相变材料蓄能式吊顶辐射供冷系统热性能模拟研究

本文将单位体积蓄能密度较大的相变材料与毛细管网格栅埋入到建筑吊顶中,设计出了一种相变材料蓄能式吊顶辐射供冷末端形式,建立了分析该吊顶在间歇运行工况下热性能的数学模型,利用该模型可以分析不同相变材料物性对该相变材料蓄能式吊顶的表面平均热流密度和蓄能比的影响。通过对影响因素的敏感性分析,得出了影响吊顶热性能的主要因素。此外,对比分析了相变材料蓄能式吊顶与混凝土蓄能式吊顶热性能的差异,指出相变材料蓄能式吊顶辐射供冷方式具有蓄能比更高的特点。     

营造可持续建筑蓄能围护结构的新思路及新方法

随着能源供求失衡日益加剧,建筑蓄能节能的重要性不断凸显。营造具有高效蓄能及可调节能力的可持续蓄能围护结构,对于建筑节能具有重要意义。本文从居住者的热舒适需求出发,通过反问题思路,提出了被动式及主动式建筑中可持续室内环境营造的一些新思路和新方法。研究发现,被动式建筑围护结构理想热质体热性能具有相变材料的特征,即热容随温度的分布接近δ函数形式。并进一步开展了建筑用相变材料的研发及应用研究,研制了建筑用定形相变材料和微胶囊化相变材料,克服了传统相变材料易泄露和导热系数偏低等缺点。最后,提出了主被动式建筑围护结构和相变材料一体化的系统应用方案,并通过实验及模拟验证了其节能舒适效果,为相变材料和建筑蓄能围护结构一体化的设计及应用提供指导。     

相变蓄能材料在建筑节能领域的应用研究

介绍了应用于建筑节能领域的相变蓄能材料,探讨了相变蓄能材料在建筑围护结构、相变蓄热供暖系统与相变蓄冷空调系统中的应用。研究表明,相变蓄能材料在建筑领域的应用可以有效地利用太阳能等清洁型能源,缓解建筑物热量供需双方不平衡矛盾,提高室内舒适度,减小建筑能源消耗。总结并展望了未来相变蓄能材料在节能建筑领域应用的研究方向和发展前景。     

相变蓄能材料在建筑节能中的应用

相变材料可以与传统建材复合成具有蓄热和调温功能的新型建筑材料。本文结合相变蓄能材料的性质、优点,把相变蓄能材料划分为三类,分析了其在节能建筑中的应用,并提出了以后应注意的问题。     

FTC自调温相变蓄能材料应用

针对建筑节能的重要性,从材料特点、基本原理、应用范围、施工工艺等方面介绍了FTC自调温相变蓄能材料,进行了该蓄能材料的效益分析,并通过FTC自调温相变蓄能材料应用的实例说明了该材料施工简捷、操作容易、料体质轻、凝固快、综合造价低等特点。     

轻质建筑中相变蓄能石膏板热性能研究

现代轻质建筑由于热惯性较小,室内温度昼夜波动较大。相变蓄能具有温度变化小、蓄能密度大的特点。将相变材料（PCM）掺入轻质建材中,制成相变蓄能建筑构件,可以有效增加建筑围护结构热惯性,提高室内热舒适度,节约采暖空调能耗。本文研究了相变蓄能石膏板在北京地区轻质建筑中的冬季使用效果,从相变温度、相变材料含量和相变石膏板厚度三个方面对相变蓄能石膏板的使用进行了优化,并比较了普通石膏板和混凝土隔墙的使用效果。研究表明相变蓄能石膏板能有效抑制室内温度波动,提高室内热舒适度。     

太阳房与相变蓄能结合技术应用研究

根据国内外对相变蓄能技术结合太阳房应用的实验研究,从系统特点、相变材料与建筑的结合方式及作用效果总结了相变蓄能技术与太阳能建筑集成应用的特点与形式;分析了Team Ontario/BC设计的太阳房在建筑围护结构中添加相变材料后对负荷、室内温度、能耗的影响。指出了将相变蓄能结合太阳能建筑利用的潜力及亟待解决的实际问题。     

