Absolute dielectronic recombination rate coefficients of highly charged ions at the storage ring CSRm and CSRe

Dielectronic recombination(DR)is one of the dominant electron-ion recombination mechanisms for most highly charged ions(HCIs)in cosmic plasmas,and thus,it determines the charge state distribution and ionization balance therein.To reliably interpret spectra from cosmic sources and model the astrophysical plasmas,precise DR rate coefficients are required to build up an accurate understanding of the ionization balance of the sources.The main cooler storage ring(CSRm)and the experimental cooler storage ring(CSRe)at the Heavy-Ion Research Facility in Lanzhou(HIRFL)are both equipped with electron cooling devices,which provide an excellent experimental platform for electron-ion collision studies for HCIs.Here,the status of the DR experiments at the HIRFL-CSR is outlined,and the DR measurements with Na-like Kr25^(+)ions at the CSRm and CSRe are taken as examples.In addition,the plasma recombination rate coefficients for Ar12^(+),14^(+),Ca14^(+),16^(+),17^(+),Ni19^(+),and Kr25^(+)ions obtained at the HIRFL-CSR are provided.All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00113.00092.

Heat transfer and parametric studies of an encapsulated phase change material based cool thermal energy storage system

This work investigates the transient behaviour of a phase change material based cool thermal energy storage (CTES) system comprised of a cylindrical storage tank filled with encapsulated phase change materials (PCMs) in spherical container integrated with an ethylene glycol chiller plant. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid (HTF) and the phase change material at any axial location during the charging period. The results of the model were validated by comparison with experimental results of temperature profiles of HTF and PCM. The model was also used to investigate the effect of porosity, Stanton number, Stefan number and Peclet number on CTES system performance. The results showed that increase in porosity contributes to a higher rate of energy storage. However, for a given geometry and heat transfer coefficient, the mass of PCM charged in the unit decreases as the increase in porosity. The St number as well as the Ste number is also influential in the performance of the unit. The model is a convenient and more suitable method to determine the heat transfer characteristics of CTES system. The results reported are much useful for designing CTES system.

Seasonal coolth storage system for residential buildings in Australia

Night sky cooling is explored as an alternative to the conventional cooling technologies using fossil fuels.The night sky cooling method is based on the long wave radiation of unglazed collectors to the sky at night.An evaluation of the night sky cooling system is present for a residential building in three cities of Australia,namely Alice Springs,Darwin and Melbourne.The system comprises an unglazed flat plate solar collector integrated with borehole storage.It uses night sky radiation to reduce the temperature of the ground near to the boreholes.The system was simulated with TRNSYS,a transient simulation program.The simulation results for adequately sized systems show that night sky radiation is able to reduce the coolth storage borehole temperature and the proposed system is able to meet the cooling load of the residential building simulated in three locations.Borehole lengths of 270,318 and 106 m are required for coolth storage with 90,260 and 14 m2 collector area for heat rejection in Alice Springs,Darwin and Melbourne,respectively.At the 20th simulation year,the proposed system is able to achieve a system cooling coefficient of performance of 2.2 in Alice Springs,and 2.8 in Darwin and Melbourne.

Effect of thermal storage performance of concrete radiant cooling room on indoor temperature

A building model with radiant cooling system was established and the cooling load,indoor temperature,surface temperature of the walls and other parameters in non-cooling and radiant cooling room were calculated by TRNSYS.The comparative analysis of the characteristics of attenuation and delay proves that the operation of radiant cooling system increases the degree of temperature attenuation of the room and reduces the inner surface temperature of the wall significantly,but has little effect on the attenuation coefficient and delay time of wall heat transfer.The simulation results also show that the inner surface temperature of the walls in the radiant cooling room is much lower than that in non-cooling room in the day with the maximum cooling load,which reduces the indoor operation temperature largely,and improves the thermal comfort.Finally,according to the analysis of indoor temperature of the rooms with different operation schedules of cooling system,it can be derived that the indoor mean temperature changes with the working time of radiant cooling system,and the operation schedule can be adjusted in practice according to the actual indoor temperature to achieve the integration of energy efficiency and thermal comfort.

