Drive Train Cooling Options for Electric Vehicles

Electrification of vehicles intensifies their cooling demands due to the requirements of maintaining electronics/electrical systems below their maximum temperature threshold.In this paper,passive cooling approaches based on heat pipes have been considered for the thermal management of electric vehicle(EV)traction systems including battery,inverter,and motor.For the battery,a heat pipe base plate is used to provide high heat removal(180 W per module)and better thermal uniformity(<5°C)for the battery modules in a pack while downsizing the liquid cold plate system.In the case of Inverter,two phase cooling system based on heat pipes was designed to handle hot spots arising from high heat flux(∼100 W/cm2)–for liquid cooling and provide location independence and a dedicated cooling approach-for air cooling.For EV motors,heat pipebased systems are explored for stator and rotor cooling.The paper also provides a glimpse of development on high-performance microchannel-based cold plate technologies based on parallel fins and multi-layer 3D stacked structures.Specifically,this work extends the concept of hybridization of two-phase technology based on heat pipes with single-phase technology,predominately based on liquid cooling,to extend performance,functionalities,and operational regime of cooling solutions for components of EV drive trains.In summary,heat pipes will help to improve and extend the overall reliability,performance,and safety of air and liquid cooling systems in electric vehicles.

Influences of Urban Temperature on the Electricity Consumption of Shanghai

By using data of daily electricity consumption and temperature for the period 2003–2007 in Shanghai, the variation of energy consumption and the correlations between energy consumption and temperature are analyzed. The results indicate that winter and summer are the two peak seasons of energy consumption due to the urban residential heating and cooling demand. The base temperature of electricity and daily temperature is 10℃ in winter and 22℃ in summer respectively. When the outdoor temperature is below 10℃, the heating demand becomes obvious, and with over 22℃ the cooling demand. The spatial distribution of cooling degree-days(CDD) and heating degree-days(HDD) clearly shows urbanization effects. By the influence of urbanization the central city experiences greater CDD in summer and lower HDD in winter. The projected temperature for 2011–2050 implies a significant increase in CDD and a decrease in HDD. This may have implications on the future energy demand if the current energy consumption pattern does not change.

Mathematical model on heat transfer of water-cooling steel-stick bottom electrode of DC electric arc furnace

For predicting and controlling the melted depth of bottomelectrode during the process of steelmaking, the water-cooling steel-stick electrode is taken as an example, to analyze the process ofheat transfer, then 3D mathematical model by control capacity methodis built. At the same time, the measurement on the melted depth ofbottom electrode is conducted which verified the correctness of thebuilt mathematical model. On the base of verification, all kinds ofkey parameters are calculated through the application and a series ofresults are simulated. Finally, the optimum parameters are found andthe service life of bottom electrode is prolonged.

Analysis and Economic Evaluation of Hourly Operation Strategy Based on MSW Classification and LNG Multi-Generation System

In this study,a model of combined cooling,heating and power system with municipal solid waste(MSW)and liquefied natural gas(LNG)as energy sources was proposed and developed based on the energy demand of a large community,andMSW was classified and utilized.The systemoperated by determining power by heating load,and measures were taken to reduce operating costs by purchasing and selling LNG,natural gas(NG),cooling,heating,and power.Based on this system model,three operation strategies were proposed based on whether MSW was classified and the length of kitchen waste fermentation time,and each strategy was simulated hourly throughout the year.The results showed that the strategy of MSW classified and centralized fermentation of kitchen waste in summer(i.e.,strategy 3)required the least total amount of LNG for the whole year,which was 47701.77 t.In terms of total annual cost expenditure,strategy 3 had the best overall economy,with the lowest total annual expenditure of 2.7730×108 RMB at LNG and NG unit prices of 4 and 4.2 RMB/kg,respectively.The lower heating value of biogas produced by fermentation of kitchen waste from MSW being classified was higher than that of MSW before being classified,so the average annual thermal economy of the operating strategy of MSW being classified was better than that of MSW not being classified.Among the strategies in which MSW was classified and utilized,strategy 3 could better meet the load demand of users in the corresponding season,and thus this strategy had better thermal economy than the strategy of year-round fermentation of kitchen waste(i.e.,strategy 2).The hourly analysis data showed that the net electrical efficiency of the system varies in the same trend as the cooling,heating and power loads in all seasons,while the relationship between the energy utilization efficiency and load varied from season to season.This study can provide guidance for the practical application of MSW being classified in the system.

