Abstract:In response to the demand for heat source integration and improvement of heating stability in the main urban area of a certain city,a multi-source networked heating system model is established using the MAP hydraulic calculation software.The hydraulic characteristics and accident conditions of the'one network'operation are simulated and analyzed.Suggestions for heat source allocation and the network system are proposed,and corresponding solutions are provided for each heat source in accident conditions.The results show that in the recent non-interconnection mode of the network,each heat source operates independently and meets the economic and friction resistance requirements.Compared with single heat source heating,the multi-source network operation has a significant advantage in ensuring the stability of heating,and can significantly improve the stability of heating.

Abstract:Large-scale science and technology museums,as typical public buildings with complex functions and high energy consumption,have considerable economic benefits from their energy-saving and emission-reduction practices.Based on the actual operation data of several large-scale science and technology museums in China,the study systematically reviews the energy-saving technologies and management measures adopted in key aspects such as building envelope,HVAC systems,lighting systems,renewable energy application,and intelligent operation and management.It conducts a comprehensive evaluation of the implementation effects from three dimensions:Economy,environment,and society.The results show that energy-saving and emission reduction in science and technology museums have reduced operating costs and carbon emissions,expanded green science and technology education functions,and should develop towards the'integrated smart energy system'and'full life cycle carbon neutrality'directions in the future.

Abstract:To reveal the flow resistance mechanism of supercritical CO2 in the rectangular microchannels of the printed circuit board heat exchanger(PCHE),a resistance characteristic test study is conducted under high heat flux conditions in rectangular microchannel with a hydraulic diameter of 0.16 mm.The influence laws of mass flow rate,heat flux density and system pressure on the friction pressure drop and acceleration pressure drop are systematically investigated using the control variable method.Combined with the changes in physical parameters near the wall and in the main flow region,the intrinsic mechanism of resistance variation is revealed.The results show that the friction factor of supercritical CO2 has a peak characteristic before the pseudo-critical enthalpy value.High heat flux is prone to cause heat transfer deterioration.At this time,the mass flow rate is the main factor affecting the friction pressure drop in the channel.The change in system pressure has a weak influence on the friction pressure drop in the channel,and the change in heat flux density only affects the friction pressure drop in the low enthalpy region.Resistance variation is closely related to the fluid heat transfer characteristics.While conducting the structural design,it is necessary to take into account the changes in fluid heat transfer performance.

Abstract:Under the backdrop of'double carbon'goals,the heating industry in Shandong Province is under pressure for a green and low-carbon transformation.Geothermal energy has great potential as a substitute for coal.By combining literature review and case analysis,systematically examines the distribution of deep geothermal resources,the current heating situation,and supporting policies in Shandong Province.Taking the geothermal clean heating project in Dongying economic development zone as an empirical case,it analyzes the innovative technologies and investment operation models such as heat exchanger+heat pump cascade utilization,balanced extraction and injection of centralized collection and distribution,and intelligent management,and propose suggestions and measures to address the existing problems.

Abstract:In response to the demand for renewable energy consumption,a micro isolated compressed air energy storage and hydrogen coupling system is proposed.By establishing thermodynamic mathematical models for the compressor,storage tank,electrolyzer and fuel cell,and combining the first and second laws of thermodynamics to evaluate the system's energy efficiency,the effects of multi-stage compression,expander efficiency and hydrogen fuel cell waste heat recovery on system performance are studied using energy balance and exergy analysis methods.The results show that when the efficiency of the expander increases from 60%to 90%,the system cycle efficiency rises from 40.82%to 61.23%.By recovering 1 980 kJ of heat from the fuel cell,the system cycle efficiency can be increased from 57.83%to 60.55%,an increase of 2.72 percentage points,and the relative efficiency improvement reaches 4.70%.The multi-stage compression optimization indicates that when the total compression ratio is 25,increasing the number of compression stages can reduce the outlet temperature and isentropic power consumption.The output power of the hydrogen fuel cell increases significantly with the increase in current density.When the working current is 25 A,the power reaches 2 kW,and the hydrogen molar consumption is 0.010 364 mol/s.The coupling system provides a new path for the development of renewable energy consumption and hybrid energy storage technology through energy cascade utilization and waste heat recovery.

