An overview of current thermal challenges in transport electrification is introduced in order to underpin the research developments and trends of recent thermal management techniques.Currently,explorations of intellig...An overview of current thermal challenges in transport electrification is introduced in order to underpin the research developments and trends of recent thermal management techniques.Currently,explorations of intelligent thermal management and control strategies prevail among car manufacturers in the context of climate change and global warming impacts.Therefore,major cutting-edge systematic approaches in electrified powertrain are summarized in the first place.In particular,the important role of heating,ventilation and air-condition system(HVAC)is emphasised.The trends in developing efficient HVAC system for future electrified powertrain are analysed.Then electric machine efficiency is under spotlight which could be improved by introducing new thermal management techniques and strengthening the efforts of driveline integrations.The demanded integration efforts are expected to provide better value per volume,or more power output/torque per unit with smaller form factor.Driven by demands,major thermal issues of high-power density machines are raised including the comprehensive understanding of thermal path,and multiphysics challenges are addressed whilst embedding power electronic semiconductors,non-isotropic electromagnetic materials and thermal insulation materials.Last but not least,the present review has listed several typical cooling techniques such as liquid cooling jacket,impingement/spray cooling and immersion cooling that could be applied to facilitate the development of integrated electric machine,and a mechanic-electric-thermal holistic approach is suggested at early design phase.Conclusively,a brief summary of the emerging new cooling techniques is presented and the keys to a successful integration are concluded.展开更多
Over 25 percent of the world’s population lives without access to electricity from a utility-supplied grid[1].In underdeveloped and developing countries,the reason is primarily a lack of government-sponsored utility ...Over 25 percent of the world’s population lives without access to electricity from a utility-supplied grid[1].In underdeveloped and developing countries,the reason is primarily a lack of government-sponsored utility infrastructure due to the high cost of power line extension.In developed countries,power line extension costs are again the primary factor in lack of a grid connection,as in most cases the end user must foot the bill for such improvements.In the United States,power line extension can cost over$50,000 per kilometer[2],so the cost of an off-grid electrical system that uses renewable sources to charge a large battery bank for energy storage can compare favorably to that of grid extension-but not always.However,both the design and implementation of such off-grid renewable energy systems differ greatly from more common grid-tied applications,where the utility grid is used as“battery”with which the system can buy and sell electrical energy from and to the utility as needed.Energy efficiency and conservation are paramount in all off-grid renewable energy system designs,as these measures extend at low cost the hours or days of autonomous operation time before a backup power source(usually an internal-combustion generator)must be used for battery charging during periods of no input from renewable solar,wind,or hydroelectric sources.The techniques used in designing and operating an off-grid building can seem extreme compared to the norm,and provide a whole set of new challenges if the retrofitting of an existing structure is required.But the lessons learned from these experiences are quite relevant to modern buildings in urban and suburban areas,as the goal is the same-first reduce energy consumption through efficiency and conservation,rather than simply increasing energy production.With off-grid systems,the payback from these measures simply has a more immediate effect.And at the end of the day,non-electrical energy efficiency measures prove to be at least as effective as electrical ones.展开更多
End-use electrical loads in residential and commercial buildings are evolving into flexible and cost-effective resources to improve electric grid reliability,reduce costs,and support increased hosting of distributed r...End-use electrical loads in residential and commercial buildings are evolving into flexible and cost-effective resources to improve electric grid reliability,reduce costs,and support increased hosting of distributed renewable generation.This article reviews the simulation of utility services delivered by buildings for the purpose of electric grid operational modeling.We consider services delivered to(1)the high-voitage bulk power system through the coordinated action of many,distributed building loads working together,and(2)targeted support provided to the operation of low-voltage electric distribution grids.Although an exhaustive exploration is not possible,we emphasize the ancillary services and voltage management buildings can provide and summarize the gaps in our ability to simulate them with traditional building energy modeling(BEM)tools,suggesting pathways for future research and development.展开更多
基金This project has been supported in the frame of the BIS-Funded Programme 113167the Royal Society project 1130182 and European Union project H2020-MSCA-RISE 778104.
