In order to use micro ultrasonic bonding technique to package polymer microfluidic chips,an auxiliary microstructure named micro energy director is designed and fabricated.The hot embossing process for PMMA (polymethy...In order to use micro ultrasonic bonding technique to package polymer microfluidic chips,an auxiliary microstructure named micro energy director is designed and fabricated.The hot embossing process for PMMA (polymethyl methacrylate) substrates with both concave micro channel and convex micro energy director for ultrasonic bonding is studied.The embossing processes with different embossing temperatures are simulated using Finite Element Method (FEM).The optimized parameters are:the embossing temperature of 135 ℃,holding time of 200 s,and the embossing pressure of 1.65 MPa.The experimental results show that the replication error between experiments and simulations is less than 2% and the replication accuracy of the microstructure is more than 96%.The study offers a method for quick optimizing parameters for hot embossing both concave and convex microstructures.展开更多
To utilize heat and electricity in a clean and integrated manner,a zero-carbon-emission micro Energy Internet(ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage(NS...To utilize heat and electricity in a clean and integrated manner,a zero-carbon-emission micro Energy Internet(ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage(NSF-CAES) hub.A typical ZCE-MEI combining power distribution network(PDN) and district heating network(DHN) with NSF-CAES is considered in this paper.NSF-CAES hub is formulated to take the thermal dynamic and pressure behavior into account to enhance dispatch flexibility.A modified Dist Flow model is utilized to allow several discrete and continuous reactive power compensators to maintain voltage quality of PDN.Optimal operation of the ZCE-MEI is firstly modeled as a mixed integer nonlinear programming(MINLP).Several transformations and simplifications are taken to convert the problem as a mixed integer linear programming(MILP)which can be effectively solved by CPLEX.A typical test system composed of a NSF-CAES hub,a 33-bus PDN,and an 8-node DHN is adopted to verify the effectiveness of the proposed ZCE-MEI in terms of reducing operation cost and wind curtailment.展开更多
The interconnection between initially independent energy infrastructures offers additional system flexibility and efficiency.The integration at distribution level simplifies the implementation of the integrated energy...The interconnection between initially independent energy infrastructures offers additional system flexibility and efficiency.The integration at distribution level simplifies the implementation of the integrated energy system functionalities.This paper proposes concepts and design principles of a smart micro energy grid(MEG)for accommodating micro-grids,distributed poly-generation systems,energy storage facilities,and associated energy distribution infrastructures.The energy management system is responsible for the smart operation of the MEG while supporting multiple criteria,such as safety,economy,and environmental protection.To realize the vision of the smart MEG,an engineering game theory based energy management system with self-approaching-optimum capability is investigated.Based on the proposed concepts,design principles,and energy management system,this paper presents a prototype of China’s first conceptual solar-based smart MEG,established in Qinghai University.展开更多
Liquid air energy storage(LAES)has been regarded as a large-scale electrical storage technology.In this paper,we first investigate the performance of the current LAES(termed as a baseline LAES)over a far wider range o...Liquid air energy storage(LAES)has been regarded as a large-scale electrical storage technology.In this paper,we first investigate the performance of the current LAES(termed as a baseline LAES)over a far wider range of charging pressure(1 to 21 MPa).Our analyses show that the baseline LAES could achieve an electrical round trip efficiency(e RTE)above 60%at a high charging pressure of 19 MPa.The baseline LAES,however,produces a large amount of excess heat particularly at low charging pressures with the maximum occurred at~1 MPa.Hence,the performance of the baseline LAES,especially at low charging pressures,is underestimated by only considering electrical energy in all the previous research.The performance of the baseline LAES with excess heat is then evaluated which gives a high e RTE even at lower charging pressures;the local maximum of 62%is achieved at~4 MPa.As a result of the above,a hybrid LAES system is proposed to provide cooling,heating,hot water and power.To evaluate the performance of the hybrid LAES system,three performance indicators are considered:nominal-electrical round trip efficiency(ne RTE),primary energy savings and avoided carbon dioxide emissions.Our results show that the hybrid LAES can achieve a high ne RTE between 52%and 76%,with the maximum at~5 MPa.For a given size of hybrid LAES(1 MW×8 h),the primary energy savings and avoided carbon dioxide emissions are up to 12.1 MWh and 2.3 ton,respectively.These new findings suggest,for the first time,that small-scale LAES systems could be best operated at lower charging pressures and the technologies have a great potential for applications in local decentralized micro energy networks.展开更多
As renewable energy source(RES)tend to be integrated more and more at home and electric vehicles(EVs)take a greater share in the personal automobile market,users see a chance to charge their EVs by microRES.In this co...As renewable energy source(RES)tend to be integrated more and more at home and electric vehicles(EVs)take a greater share in the personal automobile market,users see a chance to charge their EVs by microRES.In this context,this paper presents a review about opportunities and challenges needed to be overcome by the EV users to implement a vehicle to home system in their homes,as well as the integration of micro-RES.Several practical scenarios are presented,with different demand profiles,by integrating renewable energy that could be used to charge the EV.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.50975037)the State Key Development Program for Basic Research of China(Grant No.2011CB013105).
