电化学储能系统电池柜散热的影响因素分析

电化学储能系统是"双碳"目标实现的有利抓手,安全是电化学储能系统发展的生命线.由于大量电池存放于储能电池柜,因此对其散热性能的研究具有重要的意义.针对磷酸铁锂锂离子电池系统机柜:构建了电池系统数值模型,获得了电池柜内的温度场和气流组织,试验结果验证了模型的合理性;研究了进口风速、单体电池间距以及电池组间距对电池柜散热性...     

数字化变电站智能终端柜降温方案

由于传统箱体散热效果不佳导致500kV芝堰变智能终端柜内温度过高,使智能终端缺陷发生率居高不下,为提高变电站的安全稳定运行,介绍了智能终端当前的运行现状,提出加装隔热柜、加装空调、加装热交换器三种降温方案,并采用层次分析法进行方案选择。结果表明,加装翅片热板隔离式热交换器后箱内温度与未改造箱体相比降低了15℃,散热效果比较理想,基本满足了智能变电站室外场地智能终端正常运行的需要。     

数据中心服务器水冷散热器的数值模拟与实验验证

水冷散热器在数据中心服务器CPU芯片冷却技术中发挥着重要的作用。如何获得高性能的散热效率成为了该领域关注的重点。针对一种翅柱式水冷散热器,用数值模拟的方法,通过改变翅柱的结构参数来优化散热器的散热性能以及流动特性。在相同的翅柱间距下,改变翅柱的直径和高度,在不同的入口流量下,研究其温度,努塞尔数,压降,摩擦系数,分析比较其综合系数对散热性能的影响,并对结果进行了实验验证。结果表明翅柱高度3.9mm,直径为0.9mm的散热器其综合系数最大     

数据中心服务器水冷散热器的数值模拟及实验验证

水冷散热器在数据中心服务器CPU芯片冷却技术中发挥着重要的作用。如何获得高性能的散热效率成为了该领域关注的重点。针对一种翅柱式水冷散热器,用数值模拟的方法,通过改变翅柱的结构参数来优化散热器的散热性能以及流动特性。在相同的翅柱间距下,改变翅柱的直径和高度,在不同的入口流量下,研究其温度、努塞尔数、压降、摩擦系数,分析比较其综合系数对散热性能的影响,并对结果进行了实验验证。结果表明,翅柱高度3.9 mm、直径为0.9 mm的散热器其综合系数最大。     

简单实用的太阳能电热一体化组件

简要介绍了温度对太阳电池性能的影响和太阳电池散热及光伏光热综合利用模式.研究了水冷扁盒式不锈钢结构和水冷管板式铜铝复合结构的光伏热转换技术及太阳能电热联产一体化(PV/T)组件的设计制造及性能.通过测试对比表明:水冷管板式铜铝复合PV/T组件简单实用,具有推广价值.     

一种风电变流器防凝露系统的设计与试验

针对中国华电仰天湖风场的TW1650型风力发电机组变流柜的凝露问题,采用转轮除湿机为核心设计了一种防凝露系统,并将该系统加装在风机变流柜上进行现场试验,记录了变流柜内及机舱内、外的环境温度与相对湿度变化情况。试验结果表明,机舱外环境平均温度为17.2℃、平均相对湿度为93.1%,机舱内空气平均温度为24.9℃、平均相对湿度为53%的条件下,在防凝露系统作用下变流柜内空气相对湿度在短时间内下降至设定值(柜内空气平均相对湿度为35.7%)后便保持稳定,最低降至17.5%,同时柜内热负荷未明显增加,可见该防凝露系统能有效地对风机变流柜进行除湿防潮。     

基于R1233zd的泵驱两相流锂电池散热系统研究

随着人们环保意识的提升,车用锂电池得以飞速发展,水冷系统以其简单的系统结构被广泛应用于车用锂电池散热领域。水冷系统利用工质显热换热,不仅换热能力有限,也存在因工质泄露而引发短路、燃烧的安全隐患。泵驱两相流系统散热能力较强且安全,近年来多应用于航空航天领域,但是在车用锂电池散热方面的应用和研究较少,因此本文提出基于R1233zd的泵驱两相流系统替代水冷系统的锂电池散热方案。R1233zd具有无毒、不可燃且绝缘的特性,同时兼具环保性和较高的散热潜力,相比于传统制冷剂R134a,R1233zd具有更低的GWP和更高的潜热。本研究使用实验的方法,在使用相同实验台架且保持环境温度和冷源温度相同的情况下,对比分析热负荷为500W、700W、900W和1100W时,水冷系统和泵驱两相流系统的散热效果。结果表明：1）在相同散热量的情况下,泵驱两相流系统需要更低的流量,本实验中,泵驱两相流系统的流量仅为水冷系统流量的1/7;2）泵驱动两相流系统具有更好的散热效果,本实验中,其冷板温度比水冷系统低2℃到6℃、冷板下表面温差为水冷系统的1/7;3）泵驱两相流系统能够更好地抑制局部热点的蔓延。综上所述,基于R1233zd的泵驱两相流锂电池散热系统具有非常广阔的应用前景。     