Designing the cooling system of a hybrid electric vehicle with multi-heat source

In order to reduce the power consumption and meet the cooling demand of every heat source component, three kinds of multi-heat source cooling system schemes were designed base on the characteristic of power split hybrid electric vehicle （HEV）. Using the numerical simulation meth- od, the power system heat transfer model was built. By comparing the performance of three differ- ent schemes through the Simulink simulation, the best cooling system scheme was found. Base on characteristics of these cooling system structures, the reasonableness of the simulation results were analyzed and verified. The results showed that the cooling system designation based on the numerical simulation could describe the cooling system performance accurately. This method could simplify the design process, improve design efficiency and provide a new way for designing a multi-heat source vehicle cooling system.

考虑变掺氧富氧燃烧与利用LNG冷能的LAES的综合能源系统低碳经济调度

为促进风电消纳,减少火电机组的碳排放,解决综合能源系统(Integrated Energy System,IES)低碳经济运行问题,文中引入变掺氧富氧燃烧技术对燃气机组进行改造,并结合利用液化天然气(Liquefied Natural Gas,LNG)冷能的液化空气储能(Liquid Air Energy Storage,LAES),提出了一种电热气冷IES低碳经济优化策略。首先,构建含变掺氧富氧燃烧燃气机组、利用LNG冷能的LAES、电转气(Power To Gas,P2G)设备、中央空调和溴化锂制冷机的IES架构,并建立各设备的数学模型;其次,引入阶梯式碳交易机制,建立了以系统运行成本最小为目标的电热气冷IES低碳经济调度模型;最后,采用MATLAB调用GUROBI求解器对多个场景进行求解,验证了文中提出的低碳经济优化调度策略可以提高系统的风电消纳、有效降低系统运行成本,实现碳减排。

基于多变量相空间重构和径向基函数神经网络的综合能源系统电冷热超短期负荷预测

为解决能源危机问题,提高能源利用率,综合能源系统(integrated energy system,IES)成为发展创新型能源系统的重要方向。准确的多元负荷预测对IES的经济调度和优化运行有着重要的影响,而借助混沌理论能够进一步挖掘IES多元负荷潜在的耦合特性。提出了一种基于多变量相空间重构(multivariate phase space reconstruction,MPSR)和径向基函数神经网络(radial basis function neural network,RBFNN)相结合的IES超短期电冷热负荷预测模型。首先,分析了IES中能源子系统之间的耦合关系,运用Pearson相关性分析定量描述多元负荷和气象特征的相关性。然后,采用C-C法对时间序列进行MPSR以进一步挖掘电冷热负荷和气象特征在时间上的耦合特性。最后,利用RBFNN模型对电冷热负荷间耦合关系进行学习并预测。实验结果表明,所提方法有效挖掘并学习电冷热负荷在时间上的耦合特性,且在不同样本容量下具有良好且稳定的预测效果。

增程式电动汽车动力系统一体化冷却传热分析

以一款增程式轻型卡车为研究对象,对增程式动力系统的发动机和电机采用一体化冷却系统设计。在预设的运行工况,通过试验测试,计算出工况点增程器和电驱系统的散热需求,对冷却液和冷却水泵进行选型匹配。结合试验测试建立了增程器和电驱系统冷却回路一维仿真模型,对比分析了电驱系统冷却管道串联与并联的冷却效果与能耗情况,验证了驱动电机冷却液帮助发动机冷起动的可行性。研究结果表明:通过试验测量散热量选择到的电子水泵,能更加高效准确地控制冷却液流量,冷却效果更好。冷却系统一维仿真分析中能从温升曲线直观看到并联冷却管路冷却效果更好,并联管路中的电磁阀根据工况不同控制开口大小,比串联管路统一控制冷却液流量冷却更高效。并联冷却管路中驱动电机冷却时快速产生热量,在与发动机冷起动时进行热交互可以帮助发动机快速暖机,改善发动机冷起动排放差、动力弱的情况。