Abstract:Permanent magnet drives are widely used in the energy sector.However,the dry-type permanent magnet speed regulation devices operate in complex environments and are often affected by faults such as overcurrent,overheating,and vibration.In response to the common fault problems of the dry-type permanent magnet regulation system for coal-fired unit crushers in complex operating environments,a protection optimization scheme based on multi-parameter collaborative control is proposed.By introducing temperature,vibration,electrical,magnetic field,and overspeed protection measures,combined with a fault warning system,the original logic control strategy is optimized.The results show that the optimized system significantly reduces the overload rate of the crusher,shortens the fault diagnosis time,and reduces the hourly power consumption.Through dynamic load protection algorithms and regular inspection and maintenance management measures,the reliability and operational stability of the system are further improved.The optimization scheme effectively extends the equipment lifespan,reduces operating and maintenance costs,and provides a new practical path for energy-saving and green development in the power industry.

Abstract:The combustion of coal powder will produce acidic gases,which will harm the environment.The desulfurization tower,as the main equipment for recovering these acidic gases,often suffers from corrosion due to its poor internal conditions.To deeply study the corrosion and protection measures of the desulfurization tower,analyze the mechanisms of chemical and physical corrosion,summarize the corrosion characteristics of the desulfurization tower's interior under different conditions,discuss the existing protection measures and their deficiencies,and propose further research methods and ideas to reduce the internal corrosion of desulfurization towers in coal-fired power plants.

Abstract:By using computational fluid dynamics(CFD)numerical simulation and heat transfer analysis methods,a systematic study is conducted on the mechanism by which the composite energy-absorbing disk enhances the limit thermal efficiency of the gas stove.The results show that increasing the number of layers of the energy-absorbing disk and filling it with aerogel can increase the thermal efficiency to around 78.5%.The structure increases the internal radiation heat resistance,reduces heat loss,and simultaneously raises the surface temperature on the upper part to enhance the radiation heat transfer at the bottom of the pot and reduces the excess air volume to increase the combustion temperature.However,structures with more than three layers tend to reach saturation due to diminishing marginal benefits,and the heat loss becomes dominated by solid heat conduction between stainless steel components.The bridge-type composite energy-absorbing disk,although able to eliminate radiation and direct heat conduction paths,causes a decrease in combustion temperature due to an increase in air volume,resulting in limited improvement in the overall thermal efficiency.Combining the bridge-type composite energy-absorbing disk with the oxygen control scheme can further enhance the thermal efficiency and reduce the air volume,and reducing the air volume can increase the flue gas temperature and the temperature difference between the flue gas and the grate,enhance the temperature of the upper wall of the energy-absorbing disk,and strengthen the radiation heat transfer at the bottom of the pot.

Abstract:In response to the insufficient research on key technical parameters of the residual heat exchanger for the oil-in-water screw air compressor in coal mines under different loading rates,taking an air compressor residual heat project in Inner Mongolia as the research object and adopting a method combining theoretical calculation and on-site testing to conduct design research on the key technical parameters of the oil-water tube shell heat exchanger.The results show that the comprehensive heat transfer coefficient of the heat exchanger is 514 W/(m2·K).When the air compressor loading rate is 98%,after the system operates stably,the cooling water temperature rises from 9.9℃to 54.0℃,and the production water volume reaches 4.18 m3/h,meeting the heat demand of the mining area.Increasing the flow velocity of the tube pass and reducing the inner diameter of the tube can effectively improve the heat transfer performance.

Abstract:To address the issues of high energy consumption and poor stability in long-distance transmission of offshore wind power,the research focuses on the structural optimization of the DC transmission system and the grid connection control strategy.By combining theoretical analysis with simulation verification,the influence of transmission voltage level,lightweight converter platform,and cable transmission efficiency on system losses is analyzed.The maximum power point tracking technology(MPPT)dynamic power distribution,voltage stability coordinated regulation,and fault current limiting control strategies are proposed.System energy efficiency evaluation indicators are constructed.The results show that increasing the voltage level can reduce line losses.The SiC device converter scheme has a 32.8%lower energy consumption under light load compared to IGBT.Dynamic power control can reduce the energy consumption per unit of electricity by 8 kWh/MWh.

