[Objective]The research was designed to explore the effect of long-term stacking of solid waste produced in the coal-burning process of central heating enterprises on physical and chemical properties of soil.[Method]T...[Objective]The research was designed to explore the effect of long-term stacking of solid waste produced in the coal-burning process of central heating enterprises on physical and chemical properties of soil.[Method]This study took the heating enterprises in Shenyang City as the research object.The morphological structure and element composition of coal cinder were determined by continuously collecting coal and cinder samples in different periods.At the same time,the original soil and cinder soil of the stacking site were collected to determine the changes of soil morphological structure,element composition and physical and chemical properties,so as to provide reference for the resource utilization of local cinder waste and the potential pollution risk of the stacking site.[Result]The contents of C,H,O,N,and S non-metallic elements in coal cinder decreased by 69.5%,71.2%,76.0%,74.5%,and 34.6%,respectively when compared with raw coal;while the content of Si increased significantly by 95.7%.The contents of Al,K,and Fe in cinder decreased by 4.3%,60.2%,and 33.3%,respectively,while the contents of Mg and Na increased by 36.1%and 130.9%,respectively.Compared with the original soil,the contents of C,H,and O in shallow cinder soil and deep cinder soil increased by 126.5%,67.9%,80.93%,and 21.3%,25.0%and 42.3%,respectively.The residual carbon existed in the form of activated carbon.The contents of Mg,Al,K,Na,Ca,and Fe in shallow cinder soil and deep cinder soil increased by 61.6%,5.4%,46.1%,35.8%,32.5%,6.3%and 22.3%,12.3%,12.2%,15.6%,5.8%and 2.8%,respectively compared with the original soil.The content of heavy metal elements in coal cinder did not reach the detection limit.Under the scanning electron microscope,the raw coal is mainly block structure,while the cinder is honeycombed and porous and dust.[Conclusion]Cinder stacking can significantly improve the content of organic matter and available K in shallow cinder soil,and improve the porosity and permeability of soil.In addition,cinder waste has high pH and pore structure,which can be used as acid soil conditioner,seedling flower matrix and compound fertilizer filler to take full advantage of cinder waste,improve soil structure and supply nutrients.展开更多
In the present paper the problem of disturbance rejection of single input-single output neutral time delay systems with multiple measurable disturbances is solved via dynamic controllers. In particular, the general fo...In the present paper the problem of disturbance rejection of single input-single output neutral time delay systems with multiple measurable disturbances is solved via dynamic controllers. In particular, the general form of the controller matrices is presented, while the necessary and sufficient conditions for the controller to be realizable are offered. The proposed technique is applied to a test case neutral time delay central heating system. In particular, the nonlinear model of the plant and its linearized approximation are presented. Based on the linearized model, a two-stage controller is designed in order to regulate the room temperature and the boiler effluent temperature. The performance of the closed loop system is investigated through computational experiments.展开更多
In this study,a system that recovered waste heat from data center’s centralized water-cooling system to preheat centralized heating systems was proposed,and the optimal design parameters were investigated,resolving t...In this study,a system that recovered waste heat from data center’s centralized water-cooling system to preheat centralized heating systems was proposed,and the optimal design parameters were investigated,resolving the mismatch between waste heat and building demand.Firstly,parametric analyses were conducted under the design condition of centralized heating.Effects of mass flow rate and temperature after heat recovery of the data center’s chilled water on performances of the system were investigated.The results showed that,there existed an optimal temperature after heat recovery minimizing primary energy consumption of the system for each mass flow rate,and the values of optimal temperature after heat recovery for different mass flow rate were quite different.Then,the optimal mass flow rate and temperature after heat recovery were determined for different heat capacity ratio between heat supply from data center and heat demand of the centralized heating system.With the data center’s heat density being 500,800,and 1100 W/m2,and the ratio varying from 0.25 to 2,the optimal parameters were summarized.Based on the optimized values,a random forest-based parameter estimation model for machine learning tool was yielded to determine the optimal parameters.Percentage errors of the model were within±15%.With the system being designed following the optimization values,primary energy saving ratio was from 58.7%to 78.2%compared with the traditional ones.This work provides a replicable tool a to assist optimal design and equipment selection of the heat recovery system.展开更多
Large-scale wind power penetration can affect the supply continuity in the power system.This is a matter of high priority to investigate,as more regulating reserves and specified control strategies for generation cont...Large-scale wind power penetration can affect the supply continuity in the power system.This is a matter of high priority to investigate,as more regulating reserves and specified control strategies for generation control are required in the future power system with even more high wind power penetration.This paper evaluates the impact of large-scale wind power integration on future power systems.An active power balance control methodology is used for compensating the power imbalances between the demand and the generation in real time,caused by wind power forecast errors.The methodology for the balance power control of future power systems with large-scale wind power integration is described and exemplified considering the generation and power exchange capacities in2020 for Danish power system.展开更多
