In Brayton cycle energy storage systems powered by supercritical carbon dioxide(sCO_(2)),compressors are among themost critical components.Understanding their internal flowloss characteristics is,therefore,essential f...In Brayton cycle energy storage systems powered by supercritical carbon dioxide(sCO_(2)),compressors are among themost critical components.Understanding their internal flowloss characteristics is,therefore,essential for enhancing the performance of such systems.This study examines the main sCO_(2) compressor from Sandia Laboratory,utilizing entropy production theory to elucidate the sources and distribution of energy losses both across the entire machine and within its key flow components.The findings reveal that turbulent viscous dissipation is the predominant contributor to total entropy production.Interestingly,while the relative importance of the entropy produced by various sources as the mass flow rate rises remains essentially unchanged,the total entropy production exhibits a nonmonotonic trend,first decreasing and then increasing with the mass flow rate.High entropy production in the impeller is primarily concentrated in the clearance region and along the rear cover of the impeller tip.In the diffuser,it is most pronounced on the front and rear plates and within the central flow path.Meanwhile,in the volute,the highest entropy production occurs around the diffuser outlet and along the outer region of the volute’s centerline.展开更多
The spherical oscillation of a gas bubble in liquids is important to growth in liquids during rectified diffusions( e. g., the onset of the sonoluminescence and the enhancement of sonochemical reactions). The present ...The spherical oscillation of a gas bubble in liquids is important to growth in liquids during rectified diffusions( e. g., the onset of the sonoluminescence and the enhancement of sonochemical reactions). The present paper numerically shows stability maps( divided into four zones),in which gas bubbles maintain the linearly spherical oscillation without nonlinear disturbance of rectified diffusions within a large range of bubble radius. The critical pressures of spherical and diffusional oscillations are two decisive indexes determining the stability status. Specifically,the stability boundaries and influential factors( including acoustic parameters and gas concentration in liquids) were discussed and analyzed. The results show that the variations of gas concentration and acoustic parameters dramatically changed the stable status of the gas bubbles. The gas bubble maintained stable status when external parameters and gas concentration were set between the two critical values properly. The cases of high-frequency and low-frequency limits were also introduced at the end of the whole paper.展开更多
This study explores the aerodynamic performance and flow field characteristics of supercritical carbon dioxide(sCO_(2))centrifugal compressors under varying operating conditions.In particular,the Sandia main compresso...This study explores the aerodynamic performance and flow field characteristics of supercritical carbon dioxide(sCO_(2))centrifugal compressors under varying operating conditions.In particular,the Sandia main compressor impeller model is used as a reference system.Through three-dimensional numerical simulations,we examine the Mach number distribution,temperature field,blade pressure pulsation spectra,and velocity field evolution,and identify accordingly the operating boundaries ensuring stability and the mechanisms responsible for performance degradation.Findings indicate a stable operating range for mass flow rate between 0.74 and 3.74 kg/s.At the lower limit(0.74 kg/s),the maximum Mach number within the compressor decreases by 28%,while the temperature gradient sharpens,entropy rises notably,and fluid density varies significantly.The maximum pressure near the blades increases by 6%,yet flow velocity near the blades and outlet declines,with a 19%reduction in peak speed.Consequently,isentropic efficiency falls by 13%.Conversely,at 3.74 kg/s,the maximum Mach number increases by 23.7%,with diminished temperature gradients and minor fluid density variations.However,insufficient enthalpy gain and intensified pressure pulsations near the blades result in a 12%pressure drop.Peak velocity within the impeller channel surges by 23%,amplifying velocity gradients,inducing flow separation,and ultimately reducing the pressure ratio from 1.47 to 1.34.展开更多
The permeability contrast between the Hot Dry Rock(HDR)reservoir and the surrounding formations is a key factor governing fluid loss in Enhanced Geothermal Systems(EGS).This study thus aims to investigate its impact o...The permeability contrast between the Hot Dry Rock(HDR)reservoir and the surrounding formations is a key factor governing fluid loss in Enhanced Geothermal Systems(EGS).This study thus aims to investigate its impact on system performance under varying operating conditions,and a three-dimensional thermo–hydro–mechanical(THM)coupled EGS model is developed based on the geological parameters of the GR1 well in the Qiabuqia region.The coupled processes of fluid flow,heat transfer,and geomechanics within the reservoir under varying reservoir–surrounding rock permeability contrasts,as well as the flow and heat exchange along the