The thermal stress-induced deformation issue of receiver is crucial to the performance and reliability of a parabolic-trough(PT) concentrating solar power(CSP) system with the promising direct steam generation(DSG) te...The thermal stress-induced deformation issue of receiver is crucial to the performance and reliability of a parabolic-trough(PT) concentrating solar power(CSP) system with the promising direct steam generation(DSG) technology.The objective of the present study is to propose a new-type receiver with axially-hollow spiral deflector and optimize the geometric structure to solve the above issue.To this end,optical-flow-thermal multi-physics coupling models have been established for the preheating,boiling and superheating sections of a typical PT-DSG loop.The simulation results show that our proposed new-type receiver demonstrates outstanding comprehensive performance.It can minimize the circumferential temperature difference through the spiral deflector while lower the flow resistance cost through the axially hollow structure at the same time.As quantitatively evaluated by the temperature uniformity improvement(ε_(ΔT)) and the performance evaluation criteria(PEC),different designs are achieved based on different optimal schemes.When ε_(ΔT)is of primary importance,the optimal design with torsional ratio of 1 is achieved,with ε_(ΔT)=25.4%,25.7%,41.5% and PEC=0.486,0.878,0.596corresponding to preheating,boiling,superheating sections,respectively.When PEC is of primary importance,the optimal design with torsional ratio of 6-6.5 is achieved,with PEC=0.950,2.070,0.993 and ε_(ΔT)=18.2%,13.3 %,19.4% corresponding to preheating,boiling,superheating sections,respectively.展开更多
Solar multiple （SM） and thermal storage capacity are two key design parameters for revealing the performance of direct steam generation （DSG） solar power tower plant. In the case of settled land area, SM and therm...Solar multiple （SM） and thermal storage capacity are two key design parameters for revealing the performance of direct steam generation （DSG） solar power tower plant. In the case of settled land area, SM and thermal storage capacity can be optimized to obtain the minimum levelized cost of electricity （LCOE） by adjusting the power generation output. Taking the dual-receiver DSG solar power tower plant with a given size of solar field equivalent electricity of 100 MWe in Sevilla as a reference case, the minimum LCOE is 21.77 /kWhe with an SM of 1.7 and a thermal storage capacity of 3 h. Besides Sevilla, two other sites are also introduced to discuss the influence of annual DNI. When compared with the case of Sevilla, the minimum LCOE and optimal SM of the San Jose site change just slightly, while the minimum LCOE of the Bishop site decreases by 32.8% and the optimal SM is reduced to 1.3. The influence of the size of solar field equivalent electricity is studied as well. The minimum LCOE decreases with the size of solar field, while the optimal SM and thermal storage capacity still remain unchanged. In addition, the sensitivity of different investment in sub-system is investigated. In terms ofoptimal SM and thermal storage capacity, they can decrease with the cost of thermal storage system but increase with the cost of power generation unit.展开更多
采用模块化建模方法研究了无蓄热装置再循环方式直接产生蒸汽型抛物面槽式太阳能热动力发电站(solar thermal power plant using direct steam generation in parabolic trough collectors filed,DSG-PTCs-STTP)热力系统动态仿真模型。...采用模块化建模方法研究了无蓄热装置再循环方式直接产生蒸汽型抛物面槽式太阳能热动力发电站(solar thermal power plant using direct steam generation in parabolic trough collectors filed,DSG-PTCs-STTP)热力系统动态仿真模型。依照守恒定律和热力学、传热学、流体力学等基本关系式,在一定简化条件下,研究了抛物面槽式聚光集热系统的聚光器、预热段、蒸发段、过热段及汽水缓冲分离器的数学模型,结合其他已有的仿真模型(如流体网络、汽轮机、凝汽器、除氧器、水泵、发电励磁等过程及设备模型等),建立了完整的DSG-PTCs-STTP热力系统实时动态仿真模型。仿真试验表明所开发的仿真模型能够正确反映研究对象热力系统动态特性和全工况运行过程,模型运算稳定可靠。可用于DSG-PTCs-STTP机组实时仿真系统的开发,还可为机组运行特性研究和控制系统验证提供良好的非线性对象模型。展开更多
Harvesting water from the air using adsorbents and obtaining fresh water by solar-driven desorption is considered as one of the most effective ways to solve the freshwater crisis in arid and desert regions.Based on a ...Harvesting water from the air using adsorbents and obtaining fresh water by solar-driven desorption is considered as one of the most effective ways to solve the freshwater crisis in arid and desert regions.Based on a simple and low-cost photothermal hygroscopic hydrogel,a new strategy is proposed to boost solar energy efficiency by coupling solar-driven atmospheric water harvesting technology with thermoelectric power generation technology in this paper.Photothermal hygroscopic hydrogel ink PAM-CaCl_(2)is prepared by in situ polymerization using Acrylamide as monomer,Ammonium persulfate as thermal initiator and CaCl_(2)as hygroscopic component.During the day,the photothermal hygroscopic hydrogel absorbs solar energy and evaporates its own internal water to obtain fresh water.Simultaneously,the residual waste heat is utilized to power the thermoelectric panel,which produces electricity based on Seebeck effect.At night,the hydrogel harvests water molecules in the air to achieve regeneration.This hybrid system can achieve a water production rate of 0.33 kg m^(-2)h^(-1)and an additional electrical energy gain of 124 mW m^(-2)at 1 kW m^(-2)solar intensity.Theoretical model of the hybrid system is developed to understand the heat flow and thermoelectric generation process.The results provide new insights into energy and freshwater replenishment options in arid or desert areas with abundant solar energy.展开更多
