In this paper, Aspen Plus process simulation software was used to compare the effects of adding CO2 adsorbent on hydrogen production by steam reforming of biomass under different conditions [gasification temperature, mass ratio of water to carbon in biomass (S/C), reaction pressure]. Based on the energy consumption and material consumption required for producing hydrogen per unit volume, the matrix analysis method was used to optimize, and the best conditions of adsorption enhanced biomass steam reforming gasification were obtained: When the gasification temperature is 500 °C, S/C=2 and the gasification pressure is 0.1 MPa, under this condition, the hydrogen production is 1.56 m³/kg, the hydrogen concentration is 98.3%, and the energy consumption and material consumption required for producing the unit volume of hydrogen are 4.16 MJ/m³ and 0.64 kg/m³, respectively.

In this paper, biochar composite carrier was constructed by using biochar loaded with different concentrations of sodium bicarbonate, humic acid, Tween 20 and other catalytic regulators, and each composite carrier was added to the rice stubpig manure mixed anaerobic fermentation system for anaerobic fermentation. By measuring the gas production, methane production and the degradation rate of straw lignocellulose of each treatment, the role of biochar composite carrier on methane production in mixed anaerobic fermentation and straw degradation was revealed. The results show that the biochar composite carrier can increase the peak value of methane production and shorten the time of peak value of methane production. Biochar composite carriers can significantly increase the cumulative gas production and the cumulative methane production of anaerobic fermentation systems, with the best effect of biocharloaded Tween 20, followed by biocharloaded humic acid and biocharloaded sodium bicarbonate. Compared with the control group, the gas production and the methane production of biochar loaded Tween 20 treatment increased by 23.18% and 62.20%, respectively. In each treatment, the degradation degree of straw was the highest in biochar loaded Tween 20 treatment, followed by biocharloaded humic acid, biochar loaded sodium bicarbonate and control group. The optimal loading concentrations of Tween 20, humic acid and sodium bicarbonate were 2.25, 0.75, 2.10 g/L, respectively.

Based on a highpressure common rail diesel engine, a methanol injection system is installed at the intake manifold. A twostage direct injection (preinjection + main injection) of coaltoFischerTropsch (FT) diesel is installed in the cylinder. A twostage injection FT diesel/methanol (F/M) dualfuel engine test stand is built to explore the effect of different methanol substitution rates on engine emission performance at 2 000 r/min and loads of 25%, 50%, 75% and 100%. Simultaneously, the theoretical basis for realizing the FT diesel/methanol reactivity controlled compression ignition (RCCI) mode is explored. The results indicates that the fuel economy of the F/M dualfuel engine is better at medium and high loads. The emissions of HC, CO, Soot, methanol and formaldehyde increase in the F/M dualfuel combustion mode compared with the singlefuel compressionignition mode. These emissions increase with the augmentationmethanol substitution rate and decrease with an increase in load. In contrast, the emissions of CO2, NOx and NO decrease with an increase in methanol substitution rate but increase with an increase in load. The emissions of NO2 increase with both the rise in methanol substitution rate and load. The test results show that simply adding a methanol injection system to the intake manifold cannot achieve an efficient and lowemission RCCI combustion mode, and its fuel injection strategy needs to be calibrated.

This paper investigates the effect of surface temperature on the efficiency of photovoltaic cells under high concentrating power, and investigates the coupled fin heat pipe heat sink in concentrating photovoltaic cell systems. Study the effect of the number of fins, distribution and fluid flow on the cell efficiency and surface uniformity of the heat pipe radiator under water cooling and air cooling, and compare it with ordinary radiators. The results show that the minimum temperature of the battery surface with the heat pipe radiator occupies less area, the uniformity is significantly improved, and the battery efficiency is improved; under the working condition of 0.64 m/s flow rate, the fin spacing is 1.5 mm, and the fin thickness is 0.4 mm, the overall performance of the battery is the best, the surface temperature is 314 K, the temperature difference is less than 1 K, the uniformity is best, then the electrical efficiency is 31.25%, and the thermal efficiency is 66.03%.

In this paper, considering the soil stratification and groundwater seepage, combined with the measured data, the fluid temperature inside the buried pipe and the thermophysical parameters of different layered soils are obtained through the calculation of the outer wall temperature of the buried pipe, so as to establish the heat transfer model of the buried pipe stratified according to the equivalent physical properties of the soil. The experimental results show that the strati–fied heat transfer model is closer to the measured value than the conventional homogeneous model, and the error is smaller; The average absolute error between the simulated outlet water temperature and the measured value is 0.21 °C, and the average absolute error between the simulated inlet and outlet heat transfer temperature difference and the measured value is 0.14 °C based on the equivalent physical properties of soil stratification, which has a high accuracy and can provide a basis for engineering design and serve as the basis for the subsequent optimization study of the buried pipe heat transfer.