Cool storage time of phase change wallboard room in summer

More and more attention was paid to phase change energy storage in air conditioning domain and construction energy conservation,and became the focus of the international research. Through the test and analysis of the parameters of the indoor thermal property in phase change wallboard room and ordinary room,the effects of using phase change wallboards on indoor temperature in summer and air conditioning are obtained. The combination of construct enclosure and phase change materials can stabilize indoor temperature,improve indoor thermal comfort,reduce the frequency of the operation of air conditioning facility,cut the initial investment and operation expense,and meanwhile play an practical role in "the power balancing between the peak period and the valley period" policy. Through the experiment and the test of the effects exerted by phase change wallboard room and ordinary room on the indoor thermal environment,it is obtained that the phase change wallboard can reduce the fluctuation range of indoor temperature and the heat flow from the outside into indoor environment in summer. According to the study,it is found that the effect of cool-storing for 5 h is obvious. Through the analysis of the phase change wallboard without air conditioning in daytime,it is obtained that the frequency of the operation of air conditioning in phase change wallboard room is smaller than that in the ordinary room,which can prolong the lifetime of the facility and reduce operation expense.

Performance analysis of thermal storage unit with possible nano enhanced phase change material in building cooling applications

The heat transfer performance of the phase change materials used in free cooling and air conditioning applications is low,due to the poor thermal conductivity of the materials.The recent phenomenal advancement in nano technology provides an opportunity for an appreciable enhancement in the thermal conductivity of the phase change materials.In order to explore the possibilities of using nano technology for various applications,a detailed parametric study is carried out,to analyse the heat transfer enhancement potential with the thermal conductivity of the conventional phase change materials and nano enhanced phase change materials under various flow conditions of the heat transfer fluid.Initially,the theoretical equation,used to determine the time for outward cylindrical solidification of the phase change material,is validated with the experimental results.It is inferred from the parametric studies,that for paraffinic phase change materials with air as the heat transfer fluid,the first step should be to increase the heat transfer coefficient to the maximum extent,before making any attempt to increase the thermal conductivity of the phase change materials,with the addition of nano particles.When water is used as the phase change material,the addition of nano particles is recommended to achieve better heat transfer,when a liquid is used as the heat transfer fluid.

Thermal properties in phase change wallboard room based on air conditioning cold storage

By comparing the thermal performance parameters of an ordinary wall room with a phase change wall (PCW) room,the effect of phase change wallboard on the fluctuation of temperature in air-conditioning room in summer was studied. And PCW room and an ordinary wall room,which are cooled by air-conditioner,were built up. Differential scanning calorimetry (DSC) was used to test the temperature field and heat flow fluctuation in these rooms. Through analyzing the data tested,it is found that the mean temperature of PCW is lower than that of ordinary wall room by 1-2 ℃,and PCW can lower the heat flow by 4.6 W/m2. Combining phase change material to building envelope can lower the indoor temperature,make the room thermal comfortable,and cut down the turn-on-and-off frequency of air-conditioner,the primary investment and operating costs. It alleviates urgent need of the electric power. Building envelope which contains phase change wallboard can improve the indoor thermal environment,and decrease energy consumption in buildings. Phase change wallboard can make impressive effect on energy efficiency of buildings.

新型迷你通道-相变热沉实验研究

电子元件的集成化、微型化等特点加剧了芯片的热问题,基于相变材料的被动式冷却技术已无法满足功率波动的高功率电子设备的需求。本文将相变技术与主动冷却技术相结合,提出了一种用于风冷散热的新型迷你通道-相变热沉结构。该结构改善了相变材料导热性能差的问题,也解决了相变材料熔化后泄漏的问题。通过实验测试了不同热流密度、不同风速对其热控性能的影响,总结了热沉的蓄放热特性,并与未填充相变材料热沉的热控性能进行了对比。实验中热流密度变化范围为1.81~3.47 W/cm^(2),风速变化范围为0~4 m/s。研究表明:热流密度的增大和风速的降低均会导致热沉温控时间的缩短。2 m/s风速足以满足热流密度小于2.91 W/cm^(2)的芯片散热需求,4 m/s风速可以在热流密度为3.47 W/cm^(2)的情况下将热沉底面温度维持在70℃。与未填充相变材料热沉相比,本研究提出的热沉可以起到延长温控时长,降低稳态温度的作用。此外,风扇的开启可以有效缩短热沉的冷却时间,对于间歇性工作的电子设备具有重要的应用意义。研究结果可为迷你通道-相变热沉在实践中的应用提供参考依据。