相变蓄热围护结构实验研究

文章阐述相变材料在建筑围护结构中的几种应用,介绍相变材料墙体实验室,通过对比实验,测试相变材料对墙体蓄热性能的影响。经过实验数据分析,总结相变材料的应用效果及存在的一些问题,对相变温度的选择做出定性判断,对相变蓄能在建筑中的应用前景和研究方向进行预测。     

石蜡为介质的一体化太阳能热泵热水器实验研究

本文提出了1种新型蓄能型一体化太阳能热泵热水器系统(SHPWHICSE),搭建了实验测试装置。在南京地区春季典型工况下,对集热/蓄能/蒸发一体化太阳能热泵热水器系统充灌蓄能材料石蜡前后的蓄能特性进行了实验研究。结果表明:充灌相变材料石蜡后,相变材料通过固-液相变储存足够的太阳能,SHPWHICSE系统可保证在1天中任意时刻启动。采用石蜡为蓄能介质的一体化太阳能热泵热水器系统的COP和得热效率均高于未充灌相变材料的系统。太阳辐射强度的不稳定波动对采用石蜡为蓄能介质的一体化太阳能热泵热水器系统得热效率的影响比其对未充灌相变材料的太阳能热泵热水器系统的影响小。     

相变材料十四酸改良凝固-熔化研究

本文介绍了相变材料十四酸在蓄热技术中的应用,用FLUENT软件模拟了纯十四酸及向其中添加不同质量石墨组成的复合相变材料的相变过程,并对模拟和实验结果进行分析。所得到的结论对十四酸及其与石墨组成的改良相变材料在实际工程中的应用、相变蓄能装置的设计具有一定的理论参考价值。     

相变材料在建筑中的应用

相变材料是一种高效的贮热物质。在一定的温度下，它发生相变，并伴随着吸热、放热。根据相变材料化学成分、相变过程形态和相变温度，相变材料可以分为不同的种类。相变材料结合微胶囊技术制造的相变材料微胶囊具有导热系数好，易于与建筑材料结合，经济等优点。本文介绍了相变材料在墙体、混凝土制品、地板中的应用，以达到节能和室内舒适的目的，并指出了今后还需要进一步研究的一些问题。     

蓄能保温砖的制备和保温性能实验

基材砖体以粉煤灰和硅酸钠为主要原料制备,砖体内部填充定量的水合盐相变储能包覆材料后,制备了一种新型复合储能建材——粉煤灰胶体保温蓄能砖(PCM砖)。对该砖体进行了48h的仿真环境热学性能试验,与普通红砖进行了对比,试验结果表明,由于储能的作用,PCM砖起到了调节温度热波动的作用。热流的波动幅度被削弱,作用的时间被推后,将温度变化维持在较小的范围内,可作为保温墙体材料进行应用。     

空气源热泵相变蓄能除霜系统蓄热模式及除霜特性的研究

本文阐述了基于相变蓄热的空气源热泵蓄能除霜系统及其相变蓄热器的设计,提出了3种蓄热模式并搭建了空气源热泵蓄能除霜试验台.通过对实验数据进行分析,认为串联蓄热模式时,系统可有效完成蓄热且相变蓄热器的蓄热速度较快;单独蓄热模式和并联蓄热模式时系统不能有效运行,压缩机的吸、排气温度偏高,而吸、排气压力偏低,功率偏低,相变材料...     

Performance of phase change material boards under natural convection

The high thermal storage capacity of phase change material (PCM) can reduce energy consumption in buildings through energy storage and release when combined with renewable energy sources, night cooling, etc. PCM boards can be used to absorb heat gains during daytime and release heat at night. In this paper, the thermal performance of an environmental chamber fitted with phase change material boards has been investigated. During a full-cycle experiment, i.e. charging–releasing cycle, the PCM boards on a wall can reduce the interior wall surface temperature during the charging process, whereas the PCM wall surface temperature is higher than that of the other walls during the heat releasing process. It is found that the heat flux density of the PCM wall in the melting zone is almost twice as large as that of ordinary wall. Also, the heat-insulation performance of a PCM wall is better than that of an ordinary wall during the charging process, while during the heat discharging process, the PCM wall releases more heat energy. The convective heat transfer coefficient of PCM wall surface calculated using equations for a normal wall material produces an underestimation of this coefficient. The high convective heat transfer coefficient for a PCM wall is due to the increased energy exchange between the wall and indoor air.     