In this study, the Capricpalmitic acid (CAPA) binary eutectic PCM was vacuum impregnated into the expanded vermiculite (EVM) to prepare CAPA/EVM composite phase change thermal storage material. FTIR, DSC, TG, and thermal cycling were used to assess the chemical compatibility, heat storage performance, thermal stability, and thermal reliability of CAPA/EVM. The results showed that CAPA was stably loaded in the layered pores of EVM through physical interaction, and CAPA/EVM had excellent chemical compatibility. The Melting and solidification phase transition temperatures of CAPA/EVM were 23.61 and 20.41 °C, respectively. The latent heat of melting and solidification phase transition were 67.22 and 64.87 J/g, respectively. The amount of CAPA encapsulated in EVM could reach 52.22%, and it had favorable thermal stability at working temperature. In addition, the CAPA/EVM maintained great thermal reliability after 100 thermal cycles, indicating its potential application in the building energy conservation field.

In cold regions, offshore wind turbine structures are susceptible to complex environmental loads, which can lead to vibrationrelated safety concerns. Taking a 6.45 MW offshore monopile wind turbine structure as an example, the vibration response of the structure under the combined action of wind and ice loads is analyzed and compared before and after the implementation of the MTMD (Multiple Tuned Mass Damper) system. The results indicate that the wind and ice loads induce severe vibration responses in the wind turbine tower, with the maximum displacement response occurring at the top of the tower and the maximum acceleration response near the amplitude point of the second mode of vibration. In addition to the first two natural frequencies, the wind and ice loads also excite higherorder responses in the tower structure. By employing an MTMD system that controls the first and second mode frequencies, the displacement, acceleration, and overturning moment responses of the tower structure can be effectively controlled, resulting in significant vibration reduction. However, it should be noted that the TMD (Tuned Mass Damper) device exhibits frequency sensitivity and cannot effectively mitigate vibration responses induced by higherorder frequencies of the structure.

Wind turbine blade stall will reduce wind turbine output power. In this paper, the aerodynamic analysis model of NREL Phase VI wind turbine was established based on Fluent software, and the pressure coefficient and power characteristics of the wind turbine blade section were calculated at 13 m/s wind speed, and the accuracy of the aerodynamic analysis method of the wind turbine was verified by comparing with the wind tunnel experimental data. Then, the active jet and vortex generator (VGs) were coupled to the blade of the wind turbine. It was found that the power of the wind turbine increased first and then decreased with the increase of the width of the jet hole and the height of the vortex generator. A wind turbine aerodynamic analysis model with mixed flow control was established to study the influence of the chord distance between jet and vortex generator and the height of VGs at the trailing edge on the aerodynamic characteristics of the wind turbine. The results show that the wind turbine output power reaches the highest when the distance is 0.3C(C is the chord length of airfoil), and the increase is 6.61% compared with the single jet control. When the trailing edge VGs height is 15 mm, the hybrid flow control has the best effect and the highest fan power.

The joint participation of energy storage stations and wind farms in the black start of a system can reduce load outage time and accelerate system recovery. This paper focuses on a large energy storage power station and wind farm combined power generation system and proposes a coordinated control strategy for black start considering the restoration capability of energy storage power stations. The wind farm employs a maximum power tracking control method, while the energy storage power station adopts the V/f control method to jointly form a black start power source. Soft energization is employed for the energy storage power station and critical load restoration are performed before the wind turbines are connected to enhance the stability of restored system. An estimation method for the recovery amount of load is introduced, considering the recovery capability of energy storage stations. Based on the auxiliary load demand of the thermal power plant and wind power prediction, the state of charge of the energy storage power station during the black start process is predicted. Then, considering the power and state of charge constraints of the energy storage power station, the amount of critical load to be restored is determined. Transient simulations are carried out in PSCAD/EMTDC to verify the effectiveness of the proposed strategy.

In order to improve the grid connected efficiency of largescale renewable energy and reduce the impact on traditional power grid, this paper studies the method of aggregating distributed renewable energy and energy storage stations into virtual power plants. By describing the feasible operation domain after aggregation, peak shaving and load filling can be realized, and fossil energy consumption and environmental pollution can be reduced. A virtual power plant flexible polymerization method based on Minkowski sum and convex cell edge detection is proposed. Based on Multiple Objective Particle Swarm Optimization (MOPSO) algorithm, A set of objective functions was established considering both conventional unit operation constraints and energy conservation and capacity constraints of energy storage power station. The multiobjective optimization problem of optimal output of multitype units and charge and discharge sequence of the distributed energy storage was solved, and the unit commitment optimization with virtual power plant was realized. Furthermore, wind power plant and distributed energy storage are added into the standard case of IEEE11 units for simulation verification. The calculation results show that the virtual power plant scheme based on MOPSO optimization has significant effects on renewable energy accommodation, operation cost reduction and fossil energy saving.