river water,the gross specific extractable energy by the NPG system is very low(~0.1 kW?h?m?3)and is further compromised by the parasitic energy consumptions in the system(notably,pumping of the seawater and river water solutions and their pretreatment).Overall,NPG systems produce very low net specific extractable energy(<0.025 kW?h?m?3)and net power density(<0.1 W?m?2).Our study highlights the significant practical limitations in NPG operations,casting doubt on the viability of NPG as a technology for blue energy harvesting.
基金funded by the National Natural Science Foundation of China[52106246]the Postgraduate Research&Practice innovation Program of Jiangsu Province[KYCX24_1641].
文摘Based on the rapid advancements in nanomaterials and nanotechnology,the Nanofluidic Reverse Electrodialysis(NRED)has attracted significant attention as an innovative and promising energy conversion strategy for extracting sustainable and clean energy fromthe salinity gradient energy.However,the scarcity of research investigating the intricate multi-factor coupling effects on the energy conversion performance,especially the trade-offs between ion selectivity and mass transfer in nanochannels,of NRED poses a great challenge to achieving breakthroughs in energy conversion processes.This numerical study innovatively investigates the multi-factor coupling effect of three critical operational factors,including the nanochannel configuration,the temperature field,and the concentration difference,on the energy conversion processes of NRED.In this work,a dimensionless amplitude parameter s is introduced to emulate the randomly varied wall configuration of nanochannels that inherently occur in practical applications,thereby enhancing the realism and applicability of our analysis.Numerical results reveal that the application of a temperature gradient,which is oriented in opposition to the concentration gradient,enhances the ion transportation and selectivity simultaneously,leading to an enhancement in both output power and energy conversion efficiency.Additionally,the increased fluctuation of the nanochannel wall from s=0 to s=0.08 improves ion selectivity yet raises ion transport resistance,resulting in an enhancement in output power and energy conversion efficiency but a slight reduction in current.Furthermore,with increasing the concentration ratio cH/cL from 10 to 1000,either within a fixed temperature field or at a constant dimensionless amplitude,the maximumpower consistently attains its optimal value at a concentration ratio of 100 but the cation transfer number experiences amonotonic decrease across this entire range of concentration ratios.Finally,uponmodifying the operational parameters fromthe baseline condition of s=0,c_(H)/c_(L)=10,andΔT=0 K to the targetedconditionof s=0.08,c_(H)/c_(L)=50,andΔT=25 K,there is a concerted improvement observed in the open-circuit potential,short-circuit current,andmaximumpower,with respective increments of 8.86%,204.97%,and 232.01%,but a reduction in cation transfer number with a notable decrease of 15.37%.
基金supported by the National Natural Science Foundation of China(Grants No.51079072 and 51279088)the National High Technology Research and Development Program of China(Grant No.2012AA052602)the Tsinghua University Initiative Scientific Research Program(Grant No.20101081791)
文摘Based on a general review of marine renewable energy in China, an assessment of the development status and amount of various marine renewable energy resources, including tidal energy, tidal current energy, wave energy, ocean thermal energy, and salinity gradient energy in China＇s coastal seas, such as the Bohai Sea, the Yellow Sea, the East China Sea, and the South China Sea, is presented. We have found that these kinds of marine renewable energy resources will play an important role in meeting China＇s future energy needs. Additionally, considering the uneven distribution of China＇s marine renewable energy and the influences of its exploitation on the environment, we have suggested several sites with great potential for each kind of marine energy. Furthermore, perspectives on and challenges related with marine renewable energy in China are addressed.
文摘The practical application of semiconductor-based high-efficiency white-light sources, also known as light-emitting diodes, or LEDs, is a recent development of Japanese engineering. This development could be a game-changer for lighting worldwide, given that current power consumption for lighting accounts for 16% of the total electricity consumption in Japan.
基金supported by the U.S.Department of Interior Bureau of Reclamation(No.R19AC00101).
文摘Two-thirds of the world’s population has limited access to potable water.As we continue to use up our freshwater resources,new and improved techniques for potable water production are warranted.Here,we present a general concept called“salinity exchange”that transfers salts from seawater or brackish water to treated wastewater until their salinity values approximately switch,thus producing wastewater with an increased salinity for discharge and desalinated seawater as the potable water source.We have demonstrated this process using electrodialysis.Salinity exchange has been successfully achieved between influents of different salinities under various operating conditions.Laboratory-scale salinity exchange electrodialysis(SEE)systems can produce high-quality desalinated water at~1 mL/min with an energy consumption less than 1 kWh/m3.SEE has also been operated using real water,and the challenges of its implementation at a larger scale are evaluated.
基金National Natural Science Foundation of China(52176070).
文摘Multi-stage reverse electrodialysis(MSRED)offers a promising way for efficient salinity gradient energy harvesting.Here,an improved model of the MSRED system under serial control strategy is proposed.The technical–economic analysis is conducted with considering discount,depreciation and different regional tax and electricity price lev-els under the maximum net power output conditions.Results reveal that net power output and energy efficiency both increase first with increasing stage numbers,reach their maximum values,and then decrease.For 5 M/0.05 M solutions,the optimal net power output of 4.98 kW is obtained at the stage number n=12.The optimal stage number corresponding to the maximum net power increases with increasing feed solution concentrations.Due to the com-promise between net power generation and capital cost,there exist optimal stage numbers leading to the lowest LCOE and largest NPV,respectively.Higher feed solution concentration can significantly decrease the system LCOE and increase the NPV.The optimal stage number corresponding to the maximum NPV increases with increasing feed solution concentrations.In Germany,for 5 M/0.05 M solutions,the lowest LCOE of 0.061€·kWh^(-1) is achieved at n=3 while the highest NPV over the system lifecycle of 52,005€is obtained at n=8.Lower tax,higher electricity price,appropriate membrane price and stage numbers,and high salinity gradient sources can significantly accelerate the commercial completeness of the MSRED systems.
