Establishing alternative methods for freshwater production is imperative to effectively alleviate global water scarcity,particularly in land-locked arid regions.In this context,extracting water from the ubiquitous atm...Establishing alternative methods for freshwater production is imperative to effectively alleviate global water scarcity,particularly in land-locked arid regions.In this context,extracting water from the ubiquitous atmospheric moisture is an ingenious strategy for decentralized freshwater production.Sorption-based atmospheric water harvesting(SAWH)shows strong potential for supplying liquid water in a portable and sustainable way even in desert environments.Herein,the latest progress in SAWH technology in terms of materials,devices,and systems is reviewed.Recent advances in sorbent materials with improved water uptake capacity and accelerated sorption–desorption kinetics,including physical sorbents,polymeric hydrogels,composite sorbents,and ionic solutions,are discussed.The thermal designs of SAWH devices for improving energy utilization efficiency,heat transfer,and mass transport are evaluated,and the development of representative SAWH prototypes is clarified in a chronological order.Thereafter,state-of-the-art operation patterns of SAWH systems,incorporating intermittent,daytime continuous and 24-hour continuous patterns,are examined.Furthermore,current challenges and future research goals of this cutting-edge field are outlined.This review highlights the irreplaceable role of heat and mass transfer enhancement and facile structural improvement for constructing high-yield water harvesters.展开更多
Atmospheric water harvesting(AWH)is a promising solution to the water shortage problem.Current sorption-based AWH(SAWH)systems seldom obtain both wide climatic adaptability and high energy efficiency due to the lack o...Atmospheric water harvesting(AWH)is a promising solution to the water shortage problem.Current sorption-based AWH(SAWH)systems seldom obtain both wide climatic adaptability and high energy efficiency due to the lack of thermodynamic optimization.To achieve the ideal harvesting circulation in SAWH systems,the“optimal harvesting window”(OHW)design based on thermodynamic analysis was first proposed and validated by our prototype.The“OHW”theory indicates the water production rate and energy efficiency could be improved by properly reducing the adsorption temperature.As the humidity increases,the optimal adsorption temperature should be closer to the dew point of the environment.Experimental results revealed that,loaded with 3 kg widely adopted silica gel,the daily water production could reach 5.76-17.64 L/d with ultrahigh energy efficiency of 0.46-1.5 L/kWh.This prototype could also achieve optimal performance in wide climatic conditions in terms of 13-35℃and 18%-72%RH.Lastly,the performance of photovoltaic(PV)-driven SAWH was evaluated.Results showed that a 1 m^(2)PV panel could generate 0.66-2 L water per day in Shanghai throughout the year,the highest in opening literature.Notably,this work introduces a promising concept that can help achieve large-scale,ultra-fast,energyefficient AWH worldwide.展开更多
Absorption heat pump attracts increasing attention due to its advantages in low grade thermal energy utilization. It can be applied for waste heat reuse to save energy consumption, reduce environment pollution, and br...Absorption heat pump attracts increasing attention due to its advantages in low grade thermal energy utilization. It can be applied for waste heat reuse to save energy consumption, reduce environment pollution, and bring considerable economic benefit. In this paper, three important aspects for absorption heat pump for waste heat reuse are reviewed. In the first part, different absorption heat pump cycles are classified and introduced. Absorption heat pumps for heat amplification and absorp- tion heat transformer for temperature upgrading are included. Both basic single effect cycles and advanced cycles for better performance are introduced. In the second part, different working pairs, including the water based working pairs, ammonia based working pairs, alcohol based working pairs, and halogenated hydrocarbon based working pairs, for absorption heat pump are classified based on the refrigerant. In the third part, the applications of the absorption heat pump and absorption heat transformer for waste heat reuse in different industries are introduced. Based on the reviews in the three aspects, essential summary and future perspective are presented at last.展开更多
