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Seasonal thermal energy storage using natural structures:GIS-based potential assessment for northern China

Building Simulation 2024年第4期17卷 561-574页

作者： Yichi Zhang Jianjun Xia midea hvac heating&ventilation equipment co. LtdFoshan528311China Building Energy Research Center Tsinghua UniversityBeijing100084China

Seasonal thermal energy storage(STES)allows storing heat for long-term and thus promotes the shifting of waste heat resources from summer to winter to decarbonize the district heating(DH)*** being a promising solution for sustainable energy system,large-scale STES for urban regions is lacking due to the relatively high initial investment and extensive land *** close the gap,this study assesses the potentials of using two naturally available structures for STES,namely valley and ground pit *** on geographical information system(GIS)methods,the available locations are searched from digital elevation model and selected co.sidering several criteria from land uses and co.struction *** co.ts of dams to impound the reservoir and the yielded storage capacities are then quantified to guide the choice of suitable *** assessment is co.ducted for the northern China where DH systems and significant seasonal differences of energy demand *** total,2,273 valley sites and 75 ground pit sites are finally identified with the energy storage capacity of 15.2 billion GJ,which is much larger than the existing DH demand in northern *** results also prove that 682 valley sites can be achieved with a dam co.t lower than 20 CNY/m^(3).By co.ducting sensitivity analysis on the design dam wall height and elevations,the choices of available natural structures are expanded but practical issues about water pressures and co.structions are also ***,the identified sites are geographically mapped with nearest urban regions to reveal their roles in the DH *** general,560 urban regions are found with potential STES units and most of them have STES storage capacities larger than their own DH *** novel planning methodology of this study and publicly available datasets create possibilities for the implementations of large-scale STES in urban DH systems.

关键词： seasonal thermal energy storage geographical information system district heating water reservoir

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Performance and Optimization of Air Source Heat Pump Water Heater with Cyclic heating

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Journal of Shanghai Jiaotong university(Science) 2024年第2期29卷 179-187页

作者：李凡陆高锋丁云霄郑春元李斌翟晓强 co.lege of Mechanical and Power Engineering Shanghai Jiao Tong UniversityShanghai 200240China Guangdong midea hvac equipment co. Ltd.Foshan 528311GuangdongChina

A new type of microchannel co.denser applied in the air source heat pump water heater(ASHPWH)with cyclic heating was proposed in this *** operating performance of the ASHPWH was frst ***,the structure of the microchannel co.denser was optimized with the implement of vortex ***,a numerical model of the ASHPWH was established and the optimized microchannel co.denser was *** experimental results showed that the average co.fficient of performance(co.)of the 1HP(735 W)ASHPWH reached *** addition,the optimized microchannel co.denser co.ld be matched with a 3 HP(2430W)ASHPWH with an average heating capacity of 10.30 kW,and achieving an average co. of 4.24,14.6%higher than the limit value in the national standard.

关键词： air source heat pump water heater(ASHPWH) cyclic heating microchannel co.denser

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Development of data-driven thermal sensation prediction model using quality-co.trolled databases

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Building Simulation 2022年第12期15卷 2111-2125页

作者： Xiang Zhou Ling Xu Jingsi Zhang Lie Ma Mingzheng Zhang Maohui Luo School of Mechanical Engineering Tongji UniversityShanghai200092China Guangdong midea Air-co.ditioning equipment co. LTDGuangdong 528311China

Predicting the thermal sensations of building occupants is challenging,but useful for indoor environment *** this study,a data-driven thermal sensation prediction model was developed using three quality-co.trolled thermal co.fort *** machine-learning algorithms were co.pared in terms of prediction accuracy and *** model was further improved by adding categorical inputs,and building submodels and general models for different co.texts.A co.prehensive data-driven thermal sensation prediction model was *** results indicate that the multilayer perceptron(MLP)algorithm achieves higher prediction accuracy and more rational results than the other four algorithms in this specific *** AC and NV scenarios,climate zones,and co.ling and heating seasons can improve model *** submodels for specific scenarios can result in better thermal sensation vote(TSV)predictions than using general models with or without *** 11 submodels co.responding to 11 scenarios,and three general models without labels,the final TSV prediction model achieved higher prediction accuracy,with 64.7%–90.7%fewer prediction errors(reducing SSE by 3.2–4.9)than the predicted mean vote(PMV).Possible applications of the new model are *** findings of this study can help in development of simple,accurate,and rational thermal sensation prediction tools.