电厂辅机变频器柜运行可靠性提升方案的研究

引发火力发电厂辅机变频器运行异常最主要的原因是变频器直流母线滤波电容老化与屏柜散热不良,提出了一种提升变频器的运行可靠性的方案,阐述了对屏柜散热技术、变频器直流母线部分的改进措施,对改进方案进行了验证,可有效地提高辅机变频器柜的工作可靠性,降低因辅机设备异常停机导致的跳闸概率。     

大功率晶闸管风冷重力热管散热器的新结构与传热试验

本文介绍了蒸发段内壁采用轴向槽道加抑泡孔管的风冷重力热管散热器。性能试验表明:这种热管散热器的热阻低达0.0129℃/W,主要性能指标优于国内外同类热管散热器,风冷散热能力达到水冷散热器水平。     

蜂窝状CPCM/水冷复合式圆柱型锂电池散热性能

为了进一步减小圆柱型锂电池在高热负荷下的温升、最大温差及轴向温差,提出一种基于石蜡/膨胀石墨(EG)的蜂窝状相变材料(PCM)水冷复合式电池散热结构.通过数值模拟,研究了环境温度40℃时,冷却液流速、微型流道数量、CPCM厚度及EG的质量分数对该系统散热性能的影响.结果表明,当液体流速超过0.05 m/s时,流速的继续...     

复合式土壤源热泵系统设计

设计了一套复合式土壤源热泵性能实验台,采用冷却塔作辅助冷源、太阳能热水器作辅助热源,能够实现冬季供暖、夏季供冷、一年四季提供60~80℃生活热水的功能。给出了系统中热泵机组、空调末端设备、冷却塔、水泵、太阳能热水器等主要部件的选型计算方法,经搭建好的土壤源热泵性能实验台运行测试,制冷和制热效果良好,同时也解决了土壤热平衡问题。     

水源热泵在空调系统中应用的经济性分析

本文对水源热泵的能耗进行了分析,表明水源热泵机组的性能系数与水源的温度直接相关,讨论了水源热泵在嵊州市空调系统集中供冷供热的可行性,对集中冷热水供水系统夏季空调工况与冬季热泵工况的经济性进行了计算与分析,结果表明,嵊州市利用水源热泵建立集中冷热水供水系统的社会经济效益显著,具有重要的节能与环保意义。     

溴化锂制冷技术在低温热回收利用中的应用

九江石化为了降低炼油能耗,实施了延迟焦化装置低温余热回收综合利用改造,将50℃热媒水分别进入常减压、1号催化、2号催化等6套热源装置,换热到128℃后,用于再沸器加热,为控制热媒水温度,在末端配有冷却循环水,控制热媒水返回温度在50℃左右。为了增加低温热系统的操作弹性,改造中引入了溴化锂制冷技术。溴化锂制冷机理为水在物体表面蒸发汽化,带走物体表面的热量,在真空条件下,物体表面温度会降到很低。溴化锂是一种吸水性极强的盐类物质,可以连续不断地将周围的水蒸气吸收过来,可创造和维持真空条件。溴化锂吸收式制冷机是利用溴化锂作吸收剂,用水作制冷剂,利用不同温度下溴化锂水溶液对水蒸气的吸收与释放来实现制冷的。应用溴化锂机组后,装置热平衡系统得到优化,循环热媒水末端温度下降到64℃(投用前为76℃),可节约冷却循环水600t/h;焦化装置干气吸收效果明显改善,C3+组分平均值为2.75%(体积分数),同比下降3.11个百分点。     

Performance evaluation of a vertical ground‐source heat pump system in Izmir,Turkey

This study summarizes the cooling performance of a ground‐source heat pump system which was installed in a 65‐m² room in the Solar Energy Institute, Ege University, Izmir (568 degree‐days cooling, base: 22°C; 1226 degree‐days heating, base: 18°C) Turkey. The institute, built in 1986, has a liveable floor area of 3000 m², and uses passive solar techniques. The heating and cooling loads of the room were, respectively, 3.8 and 4.2 kW at design conditions. The system was commissioned in May 2000 and the performance tests have been carried out since then. Based upon the measurements, the heat rejection rate to the soil with an average thermal diffusivity of 0.00375 m²h^?1 in the cooling mode was found to be in average 51 W m^?1 of bore depth, while the maximum entering water temperature to the unit was recorded as 35.9°C. The cooling coefficient of performance of the heat pump and the whole system was relatively low when compared to other heat pumps operating under conditions at or near design values. The primary reasons for this were discussed in detail and the potential for performance improvements was also suggested. Copyright © 2002 John Wiley & Sons, Ltd.     