电动飞机电池组微通道风冷散热研究

电动飞机已成为航空飞行器的重要发展方向。电动飞机配置的电池组能量密度更高,工作时功率大产热多,如果热管理不善,容易使电池组自燃,且飞行过程难以紧急避险,所以必须重视电动飞机电池组热管理。提出在常规Z型风冷系统中增设微通道冷板的方案,对电动飞机电池组进行散热;对电池组工作过程进行仿真,计算各种环境和使用条件下电池组生热及散热功率,以便采取措施更有效地实施电池组热管理。仿真计算了电动飞机滑跑、加速和爬升段飞行时的无风条件、常规Z型风冷和增设微通道冷板新型Z型风冷的生热和散热功率。结果表明:增设微通道冷板新型Z型风冷散热效果最好,与常规Z型风冷比较,电池组最高温度下降约7℃,温差下降约6℃。

个体冷热调节服装的研究进展

为促进个体冷热调节服装(PTRC)在热舒适性调节和建筑节能中的应用与发展,系统介绍了个体冷却服、加热服的分类特性及进展,比较分析了不同类型PTRC的优缺点,提出了未来的发展方向。总结发现:个体冷却服存在笨重、便携性差和冷却效率低等问题,未来应结合实际应用场景,从多方面(面料、结构、附加设备等)进行综合考虑,寻找更高能量密度的电池,降低服装重量;对于个体加热服,多驱动能源技术是未来的发展方向,应充分结合不同学科知识实现服装的智能化控制,满足不同场景中的加热需求;针对使用新型制造工艺与材料的动态调节技术,优化纺织材料的性能和生产工艺,建立全面的适用安全标准体系和评估方法,以促进其商业化的发展进程。

A Deep Neural Network Coordination Model for Electric Heating and Cooling Loads Based on IoT Data

As the ubiquitous electric power internet of things(UEPIoT)evolves and IoT data increases,traditional scheduling modes for load dispatch centers have yielded a variety of chal-lenges such as calculation of real-time optimization,extraction of time-varying characteristics and formulation of coordinated scheduling strategy for capacity optimization of electric heating and cooling loads.In this paper,a deep neural network coor-dination model for electric heating and cooling loads based on the situation awareness(SA)of thermostatically controlled loads(TCLs)is proposed.First,a sliding window is used to adaptively preprocess the IoT node data with uncertainty.According to personal thermal comfort(PTC)and peak shaving contribution(PSC),a dynamic model for loads is proposed;meanwhile,personalized behavior and consumer psychology are integrated into a flexible regulation model of TCLs.Then,a deep Q-network(DQN)-based approach,using the thermal comfort and electricity cost as the comprehensive reward function,is proposed to solve the sequential decision problem.Finally,the simulation model is designed to support the validity of the deep neural network coordination model for electric heating and cooling loads,by using UEPIoT intelligent dispatching system data.The case study demonstrates that the proposed method can efficiently manage coordination with large-scale electric heating and cooling loads.

