The deficiency of potable water resources and energy supply is emerging as a significant and concerning obstacle to sustainable development.Solar and waste heat-powered humidification dehumidification(HDH)desalination...The deficiency of potable water resources and energy supply is emerging as a significant and concerning obstacle to sustainable development.Solar and waste heat-powered humidification dehumidification(HDH)desalination systems become essential due to the severe impacts of global warming and water shortages.This problem highlights the need to apply boosted water desalination solutions.Desalination is a capital-intensive process that demands considerable energy,predominantly sourced fromfossil fuels worldwide,posing a significant carbon footprint risk.HDH is a very efficient desalination method suitable for remote areas with moderate freshwater requirements for domestic and agricultural usage.Several operational and maintenance concerns are to blame.The flow and thermal balances of humidifiers and dehumidifiers under the right conditions are crucial for system efficiency.These systems comprise a humidifier and dehumidifier,energy foundations for space or process heating and electricity generation,fluid transfer or efficiency enhancement accessories,and measurement-control devices.All technologies that enhance the performance of HDH systems are elucidated in this work.These are utilizing efficient components,renewable energy,heat recovery via multi-effect and multi-stage processes,waste heat-powered,and accelerating humidification and dehumidification processes through pressure variation or employing heat pumps,in addition to exergy and economical analyses.According to the present work,the seawater HDH system is feasible for freshwater generation.Regarding economics and gain output ratio,humidification–dehumidification is a viable approach for decentralized small-scale freshwater production applications,but it needs significant refinement.Systemproductivity of fresh water is much higher with integrated solar water heating than with solar air heating.The HDH offers the lowest water yield cost per liter and ideal system productivity when paired with a heat pump.The suggested changes aim to enhance system and process efficiency,reducing electrical energy consumption and cost-effective,continuous,decentralized freshwater production.This thorough analysis establishes a foundation for future research on energy and exergy cycles based on humidification and dehumidification.展开更多
The modelling and experimental investigation of a thermally coupled humidification-dehumidification desalination process using a carbon-filled-polypropylene shell-tube column are presented. A heat/mass transfer model ...The modelling and experimental investigation of a thermally coupled humidification-dehumidification desalination process using a carbon-filled-polypropylene shell-tube column are presented. A heat/mass transfer model is established to study the correlation among productivity, thermal efficiency, physicochemical parameters （gas/liquid phase temperature, heat/mass transfer coefficient, Reynolds number etc.）, and operating conditions （the temperature of feed water, the flow rates of external steam, feed water, and carrier air）; at the same time, the effects of operating conditions on the productivity and thermal eficiency of the column are investigated both theoretically and experimentally, which indicate that the optimum flow rates of external steam, feed water, and carder gas are 0.18, 60, and 10kg.h^-l, respectively, and the higher the feed water temperature （≤95℃） is, the greater the productivity and the thermal efficiency will be. Furthermore, performance comparison with the previous study shows that the condensate productivity of this carbon-filled-plastic column is not lower than that of the copper column, which demonstrates the practicability and feasibility of applying such a plastic column to the humidification-dehumidification desalination process.展开更多
Seawater greenhouse(SWGH)is a technology established to overcome issues related to open field cultivation in arid areas,such as the high ambient temperature and the shortage of freshwater.It adopts the humidification-...Seawater greenhouse(SWGH)is a technology established to overcome issues related to open field cultivation in arid areas,such as the high ambient temperature and the shortage of freshwater.It adopts the humidification-dehumidification concept where evaporated moisture from a saline water source is condensed to produce freshwater within the greenhouse body.Various condenser designs are adopted to increase freshwater production in order to meet the irrigation demand.The aim of this study was to experimentally investigate the practicality of using the packed-type direct contact condenser in the SWGH to produce more freshwater at low costs,simple design and high efficiency,and to explore the impact of the manipulating six operational variables(inlet air temperature of the humidifier,air mass flowrate of the humidifier,inlet water temperature of the humidifier,water mass flowrate of the humidifier,inlet water temperature of the dehumidifier and water mass flowrate of the dehumidifier)on freshwater condensation