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基于1MW固体电蓄热的换热系统对其换热过程进行研究分析,从风机效率以及换热器本身结构上分析出热风最低换热温度为250~300℃;在进行换热器设计时为保证换热量,应以最高出风温度参数为基准;还基于1MW机组的换热器设计进行整体和参数化性能分析。此外针对翅片管换热器换热特性,分析其管间距、翅片高度、迎风面积及翅片节距对翅片管换热器换热面积以及出风压力的影响。 相似文献
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在10kW的电热固体蓄热装置上,对其蓄热过程进行了实验研究,得到了不同加热方式、不同控制温度下蓄热体内温度分布规律、升温速度和蓄热量。 相似文献
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随着蓄热体基础部件的尺寸细小化,玄武岩蓄热体的纤维直径微小,顺排排列后,内部形成微细流道。为探究微尺度下产生的尺度效应对玄武岩纤维束内部流道流动和传热的数值模拟的影响,建立了蓄热体的二维层流模型。通过Ansys 17.0 fluent中的UDF函数添加了滑移边界条件,以添加滑移边界条件前后的壁面努塞尔数(Nu)减小百分比为评价指标,对比分析二维纤维束微流道的数值模拟中,滑移边界条件对不同工况下流固换热的影响程度。模拟结果表明:随着温度和间距的增大,添加滑移边界条件后的Nu下降程度会增大;随着纤维排数和入口速度的增加,Nu下降程度会减小;纤维束直径d为20μm,排数小于5排,中心间距超过3 d时,添加了滑移边界条件的Nu的降幅达到了1%以上,在数值模拟中不可忽略滑移流区的影响。 相似文献
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为了进一步减少HiTAC(高温空气燃烧)过程中产生的氮氧化物NOx,将蜂窝状SCR(选择性催化还原)催化剂植入HiTAC系统的蓄热室中,建立了关于蓄热式换热及NO催化还原的一维数学模型,其中反应物吸附及反应过程依从Eley-Rideal机理,对催化剂在非稳态下脱硝性能进行了数值模拟研究。结果表明:反应速率常数与停留时间对应值——速度的倒数的变化幅度均随换向时间延长而增大;气体速度随空速呈完全线性变化;出口NO浓度呈周期性变化;NO转化率随换向时间的延长而增大,随空速的增大而减小。 相似文献
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Study on key parameters design and economic evaluation of the electric heating and solid sensible heat thermal storage device 下载免费PDF全文
XING Zuoxia ZHAO Haichuan MA Shiping DAI Junwen LIU Yuting SUN Zhenting 《储能科学与技术》2019,8(6):1211-1216
电制热固体储热系统对可再生能源消纳、能源清洁化利用具有重要意义。电制热固体储热装置的关键参数设计以及经济性分析是提高经济效益的重要手段。因此,本文提出了电制热固体储热装置投资运行费用计算方法。通过对比不同供暖方式所需费用分析了电制热固体储热装置的经济性。同时研究了谷电利用系数对电制热固体储热装置经济性的影响。最后,采用案例分析验证本文所提经济性评估方法的合理性与正确性。本文的研究内容为用户对电制热固体储热装置的选择提供参考。 相似文献
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Thermal-fluid-solid coupling of electric heat storage device based on wind power absorption 下载免费PDF全文
电网调峰能力不足,弃风问题严重,已成为我国风力发电规模进一步扩大的瓶颈。通过配置蓄热装置参与风电调峰,改变传统“以热定电”的约束模式,是解决我国大量弃风问题的一个趋势。提高电热蓄能装置效率及优化蓄热装置分布对于实现有效调峰具有重要意义。本文针对固体电蓄热装置内流动、传热、应力等现象,建立了热-流-固多场三维耦合传热数学模型,采用流-固耦合传热模型将难以确定的热流边界转化为系统内部边界,分析固体电蓄热装置温度场及应力场分布,并对比三种不同孔隙率、电热丝排布方式对蓄热装置温度分布均匀性及热膨胀量的影响。研究结果对提高固体电蓄热装置的效率以及电网调峰具有一定的参考价值。 相似文献
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列管式换热器具有结构牢固、传热面积大、材料使用适应性强等优点,是相变储热领域应用较为广泛的一种换热器。但由于大部分相变材料热导率偏低,导致换热器的换热性能较差,因此提高相变储热器的储热效率,是目前国内外研究的热点。本工作对列管式相变储热单元进行了二维非稳态模拟优化,研究了换热器结构、翅片数目及中心距3种参数对储热性能的影响,并探讨了熔化过程中相变材料的温度和液相率变化趋势。研究结果表明,与圆形换热器结构相比,正方形换热器储热性能更优;相比于无翅片的储热换热器,添加翅片后储热性能得到显著提升,相变材料熔化时间缩短66%;对中心距而言,在一定范围内,随中心距减小进出口降压增大,但储热性能相应提高。 相似文献
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Solar multi-mode heating system based on latent heat thermal energy storage and its application 下载免费PDF全文
为克服太阳能间断性和不稳定性的缺点进而实现太阳能集热与采暖的能量供需调节和全天候连续供热,提出了基于相变储热的太阳能多模式采暖方法(太阳能集热直接采暖、太阳能集热采暖+相变储热、太阳能相变储热采暖),并在西藏林芝市某建筑搭建了太阳能与相变储热相结合的采暖系统,该系统可根据太阳能集热温度和外界供热需求实现太阳能多模式采暖的自动控制和自动运行。实验研究表明:在西藏地区采用真空管太阳能集热器可以和中低温相变储热器很好地结合,白天储热器在储热过程中平均储热功率为10.63 kW,储热量达到92.67 kW·h,相变平台明显;晚上储热器在放热过程中供热量达85.23 kW·h,放热功率和放热温度平稳,储放热效率达92%,其储热密度是传统水箱的3.6倍,可连续供热时间长达10 h,从而实现了基于相变储热的太阳能全天候连续供热,相关研究结果对我国西藏地区实施太阳能采暖具有一定的指导作用。 相似文献
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Anurag Singh M.P. Maiya S. Srinivasa Murthy 《International Journal of Hydrogen Energy》2017,42(22):15226-15235
The absorption and desorption performances of a solid state (metal hydride) hydrogen storage device with a finned tube heat exchanger are experimentally investigated. The heat exchanger design consists of two “U” shaped cooling tubes and perforated annular copper fins. Copper flakes are also inserted in between the fins to increase the overall effective thermal conductivity of the metal hydride bed. Experiments are performed on the storage device containing 1 kg of hydriding alloy LaNi5, at various hydrogen supply pressures. Water is used as the heat transfer fluid. The performance of the storage device is investigated for different operating parameters such as hydrogen supply pressure, cooling fluid temperature and heating fluid temperature. The shortest charging time found is 490 s for the absorption capacity of 1.2 wt% at a supply pressure of 15 bar and cooling fluid temperature and velocity of 288 K and 1 m/s respectively. The effect of copper flakes on absorption performance is also investigated and compared with a similar storage device without copper flakes. 相似文献
