Storage and exchange thermal characteristic analysis of phase change wallboard room with different conditions

Based on the phase change material (PCM) thermal characteristic,some testing methods such as differential scanning calorimeter (DSC) etc were used to select the low melting mixture of capric and lauric acid as PCM of phase change wallboard (PCW). The PCW room was established,and some contrast analysis of the storage and exchange thermal characteristic of PCW room and ordinary wall room were made under different conditions. The results show that the fluctuation of indoor air temperature in PCW room is smaller than that in ordinary room obviously. The exchange energy of PCM room with outdoor is less than that of ordinary wall room. In the winter condition,PCW room utilizes valley period electricity to storage energy in the night,while releases at peak period electricity in daytime,which can divert 40% of peak load. In the summer condition,PCW room can reduce the peak cooling load by 25% compared with ordinary wall room.

Energy Storage System with Ultracapacitors for Thermal Underwater Glider

A power system with proton exchange membrane fuel cells (PEMFC) was designed for thermal underwater glider.Heat generated by PEMFC is used as the propulsion power of the glider,and the electricity is used in the control and sensor system.An electric energy storage system (ESS) is required which possesses high power density with good cycle life.Ultracapacitors which exhibit high power density and cycle life are considered as energy storage devices.Simulations based on a specific voyage condition indicate that ESS with ultracapacitors has positive effects on reducing the output power demand of PEMFC and lightening the power system.Experimental results show that the state of charge (SOC) is related to the capacitance and resistance in ultracapacitor ESS.

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.

High Na-ion conductivity andmechanical integrity of anion-exchanged polymeric hydrogel electrolytes for flexible sodium ion hybrid energy storage

The polymeric gel electrolytes are attractive owing to their higher ionic conductivities than those of dry polymer electrolytes and lowered water activity for enlarged potential window.However,the ionic conductivity and mechanical strength of the Na-ion conducting polymeric gel electrolytes are limited by below 20 mS cm−1 and 2.2 MPa.Herein,we demonstrate Na-ion conducting and flexible polymeric hydrogel electrolytes of the chemically coupled poly(diallyldimethylammonium chloride)-dextrin-N,N′-methylene-bisacrylamide film immersed in NaClO_(4) solution(ex-DDA-Dex+NaClO_(4))for flexible sodium-ion hybrid capacitors(f-NIHC).In particular,the anion exchange reaction and synergistic interaction of ex-DDA-Dex with the optimum ClO_(4)−enable to greatly improve the ionic conductivity up to 27.63 mS cm−1 at 25◦C and electrochemical stability window up to 2.6 V,whereas the double networking structure leads to achieve both the mechanical strength(7.48 MPa)and softness of hydrogel electrolytes.Therefore,the f-NIHCs with the ex-DDA-Dex+NaClO_(4) achieved high specific and high-rate capacities of 192.04 F g^(−1)at 500 mA g^(−1)and 116.06 F g^(−1)at 10000 mA g^(−1),respectively,delivering a large energy density of 120.03Wh kg^(−1)at 906Wkg^(−1)and long cyclability of 70%over 500 cycles as well as demonstrating functional operation under mechanical stresses.

Enabling low-cost decentralized power reserves adopting carbon dioxide for green methane exchange in stabilized clathrate adsorbent

1.Challenges circular methane energy systems In recent decades,methane-based energy systems have rapidly gained traction across the globe because of the increasing availability of low-cost methane production capacity.However,fossil methane production and combustion lead to large greenhouse gas emissions,contributing to climate change[1].

回收工业余热用于供暖的相变换热装置储能材料的研究

我国工业余热资源丰富,利用相变换热器回收余热用于建筑供暖为清洁供热提供了可靠的新途径。按不同比例制备了石蜡和硬脂酸二元混合相变材料,并对混合相变材料的相变温度、相变潜热、热导率的变化规律进行了实验研究,旨在寻找适合回收余热用相变换热器的储能材料。研究结果表明,62~#石蜡与硬脂酸混合物的相变温度在43~66℃范围内波动;当62^(#)石蜡与硬脂酸的配比为20∶80时,相变温度为62.73℃,相变潜热较大,为205.53J/g;二元混合物熔化潜热与凝结潜热相差不大,材料过冷度较小,是用于低温余热回收的相变蓄热换热装置的理想储能材料。将储能材料用于相变换热器中,储能材料熔化回收工业余热进行蓄热,蓄热量用于加热散热器回水,实现间歇性工业余热转变为连续输出热量进行供暖。