Optimized scheduling of integrated energy systems for low carbon economy considering carbon transaction costs

With the introduction of the“dual carbon”goal and the continuous promotion of low-carbon development,the integrated energy system(IES)has gradually become an effective way to save energy and reduce emissions.This study proposes a low-carbon economic optimization scheduling model for an IES that considers carbon trading costs.With the goal of minimizing the total operating cost of the IES and considering the transferable and curtailable characteristics of the electric and thermal flexible loads,an optimal scheduling model of the IES that considers the cost of carbon trading and flexible loads on the user side was established.The role of flexible loads in improving the economy of an energy system was investigated using examples,and the rationality and effectiveness of the study were verified through a comparative analysis of different scenarios.The results showed that the total cost of the system in different scenarios was reduced by 18.04%,9.1%,3.35%,and 7.03%,respectively,whereas the total carbon emissions of the system were reduced by 65.28%,20.63%,3.85%,and 18.03%,respectively,when the carbon trading cost and demand-side flexible electric and thermal load responses were considered simultaneously.Flexible electrical and thermal loads did not have the same impact on the system performance.In the analyzed case,the total cost and carbon emissions of the system when only the flexible electrical load response was considered were lower than those when only the flexible thermal load response was taken into account.Photovoltaics have an excess of carbon trading credits and can profit from selling them,whereas other devices have an excess of carbon trading and need to buy carbon credits.

Energetic, economic, and environmental analysis of solid oxide fuel cell-based combined cooling, heating, and power system for cancer care hospital

In this study,energetic,economic,and environmental analysis of solid oxide fuel cell-based combined cooling,heating,and power(SOFC-CCHP)system is proposed for a cancer care hospital building.The energy required for the hospital power,cooling,and heating demands was obtained based on real and detailed field data,which could serve as a reference for future works in the field.These data with a 3D model for the hospital building are constructed and created in eQUEST software to precisely calculate the energy demands of the existing system(baseline case).Then,energetic,economic,and environmental models were developed to compare and assess the performance of the proposed SOFC-CCHP system.The results show that the proposed system can cover about 49% to 77% of the power demand of the hospital with an overall efficiency of 78.3%.Also,the results show that the levelized cost of electricity of the system and its payback period at the designed capacity of the SOFC is 0.087S/kWh and 10 years,respectively.Furthermore,compared to the baseline system of the hospital,the SOFC-CCHP reduces the CO_(2) emission by 89% over the year.The sensitivity analysis showed that a maximum SOFC efficiency of 52%and overall efficiency of 80%are achieved at cell operating temperature of 1027℃ and fuel utilization factor of 0.85.

电动汽车动力电池组液冷散热优化

电动汽车动力电池在充放电过程中快速产生大量的热量,开展高效散热设计有利于提升电池组工作效率及其安全性。采用冷板和电池组相结合的方式进行电池组液冷散热设计,以50℃作为临界最高温度进行研究,结果表明冷板与电池组采用侧面侧方布置时电池表面平均温度最低,温度均匀性较好。满足散热设计对应的相间侧向所需质量流量最小且为0.05 kg/s,而相间上向模型的压降最小。因此,电池组散热设计时可优先选择电池单体与冷板相间布置的结构。

高速公路服务区冷热电联供技术研究

在我国积极稳妥推进碳达峰碳中和的背景下,重新思考如何规划设计高速公路服务区的供能体系,使其成为交通运输领域低能耗、零碳排放的典范,意义重大。该文详细介绍冷热电联供技术的结构及其优势,着重分析锅炉、制冷设备(包括压缩式制冷机等)等设备的数学模型,以及由这些设备组成的系统的约束条件和优化思路。该文提出冷热电联供的研究思路,并选取燃气轮机额定容量、电制冷占比和燃气锅炉额定容量等作为优化变量,以满足服务区需求为目标函数。该研究对于提高高速公路服务区能源利用效率、降低能源消耗和环境污染具有重要的理论指导和实践意义。