wellbores fromthe reservoir to the surface are simulated.Then,the influence of permeability contrast,production pressure,injection rate,and injection temperature on fluid loss and heat extraction performance over a 35-year operation period is quantitatively assessed.Theresults show that increasing the permeability contrast effectively suppresses fluid loss and enhances early-stage heat production,but also accelerates thermal breakthrough and shortens the stable operation period.When the contrast rises from 1×10^(3) to 1×10^(5),the cumulative fluid loss rate drops from 54.34%to 0.23%,and the total heat production increases by 132%,although the breakthrough occurs 5 years earlier.Meanwhile,higher production pressure delays thermal breakthrough and slows transient temperature decline,but exacerbates fluid loss and reduces heat production power.For instance,raising the pressure from 17 to 21 MPa increases the fluid loss rate from 33.17%to 54.34%and reduces average annual heat production power from 25.43 to 14.59MWth.In addition,increasing the injection rate(46 to 66 kg/s)lowers fluid loss rate but brings forward thermal breakthrough by 9 years and causes a 41 K temperature drop at the end of operation.Notably,under high fluid loss,the dynamic response pattern of heat production power shifts from a temperature-dominated“stable–breakthrough–decline”mode to a novel“rising–breakthrough–decline”mode jointly governed by both production temperature and flow rates.These findings provide theoretical support and engineering guidance for improving EGS performance.展开更多
Deep exploration of user-side flexibility resources is crucial for large-scale renewable energy consumption.This paper proposed a typical integrated energy system(IES)that comprehensively includes wind power,photovolt...Deep exploration of user-side flexibility resources is crucial for large-scale renewable energy consumption.This paper proposed a typical integrated energy system(IES)that comprehensively includes wind power,photovoltaic,thermal power,combined heat and power,hybrid energy storage,and flexible load and constructed the system’s unified power flow model based on the heat current method.On this basis,the regulation capabilities of different typical industrial and residential flexible loads were considered the symmetrical source-type load,which can transfer load and align user demand with the peaks and valleys of renewable energy generation,thus achieving power-energy decoupling.This contributes effectively to renewable energy accommodation capacity when the total electrical energy consumption remains constant.In both typical industrial and residential load scenarios,flexible load reduces integrated costs,increases renewable energy consumption,lowers peak thermal power generation,and decreases the requirement for a battery energy storage system(BESS).Besides,on typical industrial and residential load days,smoothing thermal power generation necessitates 12%and 18%flexible load,respectively,while replacing BESS requires 18%and 23%flexible load,respectively.Therefore,we can obtain the feasible operation ranges of symmetrical source-type load and provide suggestions for configuration capacity design of demand response in integrated energy systems.展开更多
Hydrogen is one of the best energy carriers.Fluidized bed reactor provides a promising approach for hydrogen production. To describe the hydrogen generating rate with methanol steam reforming in fluidized bed reactor ...Hydrogen is one of the best energy carriers.Fluidized bed reactor provides a promising approach for hydrogen production. To describe the hydrogen generating rate with methanol steam reforming in fluidized bed reactor quantitatively, dual-rate kinetic models of the reactions with exponent form were developed, including that of steam reforming reaction(SR) and decomposition reaction(DE).The reaction rate per unit mass of catalyst was related to partial pressures of components. The exponentials in kinetic equations were obtained by linear least-squares method based on the experimental data. The variance homogeneity test(F test) shows that the dynamic models are feasible with high accuracy, which can be used to predict the generating rate of hydrogen under different reaction temperatures and feed flow rates in fluidized bed reactor. The SR and DE activation energy obtained indicates that ESR\ EDE, which can explain the previous observation that the CO_2 selectivity decreased with the temperature increase.展开更多
Multi-energy complementary distributed energy system(MECDES)is an important development direction for the energy system.It has the advantages of energy conservation and environmental protection and has great potential...Multi-energy complementary distributed energy system(MECDES)is an important development direction for the energy system.It has the advantages of energy conservation and environmental protection and has great potential to realize efficient energy cascade utilization through the energy conversion and utilization of cooling,heating,and power in place,achieving a user-oriented energy supply.The present study thoroughly reviews the current research status and puts forward the key scientific issues that urgently need to be resolved by investigating the problems and challenges of the MECDES from the perspectives of the