Proposal of a Solar Thermal Power Plant at Low Temperature Using Solar Thermal Collectors

To this day, only two types of solar power plants have been proposed and built: high temperature thermal solar one and photovoltaic one. It is here proposed a new type of solar thermal plant using glass-top flat surface solar collectors, so working at low temperature (i.e., below 100°C). This power plant is aimed at warm countries, i.e., the ones mainly located between -40° and 40° latitude, having available space along their coast. This land based plant, to install on the seashore, is technologically similar to the one used for OTEC (Ocean Thermal Energy Conversion). This plant, apart from supplying electricity with a much better thermodynamic efficiency than OTEC plants, has the main advantage of providing desalinated water for drinking and irrigation. This plant is designed to generate electricity (and desalinated water) night and day and all year round, by means of hot water storage, with just a variation of the power delivered depending on the season.

Feasibility Demonstrations of Liquid Turbine Power Generator Driven by Low Temperature Heats

Lower temperature waste heats less than 373 K have strong potentials to supply additional energies because of their enormous quantities and ubiquity. Accordingly, reinforcement of power generations harvesting low temperature heats is one of the urgent tasks for the current generation in order to accomplish energy sustainability in the coming decades. In this study, a liquid turbine power generator driven by lower temperature heats below 373 K was proposed in the aim of expanding selectable options for harvesting low temperature waste heats less than 373 K. The proposing system was so simply that it was mainly composed of a liquid turbine, a liquid container with a biphasic medium of water and an underlying water-insoluble low-boiling-point medium in a liquid phase, a heating section for vaporization of the liquid and a cooling section for entropy discharge outside the system. Assumed power generating steps via the proposing liquid turbine power generator were as follows: step 1: the underlying low-boiling-point medium in a liquid phase was vaporized, step 2: the surfacing vapor bubbles of low-boiling-point medium accompanied the biphasic medium in their wakes, step 3: such high momentum flux by step 2 rotated the liquid turbine (i.e. power generation), step 4: the surfacing low-boiling-point medium vapor was gradually condensed into droplets, step 5: the low-boiling-point medium droplets were submerged to the underlying medium in a liquid phase. Experiments with a prototype liquid turbine power generator proved power generations in accordance with the assumed steps at a little higher than ordinary temperature. Increasing output voltage could be obtained with an increase in the cooling temperature among tested ranging from 294 to 296 K in contrast to normal thermal engines. Further improvements of the direct current voltage from the proposing liquid turbine power generator can be expected by means of far more vigorous multiphase flow induced by adding solid powders and theoretical optimizations of heat and mass transfers.

Anomalous low-temperature heat capacity in antiperovskite compounds

The low-temperature heat capacities are studied for antiperovskite compounds AX M_3（A = Al, Ga, Cu, Ag, Sn, X = C,N, M = Mn, Fe, Co）. A large peak in（C- γ T）/T^3 versus T is observed for each of a total of 18 compounds investigated,indicating an existence of low-energy phonon mode unexpected by Debye T^3 law. Such a peak is insensitive to the external magnetic field up to 80 k Oe（1 Oe = 79.5775 A·m-1）. For compounds with smaller lattice constant, the peak shifts towards higher temperatures with a reduction of peak height. This abnormal peak in（C- γ T）/T^3 versus T of antiperovskite compound may result from the strongly dispersive acoustic branch due to the heavier A atoms and the optical-like mode from the dynamic rotation of X M_6 octahedron. Such a low-energy phonon mode may not contribute negatively to the normal thermal expansion in AX M_3 compounds, while it is usually concomitant with negative thermal expansion in open-structure material（e.g., ZrW_2O_8, Sc F_3）.

Fundamental study of novel mid-and low-temperature solar thermochemical energy conversion

