Using Parallel Packed Bed within a High Temperature Thermal Energy Storage System for CSP-Plants

In order to optimize the electricity yield of CSP （concentrated solar power） plants, TES （thermal energy storage） systems are regarded as an essential component. Furthermore, for many electricity grid operators, it is important to have spinning reserves in the grid and dispatchable power available, both offered by CSP-plants with integrated thermal energy storage. Enolcon is developing a new TES-system since several years. The system itself was designed to offer a principle simple and robust setup （with regard to execution and operation） and which is reducing the electricity costs of CSP-power plants by the consequent use of state of the art technology. Furthermore, such system shall be open to future developments of CSP-systems with regard to increasing steam temperatures and steam pressure. Such TES-system shall be commercially available for large scale application already in year 2014/2015. The key elements of the enolcon-TES are the open cycle using always ambient air with an air-air-heat exchanger and the arrangement of the storage material in such way to minimize the pressure losses and the own electricity consumption. The development is progressing in a structured way by studies, engineering works, TES-pilot plants, isothermal air flow test plant for the verification of the CFD-calculations, and since end of 2012 by the operation of a high temperature TES-module with all features of the large scale modules.

Research progress on protective coatings against molten nitrate salts for thermal energy storage in concentrating solar power plants

Concentrating solar power(CSP) has garnered considerable global attention as a reliable means of generating bulk electricity, effectively addressing the intermittent nature of solar resources.The integration of molten salt technology for thermal energy storage(TES) has further contributed to the growth of CSP plants;however, the corrosive nature of molten salts poses challenges to the durability of container materials, necessitating innovative corrosion mitigation strategies.This review summarizes scientific advancements in high-temperature anticorrosion coatings for molten nitrate salts, highlighting the key challenges and future trends.It also explores various coating types, including metallic, ceramic, and carbon-based coatings, and compares different coating deposition methods.This review emphasizes the need for durable coatings that meet long-term performance requirements and regulatory limitations, with an emphasis on carbon-based coatings and emerging nanomaterials.A combination of multiple coatings is required to achieve desirable anticorrosion properties while addressing material compatibility and cost considerations.The overall goal is to advance the manufacturing, assembly, and performance of CSP systems for increased efficiency, reliability, and durability in various applications.

High temperature polyimide nanocomposites containing twodimensional nanofillers for improved thermal stability and capacitive energy storage performance

Future electronic devices toward high integration and miniaturization demand reliable operation of dielectric materials at high electric fields and elevated temperatures.However,the electrical deterioration caused by Joule heat generation remains a persistent challenge to overcome.Here,the solution-processed polyimide(PI)nanocomposites with unique two-dimensional(2D)alumina nanoplates are reported.Substantial improvements in the breakdown strength,charge–discharge efficiency and discharged energy density at elevated temperatures have been demonstrated in the composites,owing to simultaneously suppressed conduction loss and increased thermal conductivity upon the incorporation of 2D Al_(2)O_(3) nanofillers possessing excellent dielectric insulation and thermophysical properties.The predominance of Al_(2)O_(3) nanoplates in enhancing thermal stability and high-temperature capacitive performance over nanoparticles and nanowires is validated experimentally and is further rationalized via finite element simulations.Notably,the Al_(2)O_(3) nanoplates filled PI nanocomposite exhibits a hightemperature capability up to 200℃ and remarkable efficiency(e.g.≥95% at 200 MV/m)over a wide temperature range,which outperforms commercial dielectric polymers and rivals the state-of-the-art polyimide nanocomposites.

High-temperature energy storage dielectric with inhibition of carrier injection/migration based on band structure regulation

Dielectric capacitors have a high power density,and are widely used in military and civilian life.The main problem lies in the serious deterioration of dielectric insulation performance at high temperatures.In this study,a polycarbonate(PC)-based energy storage dielectric was designed with BN/SiO_(2)heterojunctions on its surface.Based on this structural design,a synergistic suppression of the carrier injection and transport was achieved,significantly improving the insulating properties of the polymer film.In particular,the composite film achieves optimal high-temperature energy-storage properties.The composite film can withstand an electric field intensity of 760 MV m^(-1)at 100℃and obtain an energy storage density of 8.32 J cm^(-3),while achieving a breakthrough energy storage performance even at 150℃(610 MV m^(-1),5.22 J cm^(-3)).Through adjustment of the heterojunction structure,free adjustment of the insulation performance of the material can be realized;this is of great significance for the optimization of the material properties.

