The article first collects near infrared spectra and corresponding COD mass concentrations of standard water samples containing Cl, Br, and NO2. Subsequently, the optimal combination of nearinfrared characteristic wavelengths is determined using the interval random frog algorithm, and a COD mass concentration prediction model for highconcentration inorganic anion digestate is established via partial least squares regression. Finally, the model is applied to predict COD mass concentrations in actual biogas slurry. The results show that the determination coefficients (R2) of the COD prediction models for standard water samples with added Cl, Br¯, and NO2 are 0.98, 0.99, and 0.99, respectively, with relative prediction deviations (RPD) of 8.89, 8.95, and 11.75, respectively. For the COD prediction models in biogas slurry, the R² values are 0.77, 0.95, and 0.76, respectively, and the RPD values are 2.23, 5.02, and 2.19, respectively. The model effectively extracts spectral features from nearinfrared data of COD in highconcentration inorganic anion biogas slurry.

In order to achieve good aerodynamic and structural performance of wind turbine airfoils simultaneously, an integrated optimization method for aerodynamic shape and internal topology of airfoils is proposed. The airfoil aerodynamic shape is represented using the Hicks Henne type function, and its aerodynamic performance is calculated by using XFOIL. A finite element model of the airfoil is established by using ANSYS, and the structural topology performance is computed. Based on this, a MATLAB program is developed by using a genetic algorithm with the objectives of maximizing the lifttodrag ratio and minimizing the compliance. Five basic airfoils of a 1.5 MW wind turbine blade are optimized under 3 objective weight factors, and the results showed that compared to the initial airfoils, all optimized airfoils exhibit increase in maximum lifttodrag ratio and decrease in structural compliance. At the same time, basically consistent internal structural conceptual design solutions are obtained with the spar caps on the upper and lower surfaces offset towards the leading and trailing edges, respectively. A comparison is made between the new blade using the optimized airfoils and the original blade, and the results indicate that the application of optimized airfoils combined with minor main spar caps offset, the aerodynamic and structural performance of the blades could be effectively improved.

Because of offshore wind turbine fully coupling calculation software FAST V8 can not simulate pile soil interaction, the updated FAST V8 is introduced by distributed linear spring boundary constraint condition and the coupled motion equation of substructure is derived. A coupled numerical simulation model of rotor nacelle –hub towerpile foundation structure with distributed linear spring boundary condition is established. The dynamic characteristics of the base fixed boundary and distributed linear coupled spring boundary model under the combined action of wind and wave are analyzed. The results show that the time history and frequency domain responses of the tower top displacement and the base bending moment change significantly, especially for the secondorder frequency of the structure. At the same time, it can be observed that the distribution spring boundary constraint condition has a more obvious effect on low wind speeds, while the fixed boundary constraint condition model has a more significant effect on high wind speeds.

In Active Distribution Network (ADN), the penetration rate of Renewable Energy Sources (RES) is continuously increasing, leading to more complex and uncertain operational scenarios. This complexity introduces significant risks in the daily operations of ADN. This study proposes a collaborative configuration of distributed power sources within ADN to enhance the absorption capacity for renewable power. The proposed model thoroughly considers the variability of RES, the characteristics of adjustable demand response resources, the bidirectional flow of ADN, and the constraints of safe operation. To address the contradiction between the effective absorption of renewable energy and the economic operation of ADNs, this paper introduces a multiobjective Bayesian optimization algorithm based on hyperspace indicators (EBO). This method probabilistically models multiple objective functions, effectively balancing the exploration of solution space and the unidirectionality of optimization. Moreover, its computational efficiency surpasses traditional heuristicbased multiobjective planning algorithms.

In view of the declining performance of wind turbines, it is of great significance to construct a set of objective, comprehensive and accurate dynamic modeling methods of wind turbine power generation performance for the identification of equipment operating conditions, operation and maintenance, and assessment of gridconnected performance. This paper establishes a framework for modeling the power generation performance of wind turbines, and establishes a hierarchical "inputoutput" index system for wind turbine power generation performance based on three types of criteria, namely, wind resource characteristics, output characteristics and operation characteristics; and utilizes the fuzzy hierarchical clustering analysis method and fusion data characterization method to construct a subjective and objective combination of multiindicator empowerment scheme, and constructs an absolute performance evaluation model for the power generation performance of the turbine. The absolute performance evaluation model of power generation performance is constructed; the relative power generation performance scale evaluation model of wind turbine is constructed by using the data inclusion analysis method to characterize the operation efficiency of the turbine; the information entropy and temporal degree are introduced to calculate the dynamic timesequence weighting matrix, so as to realize the dynamic evaluation of absolute and relative performance of wind turbine, and to analyze the operation condition and evolution trend; the operation data of wind turbine in a wind farm verify the effectiveness and reasonableness of the proposed system. A case study of wind turbine operation data from a wind farm verifies the effectiveness and rationality of the proposed system.