文摘An overview of current thermal challenges in transport electrification is introduced in order to underpin the research developments and trends of recent thermal management techniques.Currently,explorations of intelligent thermal management and control strategies prevail among car manufacturers in the context of climate change and global warming impacts.Therefore,major cutting-edge systematic approaches in electrified powertrain are summarized in the first place.In particular,the important role of heating,ventilation and air-condition system(HVAC)is emphasised.The trends in developing efficient HVAC system for future electrified powertrain are analysed.Then electric machine efficiency is under spotlight which could be improved by introducing new thermal management techniques and strengthening the efforts of driveline integrations.The demanded integration efforts are expected to provide better value per volume,or more power output/torque per unit with smaller form factor.Driven by demands,major thermal issues of high-power density machines are raised including the comprehensive understanding of thermal path,and multiphysics challenges are addressed whilst embedding power electronic semiconductors,non-isotropic electromagnetic materials and thermal insulation materials.Last but not least,the present review has listed several typical cooling techniques such as liquid cooling jacket,impingement/spray cooling and immersion cooling that could be applied to facilitate the development of integrated electric machine,and a mechanic-electric-thermal holistic approach is suggested at early design phase.Conclusively,a brief summary of the emerging new cooling techniques is presented and the keys to a successful integration are concluded.
文摘Over 25 percent of the world’s population lives without access to electricity from a utility-supplied grid[1].In underdeveloped and developing countries,the reason is primarily a lack of government-sponsored utility infrastructure due to the high cost of power line extension.In developed countries,power line extension costs are again the primary factor in lack of a grid connection,as in most cases the end user must foot the bill for such improvements.In the United States,power line extension can cost over$50,000 per kilometer[2],so the cost of an off-grid electrical system that uses renewable sources to charge a large battery bank for energy storage can compare favorably to that of grid extension-but not always.However,both the design and implementation of such off-grid renewable energy systems differ greatly from more common grid-tied applications,where the utility grid is used as“battery”with which the system can buy and sell electrical energy from and to the utility as needed.Energy efficiency and conservation are paramount in all off-grid renewable energy system designs,as these measures extend at low cost the hours or days of autonomous operation time before a backup power source(usually an internal-combustion generator)must be used for battery charging during periods of no input from renewable solar,wind,or hydroelectric sources.The techniques used in designing and operating an off-grid building can seem extreme compared to the norm,and provide a whole set of new challenges if the retrofitting of an existing structure is required.But the lessons learned from these experiences are quite relevant to modern buildings in urban and suburban areas,as the goal is the same-first reduce energy consumption through efficiency and conservation,rather than simply increasing energy production.With off-grid systems,the payback from these measures simply has a more immediate effect.And at the end of the day,non-electrical energy efficiency measures prove to be at least as effective as electrical ones.
基金This work was authored in part by the National Renewable Energy Laboratory,operated by Alliance for Sustainable Energy,LLC,for the U.S.Department of Energy(DOE)under Contract No.DE-AC36-08GO28308Funding provided by the National Renewable Energy Laboratory(NREL)Laboratory Directed Research and Development(LDRD)program.
文摘End-use electrical loads in residential and commercial buildings are evolving into flexible and cost-effective resources to improve electric grid reliability,reduce costs,and support increased hosting of distributed renewable generation.This article reviews the simulation of utility services delivered by buildings for the purpose of electric grid operational modeling.We consider services delivered to(1)the high-voitage bulk power system through the coordinated action of many,distributed building loads working together,and(2)targeted support provided to the operation of low-voltage electric distribution grids.Although an exhaustive exploration is not possible,we emphasize the ancillary services and voltage management buildings can provide and summarize the gaps in our ability to simulate them with traditional building energy modeling(BEM)tools,suggesting pathways for future research and development.