rate.For this purpose,a direct contact condenser was designed and manufactured.Sixty-four full factorial experiments were conducted to study the effect of the six operational variables.Each variable was operated at two levels(high and low flowrate),and each experiment lasted for 10 min and followed by a 30-min waiting time.Results showed that freshwater production varied between 0.257 and 2.590 L for every 10 min.When using Minitab statistical software to investigate the significant variables that contributed to the maximum freshwater production,it was found that the inlet air temperature of the humidifier had the greatest influence,followed by the inlet water temperature of the humidifier;the former had a negative impact while the latter had a positive impact on freshwater production.The response optimizer tool revealed that the optimal combination of variables contributed to maximize freshwater production when all variables were in the high mode and the inlet air temperature of the humidifier was in the low mode.The comparison between the old plastic condenser and the new proposed direct contact condenser showed that the latter can produce 75.9 times more freshwater at the same condenser volume.展开更多
A novel solar polygeneration system for heat, power and fresh water production with absorption heat pump(AHP) and humidification-dehumidification(HDH) desalination system was proposed for high-efficiency utilization o...A novel solar polygeneration system for heat, power and fresh water production with absorption heat pump(AHP) and humidification-dehumidification(HDH) desalination system was proposed for high-efficiency utilization of solar energy. A case study of the proposed system was investigated based on 1 MW solar thermal power(STP) tower plant located in Beijing. Depending on mathematical modeling of the proposed system, corresponding modules were developed in TRNSYS. Meanwhile, control and operation strategies were fully studied with principal of solar energy cascade utilization. The thermodynamic performance of the proposed system was dynamically simulated at one minute intervals in a typical day. It was found that solar energy utilization level was improved with the help of solar thermal storage system and continuous heating in different operation modes met well with flexible heating loads from 93.76 kW to 169.49 kW. During AHP operation period, its Coefficient of Performance(COP) varied from 1.39 to 1.73 due to recoverable condensate heat restricted by heating demand. Meanwhile, fresh water production of HDH increased from 352.05 kg/h to 416.62 kg/h with Gained Output Ratio(GOR) increase from 2.48 to 2.67. Compared with original STP tower plant, maximum power generation efficiency was increased from 18.66% to 19.22% with power from 1169.69 kW to 1204.44 kW.展开更多
文摘The deficiency of potable water resources and energy supply is emerging as a significant and concerning obstacle to sustainable development.Solar and waste heat-powered humidification dehumidification(HDH)desalination systems become essential due to the severe impacts of global warming and water shortages.This problem highlights the need to apply boosted water desalination solutions.Desalination is a capital-intensive process that demands considerable energy,predominantly sourced fromfossil fuels worldwide,posing a significant carbon footprint risk.HDH is a very efficient desalination method suitable for remote areas with moderate freshwater requirements for domestic and agricultural usage.Several operational and maintenance concerns are to blame.The flow and thermal balances of humidifiers and dehumidifiers under the right conditions are crucial for system efficiency.These systems comprise a humidifier and dehumidifier,energy foundations for space or process heating and electricity generation,fluid transfer or efficiency enhancement accessories,and measurement-control devices.All technologies that enhance the performance of HDH systems are elucidated in this work.These are utilizing efficient components,renewable energy,heat recovery via multi-effect and multi-stage processes,waste heat-powered,and accelerating humidification and dehumidification processes through pressure variation or employing heat pumps,in addition to exergy and economical analyses.According to the present work,the seawater HDH system is feasible for freshwater generation.Regarding economics and gain output ratio,humidification–dehumidification is a viable approach for decentralized small-scale freshwater production applications,but it needs significant refinement.Systemproductivity of fresh water is much higher with integrated solar water heating than with solar air heating.The HDH offers the lowest water yield cost per liter and ideal system productivity when paired with a heat pump.The suggested changes aim to enhance system and process efficiency,reducing electrical energy consumption and cost-effective,continuous,decentralized freshwater production.This thorough analysis establishes a foundation for future research on energy and exergy cycles based on humidification and dehumidification.
基金Supported by the National Natural Science Foundation of China and China Energy Conservation Investment Corporation as a Key Project （No.20236030）.
