高温相变蓄热的研究进展

从如下两个方面总结了高温相变蓄热的研究现状：①在高温相变材料(PCM)方面，重点介绍了高温相变材料的一些重要性能及其测量，高温相变材料的封装，高温复合相变材料及高温相变材料的应用；②在传热分析方面，主要介绍了相变过程的数值模拟和相变蓄热系统(LTES)的热力学优化。     

太阳能蓄热墙相变蓄热材料的研究进展

综述了国内外关于太阳能蓄热墙相变材料的研究进展.其中包括太阳能相变材料的分类,物理、化学性质等.目前对于一些相变材料缺陷的改进方法,及相变材料在墙体中的应用.     

含相变材料的壁板的潜热蓄热试验

含相变材料的壁板具有潜热蓄热能力。本文研究安装含相变材料的壁板的房间做了蓄热试验，并将试验结果与安装普通壁板的主心间进行了比较。     

电加热相变材料蓄热地板采暖的热性能模拟

为消除电采暖引起的电网峰谷差并降低采暖运行费用，该文提出了一种带有相变材料潜热贮能板的地板电采暖系统，并建立了分析此系统热性能的地板和房间理论模型，对给定的电加热相变蓄热地板采暖房间，模拟了室内空气温度和地面温度的变化，藉此分析了我国几个气候地区冬季该系统的应用效果，结果证明此采暖方式在使房间热负荷不大的建筑和气候条件下，基本能满足人的热舒适性要求，有较好的应用前景。     

陶土基高温相变蓄热复合材料的制备

高级陶瓷基高温相变蓄热复合材料具有蓄热密度较高、基体耐腐蚀强等优点,但也存在制作成本高的缺点。本研究采用粉末烧结工艺将陶土分别同性能优良的高温熔融盐复合,成功地制备出蓄热密度高、耐腐蚀性好且成本低廉的相变蓄热复合材料。并对相变蓄热复合材料制备过程的工艺参数进行初步研究。     

高温相变蓄热容器传热的隐式求解

空间太阳能热动力发电系统是非常有前景的未来空间能源供应系统,关键部件之一是吸热/蓄热器,高温蓄热容器是其中的基本部位,它的传热性能直接影响玻整个热动力系统的性能。采用一种预测-修正的隐式迭代法对相变蓄热容器进行了三维热分析。并且与显式求解方法在计算时间和计算结果上进行了比较分析。证明这种方法可以明显提高计算速度,并可以获得较好的结果。     

组合式相变材料蓄热系统中相变温度分布研究

建立了组合式相变材料蓄热系统物理模型，在忽略显热的假设条件下研究了相变温度呈线性分布的组合式相变材料蓄热系统传热特性，得出了最优线性相变温度分布，并采用考虑显热的数值计算（有限差分法）证实了理论分析得出的最优相变温度与实际相变温度分布几乎相同。     

固-固相变蓄热材料在太阳能高温空气集热系统中的应用研究

为利用太阳能获得稳定持续的高温空气工质,除了有效集热外,还需要解决因太阳辐射强度变化导致输出工质温度波动的问题。在性能优良的太阳能集热系统中采用蓄热技术是解决此问题的有效途径。根据给定的设计目标,研究将固-固相变蓄热材料季戊四醇应用到太阳能集热蓄热一体化的实验装置中。实验结果表明:按集热蓄热一体化思路设计的实验装置,集热单元能够输出最高温度超过220℃的高温空气,蓄热单元能够将高温空气的温度稳定在蓄热材料的相变温度附近。并且随着蓄热管级数的增加,空气出口温度稳定的时间就越长,为利用太阳能获得稳定持续的高温热媒工质奠定了基础。     

高温固液相变蓄热容器的研究与发展

介绍了近年来国内外空间太阳能动力装置PCM蓄热容器的研制情况，分析了PCM蓄热容器的传热过程及热分析方法，概括了研究中存的主要问题，认为进一步完善传热模型，寻求强化传热新途径，提高效率和可靠性及进一步的试验研究是今后发展及研究的主要方向。     

Low temperature latent heat thermal energy storage: Heat storage materials

Heat-of-fusion storage materials for low temperature latent heat storage in the temperature range 0–120°C are reviewed. Organic and inorganic heat storage materials classified as paraffins, fatty acids, inorganic salt hydrates and eutectic compounds are considered. The melting and freezing behaviour of the various substances is investigated using the techniques of Thermal Analysis and Differential Scanning Calorimetry. The importance of thermal cycling tests for establishing the long-term stability of the storage materials is discussed. Finally, some data pertaining to the corrosion compatibility of heat-of-fusion substances with conventional materials of construction is presented.     

High temperature latent heat thermal energy storage using heat pipes

A thermal network model is developed and used to analyze heat transfer in a high temperature latent heat thermal energy storage unit for solar thermal electricity generation. Specifically, the benefits of inserting multiple heat pipes between a heat transfer fluid and a phase change material (PCM) are of interest. Two storage configurations are considered; one with PCM surrounding a tube that conveys the heat transfer fluid, and the second with the PCM contained within a tube over which the heat transfer fluid flows. Both melting and solidification are simulated. It is demonstrated that adding heat pipes enhances thermal performance, which is quantified in terms of dimensionless heat pipe effectiveness.     

