Home Latest Articles
Latest Articles
  • Fucong Xu, Fei Zhao
    Renewable Energy Resources. 2024, 42(12): 1689-1696.

    To address the issue of optimization in the consumption of renewable energy in a distributed and flexible resource setting, a model based on opportunityconstrained crossregional grid renewable energy integration is proposed. This paper discusses the fundamental architecture of the twostage optimization model and analyzes the solving strategies for each stage. The twostage optimization model is established, comprising an upperlevel optimization model with opportunity constraints and a lowerlevel economic dispatch model. The paper proposes the use of a balancing constraint solving algorithm and strong duality theory to solve the model. Finally, the effectiveness of the proposed model is demonstrated through simulation analysis, and the conclusion discusses the relationship between the proportion of renewable energy consumption and grid output, load levels, and carbon societal costs.

  • Xiaoli Lu, Zirui Liu, Jiangtao Hu, Chenggang Xiao, Kangkang Feng, Wenxing Jin
    Renewable Energy Resources. 2024, 42(12): 1697-1704.

    Aiming at the optimal economic operation of energy management strategy for multi port configuration of AC/DC flexible interconnection system, this article proposes an optimization method for multi port AC/DC flexible joint energy control system based on improved Pelican algorithm, which is based on photovoltaic power generation curve, high fit between peak and valley electricity price ranges, and energy storage control. Construct an optimization model for a multi terminal oral DC flexible joint energy control system, with constraints on DC bus voltage, power control unit capacity, and power balance, to comprehensively consider the minimum network loss, optimal economy, and optimal energy storage charging/discharging state. Based on the Pelican optimization algorithm, the model constructed is solved by introducing random mass disturbance behavior to improve the global search ability of the algorithm and prevent the model from getting stuck in local optima during solution. After simulation verification, the method proposed in the article can achieve optimal scheduling of multi terminal oral DC flexible joint energy control system.

  • Teng Zhou, Yingjin Song, Beibei Yan, Junyu Tao, Lan Mu, Legeng Pei, Yamei Zeng, Guanyi Chen
    Renewable Energy Resources. 2024, 42(11): 1420-1430.

    This article first introduces the composition, properties, hazards and current treatment status of antibiotic mycelial residues, and provides an overview of the definition, principles and control parameters of hydrothermal technology. The harmless treatment effects of hydrothermal technology in removing residual antibiotics, resistance genes and stabilizing heavy metals in antibiotic mycelial residues are then discussed. The article also explores the resource utilization of hydrothermally treated mycelial residues, including their applications as feedstock for anaerobic digestion, fertilizer, solid fuel, biooil and biochar. Finally, suggestions are proposed based on current research gaps and future prospects are outlined to offer insights for the development and broader application of hydrothermal technology in treating antibiotic mycelial residues.

  • Liang Sun, Zhongqing Ma, Zhixiao Zhang, Yanjun Hu, Shurong Wang
    Renewable Energy Resources. 2024, 42(11): 1431-1439.

    In this work, 305 sets of data of hydrochar's basic properties was collected from the references. Then, the singletask and multitask prediction models of hydrochar's basic properties (mass yield, higher heating value, and carbon content) were established based on three types of the machine learning algorithms (the decision tree, the random forest, and the gradient boosting decision tree). Results showed that among the three types of the machine learning algorithms, the gradient boosting decision tree model was the best algorithm, where the average determination coefficient values of the test set were 0.88 and 0.87, and the root mean square error values were 0.34 and 0.37. The SHAP method was used to evaluate the input characteristic parameters during the modeling by using the gradient boosting decision tree. The dominant influence factors for the prediction of the mass yield, higher heating value, and carbon content of the hydrochar were the hydrothermal reaction temperature and the C content in raw biomass. The construction of the prediction model of the hydrochar's basic properties was favorable to reduce the cost for the optimization of the hydrochar production conditions.

  • Yang Sun, Shiyu Zhao, Xiaomei Zhang, Qianqian Yu, Tianhua Yang
    Renewable Energy Resources. 2024, 42(11): 1440-1448.

    Supercapacitors have excellent charging and discharging efficiency and have a broad application prospect in the field of energy storage. The electrode material is the key factor to determine the performance of supercapacitors. Biochar is considered a promising electrode material due to its wide source, high economy, and excellent performance. The article describes the characteristics of biocharbased electrode materials, details the preparation method of biochar with high specific surface area, the optimization and regulation method of biochar pore structure and the surface modification and regulation means of biochar based on defect engineering technology, summarizes the problems faced by highperformance biochar for supercapacitor electrode materials, and outlooks the future research directions of biochar based electrode materials.

  • Tianshi Zheng, Xiaojing Lü, Yiwu Weng, Yi Ma
    Renewable Energy Resources. 2024, 42(11): 1449-1457.

    Design a marine ammonia fuel SOFCGT hybrid power system based on the power requirements of ships, and establish a detailed model of the hybrid power system. Analyze the influence characteristics of ammonia decomposition conversion rate of ammonia decomposer under changes in ammonia flow rate and inlet temperature. Under the limiting conditions of fuel cell temperature gradient, compressor surge safety zone, and turbine inlet temperature, the operational performance of the hybrid power system was analyzed. The effects of ammonia flow rate and ammonia decomposer inlet temperature on the performance of the hybrid power system were studied. The main conclusions are as follows: the output power of the hybrid power system reaches 350.5 kW, and the power generation efficiency reaches 62.40%. When the inlet temperature is above 1 050 K, the conversion rate of ammonia decomposition is close to 100%. The ammonia decomposition conversion rate shows a decreasing trend with the increase of flow rate. When the inlet temperature is high, the influence of flow rate on the decrease of ammonia decomposition conversion rate gradually decreases. When the ammonia flow rate gradually approaches 1.80 mol/s, the performance of fuel cells, gas turbines, and systems gradually increases with the increase of ammonia flow rate. However, the ammonia flow rate in the system should not be too high. When the ammonia flow rate reaches 1.80 mol/s, the turbine inlet temperature has exceeded the safe operating range. When other operating conditions are design conditions, the overall performance of the system improves as the inlet temperature of the ammonia decomposition reactor gradually increases to 1 129 K.