关键词： thermal co.fort machine learning adaptive thermal co.fort multilayer perceptron

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Bionic Volute Tongue Optimization Design of Multi-blade Centrifugal Fan Inspired by the Wave Leading-edge of Humpback Whale Flippers

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Journal of Bionic Engineering 2023年第5期20卷 2209-2227页

作者： Yang Liu Qi Yuan Ziqian Xu Liming Wu Xiaomin Liu School of Energy and Power Engineering Xi’an Jiaotong UniversityXi’an710049China Guangdong midea Air-co.ditioning equipment co. Ltd.Foshan528311China Department of Electromechanical and Vehicle Engineering Taiyuan UniversityTaiyuan030032China

The volute tongue can split the gas in the multi-blade centrifugal fan to make the gas flow to the volute outlet as much as ***,the unsteady axial deflection of the gas in the impeller results in different air flow angles at the outlet of the impeller at different blade *** seriously affects the flow near the volute *** wave leading-edge structure of humpback whale flippers has a very high flow co.trol effect under co.plex flow ***,the wave leading-edge structure is studied in this paper and applied to the optimization design of multi-blade centrifugal fan volute ***,based on the wave leading-edge structure of humpback whale flippers,three-dimensional wave leading-edge airfoils with different wave direction angles are established to judge the adaptability of the new wave leading-edge structure under different attack ***,aiming at the internal flow field and noise characteristics of multi-blade centrifugal fan,a bionic volute tongue optimization design method is proposed,and studied its influence on the internal flow field and noise characteristics of the *** results show that when the wave direction angle is 45°,the wave leading-edge structure can effectively suppress the generation of the leading-edge separation vortex and the shedding of the wake vortex,which is also helpful to reduce the *** bionic volute tongue with the wave leading-edge structure can adapt to the situation that the impeller outlet air flow angle is *** the maximum volume flow rate operating point,the static pressure reco.ery co.fficient of the bionic volute tongue fan is increased by about 5%co.pared to the original fan,the air volume is increased by 5.16%,and the noise is reduced by 0.6 dB.

关键词： Multi-blade centrifugal fan Airfoil Volute tongue Biomimetic design Aerodynamic noise

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A Novel Flux-weakening co.trol Method with Quadrature Voltage co.strain for Electrolytic Capacitorless PMSM Drives

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CES Transactions on Electrical Machines and Systems 2022年第3期6卷 279-287页

作者： Junya Huo Dawei Ding Zekun Ren Gaolin Wang Nannan Zhao Lianghong Zhu Dianguo Xu the School of Electrical Engineering and Automation Harbin Institute of TechnologyHarbin 150001China the Guangdong midea Air-co.ditioning equipment co. Ltd.Foshan 528311China IEEE

In electrolytic capacitorless permanent magnet synchronous motor(PMSM) drives, the DC-link voltage will fluctuate in a wide range due to the use of slim film capacitor. When the flux-weakening current is lower than-ψf/Ld during the high speed operation, the flux-weakening co.trol loop will transform to a positive feedback mode, which means the reduction of flux-weakening current will lead to the acceleration of the voltage saturation, thus the whole system will be unstable. In order to solve this issue, this paper proposes a novel flux-weakening method for electrolytic capacitorless motor drives to maintain a negative feedback characteristic of the co.trol loop during high speed operation. Based on the analysis of the instability mechanism in flux-weakening region, a quadrature voltage co.strain mechanism is co.structed to stabilize the ***, the parameters of the co.troller are theoretically designed for easier industrial application. The proposed algorithm is implemented on a 1.5 kW electrolytic capacitorless PMSM drive to verify the effectiveness of the flux-weakening performance.

关键词： Permanent magnet synchronous motor(PMSM) Electrolytic capacitorless drive Flux-weakening co.trol Voltage co.strain Stable operation

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An IncepTransNet Model for Automatic Sleep Stage Classification Using the Skin Temperature Based Wearable Sensor System

An IncepTransNet Model for Automatic Sleep Stage Classificat...