As a research focus, energy conservation has attracted a great deal of attention in recent years due to the energy crisis and environmental pollution concerns. Many countries made great efforts on both research and im...As a research focus, energy conservation has attracted a great deal of attention in recent years due to the energy crisis and environmental pollution concerns. Many countries made great efforts on both research and implementing energy conservation technologies. Cur- rently more than 50% of the total world's delivered energy is consumed by industry and about one sixth of the total energy consumed is wasted as low-grade heat, for example through radiation loss, exhaust gas flows, and cooling fluid circuits. Therefore, the recovery and reuse of waste heat is an effective way to significantly improve energy utilization. In addition, solar energy can provide low grade heat and is a clean and renewable form of energy. The efficient use of low grade heat from these sources can play an important role for a large number of applications.展开更多
This paper aims to explore an efficient, cost-effective, and water-saving seasonal cold energy storage technique based on borehole heat exchangers to cool the condenser water in a 10 MW solar thermal power plant. The ...This paper aims to explore an efficient, cost-effective, and water-saving seasonal cold energy storage technique based on borehole heat exchangers to cool the condenser water in a 10 MW solar thermal power plant. The proposed seasonal cooling mechanism is designed for the areas under typical weather conditions to utilize the low ambient temperature during the winter season and to store cold energy. The main objective of this paper is to utilize the storage unit in the peak summer months to cool the condenser water and to replace the dry cooling system. Using the simulation platform transient system simulation program (TRNSYS), the borehole thermal energy storage (BTES) system model has been developed and the dynamic capacity of the system in the charging and discharging mode of cold energy for one-year operation is studied. The typical meteorological year (TMY) data of Dunhuang, Gansu province, in north-western China, is utilized to determine the lowest ambient temperature and operation time of the system to store cold energy. The proposed seasonal cooling system is capable of enhancing the efficiency of a solar thermal power plant up to 1.54% and 2.74% in comparison with the water-cooled condenser system and air-cooled condenser system respectively. The techno-economic assessment of the proposed technique also supports its integration with the condenser unit in the solar thermal power plant. This technique has also a great potential to save the water in desert areas.展开更多
A solid sorption combined cooling and power system driven by exhaust waste heat is proposed, which consists of a MnCl2 sorption bed, a CaCl2 sorption bed, an evaporator, a condenser, an expansion valve, and a scroll e...A solid sorption combined cooling and power system driven by exhaust waste heat is proposed, which consists of a MnCl2 sorption bed, a CaCl2 sorption bed, an evaporator, a condenser, an expansion valve, and a scroll expander, and ammonia is chosen as the working fluid. First, the theoretical model of the system is established, and the partitioning calculation method is proposed for sorption beds. Next, the experimental system is estab- lished, and experimental results show that the refrigerating capacity at the refrigerating temperature of-10℃ and the resorption time of 30 min is 1.95 kW, and the shaft power is 109.2 W. The system can provide approximately 60% of the power for the evaporator fan and the condenser fan. Finally, the performance of the system is compared with that of the solid sorption refrigeration system. The refrigerating capacity of two systems is almost the same at the same operational condition. Therefore, the power generation process does not influence the refrigeration process. The exergy efficiency of the two systems is 0.076 and 0.047, respectively. The feasibility of the system is determined, which proves that this system is especially suitable for the exhaust waste heat recovery.展开更多
Heating decarbonization is a major challenge for China to meet its 2060 carbon neutral commitment,yet most existing studies on China’s carbon neutrality focus on supply side(e.g.,grid decarbonization,zero-carbon fuel...Heating decarbonization is a major challenge for China to meet its 2060 carbon neutral commitment,yet most existing studies on China’s carbon neutrality focus on supply side(e.g.,grid decarbonization,zero-carbon fuel)rather than demand side(e.g.,heating and cooling in buildings and industry).In terms of end use energy consumption,heating and cooling accounts for 50% of the total energy consumption,and heat pumps would be an effective driver for heating decarbonization along with the decarbonization on power generation side.Previous study has discussed the underestimated role of the heat pump in achieving China’s goal of carbon neutrality by 2060.In this paper,various investigation and assessments on heat pumps from research to applications are presented.The maximum decarbonization potential from heat pump in a carbon neutral China future could reach around 1532Mton and 670Mton for buildings and industrial heating respectively,which show nearly 2 billion tons CO_(2) emission reduction,20% current CO_(2) emission in China.Moreover,a region-specific technology roadmap for heat pump development in China is suggested.With collaborated efforts from government incentive,technology R&D,and market regulation,heat pump could play a significant role in China’s 2060 carbon neutrality.展开更多