基金Supported by Open Fund Project of the Key Laboratory of Waste Fertilizer Utilization of the Ministry of Agriculture and Rural Areas (KLFAW201901)
文摘[Objective]The research was designed to explore the effect of long-term stacking of solid waste produced in the coal-burning process of central heating enterprises on physical and chemical properties of soil.[Method]This study took the heating enterprises in Shenyang City as the research object.The morphological structure and element composition of coal cinder were determined by continuously collecting coal and cinder samples in different periods.At the same time,the original soil and cinder soil of the stacking site were collected to determine the changes of soil morphological structure,element composition and physical and chemical properties,so as to provide reference for the resource utilization of local cinder waste and the potential pollution risk of the stacking site.[Result]The contents of C,H,O,N,and S non-metallic elements in coal cinder decreased by 69.5%,71.2%,76.0%,74.5%,and 34.6%,respectively when compared with raw coal;while the content of Si increased significantly by 95.7%.The contents of Al,K,and Fe in cinder decreased by 4.3%,60.2%,and 33.3%,respectively,while the contents of Mg and Na increased by 36.1%and 130.9%,respectively.Compared with the original soil,the contents of C,H,and O in shallow cinder soil and deep cinder soil increased by 126.5%,67.9%,80.93%,and 21.3%,25.0%and 42.3%,respectively.The residual carbon existed in the form of activated carbon.The contents of Mg,Al,K,Na,Ca,and Fe in shallow cinder soil and deep cinder soil increased by 61.6%,5.4%,46.1%,35.8%,32.5%,6.3%and 22.3%,12.3%,12.2%,15.6%,5.8%and 2.8%,respectively compared with the original soil.The content of heavy metal elements in coal cinder did not reach the detection limit.Under the scanning electron microscope,the raw coal is mainly block structure,while the cinder is honeycombed and porous and dust.[Conclusion]Cinder stacking can significantly improve the content of organic matter and available K in shallow cinder soil,and improve the porosity and permeability of soil.In addition,cinder waste has high pH and pore structure,which can be used as acid soil conditioner,seedling flower matrix and compound fertilizer filler to take full advantage of cinder waste,improve soil structure and supply nutrients.
文摘In the present paper the problem of disturbance rejection of single input-single output neutral time delay systems with multiple measurable disturbances is solved via dynamic controllers. In particular, the general form of the controller matrices is presented, while the necessary and sufficient conditions for the controller to be realizable are offered. The proposed technique is applied to a test case neutral time delay central heating system. In particular, the nonlinear model of the plant and its linearized approximation are presented. Based on the linearized model, a two-stage controller is designed in order to regulate the room temperature and the boiler effluent temperature. The performance of the closed loop system is investigated through computational experiments.
基金The authors appreciate the support of the project from Outstanding Youth Team of USTB(Fundamental Research Funds for the Central Universities)under grant FRFEYIT-23-06.
文摘In this study,a system that recovered waste heat from data center’s centralized water-cooling system to preheat centralized heating systems was proposed,and the optimal design parameters were investigated,resolving the mismatch between waste heat and building demand.Firstly,parametric analyses were conducted under the design condition of centralized heating.Effects of mass flow rate and temperature after heat recovery of the data center’s chilled water on performances of the system were investigated.The results showed that,there existed an optimal temperature after heat recovery minimizing primary energy consumption of the system for each mass flow rate,and the values of optimal temperature after heat recovery for different mass flow rate were quite different.Then,the optimal mass flow rate and temperature after heat recovery were determined for different heat capacity ratio between heat supply from data center and heat demand of the centralized heating system.With the data center’s heat density being 500,800,and 1100 W/m2,and the ratio varying from 0.25 to 2,the optimal parameters were summarized.Based on the optimized values,a random forest-based parameter estimation model for machine learning tool was yielded to determine the optimal parameters.Percentage errors of the model were within±15%.With the system being designed following the optimization values,primary energy saving ratio was from 58.7%to 78.2%compared with the traditional ones.This work provides a replicable tool a to assist optimal design and equipment selection of the heat recovery system.
基金funded by Sino-Danish Centre for Education and Research (SDC)
文摘Large-scale wind power penetration can affect the supply continuity in the power system.This is a matter of high priority to investigate,as more regulating reserves and specified control strategies for generation control are required in the future power system with even more high wind power penetration.This paper evaluates the impact of large-scale wind power integration on future power systems.An active power balance control methodology is used for compensating the power imbalances between the demand and the generation in real time,caused by wind power forecast errors.The methodology for the balance power control of future power systems with large-scale wind power integration is described and exemplified considering the generation and power exchange capacities in2020 for Danish power system.