文摘The modelling and experimental investigation of a thermally coupled humidification-dehumidification desalination process using a carbon-filled-polypropylene shell-tube column are presented. A heat/mass transfer model is established to study the correlation among productivity, thermal efficiency, physicochemical parameters （gas/liquid phase temperature, heat/mass transfer coefficient, Reynolds number etc.）, and operating conditions （the temperature of feed water, the flow rates of external steam, feed water, and carrier air）; at the same time, the effects of operating conditions on the productivity and thermal eficiency of the column are investigated both theoretically and experimentally, which indicate that the optimum flow rates of external steam, feed water, and carder gas are 0.18, 60, and 10kg.h^-l, respectively, and the higher the feed water temperature （≤95℃） is, the greater the productivity and the thermal efficiency will be. Furthermore, performance comparison with the previous study shows that the condensate productivity of this carbon-filled-plastic column is not lower than that of the copper column, which demonstrates the practicability and feasibility of applying such a plastic column to the humidification-dehumidification desalination process.
基金the Sultan Qaboos University for the research grant provided through His Majesty Sultan Qaboos Trust Fund(Project code:#SR/AGR/SWAE/17/01).
文摘Seawater greenhouse(SWGH)is a technology established to overcome issues related to open field cultivation in arid areas,such as the high ambient temperature and the shortage of freshwater.It adopts the humidification-dehumidification concept where evaporated moisture from a saline water source is condensed to produce freshwater within the greenhouse body.Various condenser designs are adopted to increase freshwater production in order to meet the irrigation demand.The aim of this study was to experimentally investigate the practicality of using the packed-type direct contact condenser in the SWGH to produce more freshwater at low costs,simple design and high efficiency,and to explore the impact of the manipulating six operational variables(inlet air temperature of the humidifier,air mass flowrate of the humidifier,inlet water temperature of the humidifier,water mass flowrate of the humidifier,inlet water temperature of the dehumidifier and water mass flowrate of the dehumidifier)on freshwater condensation rate.For this purpose,a direct contact condenser was designed and manufactured.Sixty-four full factorial experiments were conducted to study the effect of the six operational variables.Each variable was operated at two levels(high and low flowrate),and each experiment lasted for 10 min and followed by a 30-min waiting time.Results showed that freshwater production varied between 0.257 and 2.590 L for every 10 min.When using Minitab statistical software to investigate the significant variables that contributed to the maximum freshwater production,it was found that the inlet air temperature of the humidifier had the greatest influence,followed by the inlet water temperature of the humidifier;the former had a negative impact while the latter had a positive impact on freshwater production.The response optimizer tool revealed that the optimal combination of variables contributed to maximize freshwater production when all variables were in the high mode and the inlet air temperature of the humidifier was in the low mode.The comparison between the old plastic condenser and the new proposed direct contact condenser showed that the latter can produce 75.9 times more freshwater at the same condenser volume.
基金This study was supported by the International Partnership Program of Chinese Academy of Sciences(CAS,Grant No.182111KYSB20160005)the National Nature Science Foundation of China(Grant No.51476164).
文摘A novel solar polygeneration system for heat, power and fresh water production with absorption heat pump(AHP) and humidification-dehumidification(HDH) desalination system was proposed for high-efficiency utilization of solar energy. A case study of the proposed system was investigated based on 1 MW solar thermal power(STP) tower plant located in Beijing. Depending on mathematical modeling of the proposed system, corresponding modules were developed in TRNSYS. Meanwhile, control and operation strategies were fully studied with principal of solar energy cascade utilization. The thermodynamic performance of the proposed system was dynamically simulated at one minute intervals in a typical day. It was found that solar energy utilization level was improved with the help of solar thermal storage system and continuous heating in different operation modes met well with flexible heating loads from 93.76 kW to 169.49 kW. During AHP operation period, its Coefficient of Performance(COP) varied from 1.39 to 1.73 due to recoverable condensate heat restricted by heating demand. Meanwhile, fresh water production of HDH increased from 352.05 kg/h to 416.62 kg/h with Gained Output Ratio(GOR) increase from 2.48 to 2.67. Compared with original STP tower plant, maximum power generation efficiency was increased from 18.66% to 19.22% with power from 1169.69 kW to 1204.44 kW.