characterization of the energetic mass-energy potential,the synergistic transformation and energy-potential coupling mechanism of multi-energy complementation,energy quality improvement and storage,and proactive regulation of the MECDES.Furthermore,the latest research progress of the MECDES for trickling the key scientific issues is comprehensively presented by proposing the distributed energy system with the complementation of multi-energy sources,developing novel ways of the energy potential coupling and energy cascaded comprehensive utilization of multi-energy complementation,proposing a new theory of multi-energy complementation and energy potential coupling and a new mechanism of source complementation,processing matching and thermodynamic cycle system collaborative conversion of both the fossil energy and renewable energy,and developing a new method of proactive adjust and control for adapting to fluctuating energy input and various energy load demands.Finally,the prospects and recommendations for the future research and development direction of MECDES are provided.展开更多
In conventional photovoltaic(PV) systems, a large portion of solar energy is dissipated as waste heat since the generating efficiency is usually less than 30%. As the dissipated heat can be recovered for various appli...In conventional photovoltaic(PV) systems, a large portion of solar energy is dissipated as waste heat since the generating efficiency is usually less than 30%. As the dissipated heat can be recovered for various applications, the wasted heat recovery concentrator PV/thermal(WHR CPVT) hybrid systems have been developed. They can provide both electricity and usable heat by combining thermal systems with concentrator PV(CPV) module, which dramatically improves the overall conversion efficiency of solar energy.This paper systematically and comprehensively reviews the research and development of WHR CPVT systems. WHR CPVT systems with innovative design configurations, different theoretical evaluation models and experimental test processes for several implementations are presented in an integrated manner. We aim to provide a global point of view on the research trends, market potential, technical obstacles, and the future work which is required in the development of WHR CPVT technology. Possibly, it will offer a generic guide to the investigators who are interested in the study of WHR CPVT systems.展开更多
Emulsion is a disperse system with two immiscible liquids,which demonstrates wide applications in diverse industries.Emulsifcation technology has advanced well with the development of microfluidic process.Compared to ...Emulsion is a disperse system with two immiscible liquids,which demonstrates wide applications in diverse industries.Emulsifcation technology has advanced well with the development of microfluidic process.Compared to conventional methods,the micro-fluidics-based process can produce controllable droplet size and distribution.The droplet formation or breakup is the result of combined effects resulting from interfacial tension,viscous,and inertial forces as well as the forces generated due to hydrodynamic pressure and extermal stimuli.In the current study,typical microfluidic systems,including microchannel array,T-shape,flow-focusing,co-flowing,and membrane systems,are reviewed and the corresponding mechanisms,fow regimes,and main parameters are compared and summarized.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
Distributed energy system,a decentralized low-carbon energy system arranged at the customer side,is characterized by multi-energy complementarity,multi-energy flow synergy,multi-process coupling,and multi-temporal sca...Distributed energy system,a decentralized low-carbon energy system arranged at the customer side,is characterized by multi-energy complementarity,multi-energy flow synergy,multi-process coupling,and multi-temporal scales(n-M characteristics).This review provides a systematic and comprehensive summary and presents the current research on distributed energy systems in three dimensions:system planning and evaluation,modeling and optimization,and operation and control.Under the regional environmental,resource,and policy constraints,planning distributed energy systems should fully integrate technical,economic,environmental,and social factors and consider device characteristics,system architecture,and source-load uncertainties.Further,this review presents four modeling perspectives for optimizing and analyzing distributed energy systems,including energy hub,thermodynamics,heat current,and data-driven.The system’s optimal operation and scheduling strategies,disturbance analysis,and related control methods are also discussed from the power system and thermal system,respectively.In all,more research is required for distributed energy systems based on an integrated energy perspective in optimal system structure,hybrid modeling approaches,data-driven system state estimation,cross-system disturbance spread,and multi-subject interaction control.展开更多
基金supported by theDouble First-Class Key ProgramofGansu ProvincialDepartment of Education(grant number GCJ2022-38)Science and Technology Program of Gansu Province(grant number 22ZD6GA038)Key Research and Development Program of Gansu Province—Industrial Project(grant number 25YFGA021).
