为进一步深化民航碳排放核算与分析,采用ICAO标准排放计算模型,对江苏省九个民航机场2007—2016年起飞着陆(landing and takeoff,LTO)循环的碳排放量进行核算,并从碳排放的总量、垄断性、区域差异及排放强度的视角对机场碳排放的时间演...为进一步深化民航碳排放核算与分析,采用ICAO标准排放计算模型,对江苏省九个民航机场2007—2016年起飞着陆(landing and takeoff,LTO)循环的碳排放量进行核算,并从碳排放的总量、垄断性、区域差异及排放强度的视角对机场碳排放的时间演化特征进行分析.研究结果表明,江苏省机场碳排放赫希曼指数呈下降趋势,但排放垄断特征依旧明显;全省机场碳排放区域差异总体呈缓慢缩小趋势,其中苏南、苏中、苏北地区间的排放差异有所缩小,但各地区内的排放差异呈增大趋势;省内机场多数为"低排放-高强度"型,"低强度"型较少;全省机场环境库茨涅兹曲线未呈典型倒U形,以倒N形居多.展开更多
The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization meth...The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization method.In this paper,a short-cut optimization method with high efficiency and effectiveness is introduced for both conventional and electric air-cycle refrigeration systems.Based on the system characteristics,a four-layer parameter matching algorithm is designed which avoids computational difficulty caused by simultaneous equations.Fuel penalty is chosen as the objective function of optimization;design variables are reduced based on sensitivity analysis to improve optimization efficiency.The results show that the 3-variable optimization of the conventional air-cycle refrigeration system can obtain almost the same results as the traditional 6-variable optimization in that these two optimizations can both significantly reduce the fuel penalty.However,the computer running time of the 3-variable optimization is much shorter than that of the 6-variable optimization.The optimal fuel penalty of the electric air-cycle refrigeration system is lower than that of the conventional one.This study can provide reference for optimizing the aircycle refrigeration system of aircraft.展开更多
To solve the fundamental problem of insufficient heat available during defrosting while ensuring the efficient and safe system operation for air-source heat pumps (ASHPs). A novel reverse-cycle defrosting (NRCD) metho...To solve the fundamental problem of insufficient heat available during defrosting while ensuring the efficient and safe system operation for air-source heat pumps (ASHPs). A novel reverse-cycle defrosting (NRCD) method based on thermal energy storage to eliminate frost off the outdoor coil surface was developed. Comparative experiments using both the stand reverse cycle defrosting (SRCD) method and the NRCD method were carried out on an experimental ASHP unit with a nominal 2.5 kW heating capacity. The results indicate that during defrosting operation, using the NRCD method improves discharge and suction pressures by 0.24 MPa and 0.19 MPa, respectively, shortens defrosting duration by 60%, and reduces the defrosting energy consumption by 48.1% in the experimental environment, compared with those by the use of SRCD method. Therefore, using the NRCD method can shorten the defrosting duration, improve the indoor thermal comfort, and reduce the defrosting energy consumption in defrosting.展开更多
To meet the goal of worldwide decarbonization,the transformation process toward clean and green energy structures has accelerated.In this context,coal-fired power plant(CFPP)and large-scale energy storage represented ...To meet the goal of worldwide decarbonization,the transformation process toward clean and green energy structures has accelerated.In this context,coal-fired power plant(CFPP)and large-scale energy storage represented by compressed air energy storage(CAES)technology,are tasked with increasing renewable resource accommodation and maintaining the power system security.To achieve this,this paper proposes the concept of a CFPP-CAES combined cycle and a trigenerative system based on that.Considering the working conditions of the CFPP,thermal characteristics of three typical operation modes were studied and some general regularities were identified.The results of various potential integration schemes discussion indicated that extracting water from low-temperature points in the feedwater system to cool pressurized air and simultaneously increase the backwater temperature is beneficial for improving performance.In addition,preheating the pressurized air before the air expanders via lowgrade water in the feedwater system as much as possible and reducing extracted steam contribute to increasing the efficiency.With the optimal integration scheme,2.85 tonnes of coal can be saved per cycle and the round-trip efficiency can be increased by 2.24%.Through the cogeneration of heat and power,the system efficiency can reach 77.5%.In addition,the contribution degree of the three compression heat utilization methods to the performance improvement ranked from high to low,is preheating the feedwater before the boiler,supplying heat,and flowing into the CFPP feedwater system.In the cooling energy generation mode,the system efficiency can be increased to over 69%.Regardless of the operation mode,the benefit produced by integration is further enhanced when the CFPP operates at higher operating conditions because the coupling points parameters are changed.In addition,the dynamic payback period can be shortened by 11.33 years and the internal rate of return increases by 5.20%under a typical application scenario.Regarding the effect of differ展开更多
文摘为进一步深化民航碳排放核算与分析,采用ICAO标准排放计算模型,对江苏省九个民航机场2007—2016年起飞着陆(landing and takeoff,LTO)循环的碳排放量进行核算,并从碳排放的总量、垄断性、区域差异及排放强度的视角对机场碳排放的时间演化特征进行分析.研究结果表明,江苏省机场碳排放赫希曼指数呈下降趋势,但排放垄断特征依旧明显;全省机场碳排放区域差异总体呈缓慢缩小趋势,其中苏南、苏中、苏北地区间的排放差异有所缩小,但各地区内的排放差异呈增大趋势;省内机场多数为"低排放-高强度"型,"低强度"型较少;全省机场环境库茨涅兹曲线未呈典型倒U形,以倒N形居多.