基金supported by the National Natural Science Funds for Distinguished Young Scholar of China(52325601)the Major Program of National Natural Science Foundation of China(52293412)。
文摘Establishing alternative methods for freshwater production is imperative to effectively alleviate global water scarcity,particularly in land-locked arid regions.In this context,extracting water from the ubiquitous atmospheric moisture is an ingenious strategy for decentralized freshwater production.Sorption-based atmospheric water harvesting(SAWH)shows strong potential for supplying liquid water in a portable and sustainable way even in desert environments.Herein,the latest progress in SAWH technology in terms of materials,devices,and systems is reviewed.Recent advances in sorbent materials with improved water uptake capacity and accelerated sorption–desorption kinetics,including physical sorbents,polymeric hydrogels,composite sorbents,and ionic solutions,are discussed.The thermal designs of SAWH devices for improving energy utilization efficiency,heat transfer,and mass transport are evaluated,and the development of representative SAWH prototypes is clarified in a chronological order.Thereafter,state-of-the-art operation patterns of SAWH systems,incorporating intermittent,daytime continuous and 24-hour continuous patterns,are examined.Furthermore,current challenges and future research goals of this cutting-edge field are outlined.This review highlights the irreplaceable role of heat and mass transfer enhancement and facile structural improvement for constructing high-yield water harvesters.
基金supported by the National Natural Science Foundation of China(51922070).
文摘Atmospheric water harvesting(AWH)is a promising solution to the water shortage problem.Current sorption-based AWH(SAWH)systems seldom obtain both wide climatic adaptability and high energy efficiency due to the lack of thermodynamic optimization.To achieve the ideal harvesting circulation in SAWH systems,the“optimal harvesting window”(OHW)design based on thermodynamic analysis was first proposed and validated by our prototype.The“OHW”theory indicates the water production rate and energy efficiency could be improved by properly reducing the adsorption temperature.As the humidity increases,the optimal adsorption temperature should be closer to the dew point of the environment.Experimental results revealed that,loaded with 3 kg widely adopted silica gel,the daily water production could reach 5.76-17.64 L/d with ultrahigh energy efficiency of 0.46-1.5 L/kWh.This prototype could also achieve optimal performance in wide climatic conditions in terms of 13-35℃and 18%-72%RH.Lastly,the performance of photovoltaic(PV)-driven SAWH was evaluated.Results showed that a 1 m^(2)PV panel could generate 0.66-2 L water per day in Shanghai throughout the year,the highest in opening literature.Notably,this work introduces a promising concept that can help achieve large-scale,ultra-fast,energyefficient AWH worldwide.
基金This research is supported by National Key Research and Development Program (Grant No. 2016YFB0601200). The support fi-om the Foundation for Innovative Research Groups of the National Natural Science Foundation of China (Grant No. 51521004) is also appreciated.
文摘Absorption heat pump attracts increasing attention due to its advantages in low grade thermal energy utilization. It can be applied for waste heat reuse to save energy consumption, reduce environment pollution, and bring considerable economic benefit. In this paper, three important aspects for absorption heat pump for waste heat reuse are reviewed. In the first part, different absorption heat pump cycles are classified and introduced. Absorption heat pumps for heat amplification and absorp- tion heat transformer for temperature upgrading are included. Both basic single effect cycles and advanced cycles for better performance are introduced. In the second part, different working pairs, including the water based working pairs, ammonia based working pairs, alcohol based working pairs, and halogenated hydrocarbon based working pairs, for absorption heat pump are classified based on the refrigerant. In the third part, the applications of the absorption heat pump and absorption heat transformer for waste heat reuse in different industries are introduced. Based on the reviews in the three aspects, essential summary and future perspective are presented at last.