文摘In Brayton cycle energy storage systems powered by supercritical carbon dioxide(sCO_(2)),compressors are among themost critical components.Understanding their internal flowloss characteristics is,therefore,essential for enhancing the performance of such systems.This study examines the main sCO_(2) compressor from Sandia Laboratory,utilizing entropy production theory to elucidate the sources and distribution of energy losses both across the entire machine and within its key flow components.The findings reveal that turbulent viscous dissipation is the predominant contributor to total entropy production.Interestingly,while the relative importance of the entropy produced by various sources as the mass flow rate rises remains essentially unchanged,the total entropy production exhibits a nonmonotonic trend,first decreasing and then increasing with the mass flow rate.High entropy production in the impeller is primarily concentrated in the clearance region and along the rear cover of the impeller tip.In the diffuser,it is most pronounced on the front and rear plates and within the central flow path.Meanwhile,in the volute,the highest entropy production occurs around the diffuser outlet and along the outer region of the volute’s centerline.
基金Sponsored by the Fundamental Research Fund for Central Universities(Grant No.2017XS063)
文摘The spherical oscillation of a gas bubble in liquids is important to growth in liquids during rectified diffusions( e. g., the onset of the sonoluminescence and the enhancement of sonochemical reactions). The present paper numerically shows stability maps( divided into four zones),in which gas bubbles maintain the linearly spherical oscillation without nonlinear disturbance of rectified diffusions within a large range of bubble radius. The critical pressures of spherical and diffusional oscillations are two decisive indexes determining the stability status. Specifically,the stability boundaries and influential factors( including acoustic parameters and gas concentration in liquids) were discussed and analyzed. The results show that the variations of gas concentration and acoustic parameters dramatically changed the stable status of the gas bubbles. The gas bubble maintained stable status when external parameters and gas concentration were set between the two critical values properly. The cases of high-frequency and low-frequency limits were also introduced at the end of the whole paper.
基金National Science Foundation of China(grant numbers 52366009 and 52130607)Doble First-Class Key Programof Gansu Provincial Department of Education(grant number GCJ2022-38)+1 种基金2022 Gansu Provincial University Industry Support Plan Project(grant number 2022CYZC-21)KeyR&DProgramofGansu Province of China(grant number 22YF7GA163).
文摘This study explores the aerodynamic performance and flow field characteristics of supercritical carbon dioxide(sCO_(2))centrifugal compressors under varying operating conditions.In particular,the Sandia main compressor impeller model is used as a reference system.Through three-dimensional numerical simulations,we examine the Mach number distribution,temperature field,blade pressure pulsation spectra,and velocity field evolution,and identify accordingly the operating boundaries ensuring stability and the mechanisms responsible for performance degradation.Findings indicate a stable operating range for mass flow rate between 0.74 and 3.74 kg/s.At the lower limit(0.74 kg/s),the maximum Mach number within the compressor decreases by 28%,while the temperature gradient sharpens,entropy rises notably,and fluid density varies significantly.The maximum pressure near the blades increases by 6%,yet flow velocity near the blades and outlet declines,with a 19%reduction in peak speed.Consequently,isentropic efficiency falls by 13%.Conversely,at 3.74 kg/s,the maximum Mach number increases by 23.7%,with diminished temperature gradients and minor fluid density variations.However,insufficient enthalpy gain and intensified pressure pulsations near the blades result in a 12%pressure drop.Peak velocity within the impeller channel surges by 23%,amplifying velocity gradients,inducing flow separation,and ultimately reducing the pressure ratio from 1.47 to 1.34.
基金supported by the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZC20251944)the National Natural Science Foundation of China(No.52376044)the National Key Research and Development Program of China(2024YFE0100800).