基金financially supported by the National Natural Science Foundation of China (52176202)the Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory (41200101)。
文摘The thermal stress-induced deformation issue of receiver is crucial to the performance and reliability of a parabolic-trough(PT) concentrating solar power(CSP) system with the promising direct steam generation(DSG) technology.The objective of the present study is to propose a new-type receiver with axially-hollow spiral deflector and optimize the geometric structure to solve the above issue.To this end,optical-flow-thermal multi-physics coupling models have been established for the preheating,boiling and superheating sections of a typical PT-DSG loop.The simulation results show that our proposed new-type receiver demonstrates outstanding comprehensive performance.It can minimize the circumferential temperature difference through the spiral deflector while lower the flow resistance cost through the axially hollow structure at the same time.As quantitatively evaluated by the temperature uniformity improvement(ε_(ΔT)) and the performance evaluation criteria(PEC),different designs are achieved based on different optimal schemes.When ε_(ΔT)is of primary importance,the optimal design with torsional ratio of 1 is achieved,with ε_(ΔT)=25.4%,25.7%,41.5% and PEC=0.486,0.878,0.596corresponding to preheating,boiling,superheating sections,respectively.When PEC is of primary importance,the optimal design with torsional ratio of 6-6.5 is achieved,with PEC=0.950,2.070,0.993 and ε_(ΔT)=18.2%,13.3 %,19.4% corresponding to preheating,boiling,superheating sections,respectively.
基金This research was supported by the National Natural Science Foundation of China （Grant No. 51676069）, the 111 Project （1312034）, and the Fundamental Research Funds for the Central Universities （Grant No. 2016XS30）.
文摘Solar multiple （SM） and thermal storage capacity are two key design parameters for revealing the performance of direct steam generation （DSG） solar power tower plant. In the case of settled land area, SM and thermal storage capacity can be optimized to obtain the minimum levelized cost of electricity （LCOE） by adjusting the power generation output. Taking the dual-receiver DSG solar power tower plant with a given size of solar field equivalent electricity of 100 MWe in Sevilla as a reference case, the minimum LCOE is 21.77 /kWhe with an SM of 1.7 and a thermal storage capacity of 3 h. Besides Sevilla, two other sites are also introduced to discuss the influence of annual DNI. When compared with the case of Sevilla, the minimum LCOE and optimal SM of the San Jose site change just slightly, while the minimum LCOE of the Bishop site decreases by 32.8% and the optimal SM is reduced to 1.3. The influence of the size of solar field equivalent electricity is studied as well. The minimum LCOE decreases with the size of solar field, while the optimal SM and thermal storage capacity still remain unchanged. In addition, the sensitivity of different investment in sub-system is investigated. In terms ofoptimal SM and thermal storage capacity, they can decrease with the cost of thermal storage system but increase with the cost of power generation unit.
文摘采用模块化建模方法研究了无蓄热装置再循环方式直接产生蒸汽型抛物面槽式太阳能热动力发电站(solar thermal power plant using direct steam generation in parabolic trough collectors filed,DSG-PTCs-STTP)热力系统动态仿真模型。依照守恒定律和热力学、传热学、流体力学等基本关系式,在一定简化条件下,研究了抛物面槽式聚光集热系统的聚光器、预热段、蒸发段、过热段及汽水缓冲分离器的数学模型,结合其他已有的仿真模型(如流体网络、汽轮机、凝汽器、除氧器、水泵、发电励磁等过程及设备模型等),建立了完整的DSG-PTCs-STTP热力系统实时动态仿真模型。仿真试验表明所开发的仿真模型能够正确反映研究对象热力系统动态特性和全工况运行过程,模型运算稳定可靠。可用于DSG-PTCs-STTP机组实时仿真系统的开发,还可为机组运行特性研究和控制系统验证提供良好的非线性对象模型。
基金the National Natural Science Foundation of China(Grant No.52171317)。
文摘Harvesting water from the air using adsorbents and obtaining fresh water by solar-driven desorption is considered as one of the most effective ways to solve the freshwater crisis in arid and desert regions.Based on a simple and low-cost photothermal hygroscopic hydrogel,a new strategy is proposed to boost solar energy efficiency by coupling solar-driven atmospheric water harvesting technology with thermoelectric power generation technology in this paper.Photothermal hygroscopic hydrogel ink PAM-CaCl_(2)is prepared by in situ polymerization using Acrylamide as monomer,Ammonium persulfate as thermal initiator and CaCl_(2)as hygroscopic component.During the day,the photothermal hygroscopic hydrogel absorbs solar energy and evaporates its own internal water to obtain fresh water.Simultaneously,the residual waste heat is utilized to power the thermoelectric panel,which produces electricity based on Seebeck effect.At night,the hydrogel harvests water molecules in the air to achieve regeneration.This hybrid system can achieve a water production rate of 0.33 kg m^(-2)h^(-1)and an additional electrical energy gain of 124 mW m^(-2)at 1 kW m^(-2)solar intensity.Theoretical model of the hybrid system is developed to understand the heat flow and thermoelectric generation process.The results provide new insights into energy and freshwater replenishment options in arid or desert areas with abundant solar energy.