基于TRNSYS的主动式建筑相变蓄冷空调系统模拟

以夏热冬冷地区的办公建筑为例,利用瞬态系统仿真程序(transient system simulation program, TRNSYS)构建主动式相变蓄能地板模块,建立了主动式相变蓄能地板空调系统和常规风机盘管加新风空调系统的仿真模型,对其节能性和经济性进行模拟计算.以典型日和供冷季晚间蓄冷运行工况为条件,研究冷冻水温对主动式相变蓄能地板的蓄释能特性、室温波动与热泵制冷系数的影响.结果表明:夜间相变蓄冷工况下,在满足每平方米冷负荷为74.78 W情况下,9℃为最佳供水水温;采取晚间低电价时段间歇运行蓄冷热泵的方案,能够有效提高热泵运行时的制冷系数,并降低运行费用;主动式相变蓄能地板空调系统供冷季的能耗相比于常规风机盘管加新风空调系统减少30.5%,运行费用减少44.24%,夏季制冷综合能效比达到了2.38.

粮仓能源桩系统绿色储粮技术应用研究

简化粮食入库后全周期控温供冷储粮流程,提出满仓主动降温与夏季粮仓热平衡2种供冷方案。通过理论公式计算2种方案下的供冷量需求,并利用有限元模拟软件计算得出能源桩换热量,由此设计可满足上部粮仓供冷需求的能源桩运行方案。结果表明:在1万t储粮规模下,粮仓能源桩储粮技术可满足2种供冷方案下的能源需求,对比谷物冷却机与地源热泵储粮,其初期投入成本更低;对比空调储粮,其初期投入成本增加,但能源桩储粮技术可利用绿色清洁能源,储粮能耗最低。

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。

基于土壤蓄冷的新型果蔬预冷方案的模拟计算

如何利用自然冷源一直都是热点话题。季节性土壤蓄冷目前在舒适性空调领域已经有了相关的应用案例,但冷链物流的温度都一般都在0~5℃或-18℃,空调的系统温度一般难以满足其要求,因此在冷链物流方向的应用还是较少。在冷链物流的各个环节中,果蔬等农产品采摘后的预冷是全程冷链的第一步也是关键一步,但由于其耗能较大,源头地缘限制等因素导致其不能大面积铺开,造成食品在冷链中出现腐烂和过熟。本文基于土壤蓄冷构造了一种新型的果蔬预冷方案,探讨其节能效果。

含分层储能的冷热电联供系统运行优化

为提高冷热电联供型微电网对可再生能源的消纳能力,解决源-荷的不确定性使得系统运行稳定性降低的问题,提出含分层储能的三级混合时间尺度滚动优化方法。日前优化目标为日运行成本最低;日内上层以燃料成本和蓄热罐功率变化惩罚成本最低为目标对冷热能进行优化,下层以电网交互成本和蓄电池功率变化惩罚成本最低为优化目标对电能进行优化;实时电系统反馈以电系统削峰填谷作用量和功率波动量最低为优化目标;得出最优的系统中各设备的出力计划。结果表明:该优化方法和分层储能能够有效达到削峰填谷的作用,各设备功率波动率均处于较低水平;冬季典型日的日运行成本比日前成本有所降低。