文摘The permeability contrast between the Hot Dry Rock(HDR)reservoir and the surrounding formations is a key factor governing fluid loss in Enhanced Geothermal Systems(EGS).This study thus aims to investigate its impact on system performance under varying operating conditions,and a three-dimensional thermo–hydro–mechanical(THM)coupled EGS model is developed based on the geological parameters of the GR1 well in the Qiabuqia region.The coupled processes of fluid flow,heat transfer,and geomechanics within the reservoir under varying reservoir–surrounding rock permeability contrasts,as well as the flow and heat exchange along the wellbores fromthe reservoir to the surface are simulated.Then,the influence of permeability contrast,production pressure,injection rate,and injection temperature on fluid loss and heat extraction performance over a 35-year operation period is quantitatively assessed.Theresults show that increasing the permeability contrast effectively suppresses fluid loss and enhances early-stage heat production,but also accelerates thermal breakthrough and shortens the stable operation period.When the contrast rises from 1×10^(3) to 1×10^(5),the cumulative fluid loss rate drops from 54.34%to 0.23%,and the total heat production increases by 132%,although the breakthrough occurs 5 years earlier.Meanwhile,higher production pressure delays thermal breakthrough and slows transient temperature decline,but exacerbates fluid loss and reduces heat production power.For instance,raising the pressure from 17 to 21 MPa increases the fluid loss rate from 33.17%to 54.34%and reduces average annual heat production power from 25.43 to 14.59MWth.In addition,increasing the injection rate(46 to 66 kg/s)lowers fluid loss rate but brings forward thermal breakthrough by 9 years and causes a 41 K temperature drop at the end of operation.Notably,under high fluid loss,the dynamic response pattern of heat production power shifts from a temperature-dominated“stable–breakthrough–decline”mode to a novel“rising–breakthrough–decline”mode jointly governed by both production temperature and flow rates.These findings provide theoretical support and engineering guidance for improving EGS performance.
基金the National Natural Science Foundation of China(Grant No.52176068)the National key research and development program Intergovernmental projects(2022YFE0129400).
文摘Deep exploration of user-side flexibility resources is crucial for large-scale renewable energy consumption.This paper proposed a typical integrated energy system(IES)that comprehensively includes wind power,photovoltaic,thermal power,combined heat and power,hybrid energy storage,and flexible load and constructed the system’s unified power flow model based on the heat current method.On this basis,the regulation capabilities of different typical industrial and residential flexible loads were considered the symmetrical source-type load,which can transfer load and align user demand with the peaks and valleys of renewable energy generation,thus achieving power-energy decoupling.This contributes effectively to renewable energy accommodation capacity when the total electrical energy consumption remains constant.In both typical industrial and residential load scenarios,flexible load reduces integrated costs,increases renewable energy consumption,lowers peak thermal power generation,and decreases the requirement for a battery energy storage system(BESS).Besides,on typical industrial and residential load days,smoothing thermal power generation necessitates 12%and 18%flexible load,respectively,while replacing BESS requires 18%and 23%flexible load,respectively.Therefore,we can obtain the feasible operation ranges of symmetrical source-type load and provide suggestions for configuration capacity design of demand response in integrated energy systems.
基金supported by the National Natural Science Foundation of China(U1361108)
文摘Hydrogen is one of the best energy carriers.Fluidized bed reactor provides a promising approach for hydrogen production. To describe the hydrogen generating rate with methanol steam reforming in fluidized bed reactor quantitatively, dual-rate kinetic models of the reactions with exponent form were developed, including that of steam reforming reaction(SR) and decomposition reaction(DE).The reaction rate per unit mass of catalyst was related to partial pressures of components. The exponentials in kinetic equations were obtained by linear least-squares method based on the experimental data. The variance homogeneity test(F test) shows that the dynamic models are feasible with high accuracy, which can be used to predict the generating rate of hydrogen under different reaction temperatures and feed flow rates in fluidized bed reactor. The SR and DE activation energy obtained indicates that ESR\ EDE, which can explain the previous observation that the CO_2 selectivity decreased with the temperature increase.