Ubend Deep Borehole Heat Exchanger (UDBHE) has attracted much attention because it can effectively exploit deep geothermal energy and has high heat transfer performance. The thermophysical properties of mediumdeep ground generally change with depth, but there is a lack of indepth study on the influence of thermophysical properties of stratified ground on the heat transfer performance of Ubend deep borehole heat exchanger. Based on the UDBHE semi analytical heat transfer model established by the authors, the influence of thermophysical properties (thermal conductivity and volumetric heat capacity)of stratified ground on the heat transfer performance of UDBHE is studied. The results show that the thermal conductivity of each layer of ground has a great influence on the heat transfer performance of UDBHE, while the volumetric heat capacity of ground in each layer also has a certain influence, and the influence increases with the increase of ground layer depth. With the increase of time, the influence of ground thermal conductivity on the heat transfer performance of UDBHE gradually increases, while the influence of ground volumetric heat capacity on the heat transfer performance of UDBHE is basically unchanged. By keeping the weighted average values of the thermal conductivities of all ground layers constant, the heterogeneity of ground thermal conductivity has a great influence on the heat transfer performance of UDBHE, and the larger degree of heterogeneity of ground thermal conductivity would promote the heat transfer performance of UDBHE, otherwise it will inhibit the heat transfer performance of UDBHE. Similarly, the heterogeneity of volumetric heat capacity of ground also has a certain influence on the heat transfer performance of UDBHE, but its influence changes slightly with time. The research results provide important reference value for UDBHE performance prediction and optimization.

Based on the porous medium model, a threedimensional double Utube heat exchanger heat transfer model considering groundwater seepage was established, and the effects of seepage velocity and tube flow velocity on the temperature field of the heat exchanger were investigated by numerical simulation method. Moreover, the comparison of heat transfer performance was completed for the round tube (the crosssectional aspect ratio =1) with the flatoval tube ( is 0.54, 0.44, 0.34, respectively). The results show that increasing the seepage velocity and the tube flow velocity can increase the heat transfer capacity of the tube. When decreases, the heat transfer capacity increases more in the inlet tube than the outlet tube, and more in the vertically arranged tube than the horizontally arranged one. Reducing the aspect ratio of the tube crosssection can reduce the thermal resistance of the borehole and improve the heat exchange capacity of the tube, but it will also make the pressure drop of the tube increase, and the thermal shortcircuit loss is increase. When v=1.50×105 m/s, u=1.3 m/s, compared to the round tube, the heat exchange capacity of the flatoval tube with (=0.34 increases by 11.4%, the thermal resistance of the borehole decreases by 20.52%, and the pressure drop increases by 24.32%.

The impacts of multivalent ions and organic substances on the energy generation efficiency of Reverse Electrodialysis (RED) devices were investigated in terms of uphill transport and membrane fouling. The results showed that the maximum power density was obtained when the 0.5 mol/L NaCl solutions was used as the feeding solution of the RED device. However, the power densities decreased by 72.45%, 68.82%, and 72.14%, respectively, as the feeding solutions were switched to 0.5 mol/L multivalent salt (MgCl2, CaCl2 and Na2SO4) solutions. By adding organic foulantssodium alginate (SA) into the multivalent salt solutions, the power density was enhanced with the increase of SA concentrations and reached a maximum level with addition of 30 mg/L SA, and then was gradually decreased when SA concentration was further raised. The NaCl solutions exerted minor influences on the adsorption of SA molecules onto cationexchange membranes. In contrast, the mixture of NaCl and MgCl2 obviously exacerbated the adhesion between SA molecules and cationexchange membranes

Rural lowvoltage distribution networks was simple grid structure and weak communication infrastructure. Largescale integration of distributed photovoltaic power system will lead to voltage violations in the rural lowvoltage distribution networks. To address this issue, this paper proposes a distributedlocal voltage control strategy for rural lowvoltage distribution networks considering complex scenarios. Firstly, considering the economic cost of voltage control for users, a control framework that takes into account the interests and responsibilities of both the grid and users is proposed. Secondly, a distributed insitu collaborative control strategy is proposed, which is suitable for the grid connection of a variety of distributed energy resources, and considers complex communication scenarios, and adapts to rural scenarios with or without communication or unstable communication. Finally, verified by simulation that the proposed control strategy can balance the interests of the grid and users and effectively solve the voltage violations in rural lowvoltage distribution networks.

To achieve efficient advanced nitrogen and phosphorus removal from wastewater while simultaneously recovering energy, denitrifying phosphorus removal and electrogenesis (DPRE) system was constructed to research the influence of mass concentration of organic substance on nitrogen and phosphorus removal and electricitygenerating performance using synthetic domestic wastewater. The results showed that the influent mass concentration of organic substance had a minor effect on COD removal but significantly influenced nitrogen and phosphorus removal and power generation. When the influent COD concentration was 200~300 mg/L, the DPRE system achieved optimal pollutant removal, with the removal rates of COD, NH4+N and PO43P reaching 86.07% ~86.22%, 83.94%~85.10% and 80.29%~83.38%, respectively. When the influent COD concentration was 300~400 mg/L, the system exhibited the best electricitygenerating performance, with an average power density of 36.49~39.47 mW/m². When the influent COD concentration was 300 mg/L, the DPRE system could simultaneously obtain highefficiency removal of nitrogen and phosphorus and electricity generation.