基于降低干耗的果蔬保鲜库风机选型方法

在果蔬保鲜库的建设与运行中,合理的冷风机选型对于保持产品质量和降低能耗具有关键意义。本文分析研究了影响冷风机选型的关键设计输入参数和相关条件,并探讨了输出参数确定与技术要求校核的方法。本研究的目标是果蔬保鲜库的冷风机选型提供可行实用的流程,以减少食品干耗,确保冷库内物品保鲜效果。通过设计参数的梳理、条件确认和校核,确定了风机选型方法。结果表明,本选型方法能有效减少食品干耗并提升能效。

提高转炉汽化系统寿命及效率的技术创新

以转炉循环水系统为研究对象,将高压富裕能头用于启动或加速自然循环,实现系统的优化用能,达到系统节能兼顾尾部烟道长寿的双赢效果。研究分析前部烟道的结构缺陷,开发防大喷溅挂渣技术、随动密封装置等,使前部烟道寿命提高2 a以上,氮气消耗量降低约90%。开发应用了一系列高效节能核心动力设备,解决了汽化冷却系统蒸汽产量低、品质差的共性技术难题,使得吨钢产汽提高至100~130 kg,排污系统热损失减少50%,除氧器排汽热损失减少50%。

液冷散热式预制舱储能系统冷却液回路设计

随着液冷式预制舱储能推广,亟需冷却液回路设计方法。从工程实用角度出发,针对液冷板,提出了普适于常见3至4排电芯电池包的U形流道结构,分析了流道宽度、高度设计方法;针对液冷管路,提出管路并联式排布和管路变径的方案,阐述了管路流量、节流孔尺寸设计方法。依托1 MW/2 MWh海岛储能工程,分析了工程设计实例。收集并分析了现场运行情况,所设计方案能将电池温度控制至预定区间,电池温差不超过3℃。

液冷式锂电池储能系统高倍率调频应用研究

针对风光能源规模化接入电网造成的频率波动问题,提出了结合功率型锂电池及液冷式热管理的储能系统。基于实验测试获取了功率型锂电池的电热特性,结果表明高倍率工况下仅依靠自然对流散热不能满足电池合理工作温度需求。建立了液冷式热管理系统及其仿真模型,并通过数值仿真对4C倍率放电、不同流量以及实际AGC调频工况条件下系统热管理性能及电池热行为进行了分析。研究表明实际AGC调频工况下,电池间温差小于2℃,最高温度小于33℃,证明了液冷式热管理方案能够实现储能系统在高倍率调频工况下的长期稳定运行。

集装箱式储能电站两相冷板液冷系统的温控效果研究

长期处于高温与大温差将会损坏电池性能与使用寿命,而现有的电池储能冷却系统普遍存在冷却效率低、冷热气流组织紊乱以及漏液风险等问题。针对以上不足,本文研发了应用于大型集装箱储能的新型两相冷板液冷系统,并在湖南省湘潭市某储能电站对其温控效果进行现场实测。首先,分析了两相冷板在整个充、放电过程中对全舱与各电池箱的电池温度和温度一致性的控制效果,其次,揭示了充、放电过程结束后的静置期间电池温度变化规律。研究结果表明,两相冷板液冷系统在整个充、放电过程中能够有效降低电池的温升,并将全舱电池的最大温差从传统液冷系统的4.17℃降低至3℃以内,提高了电池温度的一致性;在同等充、放电条件下,充电时电池散发的热量高于放电时电池散发的热量;无冷却情况下,静置阶段储能电站内部电池会出现80 min及更长时间持续高温的现象。

基于相变蓄冷的核电厂主控室非能动冷却系统

为提高现有核电厂主控室紧急可居留系统的蓄冷能力及热舒适性水平,提出了基于定形相变蓄冷材料的核电厂主控室非能动冷却系统。基于主控室热负荷分布情况,该冷却系统在主控室顶板与吊顶之间、内墙面、地板底面及循环风道内,针对性地布置相应的含有定形相变材料的非能动冷却装置,进而实现事故工况下对主控室温度的精确控制。该非能动冷却系统无需引入额外冷源和管道,可靠性强,同时不破坏主体结构,且可灵活布置,解决了现有主控室非能动热阱时间余量小、热舒适性差的问题。