A new approach to application of mid-and low-temperature solar thermochemical technology was in-troduced and investigated.Concentrated solar thermal energy in the range of 150―300℃ can be effi-ciently converted into high-grade solar fuel by integrating this technique with the endothermic reaction of hydrocarbons.The conversion mechanism of upgrading the low-grade solar thermal energy to high-grade chemical energy was examined based on the energy level.The new mechanism was used to integrate two novel solar thermal power systems:A solar/methanol fuel hybrid thermal power plant and a solar-hybrid combined cycle with inherent CO2 separation using chemical-looping combustion,for developing highly efficient solar energy use to generate electricity.An innovative prototype of a 5-kW solar receiver/reactor,as the key process for realizing the proposed system,was designed and manu-factured.Furthermore,experimental validation of energy conversion of the mid-and low-temperature solar thermochemical processes were conducted.In addition,a second practical and viable approach to the production of hydrogen,in combination with the novel mid-and low-temperature solar thermo-chemical process,was proposed and demonstrated experimentally in the manufactured solar re-ceiver/reactor prototype through methanol steam reforming.The results obtained here indicate that the development of mid-and low-temperature solar thermochemical technology may provide a promising and new direction to efficient utilization of low-grade solar thermal energy,and may enable step-wise approaches to cost-effective,globally scalable solar energy systems.

碳化硅增强相变充填体热力学性能研究

矿山蓄热储能功能性充填实现了深地矿床-地热协同共采,研发具有适宜相变参数和物化性能优良的功能充填材料迫在眉睫。针对相变材料微胶囊(microencapsulated phase change materials,Micro PCM)导致充填体抗压强度、导热系数下降的现状,开展预试验探究相变充填体的强度特征和热学性能,基于获取的较佳MicroPCM添加量,进一步探究不同碳化硅(Si C)添加量(质量百分率为0%、2%、4%、6%、8%)对相变充填体抗压强度、导热系数、比热容的影响,并测试了其密度、泌水率与流动度,同时结合扫描电子显微镜-能量分散谱仪(scanning electron microscope-energy dispersive spectrometer,SEM-EDS)观测其微观形貌,开展能谱扫描分析解释宏观试验现象,探究其在高低温交变循环下的蓄热储能稳定性。得到了以下结论:MicroPCM添加量为5%时,相变充填体的比热容达到最大,为1.75 MJ/(m^(3)·K);充填体的密度在Si C添加量为2%时达到最大,为1.67 g/cm^(3);充填体的流动性和泌水性随Si C添加量的增加逐渐增强;充填体的抗压强度和导热系数随Si C添加量的增加不断增长,添加量达到4%时,其增幅分别为10.1%和21.7%,达到6.64 MPa和1.12 W/(m·K),随后增长趋势逐渐减缓;相变充填体的比热容随Si C添加量的增加呈现先增长后衰减趋势,但是波动幅度较小,在4%添加量时,比热容达到最大值,为2.32 MJ/(m^(3)·K),因此推荐Si C添加量为4%;500次高低温交变循环后,相变充填体的抗压强度得到增强,且Si C添加量越高增长幅度越大,而导热系数与比热容均有所降低,下降幅度逐渐减小。研究为实际工程中蓄热储能充填提供了数据参考。

低熔点四元硝酸盐基定型复合相变材料的制备与研究

采用冷压-热烧结方法制备研究了一种形态稳定的硝酸盐基复合相变材料,该材料具有较低的熔点和较宽的温度使用范围,适用于中低温领域的热能储存。研究选取NaNO_(3)-NaNO_(2)-KNO_(2)-LiNO_(3)共晶四元硝酸盐为相变基体材料,氧化镁为结构支撑材料,石墨为导热增强剂,并对其微观结构、化学相容性、热物理性能和循环稳定性进行了一系列表征,结果表明:在烧结前后四元硝酸盐、氧化镁以及石墨之间不发生化学反应,具有良好的化学相容性及化学稳定性。在不同质量比的样品中,四元硝酸盐与氧化镁质量比为6∶4时,为复合材料的最佳配比,且其负载质量分数8%的石墨后,仍表现出优异的结构稳定性;该复合材料的熔点较低,约为70℃,分解温度达到610℃;在50~580℃的温度范围内,具有超过749 kJ/kg的储能密度;添加8%的石墨后复合材料的热导率从0.41 W/(m·K)提高到了0.77 W/(m·K);经150次循环后,复合材料表现出良好的热循环稳定性。这种具有低熔点、宽温域的盐基复合材料是中低温热能存储的有力候选者,本研究为其在中低温领域的应用提供了实践依据。