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P. Muthukumar U. Madhavakrishna Anupam Dewan 《International Journal of Hydrogen Energy》2007,32(18):4988-4997
In this paper, a two-dimensional computational investigation of coupled heat and mass transfer process in an annular cylindrical hydrogen storage device filled with MmNi4.6Al0.4 is presented using a commercial software FLUENT 6.1.22. Hydrogen storage performance of the device is studied by varying the operating parameters such as hydrogen supply pressure and absorption temperature. Further, the effects of various bed parameters such as hydride bed thickness and overall heat transfer coefficient on the storage performance of the device are also studied. The average temperature of the hydriding bed and hydrogen storage capacity at different supply pressures showed good agreement with the experimental data reported in the literature. It is observed that as the hydriding process is initiated, the absorption of hydrogen increases rapidly and then it slows down after the temperature of the hydride bed increases due to the heat of the reaction. At any given absorption temperature, the hydrogen absorption rate and hydrogen storage capacity are found to increase with the supply pressure. The variation in the hydrogen absorption capacity, rate of reaction and temperature profiles at different supply pressures from 5 to 35 bar in steps of 5 bar are presented. Further, the effects of overall heat transfer coefficients from 750 to 1250 W/m2 K and cooling fluid temperatures from 288 to 298 K on hydrogen storage capacity are also investigated. It is shown that the heat transfer rate enhances the hydriding rate by accomplishing a rapid reaction. At the supply condition of 35 bar and 298 K, MmNi4.6Al0.4 stores about 13.1 g of hydrogen per kg of alloy. 相似文献
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ABSTRACT This study evaluates the techno-economics of replacing an air-source heat pump (ASHP) system with a solar seasonal thermal energy storage (STES) system for space heating in Hangzhou, China. Three heating systems, solar STES, ASHP, and ASHP with short-term storage of solar energy, are developed using TRNSYS for a house with 240 m2 of floor area. The ratio of tank volume to collector area (RVA) of the STES is optimized for the lowest equivalent annual cost over a lifespan of 20 y. The determined optimal RVA is 0.33 m3/m2, although it depends on the system and electricity prices. The optimized STES reduces the electricity demand to 1,269 kWh (74% reduction). Despite the superior energy performance, the economic benefit is only possible with large STES systems, which enjoy low tank prices due to scale effects. The results suggest that policy support is needed for STES, where district scaling is not an option. 相似文献
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讨论了蓄热式热泵的工作原理、特点及设计方法 ,同时介绍了一个实际工程。指出使用蓄热式热泵既可充分合理利用能源 ,降低用户运行费用 ,又为电网提供了一种调荷避峰的好方式。 相似文献
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Currently, hybrid renewable energy systems with thermal energy storage have various advantages and are widely used. This paper investigated the performance of a solar-assisted air source heat pump system with energy storage (SASHPS-ES) in Beijing, China, and proposed an optimal operation mode based on economic evaluation. The results indicate that with the optimal heat storage ratio of 50%, the rated capacity of the air source heat pump (ASHP) of the SASHPS-ES system can be reduced by 16.7%, decreasing its annual total cost by 26.5% under a peak-valley electricity price policy. The price of 620¥/m2 is critical for the solar collectors. The economics of SASHPS-ES is better than that of an air source heat pump system with energy storage (ASHPS-ES) when the price of the selected solar collector units is less than this critical price (without subsidies from the government). In the current local market, the promotion of SASHPS-ES systems and other solar energy applications requires government subsidies for a period of time. The results can guide the utilization and popularity of SASHPS-ES in China. 相似文献