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.

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.

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.

In response to the difficulties faced by the power system in wind power consumption and the shortage of regulation capacity, this article establishes a robust optimization scheduling model for source load distribution that takes into account green certificate carbon trading. Firstly, green certificate trading mechanism and carbon trading mechanism are introduced on the power supply side to enhance the grid connected power of wind power, and high load capacity is introduced on the load side to improve the system regulation capability; Secondly, in order to reduce the impact of uncertain wind power output, a datadriven distributed robust method is adopted to construct a probability distribution uncertainty set based on historical wind power output data, and then optimize the worstcase scenario using column constraint generation algorithm; Finally, based on the IEEE 39 node system, the verification results show that by integrating adjustable resources from both the source and load sides for collaborative optimization, it is possible to promote wind power consumption while ensuring good regulation capability of the power system.

The rapid simulation of wake flow has important scientific significance and engineering application. In this paper, a fast calculation method is constructed based on the equation of vortex, and a plane wake is simulated and investigated based on this method. The reliability of this method is validated through comparison with results from previous studies. It is found that this fast calculation method can accurately simulate the formation and evolution of Karman vortex street in the wake region. Analysis of the wake profiles reveals that the positions at which different turbulence statistics reach a selfsimilar state vary, and a nonequilibrium selfsimilar region is observed upstream of the wake. The results of the present study not only enhance our understanding of turbulent wake characteristics, but also be of significance for engineering applications, such as predicting and controlling wind turbine wakes in wind farms.

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.

Lowcarbon development of the power industry is an important measure for the dualcarbon goal. In order to promote carbon emission reduction and improve the economy, reliability and environmental protection of the multienergy system, an optimization model for the carbon emission reduction of the multienergy system considering the coordination of economy and reliability is proposed in this paper. Firstly, the coordination model of LowCarbon MultiEnergy System (LCMES) is established by analyzing the topology of the LCMES including electricity, gas and heat; Secondly, based on the fault characteristics of the energy conversion and storage equipment in the LCMES, the multistate reliability model of the LCMES is established; Then, under the conditions of operation constraints and reliability constraints, an optimization model of carbon emission reduction of the LCMES considering the coordination of economy and reliability is proposed with the objective of minimizing the operation cost and carbon emissions of multienergy system; Finally, it is verified by simulation numerical example that the multienergy system optimization model proposed in this paper can ensure the improvement of the operation reliability and economy of the multienergy system while achieving the carbon emission reduction.

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.

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.

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.