Modification of the land surface energy balance relationship by introducing vertical sensible heat advection and soil heat storage over the Loess Plateau

Little is known about the surface energy balance problem for a complex underlying surface.Taking data from the Loess Plateau Land-surface Processes Experiment(LOPEX) and investigating the characteristics of the surface energy balance over a complex underlying surface,this paper calculates the soil heat storage and vertical sensible heat advection,analyzes their contributions to the surface energy imbalance,and discusses the mechanism by which the vertical velocity and temperature gradient in the surface layer affect the vertical sensible heat advection transfer.We found that the vertical velocity in the surface layer provides the necessary dynamic power for vertical sensible heat advection,and a relatively strong temperature gradient is the energy source generating vertical sensible heat advection.Under an ascending condition,the effect of vertical sensible heat advection on the surface energy budget is more obvious.It is also found that when the soil heat storage term and the vertical sensible heat advection term are added to the energy balance equation,the imbalance significantly improves.The peak of average diurnal residuals decreases from 125.1 to 41.5 W m-2,the daily average absolute value of residuals falls from 59.0 to 26.4 W m-2,and the surface energy balance closure increases from 78.4% to 94.0%.

Modeling and Energy Efficiency Analysis of Thermal Power Plant with High Temperature Thermal Energy Storage(HTTES)

This paper presents the recent research on the study of the strategies for the flexible operation of the thermal power plant to meet the requirement of load balance. The study aimed to investigate the feasibility of bringing the High Temperature Thermal Energy Storage(HTTES) to the thermal power plant steam-water cycle, to identify the suitable HTTES in the cold(hot) section of the reheating pipeline and to test the efficiency of the HTTES integration to increase the flexibility of peak shaving and energy efficiency via thermal power plant with HTTTES modelling and simulation. Thermoflex was adopted to perform the simulation and a 300 MW subcritical coal-fired power plant model was implemented onto the software platform. The simulation results show that it is feasible to extract steam from the steam turbine to charge the HTTES, and to discharge the stored thermal energy back to the power generation process, and to analyse the improved capability of the plant flexible operation with HTTES. Then the study was extended to analyse the effect of thermal energy temperature, the opening of the regulating valve, and the pipeline pressure loss aspects on thermal efficiency of the whole plant. The study is beneficial to achieve more economic operation of the thermal power plant with HTTES integration. It is concluded that the introduction of the HTTES can improve the consumption of wind power, and these ideas and methods for solving the energy consumption of the renewable energy and reducing the peak energy consumption are provided.

Lowering the cost of large-scale energy storage:High temperature adiabatic compressed air energy storage

Compressed air energy storage is an energy storage technology with strong potential to play a significant role in balancing energy on transmission networks,owing to its use of mature technologies and low cost per unit of storage capacity.Adiabatic compressed air energy storage(A-CAES)systems typically compress air from ambient temperature in the charge phase and expand the air back to ambient temperature in the discharge phase.This papers explores the use of an innovative operating scheme for an A-CAES system aimed at lowering the total cost of the system for a given exergy storage capacity.The configuration proposed considers preheating of the air before compression which increases the fraction of the total exergy that is stored in the fom of high-grade heat in comparison to existing designs in which the main exergy storage medium is the compressed air itself.Storing a high fraction of the total exergy as heat allows reducing the capacity of costly pressure stores in the system and replacing it with cheaper thermal energy stores.Additionally,a configuration that integrates a system based on the aforementioned concept with solar thermal power or low-medium grade waste heat is introduced and thoroughly discussed.

Energy transformation analysis during friction welding of superalloy lnconel 718

By detecting and analyzing the variations of energy parameters-torque and temperature field during friction welding, this paper describes that during quasi-stationary heating phase, quite a little mechanical work is transformed into plastic deformation work, thus the efficiency of heat excited by friction is low.

High temperature deformation behavior and mechanism of spray deposited Al-Fe-V-Si alloy

Al-8.5Fe-1.3V-1.7Si alloy was prepared by spray deposition and hot extrusion. The high temperature plastic deformation behavior of the spray deposited Al-8.5Fe-1.3V-1.7Si alloy was investigated in the strain rate range of 2.77×10-4-2.77×10-2 s-1 and temperature range of 350-550 ℃ by Gleebe-1500 thermomechanical simulator. The mechanism of the high temperature plastic deformation of the alloys was studied by TEM associated with the analysis of Rosler-Artz physical constitutive relationship based on the model of dislocation detaching from dispersion particles. The results show that Al-Fe-V-Si alloy has low strain hardening coefficient, and even exhibits work softening. Stress exponent n and activation energy Q were calculated based on Zener-Hollomon relation and Rosler-Artz physical model respectively. The Rosler-Artz physical model can give a good prediction for the abnormal behavior of high temperature deformation of spray deposited Al-Fe-V-Si alloy, that is, n larger than 8 and Q higher than 142 kJ/mol. However, because of the highly refined microstructure, the high temperature deformation behavior of spray deposited Al-Fe-V-Si alloy deviates more or less from the law predicted by using Rosler-Artz physical model.