绝热式压缩空气储能系统中换热器的影响分析

绝热式压缩空气储能系统具有大容量、长时、安全、稳定和灵活等特点.在该类储能系统中,换热器作为关键部件,对系统效率具有重要影响.通过建立绝热式压缩空气储能热力系统模型,分析了换热器端差、空气侧压降对系统效率的影响,同时综合评价了换热器成本.结果表明:换热器上端差的增加会导致系统效率降低,在实际工程设计时,应使下端差与上端差相匹配;相比于高压级换热器,低压级换热器的空气侧压降对系统效率的影响更大;换热器的端差越小、压降越低,系统效率越高,但是设备成本也越高,因此在满足系统效率要求的前提下存在最优的端差和压降组合使换热器成本最优.

基于虚拟储能的综合能源系统用能协调控制策略

多能互补综合能源系统(Integrated Energy System,IES)是提高分布式新能源渗透率和增强终端能源消费灵活性的重要手段,针对现有技术在多能系统对外能量特性建模和多系统交互策略方面研究的不足,文章提出了一种基于虚拟储能的综合能源系统用能协调控制方法,基于多代理技术构建楼宇-代理商-配网三层能量交互架构,以描述系统对外特性的虚拟储能模型为交互接口,量化分析管控多楼宇和并网储能、微燃机等多能分布式资源的代理商的虚拟储能。在此基础上,按照系统空间范围扩大递进分析,构建基于多代理的综合能源系统用能协调控制策略,该策略能够根据决策目标最大化利用以配电网为核心的楼宇、园区等各层级综合能源系统的资源,尽可能实现自治运行。

新能源产业链构建:光伏发电-电化学储能-新能源汽车

以高速路网光伏发电-电化学储能-新能源(电)汽车全产业链为基础,描述未来新能源生态体系的构筑蓝图:①在供给侧,探讨全面普及清洁能源的战略布局,打造高速路网光伏超级电站,依托光伏发电全生命周期低成本的优势,直接为下游终端提供电力,大幅降低新能源应用端的使用成本,推动以新能源汽车为中心的下游产业扩张,减少传统能源消耗和碳排放,助推绿色发展;②在储能端,加速液流电池和液态金属电池等电网储能设备的应用以及以硅碳和三元材料为代表的高容量动力电池材料的规模化生产进程,统一电池和配套设施的制造标准,并借助互联网战略,建立电池全生命周期的监测、维护和回收利用网络;③在应用端,制定新能源汽车的全新制造标准,全面推行模块化的设计和生产,用可更换电池模组替代集成式电池模组,建设替代加油站的配套电池供应网络,提供电力接入和电池充电、更换、维护服务。另外,还简述了利用新能源产业中的弃风、弃光发展氢能源,以氢能作为当下新能源体系的补充。通过新能源产业上、中、下游的同步建设,希望在未来30年内打造一个供给端-储能端-应用端协同发展的产业链,逐步形成独立于化石能源的、包含光伏和风电等多种能源形式的新能源闭环生态体系,实现社会能源消费结构转型,助力“碳达峰、碳中和”战略实施。

基于内管移动的卧式管壳式相变储热器储热性能优化研究

相变储热技术能够实现对固态储放氢过程热量的回收和供给,实现固态储氢罐内的自热平衡,提高储放氢性能。研究针对卧式管壳式相变储热器,提出了一种新型的内管偏心放置绕中心轴线旋转的运动方式,采用Fluent数值模拟软件,基于动网格技术编写了用户自定义函数UDF,重点研究了内管偏心距离与旋转速度对储热性能的影响。结果表明:与传统中心内管静止布置相比,偏心内管的旋转运动能够显著提高储热性能,当偏心距离为9 mm,旋转速度为0.10 r/min时,储热时间达到最小值,储热时间减少了92.16%,时间平均储热速率是内管静止布置的11.51倍;当偏心距离为9 mm,旋转速度由0.30 r/min减少至0.10 r/min时,储热时间减少了13.57%;当旋转速度为0.10 r/min,偏心距离由3 mm增至9 mm时,储热时间减少了70.48%。该研究结果可为卧式管壳式相变储热器在储氢领域的性能优化研究提供新思路。