中低温煤焦油沥青组分的热解特性及动力学研究

中低温煤焦油沥青(MLP)为人造炭材料的重要原料,研究其组分的热解特性及动力学对高品质中低温煤焦油沥青基炭材料的制备具有重要意义。以中低温煤焦油沥青为原料,分别采用正丁醇(BA)和二甲基亚砜(DMSO)为萃取剂以获得4种沥青组分,通过热重分析仪对中低温煤焦油沥青和4种族组分的热解行为进行研究,利用Flynn-Wall-Ozawa法、Kissinger-Akahira-Sunose法和Satava-Sestak法计算热解活化能以及热解动力学参数。结果表明:MLP、DMSOS、BAI组分的热解反应机理符合随机成核及其后续增长模型,最佳热解机理函数分别为G(α)=[-ln(1-α)]^(4/3)、G(α)=[-ln(1-α)]^(4)、G(α)=[-ln(1-α)]2,活化能分别为73.99、180.20、46.09 kJ/mol,lg A分别为5.82、13.57、3.32;BAS组分的热解反应机理符合二维扩散模型,最佳热解机理函数为G(α)=α+(1-α)ln(1-α),E=85.36 kJ/mol,lg A=6.18;DMSOI组分的热解反应机理符合二维扩散或三维扩散模型,最佳热解机理函数为G(α)=[1-(1-α)^(1/3)]^(2),E=64.42 kJ/mol,lg A=4.00。

Performance Assessment of Low-Temperature A-CAES(Adiabatic Compressed Air Energy Storage)Plants

The widespread diffusion of renewable energy sources calls for the development of high-capacity energy storage systems as the A-CAES(Adiabatic Compressed Air Energy Storage)systems.In this framework,low temperature(100℃–200℃)A-CAES(LT-ACAES)systems can assume a key role,avoiding some critical issues connected to the operation of high temperature ones.In this paper,two different LT-ACAES configurations are proposed.The two configurations are characterized by the same turbomachines and compressed air storage section,while differ in the TES section and its integration with the turbomachinery.In particular,the first configuration includes two separated cycles:the working fluid(air)cycle and the heat transfer fluid(HTF)cycle.Several heat exchangers connect the two cycles allowing to recover thermal energy from the compressors and to heat the compressed air at the turbine inlet.Two different HTFs were considered:air(case A)and thermal oil(case B).The second configuration is composed of only one cycle,where the operating fluid and the HTF are the same(air)and the TES section is composed of three different packed-bed thermal storage tanks(case C).The tanks directly recover the heat from the compressors and heat the air at each turbine inlet,avoiding the use of heat exchangers.The LT-ACAES systems were modelled and simulated using the ASPEN-Plus and the MATLAB-Simulink environments.The main aim of this study was the detailed analysis of the reciprocal influence between the turbomachinery and the TES system;furthermore,the performance evaluation of each plant was carried out assuming both on-design and off-design operating conditions.Finally,the different configurations were compared through the main performance parameters,such as the round-trip efficiency.A total power output of around 10 MW was set,leading to a TES tank volume ranging between 500 and 700 m^(3).The second configuration with three TES systems appears to be the most promising in terms of round-trip efficiency since the energy produced during the discharging phase is greater.In particular,the round-trip efficiency of the LT-ACAES ranges between 0.566(case A)to 0.674(case C).Although the second configuration assures the highest performance,the effect of operating at very high pressures inside the tanks should be carefully evaluated in terms of overall costs.

基于200 MW等级压缩空气储能系统中温与高温储热路线技术经济对比

压缩空气储能技术由于其规模大、效率高、环境友好等特点受到广泛关注,其中非补燃式压缩空气储能技术成熟,在运行过程中没有碳排放产生,国内已有多座非补燃式绝热压缩空气储能电站投运、在建和在规划中。然而,目前压缩空气储能系统的设计参数尚未形成统一的标准化体系,使得压缩空气储能在系统设计和性能优化面临诸多挑战。为此,对200 MW等级的压缩空气储能系统进行中温、高温储热系统方案设计,确定了关键设备参数与系统边界条件,并对中、高温储热系统方案进行了性能以及技术经济性分析对比。结果表明:高温储热系统在性能指标上优于中温储热系统,但在投资成本上高于中温储热系统。这表明在选择大容量压缩空气储能系统的储热技术路线时,需要根据具体应用场景和经济预算综合考虑。

基于能量流方法的纯电动汽车低温续驶里程提升研究

以某带热泵系统的微小型纯电动乘用车为对象,开展低温CLTC-P循环工况下的续驶里程测试,通过综合研究测试数据并分解整车能量流,探讨提升续驶里程的潜在方向。基于AMESim平台建立包含热管理系统的整车动力经济性模型,经校准后仿真对比不同优化方案,制定组合优化方案。试验验证结果显示,组合优化方案可将低温续驶里程提升12.6%,其中热管理系统优化方案的贡献显著优于整车阻力优化方案和控制策略优化方案。为提升纯电动乘用车低温环境下的续驶里程提供参考思路和方法。