文摘As a research focus, energy conservation has attracted a great deal of attention in recent years due to the energy crisis and environmental pollution concerns. Many countries made great efforts on both research and implementing energy conservation technologies. Cur- rently more than 50% of the total world's delivered energy is consumed by industry and about one sixth of the total energy consumed is wasted as low-grade heat, for example through radiation loss, exhaust gas flows, and cooling fluid circuits. Therefore, the recovery and reuse of waste heat is an effective way to significantly improve energy utilization. In addition, solar energy can provide low grade heat and is a clean and renewable form of energy. The efficient use of low grade heat from these sources can play an important role for a large number of applications.
基金This work was supported by the Key Project of the National Natural Science Foundation of China for International Academic Exchanges(Grant No.51561145012)and the Gree Electric Appliances,Inc.Zhuhai,Guangdong Province.
文摘This paper aims to explore an efficient, cost-effective, and water-saving seasonal cold energy storage technique based on borehole heat exchangers to cool the condenser water in a 10 MW solar thermal power plant. The proposed seasonal cooling mechanism is designed for the areas under typical weather conditions to utilize the low ambient temperature during the winter season and to store cold energy. The main objective of this paper is to utilize the storage unit in the peak summer months to cool the condenser water and to replace the dry cooling system. Using the simulation platform transient system simulation program (TRNSYS), the borehole thermal energy storage (BTES) system model has been developed and the dynamic capacity of the system in the charging and discharging mode of cold energy for one-year operation is studied. The typical meteorological year (TMY) data of Dunhuang, Gansu province, in north-western China, is utilized to determine the lowest ambient temperature and operation time of the system to store cold energy. The proposed seasonal cooling system is capable of enhancing the efficiency of a solar thermal power plant up to 1.54% and 2.74% in comparison with the water-cooled condenser system and air-cooled condenser system respectively. The techno-economic assessment of the proposed technique also supports its integration with the condenser unit in the solar thermal power plant. This technique has also a great potential to save the water in desert areas.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 51576120).
文摘A solid sorption combined cooling and power system driven by exhaust waste heat is proposed, which consists of a MnCl2 sorption bed, a CaCl2 sorption bed, an evaporator, a condenser, an expansion valve, and a scroll expander, and ammonia is chosen as the working fluid. First, the theoretical model of the system is established, and the partitioning calculation method is proposed for sorption beds. Next, the experimental system is estab- lished, and experimental results show that the refrigerating capacity at the refrigerating temperature of-10℃ and the resorption time of 30 min is 1.95 kW, and the shaft power is 109.2 W. The system can provide approximately 60% of the power for the evaporator fan and the condenser fan. Finally, the performance of the system is compared with that of the solid sorption refrigeration system. The refrigerating capacity of two systems is almost the same at the same operational condition. Therefore, the power generation process does not influence the refrigeration process. The exergy efficiency of the two systems is 0.076 and 0.047, respectively. The feasibility of the system is determined, which proves that this system is especially suitable for the exhaust waste heat recovery.
基金National Natural Science Foundation of China:Study on cycle construction and application of large temperature lift heat pump and steam generation system(52036004).
文摘Heating decarbonization is a major challenge for China to meet its 2060 carbon neutral commitment,yet most existing studies on China’s carbon neutrality focus on supply side(e.g.,grid decarbonization,zero-carbon fuel)rather than demand side(e.g.,heating and cooling in buildings and industry).In terms of end use energy consumption,heating and cooling accounts for 50% of the total energy consumption,and heat pumps would be an effective driver for heating decarbonization along with the decarbonization on power generation side.Previous study has discussed the underestimated role of the heat pump in achieving China’s goal of carbon neutrality by 2060.In this paper,various investigation and assessments on heat pumps from research to applications are presented.The maximum decarbonization potential from heat pump in a carbon neutral China future could reach around 1532Mton and 670Mton for buildings and industrial heating respectively,which show nearly 2 billion tons CO_(2) emission reduction,20% current CO_(2) emission in China.Moreover,a region-specific technology roadmap for heat pump development in China is suggested.With collaborated efforts from government incentive,technology R&D,and market regulation,heat pump could play a significant role in China’s 2060 carbon neutrality.