压缩空气储能技术研究现状及发展趋势

[目的]压缩空气储能具有储能容量大、安全性高、寿命长、经济环保、建设周期短等优势,是未来和抽水蓄能相媲美的长时储能技术,成为未来储能重点布局的方向。在此背景下,文章通过对压缩空气储能技术现状进行综述,分析不同压缩空气储能技术的工作原理、面临挑战及解决方案,以期对压缩空气储能技术的发展提供参考。[方法]文章首先对压缩空气储能技术原理进行了介绍;对系统中的压缩机、透平膨胀机和换热器等关键设备进行了阐述,分析了大规模压缩空气储能用的关键设备;并从地面关键工艺技术和地下储气设施两个角度介绍了大规模压缩空气储能系统的常用关键技术、发展现状及工程案例;最后对压缩空气储能技术的未来发展趋势进行了分析。[结果]结果表明:蓄热式压缩空气储能是当前国内的主流技术,且高温储热成为未来压缩空气储能发展方向,也是压缩空气储能提高效率的重要途径。同时,系统关键设备和技术优化、成本降低、应用场景发展等方面尚有一定改进空间。[结论]压缩空气储能作为一种长时储能,对未来构建新型电力系统具有重要的支撑作用。

中深层地热田开发利用技术研究进展

地热能是重要的可再生能源,是我国“十四五”期间重点发展的可再生能源之一。我国地热能直接利用量连续多年保持世界第一,但中深层地热田开发利用技术与国外先进水平尚有差距。当前全球地热初创公司快速增长,地热资源开发力度持续加大,地热能利用场景多样化,地热发电装机容量稳步增长,开发利用技术取得较大进展。具体表现为4个方面:(1)中深层闭式换热系统设计技术逐渐成熟;(2)EGS技术取得历史性突破,应用潜力巨大;(3)多国重视含水层储热在弥补能源供需不平衡上的作用,加快推进含水层储热场址选择、热回收率及风险分析等方面的研究;(4)回灌成为中深层水热型热储开发的通用做法,回灌数值模拟及方案设计、防腐蚀、防结垢、防堵塞等技术进步有效延长了地热田的生命周期。“双碳”背景下,我国应将关键技术研发作为发展新质生产力的主要突破口,快速升级中深层地热田开发利用技术,有效提升地热项目经济性,实现地热利用规模持续增长。

基于储能技术的电力系统调度方法

传统电力系统调度能力滞后,而基于信息交换系统(IES)能提高电力调度能力。通过构建调度控制中心、运行中心和监测中心的调度系统提高了用户应用效率,并设计了微型电力储能装置,将电力系统中的电力能源管理器、各终端负荷、储能装置、变电站及其他模块相互结合,提高了能源分布式储能过程和电网联网的控制,并通过微电流计算法(CES)构建数学模型,使电力系统调度能力大大增强。通过实验数据表明,该研究设计硬件最高监测精度可达97.3%。

基于电动汽车换电站的配网解列下弹性提升策略的探索研究

近年来频发的自然灾害严重威胁了配电网的安全运行,而电动汽车换电站内储能电池具有易运输的特性。为提升应急供电场景下配电网弹性,本文提出了一种运输换电站储能电池的运行调度方法。首先,以应急场景下系统最小运行成本为目标,综合考虑负荷损失成本、发电成本与交通运输成本构建了含电动汽车运输交通网络的配电网络优化模型。然后,针对模型中的非线性部分展开分析,将优化问题转换为便于求解的线性混合整数优化问题,并通过算例验证了所提策略的有效性。在一定边界条件下,所提方法可智慧化调度可换电式电动汽车,将能量充足地区的储能电池调度至能量紧缺区域,降低了应急情况下电力系统运行成本,提升了电力系统整体的运行弹性。

Enhancing Heat Transfer and Energy Storage Performance of Shell-and-Tube Latent Heat Thermal Energy Storage Unit with Unequal-Length Fins

Previous studies in literatures adequately emphasized that inserting fins into phase change material is among the most promising techniques to augment thermal performance of shell-and-tube latent heat thermal energy storage unit.In this study,the novel unequal-length fins are designed from the perspective of synergistic benefits of heat transfer and energy storage performance,and the effects of arrangement,number and total length of unequal-length fins are numerically investigated.Results show that utilization of fins with ascending length,when short and long fins are located in the inlet and outlet of heat transfer fluid respectively,can further promote the heat transfer and energy storage performance compared with equal length fins,and a maximum 6.17%and 0.43%increment of heat transfer performance and stored energy is achieved in full melting time,respectively.The number of unequal-length fins plays a major role in the energy storage,and 18.95%and 0.91%improvement of heat transfer performance and stored energy is realized when equipped with 2 unequal-length fins.A 21.17%improvement of the heat transfer performance is obtained when the total length of unequal-length fins is 18 mm.The present study is helpful to make further efforts to enhance heat transfer and energy storage of shell-and-tube latent heat thermal energy storage unit with unequal-length fins.