文摘In order to use micro ultrasonic bonding technique to package polymer microfluidic chips,an auxiliary microstructure named micro energy director is designed and fabricated.The hot embossing process for PMMA (polymethyl methacrylate) substrates with both concave micro channel and convex micro energy director for ultrasonic bonding is studied.The embossing processes with different embossing temperatures are simulated using Finite Element Method (FEM).The optimized parameters are:the embossing temperature of 135 ℃,holding time of 200 s,and the embossing pressure of 1.65 MPa.The experimental results show that the replication error between experiments and simulations is less than 2% and the replication accuracy of the microstructure is more than 96%.The study offers a method for quick optimizing parameters for hot embossing both concave and convex microstructures.
基金supported in part by the National Natural Science Foundation of China(No.51321005,No.51377092,No.51577163)Opening Foundation of the Qinghai Province Key Laboratory of Photovoltaic Power Generation and Grid-connected Technology
文摘To utilize heat and electricity in a clean and integrated manner,a zero-carbon-emission micro Energy Internet(ZCE-MEI) architecture is proposed by incorporating non-supplementary fired compressed air energy storage(NSF-CAES) hub.A typical ZCE-MEI combining power distribution network(PDN) and district heating network(DHN) with NSF-CAES is considered in this paper.NSF-CAES hub is formulated to take the thermal dynamic and pressure behavior into account to enhance dispatch flexibility.A modified Dist Flow model is utilized to allow several discrete and continuous reactive power compensators to maintain voltage quality of PDN.Optimal operation of the ZCE-MEI is firstly modeled as a mixed integer nonlinear programming(MINLP).Several transformations and simplifications are taken to convert the problem as a mixed integer linear programming(MILP)which can be effectively solved by CPLEX.A typical test system composed of a NSF-CAES hub,a 33-bus PDN,and an 8-node DHN is adopted to verify the effectiveness of the proposed ZCE-MEI in terms of reducing operation cost and wind curtailment.
基金supported in part by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(51621065)in part by Key Lab Program of Science and Technology Office of Qinghai Province(2017-ZJ-Y27)in part by the National Natural Science Foundation of China(51577163).
文摘The interconnection between initially independent energy infrastructures offers additional system flexibility and efficiency.The integration at distribution level simplifies the implementation of the integrated energy system functionalities.This paper proposes concepts and design principles of a smart micro energy grid(MEG)for accommodating micro-grids,distributed poly-generation systems,energy storage facilities,and associated energy distribution infrastructures.The energy management system is responsible for the smart operation of the MEG while supporting multiple criteria,such as safety,economy,and environmental protection.To realize the vision of the smart MEG,an engineering game theory based energy management system with self-approaching-optimum capability is investigated.Based on the proposed concepts,design principles,and energy management system,this paper presents a prototype of China’s first conceptual solar-based smart MEG,established in Qinghai University.
基金the partial support from UK EPSRC Manifest Project under EP/N032888/1,EP/P003605/1a UK FCO Science&Innovation Network grant(Global Partnerships Fund)an IGI/IAS Global Challenges Funding(IGI/IAS ID 3041)。
文摘Liquid air energy storage(LAES)has been regarded as a large-scale electrical storage technology.In this paper,we first investigate the performance of the current LAES(termed as a baseline LAES)over a far wider range of charging pressure(1 to 21 MPa).Our analyses show that the baseline LAES could achieve an electrical round trip efficiency(e RTE)above 60%at a high charging pressure of 19 MPa.The baseline LAES,however,produces a large amount of excess heat particularly at low charging pressures with the maximum occurred at~1 MPa.Hence,the performance of the baseline LAES,especially at low charging pressures,is underestimated by only considering electrical energy in all the previous research.The performance of the baseline LAES with excess heat is then evaluated which gives a high e RTE even at lower charging pressures;the local maximum of 62%is achieved at~4 MPa.As a result of the above,a hybrid LAES system is proposed to provide cooling,heating,hot water and power.To evaluate the performance of the hybrid LAES system,three performance indicators are considered:nominal-electrical round trip efficiency(ne RTE),primary energy savings and avoided carbon dioxide emissions.Our results show that the hybrid LAES can achieve a high ne RTE between 52%and 76%,with the maximum at~5 MPa.For a given size of hybrid LAES(1 MW×8 h),the primary energy savings and avoided carbon dioxide emissions are up to 12.1 MWh and 2.3 ton,respectively.These new findings suggest,for the first time,that small-scale LAES systems could be best operated at lower charging pressures and the technologies have a great potential for applications in local decentralized micro energy networks.
基金supported by a grant of the Basque Government(No.PRE-2013-2-392)the University of the Basque Country-UPV/EHU(No.PES-15)
文摘As renewable energy source(RES)tend to be integrated more and more at home and electric vehicles(EVs)take a greater share in the personal automobile market,users see a chance to charge their EVs by microRES.In this context,this paper presents a review about opportunities and challenges needed to be overcome by the EV users to implement a vehicle to home system in their homes,as well as the integration of micro-RES.Several practical scenarios are presented,with different demand profiles,by integrating renewable energy that could be used to charge the EV.