基金supported by the Major Program of the National Natural Science Foundation of China(Grant No.52090060)。
文摘Multi-energy complementary distributed energy system(MECDES)is an important development direction for the energy system.It has the advantages of energy conservation and environmental protection and has great potential to realize efficient energy cascade utilization through the energy conversion and utilization of cooling,heating,and power in place,achieving a user-oriented energy supply.The present study thoroughly reviews the current research status and puts forward the key scientific issues that urgently need to be resolved by investigating the problems and challenges of the MECDES from the perspectives of the characterization of the energetic mass-energy potential,the synergistic transformation and energy-potential coupling mechanism of multi-energy complementation,energy quality improvement and storage,and proactive regulation of the MECDES.Furthermore,the latest research progress of the MECDES for trickling the key scientific issues is comprehensively presented by proposing the distributed energy system with the complementation of multi-energy sources,developing novel ways of the energy potential coupling and energy cascaded comprehensive utilization of multi-energy complementation,proposing a new theory of multi-energy complementation and energy potential coupling and a new mechanism of source complementation,processing matching and thermodynamic cycle system collaborative conversion of both the fossil energy and renewable energy,and developing a new method of proactive adjust and control for adapting to fluctuating energy input and various energy load demands.Finally,the prospects and recommendations for the future research and development direction of MECDES are provided.
基金supported by the National Natural Science Foundation of China (51406051 and 51522602)the Beijing Municipal Science and Technology Project (Z161100002616039)the Fundamental Research Funds for the Central Universities (2016MS20)
文摘In conventional photovoltaic(PV) systems, a large portion of solar energy is dissipated as waste heat since the generating efficiency is usually less than 30%. As the dissipated heat can be recovered for various applications, the wasted heat recovery concentrator PV/thermal(WHR CPVT) hybrid systems have been developed. They can provide both electricity and usable heat by combining thermal systems with concentrator PV(CPV) module, which dramatically improves the overall conversion efficiency of solar energy.This paper systematically and comprehensively reviews the research and development of WHR CPVT systems. WHR CPVT systems with innovative design configurations, different theoretical evaluation models and experimental test processes for several implementations are presented in an integrated manner. We aim to provide a global point of view on the research trends, market potential, technical obstacles, and the future work which is required in the development of WHR CPVT technology. Possibly, it will offer a generic guide to the investigators who are interested in the study of WHR CPVT systems.
基金This work was supported by the National Key Research and Development Program of China(Grant Nos.2017YFB-1103002 and 2018YFB0604304)Federal Ministry for Economic Affairs and Energy,Germany(No.03ET1093C)+1 种基金Fundamental Research Funds for the Central Universities,China(No.2017MS011)the National Natural Science Foundation of China(Grant No.51821004).
文摘Emulsion is a disperse system with two immiscible liquids,which demonstrates wide applications in diverse industries.Emulsifcation technology has advanced well with the development of microfluidic process.Compared to conventional methods,the micro-fluidics-based process can produce controllable droplet size and distribution.The droplet formation or breakup is the result of combined effects resulting from interfacial tension,viscous,and inertial forces as well as the forces generated due to hydrodynamic pressure and extermal stimuli.In the current study,typical microfluidic systems,including microchannel array,T-shape,flow-focusing,co-flowing,and membrane systems,are reviewed and the corresponding mechanisms,fow regimes,and main parameters are compared and summarized.
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.
基金the National Natural Science Foundation of China(Grant No.52090062,52176068)the Science Fund for Creative Research Groups of the National Natural Science Foundation of China(Grant No.51821004).
文摘Distributed energy system,a decentralized low-carbon energy system arranged at the customer side,is characterized by multi-energy complementarity,multi-energy flow synergy,multi-process coupling,and multi-temporal scales(n-M characteristics).This review provides a systematic and comprehensive summary and presents the current research on distributed energy systems in three dimensions:system planning and evaluation,modeling and optimization,and operation and control.Under the regional environmental,resource,and policy constraints,planning distributed energy systems should fully integrate technical,economic,environmental,and social factors and consider device characteristics,system architecture,and source-load uncertainties.Further,this review presents four modeling perspectives for optimizing and analyzing distributed energy systems,including energy hub,thermodynamics,heat current,and data-driven.The system’s optimal operation and scheduling strategies,disturbance analysis,and related control methods are also discussed from the power system and thermal system,respectively.In all,more research is required for distributed energy systems based on an integrated energy perspective in optimal system structure,hybrid modeling approaches,data-driven system state estimation,cross-system disturbance spread,and multi-subject interaction control.