Experimental research and numerical simulation of the thermal performance of a tube-fin cold energy storage unit using water/modified expanded graphite as the phase change material

In this study,experimental and numerical investigations were conducted on a tube-fin heat-exchanger latent-heat cold energy storage unit.The fin side of the heat exchanger was filled with water as the energy storage medium,and modified expanded graphite(MEG)was employed to improve the thermal characteristics of water.The water contact angle of the expanded graphite decreased from 106.31°to 0°,and the hydrophilicity and the absorption rate of water significantly improved after the modification.Moreover,the experimental analyses of the charge/discharge process showed that the cooling capacity of the system filled with 90 wt.%water/MEG was 80.8%of that of pure water,whereas its cooling time was only 69.7%of that of pure water.The average power increased by 15.9%compared with that of water.The system filled with 90 wt.%water/MEG completed two energy charging and discharging cycles,whereas the system filled with water completed only 1.5 cycles within 15000 s.Furthermore,the effects of the flow rate and inlet temperature of the heat transfer fluid on the charging process were explored.Finally,a numerical model was built and validated to investigate the phase change behavior and the effect of the structure size on the performance of the system.The heat-exchanger fin spacing had no significant effect on the cold energy storage unit,whereas the vertical spacing of the tube pass had the highest effect.It can be concluded that the heat exchanger combined with high-thermal-conductivity water/MEG exhibits better energy storage capacity and working power,showing a wide application prospect in the field of cold energy storage.

合金材料在储能技术中的应用与发展

铝硅合金相变材料的密度和热导率高,稳定性强,在储能储热系统中有着极大的研究价值和应用潜力。本文针对铝硅合金材料在储能领域的应用发展进行综述,文章首先回顾了铝硅相变材料国内外研究实例,总结核心物理参数,以此为基础提出相变储热材料与换热技术的研发方向,包括容器材料稳定性、铝硅相变物理性以及相变蓄热器的结构优化,最后总结了铝硅合金的未来应用发展方向。

模型差异性混合储能系统建模及功率分配

该文从锂电池和燃料电池的混合储能特性出发,针对已有文献的拓扑结构,对比选取适用于功率分配的混合储能拓扑模型和建模方法,并在组合过程中通过分析选取最合适的变换方式组成混合储能模型,最后通过仿真验证所提模型可在进行功率分配的前提下提高储能系统荷电状态偏移,延长储能系统寿命。

Solidification in a shell-and-tube thermal energy storage unit filled with longitude fins and metal foam:A numerical study

In this study,an innovative thermal energy storage design method was developed by adding the combination of metal foam and fin to phase change materials(PCMs).A numerical model was built and verified based on the comparison among the present model prediction,experimental measurements,and numerical results in open lit-erature.To highlight the novel design method,four cases including fin-PCM,foam-PCM,fin-foam-PCM,and PCM unit were compared by means of solidification features.The temperature distribution,solidification front propa-gation,and buoyancy-induced convection in the liquid PCM were accounted for.Numerical results demonstrated that metal foam outperformed fin regarding the improvement on solidification phase change.The combination of foam and fin achieved the best performance,leading to a 90.5%reduction in complete energy release time in comparison with the PCM unit.The proposed design method provided reference potentials for advancing energy storage engineering.However,buoyancy-induced convection in the liquid PCM before solidification was harmful to the formation of solidification front and its movement.A maximal 11.5%prolonging time for the complete solidification was found.

压缩空气储能电站储能电量计算及在线修正方法

大型压缩空气储能电站一般使用地下洞穴作为储气设施,地下洞穴的准确容积不易测量,因此通过储气容积来计算储能电量存在困难。使用少量的运行数据构建起了压缩空气储能电站储能电量与储气压力的对应关系,并使用后续运行数据对不同高温换热介质温度和不同低温换热介质温度下储能电量进行修正,得到相对准确的储能电量计算方法。