基于组合数学质量比建模的车用锂离子电池组热管理研究

为提高车用锂离子电池的热管理效率,将纳米石墨(NG)和纳米铝(NA)添加至石蜡(PA)中,制备纳米复合相变材料(NCPCM),基于组合数学建模研究了不同质量比NCPCM的热导率和相变潜热等物理参数对电池热管理效率的影响,完成组合数学质量比模式下的热导率和相变潜热,以及慢充至快充下的RGO/BN/PA CPCM、RT44HC/CF CPCM和NCPCM3的车用锂离子电池热管理试验分析,结果表明:3.5 C放电速率下,热导率为2.1 W/(m·K)、相变潜热为206.18 J/g的NCPCM3能将车用锂离子电池组的最高温度和最大温差分别降低至44.2℃和4.4℃,进一步提高NCPCM的热性能参数并不会显著提高热管理性能;NCPCM3的电池热管理效率明显优于RGO/BN/PA CPCM、RT44HC/CF CPCM,能确保车用锂离子电池组的正常工作温度。

多能联供协同干燥的压缩空气储能

【目的】为探究压缩空气储能系统(compressed air energy storage system, CAES)在冷热电场景下的工程应用,提出了一种用于木材干燥的CAES。【方法】首先搭建了CAES及其数学模型;其次分析了木材高温干燥和除湿干燥模式的能耗,通过模拟试验探究了CAES的冷热电联产特性;最后将系统产出的冷热电能与两种干燥模式的能耗负荷匹配,并进行经济性分析。【结果】储能系统采用补能预热,水流量为1 kg/s时产生最大制冷量和级间热量;当换热冷却水流量为3.3 kg/s时,木材干燥综合能效最高;高温干燥方案投资静态回收期稍微低于除湿干燥方案。【结论】本研究结果为木材干燥企业的能源转型提供参考,同时为压缩空气储能系统的工程应用开辟了新方向。

铸造工厂熔化电炉冷却系统余热回收应用的探讨

随着国家推出的高质量发展理念及“碳达峰、碳中和”政策的实施,通过收集铸造工厂熔化电炉冷却相关的资料及运行参数,结合某项目应用的实际案例,介绍了熔化电炉冷却系统余热回收应用场合,同时对采用的余热回收技术方案进行了经济技术分析,确认本次探讨的电炉冷却水余热回收系统的技术方案具备初投资低、运行费用省,能够有效降低企业的碳排放,具备良好的社会经济效益。该余热回收技术方案的推广应用,是企业降低运行费用、减少碳排放的一个有效途径。

采用水冷冷凝器的电动汽车热泵系统制热和抗结霜性能试验研究

热泵技术由于具有比电加热显著提升的制热效率,近年来逐渐应用于电动汽车以期提高冬季续航里程。文章设计了一套电动汽车热泵系统,该系统取消了传统热泵的车外冷凝器,而以低温散热器作为主要的散热和吸热部件。根据实车的零部件部件要求搭建了该热泵系统的测试台架,台架试验结果表明该热泵系统在-7℃环境下,纯热泵工况下的制热能力可以达到5.4kW,COP可以达到2.4。通过模拟电机电控的余热回收效果,试验发现低于30%的余热可以被该系统吸收用于制热。试验也表明这种类型的热泵系统在湿度较高的情况下同样存在结霜的问题,且结霜开始的时间与环境湿度和压缩机转速关系紧密。

纯电车型前舱空调冷凝器的散热特性研究

由于前舱冷却模块布置方式及格栅开孔的影响,冷凝器迎风面的冷却空气呈现非均匀的速度与温度分布,影响其散热性能。文章以纯电车型前舱冷却模块为研究对象,基于AMESim软件的独立控制元件建立一层半与两层方案数学模型,通过理论计算验证数学模型的合理性,揭示两种布置方式下冷凝器各流程的散热量及总散热量随迎风面冷却空气参数的变化规律。研究发现:对于两层方案,均匀送风条件下冷凝器具有最优的散热性能,且随着过冷区送风量的增大其散热量显著降低;对于一层半方案,冷凝器上/中/下部被遮挡时,由于内部制冷剂状态发生变化,使得其总散热量依次降低10.53%、15.34%和17%,故采用一层半布置时,应尽可能使散热器位于冷凝器上部。文章研究工作为纯电车型前舱冷却模块的布置优化与性能提升提供技术支持与理论指导。