地铁车站月平均气温随运营年限演化特性

建立了地铁车站空气热平衡理论模型,基于区间隧道空气温度和车站围岩土体蓄放热量,得到车站月平均气温在运营初期、中期和远期的逐年演化特性。研究结果表明:随着地铁车站运营年限的增长,月平均气温呈现逐年上升趋势,运营第15年较第1年,车站月平均气温在1月温升最低为3.1℃,8月温升最高为10.6℃;在现有地铁行车密度随运营年限增大的运行模式下,地铁车站运营初期行车密度仅为15对/h,夏季车站最高气温出现在第5年,为26.4℃,远低于夏季站厅站台空调设计温度平均值29℃,所以运营初期车站空调系统提供的冷量远大于车站的冷负荷需求,初期车站空调系统存在一定的节能空间。

面向高温储能应用可交联聚丙烯电介质材料研究

近几年,电磁弹射技术和电动汽车行业快速发展,对于提高薄膜介电电容器的耐高温和高储能性能的需求也越来越迫切。为此,对接枝交联抗氧化剂的聚丙烯(PPHP)进行了热处理,使其内部发生交联形成交联三维网络,可提高聚丙烯的耐高温性能、耐高压性能、介电性能以及储能性能。研究结果表明:经过热处理的接枝可交联抗氧化剂聚丙烯(CPP)相较于双向拉伸聚丙烯(BOPP)和聚丙烯(PP),在室温下其击穿场强可以达到1105 MV/m,在130℃时可达到647 MV/m,介电常数在3.0左右,介电损耗在0.01以下;在600 MV/m的电场强度下,其能量密度值为9.13 J/cm^(3),能量释放效率达到94.3%。

深层地热能丛式多分支U型井采热技术及传热算法

深层地热能是一种分布广、资源量大具有发展前景的可再生新能源,当前的主要开采方法有增强型地热系统(EGS)、环绕式井筒换热系统(AGS)、断层带流体循环开采和同轴套管开采法,但存在采热功率不稳定、地震风险高和采热效率低等难题。针对当前深层地热开采技术面临的瓶颈问题,本文以开采过程只有能量交换而没有物质交换为原则,以深层干热岩地热规模化可持续稳定开发为目标,提出了深层地热能丛式多分支U型井采热方法(UMW-DGS)及关键技术,在此基础上建立了井筒轴对称热传导模型,以青海共和盆地恰卜恰深部干热岩储层为背景,提出了高温高压岩石热导率测试新方法,计算了在定井径条件下井周温度场和采热功率的时空演化规律,分析了温度差、热导率和井径等3个敏感因素对采热功率的影响。此外,针对UMW-DGS定解问题,研发了基于有限体积法(FVM)的三维热流固耦合数值算法,研究了UMW-DGS单水平井段换热效率和在不同泵注量条件下温度场时空演化。通过分析不同流量的有效换热量、换热时长和功率发现:泵注流量的增加会导致有效换热能量和有效换热时长的降低,并且使有效换热功率先增加后减少。研究结果表明,深层地热能开发需要在平衡换热温度和功率的条件下设计注入排量,从而得到最优的换热效果。

耗能不花钱的发动机设计

热泵产生的热量是输入电能的COP倍,COP=3-6,利用其能效高的特点,设计了热泵发动机,将热泵的热利用引申到一个新的领域——热泵的机械利用;为了提高热机效率,采用了将热泵串联起来升温的方法,又将热泵热利用引申到另一个新的领域——热泵的高温利用。综合以上两个领域的研究,设计出了一种耗能不花钱的发动机,指出了该发动机带来的三个有益效果:一是不用花钱就能输出能量,二是大力推广就解决了能源危机,三是减少了温室效应,有利于早日实现“双碳”目标。

Comparative Study on Methods for Computing Soil Heat Storage and Energy Balance in Arid and Semi-Arid Areas

Observations collected in the Badan Jaran desert hinterland and edge during 19-23 August 2009 and in the Jinta Oasis during 12-16 June 2005 are used to assess three methods for calculating the heat storage of the5-20-cm soil layer.The methods evaluated include the harmonic method,the conduction-convection method,and the temperature integral method.Soil heat storage calculated using the harmonic method provides the closest match with measured values.The conduction-convection method underestimates nighttime soil heat storage.The temperature integral method best captures fluctuations in soil heat storage on sub-diurnal timescales,but overestimates the amplitude and peak values of the diurnal cycle.The relative performance of each method varies with the underlying land surface.The land surface energy balance is evaluated using observations of soil heat flux at 5-cm depth and estimates of ground heat flux adjusted to account for soil heat storage.The energy balance closure rate increases and energy balance is improved when the ground heat flux is adjusted to account for soil heat storage.The results achieved using the harmonic and temperature integral methods are superior to those achieved using the conduction-convection method.