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第43届中国控制会议

作者： Zhixin Wang Jilei Li Jiang Wang Yimin Yang Yunlong Xia Qifeng Fan Haitao Yu Bin Deng GD midea Air-co.ditioning equipment co. Ltd

Sleep is critical for human to keep health. Accurate identification of sleep stages is the basic for sleep sco.ing and diagnosis of sleep related disorders. Polysomnography(PSG) is the current gold standard in sleep monitoring;however, this method is obtrusive and expensive. co.versely, the wearable sensors are a promising alternative for long-term sleep monitoring,but cannot differentiate sleep stages accurately with a high resolution. We present a multimodal wearable sensor system measuring ambient temperature(TA), relative humidity(RH) and four points of skin temperature(ST) to build a high-resolution data-driven sleep staging model. Furthermore, the IncepTransNet model, co.bining spatial enco.e block, co.volutional neural networks(CNNs) and multi-head self-attention, is designed to identify different sleep stages. With the average accuracy of 93.91%, 91.26% and 83.51% for detecting wake and sleep;wake, rapid eye movement(REM) and non-REM(NREM);wake,NREM1, NREM2, NREM3 and REM, our method outperforms the traditional wearable sensor system. This approach will enable researchers and general public to more easily and accurately assess long-term sleep patterns, co.tribute to advancements in sleep quality assessment and potential applications in personalized interventions and therapies.

关键词： Automatic sleep staging Neural network Skin temperature Wearable sensor system

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A statistical-based online cross-system fault detection method for building chillers

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Building Simulation 2022年第8期15卷 1527-1543页

作者： Jiangyan Liu Xin Li Guannan Li Chuang Wu DingChao Li Qing Zhang Kuining Li Hailong Lu Yunqian Zhang Jinjiang Zhang Key Laboratory of Low-Grade Energy Utilization Technologies and Systems Chongqing UniversityMinistry of EducationChongqingChina School of Energy and Power Engineering Chongqing UniversityChongqingChina School of Urban co.struction Wuhan University of Science and TechnologyWuhanChina Chongqing midea General Refrigeration equipment co. LtdChongqingChina

Practical applications of data-driven fault detection(FD)are limited by their *** co.ts of model training and validation are extremely high when each system requires a model retrained on its own fault and fault-free ***,this paper proposes a statistical-based online cross-system FD method to address the problem of model *** proposed FD model can be cross-utilized between building chillers with various specifications while it only needs to update the original fault detection model by the normal operation data of the new chiller system,thus saving huge fault experimental co.ts for the fault detection of new ***,a theoretical basis for the proposed cross-system fault detection method is ***,experiments were co.ducted on three building chillers with different *** fault and fault-free data were co.lected from the three *** development and validation of the proposed cross-system fault detection method are then *** show that the cross-system fault detection models perform well when used with different *** instance,when the fault detection model of system#1 was cross-utilized to system#2,the detection accuracies of refrigerant leakage,refrigerant overcharge,and reduced evaporator water flow were 99.73%,90.17%,and 96.94%,*** with original models,the detection accuracies were improved by 33.78%,84.07%,and 65.56%,***,the proposed cross-system fault detection method has potential for online application to practical engineering FD.

关键词： fault detection cross-system chiller EWMA co.trol chart

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Numerical Simulations of Snow Accumulation in the Bogie Region of a Train co.sidering Snow Particle Rotation

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Fluid Dynamics & Materials Processing 2024年第10期20卷 2337-2352页

作者： Hong Lan Jiye Zhang Yao Zhang Lu Cai State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu610031China co.lege of Railway Transportation Hunan University of TechnologyZhuzhou412000China GD midea Air-co.ditioning equipment co. Ltd.Foshan528311China

To investigate the influence of snow particle rotational motion on the accumulation of snow in the bogie region of high-speed trains,an Euler‒Lagrange numerical approach is *** study examines the effects of snow particle diameter and train speed on the ensuing *** is shown that co.sidering snow particle rotational motion causes significant deviation in the particle trajectories with respect to non-rotating *** a deviation increases with larger snow particle diameters and higher train *** snow accumulation on the overall surface of the bogie increases,and the amount of snow on the vibration reduction device varies *** certain co.ditions,the amount of accumulated snow can increase by several orders of magnitudes.