Abstract:To recycle the pressure difference energy at the wellheads of offshore gas fields and address the issues of the difficulty in adapting land-based technologies to the compact space of offshore platforms and the presence of liquid and impurities,by reviewing the current technical status at home and abroad and statistically analyzing the data of 21 land-based demonstration projects,a technical characteristic comparison and adaptability analysis of turbine type,screw type,and double rotor type expansion generators are conducted from the dimensions of operating pressure,equipment structure,automatic control level,and medium adaptability.The results show that the double rotor expansion machine exhibits advantages such as a simple structure,zero leakage,one-button start and stop,and resistance to impact within the pressure range of 0.5 MPa to 10.0 MPa and in gas-liquid mixed conditions.It demonstrates advantages in adapting to the technology route of generating electricity from the pressure difference at the gas wellheads of offshore gas fields.However,further research is needed to develop a higher pressure(≥30 MPa)unit and to equip it with a sand removal and dehydration pre-treatment system to achieve efficient recovery of the high-pressure pressure difference energy at the wellhead and provide green electricity for offshore platforms.

Abstract:In response to the problems faced by the battery management system(BMS)in the collaborative control of multiple cells,such as lag in balancing,low energy utilization efficiency,and insufficient system robustness,a multi-cell synchronous control strategy based on artificial intelligence(AI)predictive balancing is proposed.The strategy is centered on the concept of'prediction first,synchronous control',and constructs a control framework that integrates a long short-term memory network(LSTM)prediction model and multi-objective optimization algorithm.The results show that by intelligently sensing the evolution trend of cell states,the strategy has achieved a paradigm shift from traditional passive balancing to active predictive balancing.The proposed algorithm can significantly improve energy utilization efficiency and system robustness,effectively reduce energy consumption caused by balancing lag,providing key technical support for energy-saving and emission reduction of the power battery system of new energy vehicles.Through real-time and hardware feasibility verification,the strategy lays the foundation for industrialization implementation and provides a new paradigm for battery health management throughout the entire life cycle.

Abstract:To address the frequent equipment failures,high energy consumption and non-compliance with environmental standards caused by the ineffective oil mist treatment in the air compressor station of a steel factory,a study is conducted on 23 third-level centrifugal air compressors in a steel factory.Through on-site investigation,technical comparative analysis and phased implementation of renovations,the inherent design problems of the equipment,the chain effects of filter element failure and the secondary problems of temporary measures are analyzed,and the'venturi vacuum jet+efficient filtration recovery'scheme is selected for renovation.The results show that after the renovation,the annual oil replenishment volume of the air compressors significantly decreased,the temperature of the motor bearings dropped from 85℃to 65℃,the lifespan of the air filter elements is significantly prolonged,and the concentration of oil mist emissions is greatly reduced.The practice has proved that the renovation scheme effectively solved the current operation problems of the air compressors.

Abstract:To achieve real-time monitoring and safety assessment of the operating status of steel-concrete towers for onshore wind turbines,an intelligent monitoring method integrating multiple physical quantity measurements is proposed.By installing sensors for strain,vibration,inclination,cable tension,and opening degree,a complete state monitoring system for the steel-concrete tower is constructed.Corresponding early warning and health diagnosis mechanisms are established,and the effectiveness and accuracy of the monitoring scheme are verified by combining on-site measured data with numerical simulation results.The results show that the system can promptly identify potential safety hazards such as tower tube structural damage,inclination,and resonance,providing technical support for the safe operation of steel-concrete towers.Through real-time identification and early warning of potential faults,the system effectively reduces unplanned shutdowns and improves the operational efficiency of the wind turbines,thereby enhancing the overall energy-saving benefits of the wind farm.

Abstract:Regarding the energy consumption issue of the heating water system for the cooling wheels of plastic production lines,a technical renovation scheme based on the recovery of waste heat from air compressors is proposed.Without changing the original working state of the air compressors,the residual heat from three air compressors with a power of 75 kW is utilized to produce hot water ranging from 65℃to 70℃through a heat recovery device,directly replacing the heating demand of the original mold temperature machine.The results show that the scheme could recover 972 200 kWh of heat equivalent to standard electricity per year,achieve a reduction of 275 400 kWh of annual electricity consumption,equivalent to 33.84 t of standard coal(equivalent value)of annual comprehensive energy savings,and reduce CO2 emissions by 148.58 t.The total investment of the project is 853 500 yuan,with an annual income of 181 800 yuan.The static investment recovery period is approximately 5.24 a,demonstrating excellent energy-saving effects and economic feasibility.