State-of-the-art of phase-change thermal storage at middle-low temperature

相变蓄热技术由于蓄热密度大,温度恒定,在国内外得到广泛的研究与应用,尤其在能源供给不连续的情况下,应用的尤其广泛.相变储热系统作为解决能源供应时间与空间矛盾的有效手段,是提高能源利用率的重要途径之一.本文从相变材料的选取,相变过程数值模拟,相变蓄热装置3个方面对中低温相变蓄热的研究进行了综述.首先介绍了中低温相变材料的种类及其循环稳定性,导热能力强化,其次总结了适用于中低温相变蓄热的数值模拟方法和理论,然后介绍了不同的相变储热器,最后指出了中低温相变蓄热的研究目标和方向.     

太阳能热发电高温蓄热技术

一前言太阳能热发电技术是除风电以外最有经济竞争力的可再生能源发电技术。太阳能集热器把收集到的太阳辐射能发送至接收器产生热空气或热蒸汽,用传统的电力循环来产生电能,具有技术成熟、发电成本低和容易与化石燃料形成混合发电系统的优点。太阳能高温蓄热技术是太阳能热发电的关键技术。由于太阳辐射强度时刻在变化,太阳能热发电系统在早晚或云遮间隙必须依靠储存的能量维持系     

Modeling of a heat exchanger utilizing a phase-change material for short-term storage

A computer program was proposed to simulate the behavior of a low-temperature phase-change material (PCM) in a heat exchanger for short-term storage. An experimental set-up of mainly a heat exchanger with a staggered tube arrangement and air temperature control unit were used. In the modeling approach, the PCM in the tube was divided into 10 concentric cells of equal mass, and was logically treated in terms of energy balance. Experimental inlet air temperature (at three different flow rates) was utilized as input data to test the model output results and their reliability. Excellent agreement was obtained for the outlet air temperature when compared with the experimental measurements, and differences did not exceed 0.5°C over the simulated period. The predicted PCM average temperature history showed good agreement with the experimental ones, and differences did not exceed 2° at the highest applied air flow rate. This modeling approach can be used for any PCM, provided that its thermophysical properties are available. The transient moving front for freezing or melting can be predicted, and consequently the mass fraction of either liquid or solid phase to the total PCM mass can be predicted as well.     

Fatty acids and their mixtures as phase-change materials for thermal energy storage

An analysis of thermal properties of fatty acids and their binary mixtures has shown that they are attractive candidates for latent heat thermal storage in space heating applications. In this study, the method of differential scanning calorimetry was used to determine the transition temperatures and latent heat of transition of the fatty acids and their binary mixtures. These properties are of prime importance in the design of a latent heat thermal storage system.The melting range of the fatty acids (capric, lauric, palmitic and stearic) was observed to be approximately from 30°C to 65°C. Their heat of transition was observed to have a range from approximately 153 to 182 J/g. The eutectic points were determined for the binary mixtures of the fatty acids. The melting points of the eutectics for the binary systems of capric-lauric, lauric-palmitic, lauric-stearic and palmitic-stearic acids were found to be 18°C, 32.7°C, 34°C and 51°C respectively. The corresponding heats of melting were 120, 145, 150 and 160 J/g, respectively. The fatty acids and their eutectic mixtures were examined with an infrared spectrophotometer to ascertain the polymorphic forms and material purities.     

一种与坐卧用具结合的太阳能相变蓄热采暖系统

介绍了一种将太阳能利用、相变蓄热与局部采暖技术相结合的新型太阳能相变蓄热坐卧用具采暖系统。阐述了系统的工作原理,分析了其优点,并给出其设计计算实例。     

用于储存太阳能的相变蓄热器蓄热性能研究

利用计算流体力学软件Fluent的凝固/熔化模型,模拟了用于储存太阳能的两种相变蓄热器的蓄热过程,得到了蓄热过程中相变区的温度云图,分析了两种蓄热器的蓄热能力和传热方式。研究结果表明,合理增加内管数量可以提高相变过程中的对流换热强度和蓄热能力。     

On the problem of heat transfer in phase-change materials for small Stefan numbers

The problem of solidification of an infinite liquid slab by linear convection cooling from the adjacent air is considered. It is assumed that at the initial moment the slab has a critical temperature and that on one side the air temperature has diurnal fluctuations of relatively small amplitude. The solution is found in the form of power series of small parameters. The first three terms of each series are obtained. This permits construction of a simple formula for the total solidification time. Evaluation of the accuracy of the solution based on the integral heat balance equation is suggested. Some particular cases of the problem are considered on the assumption that one side of the slab is insulated. One of these cases is the simplest Stefan problem which has an exact solution. Comparison with this solution is made.