  • Jianhua Wu, Peng Gao, Lan Wen, Wenfeng Sun, Wenke Zhang
    Renewable Energy Resources. 2024, 42(11): 1458-1467.

    As for the buildings that employs ground source heat pump (GSHP) systems for heating and cooling, the heat load is obviously higher than the cooling load, which can cause the temperature of underground medium to decrease gradually and therefore affect the heating performance of the system. This paper proposes a dualsource system in which an air source heat pump (ASHP) and a ground source heat pump (GSHP) jointly bear the heat load in winter, and proposes a novel load ratio control strategy that is better than the existing ones, and the strategy can be employed to overcome the drawbacks of single GSHP system effectively Take an office building as the research object, the TRNSYS simulation platform was used to complete the simulation calculation of building load, the mathematical models of both GSHP and ASHP units were established, and then the system modules of dual source system were established based on the simulation platform.With the objective of slowing down the temperature reduction of the subsurface medium, three strategies were designed around the dualsource system: time control, dry bulb temperature difference control and rated maximum load ratio control, and the parameters were output time by time. A comparative analysis of both a single GSHP system and a composite system showed that the composite system with a rated maximum load ratio of 70% control had the lowest soil temperature fluctuations over 10 years of operation. The research results of this paper can provide theoretical basis and technical guidance for the project of hrbrid GSHP system, and promote the popularization and application of geothermal energy technology.

  • Liyuan Yin, Chaoyue Hu, Qi Tian, Meiping Wang
    Renewable Energy Resources. 2024, 42(11): 1468-1475.

    In order to solve the problem of deterioration of heat transfer performance caused by cold air backflow and the excessive unevenness of the headon wind speed on the outdoor side heat exchanger during the heating operation of common air source heat pumps, a new integrated solar and air energy heat pump for public buildings is proposed by combining solar heat gain in the outdoor side heat exchanger. The mathematical model of the outdoor side heat exchanger was established to study the airflow distribution and heat transfer performance of the common air source heat pump, and the simulation results were verified by experiment to prove the accuracy of the mathematical model; two new outdoor side heat exchanger structures of singleinversion type and doubleinversion type are proposed, and their airflow distribution and heat transfer performance are studied. The results show that both singleinversion and doubleinversion structures can improve the unevenness of the headon wind speed of the heat exchanger, among which the doubleinversion structure has a more obvious improvement effect, with the unevenness of the headon wind speed of the outer and inner heat exchangers reduced by 46% and 83%, respectively, compared with that of the common air source heat pump outdoor side heat exchanger; In the case of the same heat exchanger area, fan type and number, the doubleinversion structure increase the heat exchanger by 5.4% compared with the singleinversion structure.

  • Dongfeng Chang, Sihai Zhao, Guolong Zhang, Yang Zhao, Wei Wang, Ping Ni, Jianyuan Zhang, Bo Wu, Qing Luo, Fei Wang
    Renewable Energy Resources. 2024, 42(11): 1477-1483.

    The hightemperature molten salt electric heater is the core equipment for achieving electric heating conversion in the heat storage system, and mastering the internal temperature distribution characteristics is the key to promoting its structural optimization. A calculation model for traditional molten salt electrical resistance heater was established, and CFD software was used to study the temperature distribution characteristics inside the heater by solving the three – dimensional N−S equation and energy equation. The variation patterns of the temperature distribution inside the electric heater under different working conditions were obtained. The results show that the temperature difference between the molten salt and the tube wall gradually increases along the flow direction, while multiple series arrangements can effectively reduce the heat transfer temperature difference. The temperature difference between the two at the heater connection can be reduced from 27 °C to 2°C; At the same time, due to the inconsistent density of the internal heating tubes, the temperature of the molten salt, resistance wire, and filling material in the center of the crosssection is significantly higher than that at the edge, and with the increase of load, the temperature gradient gradually increases. When the average heat flux density increases from 5.71 W/cm² to 28.57 W/cm², the temperature difference of the molten salt in the crosssection increases from 49 °C to 68 °C. It can be seen that reasonable distribution of the electric heating tube layout is the key to reducing the temperature difference in the crosssection and reducing thermal stress.

  • Puyang Zhang, Yibo Zhang, Jiandong Xiao, Conghuan Le, Hongyan Ding
    Renewable Energy Resources. 2024, 42(11): 1484-1490.

    A smallscale physical model test was conducted in sandy soil to investigate the bearing characteristics of a monocolumn composite bucket as a new type of offshore wind turbine foundation. In the experiment, a displacement controlled horizontal monotonic loading method was used, and the loading speed and pressure were selected as variables to obtain the horizontal bearing capacity load displacement curve. The experimental results show that the ultimate bearing capacity of the foundation is positively correlated with the loading speed and ballast mass; Summarized the variation law of pore water pressure in different compartments of the foundation during the loading process.