Abstract:To address the issue of poor stability of the foundation in coal mining subsidence areas,the component replacement method and the life cycle assessment(LCA)model are adopted to compare and analyze traditional concrete,prefabricated steel structure,and the'high-strength recycled steel+bamboo'combined structure.The results show that the unit area self-weight of this combined scheme is 129.860 kg/m2,which is 80.83%lighter than traditional concrete.The carbon emissions during the production and transportation stages of the building materials are 71.055 kgCO2e/m2,which are 83.56%and 56.43%lower than those of traditional concrete(432.144 kgCO2e/m2)and steel structure(163.080 kgCO2e/m2),respectively.The structure has both the advantages of carbon reduction and lightweighting,providing a technical path for low-carbon construction in sensitive ground areas.

Abstract:To promote the complementary and collaborative development of photovoltaic and solar thermal power generation and enhance the economic efficiency of the combined system,an optimization study on the storage capacity is carried out.A mathematical model of the combined system is constructed,and an operation strategy of'photovoltaic priority,solar thermal peak shaving,and storage shift'is established.An optimization model for storage capacity based on minimizing the levelized cost of electricity(LCOE)is established,and a simulation is conducted using a certain base station in Northwest China as the research object.The results show that there is an optimal storage duration(8 h)in the system,which results in the lowest LCOE.Sensitivity analysis indicates that the investment cost of solar thermal power and the discount rate are the most sensitive factors affecting the optimal configuration.

Abstract:To optimize wake simulation methods for wind farms and improve the accuracy of wake distribution predictions,thereby providing reliable model support for wind farm operation and layout,based on measured data from the Lillgrund offshore wind farm,Jensen wake model,BP wake model,and MCG wake model are selected and each combined pairwise with three superposition models:The linear superposition model(LS),the energy balance superposition model(EB),and the sum of squares superposition model(SS).Matlab programs are written to perform wake calculations,and the results are compared with measured data from the Lillgrund offshore wind farm.The results show that the wake superposition models formed by combining the three wake models with the sum of squares superposition model(SS)all achieved good simulation results in the selected cases.

Abstract:In order to clarify the carbon footprint characteristics of the medium to deep water thermal geothermal heating system and propose emission reduction paths,the Hancheng Energy No.3 Station is taken as the research object,focusing on the mining and irrigation well group link,and constructing a three-level physical model of'basic support-core design-guarantee optimization'and a full life cycle carbon emission calculation model.The model covers carbon emission calculations for four stages:Material production and transportation,construction,operation,demolition and recycling,and proposes emission reduction strategies for high carbon emission nodes.The results show that the total carbon emissions throughout the full life cycle of the system are 93 000.49 tCO2,and the carbon emission intensity per unit area is 294.22 kg CO2/m2.Among them,the operating phase is the core emission source,accounting for 89.47%.The carbon emissions during the early physical and chemical stage of the irrigation well group are 2 098.81 tCO2,accounting for 19.25%of the total emissions during the early stage of the system.The carbon emissions during the construction stage accounted for as high as 81.55%.The research results and strategies can provide technical references for the low-carbon development of medium to deep water thermal geothermal heating systems.

Abstract:With the acceleration of China's urbanization process,the urban heat island effect has become one of the prominent environmental problems.Urban green spaces,as the'cooling source'of the city,can effectively alleviate the urban heat island effect.Based on geographic information system(GIS)and remote sensing(RS)technologies,the surface temperature(LST)of the main urban area of Shenyang City in 2015,2018,and 2020 is inversely calculated,and the vegetation coverage(FVC)during the same period is calculated.The temporal and spatial evolution patterns are analyzed.Through the classification of heat island grades and buffer zone analysis,the spatial distribution and evolution characteristics of the heat island effect are quantitatively studied.Considering the background of population growth and urban expansion in Shenyang City,suggestions for optimizing the spatial layout of urban green spaces are proposed for the areas with concentrated heat island effects,providing references for the urban ecological planning and heat environment improvement of Shenyang City.