基金the financial supports from Pre-research Project of National Defense FoundationNational Natural Science Foundation of China(No.51706232)。
文摘The air-cycle refrigeration system is widely used in commercial and military aircraft,and its efficiency greatly affects aircraft performance.Nowadays,this system requires a more efficient design and optimization method.In this paper,a short-cut optimization method with high efficiency and effectiveness is introduced for both conventional and electric air-cycle refrigeration systems.Based on the system characteristics,a four-layer parameter matching algorithm is designed which avoids computational difficulty caused by simultaneous equations.Fuel penalty is chosen as the objective function of optimization;design variables are reduced based on sensitivity analysis to improve optimization efficiency.The results show that the 3-variable optimization of the conventional air-cycle refrigeration system can obtain almost the same results as the traditional 6-variable optimization in that these two optimizations can both significantly reduce the fuel penalty.However,the computer running time of the 3-variable optimization is much shorter than that of the 6-variable optimization.The optimal fuel penalty of the electric air-cycle refrigeration system is lower than that of the conventional one.This study can provide reference for optimizing the aircycle refrigeration system of aircraft.
基金Project(50606007) supported by the National Natural Science Foundation of China
文摘To solve the fundamental problem of insufficient heat available during defrosting while ensuring the efficient and safe system operation for air-source heat pumps (ASHPs). A novel reverse-cycle defrosting (NRCD) method based on thermal energy storage to eliminate frost off the outdoor coil surface was developed. Comparative experiments using both the stand reverse cycle defrosting (SRCD) method and the NRCD method were carried out on an experimental ASHP unit with a nominal 2.5 kW heating capacity. The results indicate that during defrosting operation, using the NRCD method improves discharge and suction pressures by 0.24 MPa and 0.19 MPa, respectively, shortens defrosting duration by 60%, and reduces the defrosting energy consumption by 48.1% in the experimental environment, compared with those by the use of SRCD method. Therefore, using the NRCD method can shorten the defrosting duration, improve the indoor thermal comfort, and reduce the defrosting energy consumption in defrosting.
文摘To meet the goal of worldwide decarbonization,the transformation process toward clean and green energy structures has accelerated.In this context,coal-fired power plant(CFPP)and large-scale energy storage represented by compressed air energy storage(CAES)technology,are tasked with increasing renewable resource accommodation and maintaining the power system security.To achieve this,this paper proposes the concept of a CFPP-CAES combined cycle and a trigenerative system based on that.Considering the working conditions of the CFPP,thermal characteristics of three typical operation modes were studied and some general regularities were identified.The results of various potential integration schemes discussion indicated that extracting water from low-temperature points in the feedwater system to cool pressurized air and simultaneously increase the backwater temperature is beneficial for improving performance.In addition,preheating the pressurized air before the air expanders via lowgrade water in the feedwater system as much as possible and reducing extracted steam contribute to increasing the efficiency.With the optimal integration scheme,2.85 tonnes of coal can be saved per cycle and the round-trip efficiency can be increased by 2.24%.Through the cogeneration of heat and power,the system efficiency can reach 77.5%.In addition,the contribution degree of the three compression heat utilization methods to the performance improvement ranked from high to low,is preheating the feedwater before the boiler,supplying heat,and flowing into the CFPP feedwater system.In the cooling energy generation mode,the system efficiency can be increased to over 69%.Regardless of the operation mode,the benefit produced by integration is further enhanced when the CFPP operates at higher operating conditions because the coupling points parameters are changed.In addition,the dynamic payback period can be shortened by 11.33 years and the internal rate of return increases by 5.20%under a typical application scenario.Regarding the effect of differ
