Electrical water heaters(EWHs)are important can-didates to provide demand-response services.The traditional optimization method for EWHs focuses on the optimization of the electricity consumption,without considering t...Electrical water heaters(EWHs)are important can-didates to provide demand-response services.The traditional optimization method for EWHs focuses on the optimization of the electricity consumption,without considering the shifting potential of the wateruse activities.This paper proposes an optimization method for EWHs considering the shifting potentials of both the electricity consumption and wateruse activities.Con-sidering that the wateruse activities could be monolithically shifted,the shifting model of the water-use activities was developed.In addition to the thermodynamic model of the EWH,the optimal scheduling model of the EWH was developed and solved using mixed-integer linear programming.Case studies were performed on a single EWH and aggregate EWHs,demon-strating that the proposed method can shift the water-use activities and therefore increase the load-shifting potential of the EWHs.展开更多
Wind power curtailment is of great importance with the increase of large-scale wind power connected to the grid. A new concept of redundant wind power accommodated by dispatching electric water heaters(EWHs) is develo...Wind power curtailment is of great importance with the increase of large-scale wind power connected to the grid. A new concept of redundant wind power accommodated by dispatching electric water heaters(EWHs) is developed in the paper. Precise predictions of wind power and EWHs load power are the basis for this work. A hybrid multi-kernel prediction approach integrating an adaptive fruit fly optimization algorithm(AFOA)and multi-kernel relevance vector machine(MKRVM) is proposed to deal with the sample distribution of multisource heterogeneous features uncovered by an energy entropy method, where AFOA is used to determine the kernel parameters in MKRVM adaptively and avoid the arbitrariness. For the large computation of the prediction approach, parallel computation based on the Hadoop cluster is used to accelerate the calculation. Then, an economic dispatching model for accommodating wind power is built taking into account the penalty of curtailed wind power and the operation cost of EWHs. The proposedscheme is implemented in an intelligent residential district.The results show that the optimization performance of the hybrid prediction approach is superior to those of four usual optimization algorithms in this case. Regular or orderly scheduling of EWHs enables accommodation of superfluous wind power and reduces dispatch cost.展开更多
Under the circumstance that deep mining is increasingly vulnerable to underlying limestone water, accurate detection of floor failure depth ranges at a mining face becomes rather critical to coal mine production in sa...Under the circumstance that deep mining is increasingly vulnerable to underlying limestone water, accurate detection of floor failure depth ranges at a mining face becomes rather critical to coal mine production in safety. Underground borehole fiber optic sensing technology is combined with 2-D parallel electrical surveying to comprehensively monitor and analyze development laws of floor deformation and failure. Moreover, a working face 1022 in a mine of Huaibei Mining Area was taken, for example, introducing the layout of monitoring borehole and installation of relevant sensing units. Based on the stope progress of a working face, data related to strain and geoelectric fields were collected regularly to analyze relationships of field source variation characteristics and strata deformation failures. In this way, the development mechanism of the floor deformation failure can be revealed. As demonstrated by results, the depth failure of the floor at coal seam 10 is calculated to be 15 m, while its disturbance depth turns out to be 22 m. Due to advanced stress, concentrated stope load and post-mining pressure relief, the floor experienced elastic deformation, shear deformation and swelling deformation successively. Without a doubt, testing results obtained have scientific guiding significance for mines with similar geological conditions.展开更多
Due to the capacity of thermal storage,electric water heater(EWH)is one of the best candidates for demand response programs.However,few attentions are given to the modeling and optimization of EWHs with thermostatical...Due to the capacity of thermal storage,electric water heater(EWH)is one of the best candidates for demand response programs.However,few attentions are given to the modeling and optimization of EWHs with thermostatically-controlled automatic water mixer(TCAWM).In this paper,differential thermodynamic model is established for EWHs with TCAWM and a piecewise linear approximation method is performed for the nonlinear thermodynamic model.The multi-objective optimization model is established by introducing an index reflecting the comfort degree of users,so that the optimal energy usage of the EWH can be obtained by mixed integer linear programming.Testing examples verify the effectiveness of the proposed method.展开更多
基金supported in part by the National Natural Science Foundation of China(No.51707099).