Experimental results of a sensible heat storage system for residential and light commercial application

This paper presents the performance results for a sensible heat storage system. The system under study operates as an air source heat pump which stores the compressor heat of rejection as domestic hot water or hot water in a storage tank that can be used as a heat source for providing building heating. Although measurements were made to quantify space cooling, space heating, and domestic water heating, this paper emphasizes the space heating performance of the unit. The heat storage system was tested for different indoor and outdoor conditions to determine parameters such as heating charge rate, compressor power, and coefficient of performance (COP). The thermal storage tank was able to store a full charge of heat. The rate of increase of storage tank temperature increased with outdoor temperature. The heating rate during a charge test, best shown by the normalized rate plots, increased with evaporating temperature due to the increasing mass flow rate and refrigerant density. At higher indoor temperature during the discharge tests, the rate of decrease of storage tank temperature was slower. Also, the discharge heating rate decreased with time since the thermal storage tank temperature decreased as less thermal energy became available for use. Copyright © 1999 John Wiley & Sons, Ltd.     

Thermal performance of flat vapor chamber heat spreader

Experiments were performed to examine the spreading thermal resistance of centrally positioned heat sources and the thermal performance of a water charged, gravity assisted flat vapor chamber to be used for electronic cooling. Parametric studies including different heat fluxes and operating temperatures were conducted, and the effect of the relevant parameters on the cooling performance in terms of the spreading resistance was presented and discussed. The present vapor chamber heat spreader showed a heat removal capacity of 220 W/cm² with a thermal spreading resistance of 0.2 °C/W.     

A small-scale silica gel-water adsorption system for domestic air conditioning and water heating by the recovery of solar energy

A small-scale silica gel-water adsorption system with modular adsorber, which utilizes solar energy to achieve the cogeneration of domestic air conditioning and water heating effect, is proposed and investigated in this paper. A heat recovery process between two adsorbers and a mass recovery process between two evaporators are adopted to improve the overall cooling and heating performance. First, the adsorption system is tested under different modes (different mass recovery, heat recovery, and cogeneration time) to determine the optimal operating conditions. Then, the cogeneration performance of domestic cooling and water heating effect is studied at different heat transfer fluid temperatures. The results show that the optimal time for cogeneration, mass recovery, and heat recovery are 600 s, 40 s, and 40 s, respectively. When the inlet temperature of hot water is around 85°C, the largest cooling power and heating power are 8.25 kW and 21.94 kW, respectively. Under the condition of cooling water temperature of 35°C, the obtained maximum COP_c, COP_h, and SCP of the system are 0.59, 1.39, and 184.5 W/kg, respectively.     

延迟焦化装置低温热利用探讨

分析了洛阳分公司140×10^4t／a延迟焦化装置低温热利用状况,顶循油、柴油、稳定汽油与低温除盐水换热后,约可回收热量194．8MJ／t,降低装置能耗4．65kg标油／t。但低温热利用设计中存在着安全隐患和低温热利用不完全的问题,通过优化低温热水系统,防止回水带油;采用热联合工艺,提高热量利用效率;优化工艺流程,尽可能回收装置低温位热量的方式来解决。若60％以上的低温热均充分利用,将回收热量5×10^4MJ/h左右,降低装置能耗6-8kg标油/t。     

溴化锂吸收式热泵的动态建模及运行特性分析

为充分挖掘吸收式热泵的动态运行特性,考虑各部件存量工质的储热特性建立考虑传质和分布参数的溴化锂吸收式热泵动态仿真模型。在机组各设备存量工质质量不同的情况下,分析了热源工质进口温度的提升对冷却水和冷媒水出口温度的动态影响及系统的热惯性特征,同时在热源工质进口、冷却水进口和冷媒水进口温度变化的情况下,分析了系统的性能系数(Coefficient of Performance, COP)变化特性及结晶风险变化特性。结果表明：该模型能准确地模拟吸收式热泵的稳态特性和动态特性;机组的热惯性主要与机组内各设备中的存量溶液质量有关;热源工质入口温度的上限受到系统COP及结晶风险的双重影响;冷却水入口温度的下降可增大系统COP,其下限受到结晶风险的限制;冷媒水入口温度的上限不受结晶特性限制;主要受用户侧的用能需求限制。     

Humidification-dehumidification water desalination system integrated with multiple evaporators/condensers heat pump unit

A study of the performance enhancement of a humidification-dehumidification (HDH) system integrated with multiple evaporators/condensers heat pump (HP) and heat recovery units is presented. The HP unit is intended to deliver necessary heating for humidifier and heating/cooling for dehumidifier in a new strategy. The proposed integrated system is capable to produce fresh water from the HDH system and HP unit. Four different configurations of the system formed by excluding/adding condensers and evaporators were investigated; mode-A (seawater precooling and reheating), mode-B (seawater reheating), mode-C (seawater precooling and humid air reheating), and mode-D (humid air reheating). Fresh water productivity, fresh water ratio, system water recovery, gain output ratio, specific work consumption, and fresh water production cost were used as performance measuring parameters of the system. The influences of operating parameters on the system performance were analytically studied and experimentally validated for different system configurations. The results indicate the enhancement of the systems' performance with increasing ambient air temperature and humidity, seawater and air flow rates, and with decreasing seawater temperature. The system configuration of mode-B shows the best performance with fresh water production of 61.94 kg/h and gain output ratio of 4.97 which are higher than those of the other configurations by 13%, 55%, 85% and 11%, 48%, and 75%, respectively. Comparisons of the proposed configurations with the other HDH desalination systems available in the literature were presented and better performance of the proposed systems was noticed.