Numerical and experimental study on heat pump water heater with PCM for thermal storage

An air source heat pump water heater with phase change material (PCM) for thermal storage was designed to take advantage of off-peak electrical energy. The heat transfer model of PCM was based upon a pure conduction formulation. Quasi-steady state method was used to calculate the temperature distribution and phase front location of PCM during thermal storage process. Temperature and thermal resistance iteration approach has been developed for the analysis of temperature variation of heat transfer fluid (HTF) and phase front location of PCM during thermal release process. To test the physical validity of the calculational results, experimental studies about storing heat and releasing heat of PCM were carried. Comparison between the calculational results and the experimental data shows good agreement. Graphical results including system pressure and input power of heat pump, time-wise variation of stored and released thermal energy of PCM were presented and discussed.     

Effects of wallboard design parameters on the thermal storage in buildings

The phase change material (PCM) could be added to the wallboard to increase the thermal mass to decrease in indoor temperature fluctuation and improve thermal comfort. In this study, experimentally validated simulation was performed to investigate the effects of various parameters of PCM including the nominal average phase change temperature, its range, the convective heat transfer coefficients and the wallboard thickness on the thermal storage performance of the wallboard such as the thermal energy storage and the time shift.It was found that the average phase change temperature should be close to the average room temperature to maximize the thermal heat storage in the wallboards. The phase change temperature should be narrow to maximize the thermal heat storage in the PCM wallboards. The thermal heat storage increased with the convective heat transfer coefficient, and the optimal average phase change temperature to maximize the storage shifted a bit to a higher temperature with it. The time shift was found to decrease with the convective heat transfer coefficient and the phase change temperature range.     

Experimental study and evaluation of latent heat storage in phase change materials wallboards

Phase change materials (PCM) can be applied in building envelops to conserve heat energy. Wallboards incorporated with PCM can automatically absorb indoor redundant heat, which can greatly reduce the load of HVAC systems and save electric energy. In experiments, a PCM wallboard room was constructed by attaching PCM wallboards, developed by incorporating about 26% PCM by weight into gypsum wallboards, to the surface of an ordinary wall. The transition temperature and latent heat of these PCM wallboards were tested by differential scanning calorimetry (DSC). The room testing was conducted to determine the latent heat storage of PCM wallboards. Through experiments, it could be proved that DSC can effectively predict the performance of a full-scale installation of PCM wallboards. Compared with an ordinary room, it was found that the PCM wallboard room could greatly reduce the energy cost of HVAC systems and transfer electric power peak load to valley.     

相变材料在建筑节能应用领域的实验研究方法初探

相变材料可在较窄的温度范围内,蓄存或释放大量的潜热,可应用于建筑外围护结构,提高建筑的热惰性,缓解室内温度波动,削减空调负荷的峰值；又可与传统空调采暖系统相结合,蓄存廉价或免费的冷热量,从而起到建筑节能的作用.应用形式的多样化,导致了研究方法及测试方法的多样化.根据测试场景和测试建筑的不同,对研究手法及测试方法进行了分类汇总,结合一些实测案例重点分析了各类实验方法的测试对象、测试工况、测试手段等,分类整理了各类实验方法的优缺点及测试的要点,为今后的研究提供了重要参考.     

Effect of double layer phase change material in building roof for year round thermal management

Efficient and economical technology that can be used to store large amounts of heat or cold in a definite volume is the subject of research for a long time. Latent heat storage in a phase change material (PCM) is very attractive because of its high-energy storage density and its isothermal behavior during the phase change process. Thermal storage plays a major role in building energy conservation, which is greatly assisted by the incorporation of latent heat storage in building products. Increasing the thermal storage capacity of a building can enhance human comfort by decreasing the frequency of internal air temperature swings so that the indoor air temperature is closer to the desired temperature for a longer period of time. However, it is impossible to select a phase change material to suit all the weather condition in a given location. The PCM that reduces the internal air temperature swing during the winter season is not suitable for the summer season as the PCM remains in the liquid state at all the times during these months and hence the system cannot exploit the latent heat effect. This paper attempts to study the thermal performance of an inorganic eutectic PCM based thermal storage system for thermal management in a residential building. The system has been analyzed by theoretical and experimental investigation. A double layer PCM concept is studied in detail to achieve year round thermal management in a passive manner.