Comparison and Optimization of Mid-low Temperature Cogeneration Systems for Flue Gas in Iron and Steel Plants

Three generation systems, namely, steam Rankine cycle （SRC）, organic Rankine cycle （ORC）, and steam-organic combined Rankine cycle （S-ORC）, were simulated using the Engineering Equation Solver fEES） to efficiently utilize flue gas emissions from 200 to 450 ℃ in iron and steel plants. Based on the simulation results for thermal efficiency, exergy efficiency, and power generation, the performances of the three power generation systems were compared and analyzed. To further utilize waste heat from the turbine exhaust steam of the ORC system, cas- cade （）RC （CORC） was designed for heat sources above 300 ℃. Based on a comprehensive performance comparison, the application of the ORC using R141b is preferable for 200 to 300 ℃ flue gas. For 300 to 450 ℃ flue gas, CORC is an alternative technology to improve the efficiency and quality of waste heat utilization. For flue gas above 450 ℃, S-ORC can achieve higher efficiency and power generation than conventional SRC, with a relatively small negative pressure and high dryness of the turbine outlet steam. Hence, S-ORC can be considered as a substitute for SRC.

低温丙烷冷能利用研究

介绍一种低温丙烷输送过程中产生的冷能用于循环水冷却和冷库供冷的节能优化方案,该方案包括一级加热系统、二级加热系统及冷媒循环系统。低温丙烷经一级加热器将冷能传给冷媒,再通过循环水在二级加热器加热同时降低了循环水的温度,升温后的丙烷送至常温丙烷球罐储存并送至下游装置或外卖;冷媒所含冷能用于冷库制冷。通过对方案流程分析及模拟计算证实了此方案的可实施性和经济价值,展望了低温丙烷冷能的利用前景。

河北省承德县王家庄北沟钼矿床地质特征、矿床成因及找矿标志

王家庄北沟钼矿床位于河北省承德县。钼矿体受近东西向正断层控制,赋存在中元古代蓟县群雾迷山组白云岩构造破碎带和下白垩统的张家口组火山岩内,并与局部发育钼矿化的石英闪长玢岩脉关系紧密。钼矿体呈似层状分布,主要为氧化矿石和混合矿石。氧化矿石发育蜂窝状和角砾状构造,混合矿石呈现脉状、浸染状、角砾状等构造。金属矿物主要为辉钼矿、钼华等。因此推测王家庄北沟钼矿床受构造破碎带控制的浅成—超浅成中低温热液型钼矿床。地表的钼华、铁帽等是直接找矿标志,构造交汇位置、元素组合异常是主要的间接找矿标志。

Novel lead-free BCZT-based ceramic with thermally-stable recovered energy density and increased energy storage efficiency

The eco-responsible lead-free piezoelectric ceramics have been intensively searched for more than adecade, however, the final goal to replace toxic ceramics like lead zirconate titanate (PZT) with lead-freecompounds, having comparable or even better performance has not yet been reached. In this road, thelead-free ceramics Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3) (BCZT), possessing excellent dielectric, ferroelectric, andpiezoelectric properties are regarded as serious candidates for the PZT replacement. Besides, nano-structuring BCZT is of paramount importance to enhance these functionalities even more. Here, BCZTmultipodes are designed by template-growth hydrothermal synthesis using hydrogen zirconate titanatenanowires. We demonstrate that the fabricated BCZT multipodes exhibit high dielectric permittivity of5300 with a temperature stability coefficient of ±5.9% between 20 and 140℃. A significant recoveredenergy density of 315.0 mJ/cm^(3) with high thermal stability and high energy storage efficiency of 87.4%,and enhanced large-signal piezoelectric coefficient d^(*)_(33) (310 pm/V) are found. Compared to the tradi-tional BCZT ceramics reported in the literature, relying on high-temperature processing, our sampleexhibits boosted energy storage parameters at a much lower temperature. These outcomes may offer anew strategy to tailor eco-responsible relaxor ferroelectrics toward superior energy storage performancefor ceramic capacitor applications.