关键词： High-speed train bogie snow particle rotation discrete phase model snow accumulation

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Temperature-dependent tensile properties of ultrafine-grained C-doped co.rFeMnNi high-entropy alloy

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Rare Metals 2022年第8期41卷 2877-2885页

作者： Yan-Zhong Tian Si-Yuan Peng Shang-Feng Chen Zi-Jian Gu Yang Yang Xiu-Ling Shang Guan-Yu Deng Li-Hong Su Shi-Jie Sun Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China Innovation Center of GD midea Air-co.ditioning equipment co. LtdFoshan528311China School of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of WollongongWollongongNSW2500Australia Institute of Metal Research Chinese Academy of SciencesShenyang110016China

Metallic materials can be strengthened by various kinds of plastic deformation ***,the deformed materials suffer poor ductility and thermal stability due to the high-density *** this work,we prepared fully recrystallized ultrafine-grained(UFG)1%Cco.rFeMnNi high-entropy alloy(C-HEA)through co.d rolling and annealing ***-static tensile tests were performed at temperatures between 77 and 823 *** micros true tures of the samples after tensile tests were characterized,and deformation mechanisms were *** is a transition of deformation mechanisms from twinning and dislocation slip to dislocation slip and grain boundary sliding with temperature *** UFG C-HEA exhibits balanced strength and ductility from the cryogenic temperature to high temperatures,indicating highly adaptive microstructure and mechanical *** strength and uniform elongation of the UFG C-HEA decrease monotonously with temperature increasing,but the elongation to failure exhibits the lowest value at the medium *** grain boundary sliding is supposed to assist the unco.ventionally high elongation at 823 K.

关键词： High-entropy alloy Temperature Ductility Strength Ultrafine grain

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Reduction effect of final-pass heavy reduction rolling on the texture development,tensile property and stretch formability of ZWK100 alloy plates

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Journal of Materials Science & Technology 2022年第16期111卷 211-223页

作者： B.Q.Shi L.Y.Zhao X.L.Shang B.H.Nie D.C.Chen C.Q.Li Y.Q.Cheng School of Materials Science and Hydrogen Energy Foshan UniversityFoshan 528000China School of Materials and Energy Guangdong University of TechnologyGuangzhouGuangdong 510006China GD midea Air-co.ditioning equipment co. Ltd.Foshan 528311China Guangdong Key Laboratory of Hydrogen Energy Technology Foshan 528000China YunFu(Foshan)R&D Center of Hydrogen Energy Standardization Yunfu 527326China

Obviously planar anisotropy due to‘TD split’orthotropic texture(TD indicates Transverse direction)always exist in the Rare-earth(RE)or Ca co.taining Mg alloy sheets,which is likely caused by the lowreduction rolling(and annealing)as revealed in our previous *** this work,the as-cast billets of a ZWK100 alloy were subjected to final-pass heavy reduction rolling(FHRR)at 500°C with different reductions(30%-70%)after rough rolling,aiming to investigate the reduction effect on the microstructure and texture *** results show that FHRR with higher reductions above 50%is in favor of shear banding formation but has little effect on the as-deformed texture co.ponents,and the excellent formability with single-pass reduction up to 70%is mainly ascribed to the activation of prismatic *** with reduction above 50%and annealing can generate uniform grain structures of~10μm and symmetrical‘oblique-line split’texture in(0001)pole figures,with basal poles tilting by about 50°from ND(Normal direction)towards some oblique-line of TD and RD(Rolling direction)as well as uniform distribution of co.nter lines as an annular shape,resulting in excellent elongation to failure of~50%and ultra-low planar anisotropyΔr_of~0.1 and high stretch formability(Erichsen value:8.1).The formation‘oblique-line split’texture in(0001)pole figures is mainly co.related with the preferred growth tendency of grains with■//RD,which was suggested to relate to the high mobility of some special boundaries such as 40°-45°■.The influences of starting textures on the mechanical properties,planar anisotropy and related deformation modes,as well as their co.relations with the stretch formability were co.paratively investigated with the‘TD split’orthotropic texture as a co.nterpoint.

关键词： Magnesium alloys Texture Plane anisotropy Stretch formability Rolled sheets

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