文摘Electrical water heaters(EWHs)are important can-didates to provide demand-response services.The traditional optimization method for EWHs focuses on the optimization of the electricity consumption,without considering the shifting potential of the wateruse activities.This paper proposes an optimization method for EWHs considering the shifting potentials of both the electricity consumption and wateruse activities.Con-sidering that the wateruse activities could be monolithically shifted,the shifting model of the water-use activities was developed.In addition to the thermodynamic model of the EWH,the optimal scheduling model of the EWH was developed and solved using mixed-integer linear programming.Case studies were performed on a single EWH and aggregate EWHs,demon-strating that the proposed method can shift the water-use activities and therefore increase the load-shifting potential of the EWHs.
基金supported by National Natural Science Foundation of China (No. 51407077)Fundamental Research Funds for the Central Universities of China (No. 2017MS095)Technology Project of State Grid Corporation of China Headquarter (No. 5204BB16000F)
文摘Wind power curtailment is of great importance with the increase of large-scale wind power connected to the grid. A new concept of redundant wind power accommodated by dispatching electric water heaters(EWHs) is developed in the paper. Precise predictions of wind power and EWHs load power are the basis for this work. A hybrid multi-kernel prediction approach integrating an adaptive fruit fly optimization algorithm(AFOA)and multi-kernel relevance vector machine(MKRVM) is proposed to deal with the sample distribution of multisource heterogeneous features uncovered by an energy entropy method, where AFOA is used to determine the kernel parameters in MKRVM adaptively and avoid the arbitrariness. For the large computation of the prediction approach, parallel computation based on the Hadoop cluster is used to accelerate the calculation. Then, an economic dispatching model for accommodating wind power is built taking into account the penalty of curtailed wind power and the operation cost of EWHs. The proposedscheme is implemented in an intelligent residential district.The results show that the optimization performance of the hybrid prediction approach is superior to those of four usual optimization algorithms in this case. Regular or orderly scheduling of EWHs enables accommodation of superfluous wind power and reduces dispatch cost.
文摘Under the circumstance that deep mining is increasingly vulnerable to underlying limestone water, accurate detection of floor failure depth ranges at a mining face becomes rather critical to coal mine production in safety. Underground borehole fiber optic sensing technology is combined with 2-D parallel electrical surveying to comprehensively monitor and analyze development laws of floor deformation and failure. Moreover, a working face 1022 in a mine of Huaibei Mining Area was taken, for example, introducing the layout of monitoring borehole and installation of relevant sensing units. Based on the stope progress of a working face, data related to strain and geoelectric fields were collected regularly to analyze relationships of field source variation characteristics and strata deformation failures. In this way, the development mechanism of the floor deformation failure can be revealed. As demonstrated by results, the depth failure of the floor at coal seam 10 is calculated to be 15 m, while its disturbance depth turns out to be 22 m. Due to advanced stress, concentrated stope load and post-mining pressure relief, the floor experienced elastic deformation, shear deformation and swelling deformation successively. Without a doubt, testing results obtained have scientific guiding significance for mines with similar geological conditions.
基金supported by National Natural Science Foundation of China(No.51707099)Natural Science Fund for Colleges and Universities of Jiangsu Province(No.16KJB470009)China Postdoctoral Science Foundation(No.2017M611859).
文摘Due to the capacity of thermal storage,electric water heater(EWH)is one of the best candidates for demand response programs.However,few attentions are given to the modeling and optimization of EWHs with thermostatically-controlled automatic water mixer(TCAWM).In this paper,differential thermodynamic model is established for EWHs with TCAWM and a piecewise linear approximation method is performed for the nonlinear thermodynamic model.The multi-objective optimization model is established by introducing an index reflecting the comfort degree of users,so that the optimal energy usage of the EWH can be obtained by mixed integer linear programming.Testing examples verify the effectiveness of the proposed method.