基于相变材料的混凝土吊罐温控数值模拟研究

为保证混凝土吊罐在垂直运输时其内部混凝土的温度,采用相变石蜡作为吊罐温控措施,通过Fluent软件探究了不同季节和不同相变石蜡厚度下混凝土温度变化情况。结果表明:在不同季节,采用相变石蜡作为吊罐温控措施,可有效控制其内部混凝土温度的波动;在冬季环境中,当相变石蜡厚度小于40 mm时,混凝土内外温度差减小有限,消峰填谷效果不理想;在夏季环境中,随着相变石蜡厚度的增加,混凝土表面最大温度的降低程度呈现先增大后减小的趋势,当相变石蜡厚度为20 mm时,混凝土表面温度达到最低。

接枝聚丙烯电容薄膜的高温储能特性

随着海上风电、电动汽车和油气勘探的迅速发展,对薄膜电容器的工作温度提出更高的要求。然而,当环境温度达到120℃时,目前使用最为广泛的双向拉伸聚丙烯电容薄膜充放电效率急剧下降,不能满足应用需求。该文制备了苯乙烯接枝聚丙烯(PP-g-St)双向拉伸电介质薄膜,在120℃下,PP-g-St可以将能量密度从0.23 J/cm^(3)提高到1.67 J/cm^(3)(储能效率在90%以上),同时接枝后击穿场强大幅提升,高温泄漏电流得到有效抑制,这源自于接枝后引入的深陷阱限制了载流子的输运。接枝样品中的自聚相经拉伸后与基体具有良好的相容性。该文研究为适用于高温高场条件的聚丙烯基电容器薄膜材料的大规模制备提供可能。

某调度通信楼空调系统节能减碳改造设计实践

重点介绍了某调度通信楼空调系统的节能减碳改造设计,通过综合运用余热回收、可再生能源、固体蓄热、高效制冷机房等多项技术,构建了安全可靠、绿色低碳、高效节能的空调系统。采用HDY-SMAD空调负荷计算及分析软件模拟了建筑物全年的空调能耗,并对优化前后空调系统的运行能耗和碳排放进行了测算。结果显示,优化方案空调系统全年节约电量100万kW·h,全年碳减排573 t,节能减碳效果显著。

中高温热化学储热材料研究进展

可再生能源在利用过程中存在瞬时性、不稳定性以及供应与需求不匹配等问题。热化学储热技术具有储能密度大、储热温度高等特点,能够实现高效长时储热,可以将不稳定的可再生能源转化为稳定的中高温热能,并满足用户侧的波动需求。针对工作温度范围为400~1 100℃的中高温热化学储热材料,阐述了其分类、基本原理和特点,系统总结了碳酸盐、氢氧化物、氧化物、金属氢化物、氨和甲烷等典型热化学储热材料及其储热性能,分析了其结构定向调控及改性方法,并对典型的工程应用进行了介绍;分析了固-气和气-气反应体系的反应器设计及系统集成的研究进展,并针对优质热化学储能材料在开发及工业应用方面存在的问题,指出了未来的发展方向。

聚氨酯型固-固相变储能材料对沥青调温效果的影响研究

聚氨酯型固-固相变储能材料可以有效提高沥青的相变储能能力,从而在调节路面温度的同时,减小温度波动。基于上述背景,针对聚氨酯型固-固相变储能材料对沥青调温效果的影响展开研究。确定相变材料的分类标准,并分别研究其储能原理及具体应用情况,完成对聚氨酯型固-固相变储能材料特性的分析。在此基础上,定义周期性储热边界条件,根据沥青调温过程中内聚能密度的变化形式,推导相变储能材料的能量变化规律,从而确定聚氨酯型固-固相变储能材料对沥青调温效果的影响能力。

基于超导储能电感的meat-grinder脉冲电源

为了探索高温超导储能用于线圈型同步感应电磁推进脉冲电源的可行性，研究了超导电感和电容混合型meat-grinder脉冲电源电路。设计并研制了一个小型的高温超导储能脉冲变压器，提出了高温超导储能脉冲变压器使用meat-grinder电路拓扑结构的脉冲成形方案，并以3个电感线圈作模拟同步感应电磁推进系统负载，进行了仿真分析和实验验证。在77K和储能电流96A的情况下，实验得到了2．35～3．04kA的电流脉冲输出，并有望在20K温度下满足线圈型电磁推进的应用要求。结果表明，提出的脉冲电源模式是可行的。因负载电流脉冲受负载阻抗影响较大，在实际电磁推进应用中，需要减小线路电阻和常导电感的内阻。