太阳能中温相变储热材料的研究进展与展望

采用相变储热材料（PCMs）的潜热储蓄技术是最有效的热能贮存方式之一,它被广泛地应用在太阳能热利用、工业余热回收、建筑节能等领域.综述了当前国内外相变储热材料的最新研究进展,介绍了储热技术及材料的分类、选择、性能及其应用.重点论述了100～450℃温度范围内中温相变储热材料的分类、制备和应用.最后展望了开发新型中温相变储热材料的努力方向和发展前景,提出开发高性能微/纳复合结构储热材料是未来研究的重点.

低温热能发电的研究现状和发展趋势

低温热能种类繁多,数量巨大,利用这部分能源意义重大。介绍了低温热能发电技术的研究现状和发展趋势。低温热能发电技术主要应用于太阳能热电、工业余热发电、地热发电、生物质能发电、海洋温差发电等方面。现阶段低温热能发电的研究重点有:工质的热物性和环保性能、循环优化研究;提高低温热能发电效率的研究,包括混合工质循环、Kalina循环、回热、氨吸收式动力制冷循环等;基于有限时间热力学的系统最优控制等方面的研究。

聚光太阳能热发电系统关键技术研究综述

太阳能光热利用是目前新能源领域中自有技术含量最高、产业化发展最快、市场贡献最大的技术之一,与常规的光伏发电形式相比具有明显优势。考虑到太阳能具有能流密度较低及间歇性等特点,本文提出了基于有机朗肯循环发电的中低温太阳能利用形式,并从聚光集热、热功转换及蓄热技术3方面分别详细阐述了各自的工作原理、国内外研究及发展现状,并指出存在的问题,展示出太阳能热发电技术的广泛前景。

中高温储热材料的研究现状与展望

开发中高温储热材料及其制备方法是储热技术发展的关键之一。本文结合中高温储热材料的分类、特点、应用及存在的问题对中高温储热材料的研究进展进行了综述,主要包括显热储热材料、热化学储热材料以及潜热储热材料。探讨了复合结构储热材料及其制备工艺,进一步介绍了其最新研究进展,并对中高温储热材料的下一步研究进行了展望,提出开发高性能纳微复合结构储热材料是未来研究的重点。

用于中低温热解的低阶烟煤型煤的制备

将低阶烟煤粉煤制成高热强度的型块用于中低温热解,可减少环境污染、提高低阶烟煤的利用率。选用东荣长焰煤为原料,以煤焦油为黏结剂,利用自制模具在液压机上压制型煤,测定型煤的强度,研究成型压力、黏结剂掺入量和原料水分对型煤性能的影响,并利用扫描电镜对型煤微观结构进行分析表征。结果表明:型煤的强度随黏结剂含量的增大而增大,随成型压力的增加先增加后减小,水分含量对型煤强度也有一定影响;煤焦油能浸润煤粒,充填在煤粒间隙,起到了良好的粘连作用;在煤焦油掺入量为10%、原料水分质量分数为13%、成型压力为63 MPa的条件下制取的型煤强度最佳,热强度、冷压强度、热稳定性和落下强度分别达到536.4 N/个、691.3 N/个、97.98%、99.49%,可满足中低温热解对原料的强度要求。

中低温能源在中国

推动中低温能源的规模化应用是中国重构能源供给格局、实现清洁、低碳与可持续发展的有效途径。然而,目前中国中低温能源尚无完善的统计和明确的专项能源规划,其开发利用情况尚不明确;同时,中低温能源品位低、能量密度小,其开发利用仍然面临获取难、转换方式单一等问题,缺乏有效的技术路线指导。该文从中国能源结构中供需匹配角度出发,对地热能、太阳能、工业余热与海洋热能四类典型中低温能源的年可利用量、利用现状与潜力等方面进行分析,并对未来的能源结构及相关前沿技术进行预测与讨论。结果显示,中国地热能、太阳能、工业余热与海洋热能年可利用量(资源量)分别达到1.17×10^(10)、4.90×10^(10)、4.86×10^(6)、2.95×10^(9)TJ,但目前中低温能源利用量仅约占中国能源总利用量的3%(2017年中国能源总利用量为1.36×10^(8)TJ)。预测结果显示,至2050年4类典型中低温能源利用将占中国能源总利用量的8%至21%,显示了中低温能源的重要地位,也凸显了相关研究与利用的广阔前景。