共查询到18条相似文献,搜索用时 531 毫秒
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高温相变蓄热技术在建筑采暖中的应用 总被引:1,自引:0,他引:1
高温相变蓄热是一种理想的电采暖技术,可以充分利用夜间廉价电蓄存热量以供白天采暖.它不仅可缓解我国城市因燃煤造成的环境污染,而且可平衡电网峰谷差,节约电采暖运行费用.介绍了一种高温相变蓄热电采暖装置的结构、工作原理及热性能测试结果,并对其应用进行了经济性分析. 相似文献
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相变蓄热装置是太阳能、工业余热等供热技术推广应用的关键装备。在分析现有相变蓄热装置特性的基础上,提出了毛细管相变蓄热罐,并结合一种复合型相变蓄热材料,对其热物性进行了测试,结果表明该复合相变蓄热材料符合太阳能供热技术的要求。同时研究了水流量和供水温度对毛细管相变蓄热管性能的影响,得出了最佳流量,为毛细管相变蓄热罐的设计提供了数据支持。 相似文献
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本文通过对高温相变蓄热材料国内外研究现状进行分析,提出探索高温相变蓄热过程热力学行为特性,建立热-结构耦合分析模型,并与实验研究相结合,是弄清相变过程热力学机理、掌握相变蓄热技术、进行吸热/蓄热器和热控系统以及相变蓄热容器合理设计的关键,并将为最终在太阳能发电、高温热能回收、航天以及冶金等其它工业领域的技术应用奠定基础。 相似文献
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对采用纯石蜡相变蓄热式与水蓄热式2种热泵热水器系统的性能进行了对比实验研究,对比分析了2种热泵热水器系统在制冷兼热回收模式下的蓄热过程、蓄热箱的冷凝热回收率以及系统的综合能效系数,在此基础上提出了改善纯石蜡相变蓄热式热水系统性能的措施。实验数据表明,与传统水蓄热式热泵热水系统相比,纯石蜡相变蓄热式热泵热水系统减小了蓄热箱的体积,蓄热过程中系统运行相对平稳,但蓄热箱的换热效果较差、冷凝热回收率相对较低,进而影响了系统的综合能效。可通过对蓄热箱内螺旋盘管进行翅片化处理或者插入铝箔、加入膨胀石墨等项措施强化蓄热箱的传热以提高冷凝热回收率,进而提高系统的综合性能。 相似文献
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本文提出一种与轻质墙体内侧结合、增强其蓄热性能的相变蓄热构件。利用多物理场耦合的有限元软件COMSOL建立复合墙体的数值计算模型并验证其准确性,以相变蓄热构件内相变材料的完全熔化时间和构件表面温差作为评价依据,分析构件内部不同参数肋片的强化传热机理并优选出最佳肋片参数;以深圳地区为例,从相变材料的用量和相变温度对相变蓄热构件的使用效果进行优化,比较了肋片在相变蓄热构件提升2种轻质墙体蓄热性能上的差异。结果表明,长而薄的肋片在适宜的肋片间距下能够提升石蜡温度场和流场变化的协同性,增强传热速率;在不影响复合墙体对室外热扰延迟时间的前提下,肋片的添加使加气混凝土复合墙体的显热蓄热和放热时长分别缩短了44.8%和26.3%,聚苯板复合墙体的显热蓄热和放热时长分别缩短了20.8%和52.9%,肋片对聚苯板复合墙体的有效蓄热量和蓄热能力的提升效果较好。本文的研究结果能够为相变蓄热构件的设计和应用提供参考依据。 相似文献
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《建筑节能》2020,(6)
建筑围护结构结合相变蓄热材料能够大幅提升其蓄热性能,削弱室外温度波动对室内热环境的不利影响,有助于充分利用自然气候资源。由于相变材料的变物性特征,相变墙体和传统围护结构的热工性能存在显著差异。基于人工控制环境下的缩尺模型实验,对比分析了在室内外双向周期性热作用下,相变墙体不同材料层顺序(相变蓄热层、保温层、结构层)对其热工性能的影响。结果表明,当墙体材料层顺序由外向内分别为"保温层-结构层-相变蓄热层"时,实验小室室内空气温度峰值最小。分析了在不同材料层顺序下相变墙体的内表面蓄热系数,结果表明当墙体的材料层顺序由外向内分别为"相变蓄热层-保温层-结构层"及"保温层-结构层-相变蓄热层"时,相变墙体的内表面蓄热系数分别为4. 39 W/(m~2·K)和4. 13 W/(m~2·K),均大于采用材料层顺序由外向内为"相变蓄热层-结构层-保温层"的相变墙体的内表面蓄热系数。内表面蓄热系数计算结果与相变墙体热工性能实验结果相符,能够准确体现相变墙体内表面蓄热性能及其对室内热环境的影响。 相似文献
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《Energy and Buildings》2006,38(3):258-265
A new hybrid thermal energy storage system (HTESS), using phase change materials, is proposed for managing simultaneously the storage of heat from solar and electric energy. Solar energy is stored during sunny days and released later at night or during cloudy days and, to smooth power demands, electric energy is stored during off-peak periods and later used during peak periods. A heat transfer model of the HTESS is developed and validated with experimental data. Simulations carried out for a period of 4 consecutive winter months indicate that, with such a system, the electricity consumption for space heating is reduced by nearly 32%. Also, more than 90% of the electric energy is consumed during off-peak hours. For electricity markets where time-of-use rate schemes are in effect, the return on the investment in such a thermal storage system is very attractive. 相似文献
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《Energy and Buildings》2006,38(10):1149-1155
A control model for operating a system that stores simultaneously sensible heat from solar and electric energy is proposed. The hybrid thermal energy storage system accumulates solar energy during sunny days and releases it later at night or during cloudy days. It also stores heat from an electric heater during off-peak periods so as to release it later during peak periods. The control model, which makes use of 24-h weather forecasts, comprises two types of controllers: a fuzzy logic controller for estimating the daily amount of thermal electric energy to be stored and a feedforward controller for determining the electricity consumption profile of the heating element during off-peak hours. Results indicate that the proposed control system is far superior to traditional control systems. It maintains a comfortable thermal environment at all times, i.e. the temperature fluctuations are kept within the imposed margins and overheating of the room never occurs. Furthermore, compared to a traditional electric base board heating system, it reduces the electricity consumption for the winter season by 24% and 94% of this electricity is consumed during off-peak hours. 相似文献
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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. 相似文献
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Modeling and simulation of under-floor electric heating system with shape-stabilized PCM plates 总被引:6,自引:0,他引:6
Kunping Lin Yinping Zhang Xu Xu Hongfa Di Rui Yang Penghua Qin 《Building and Environment》2004,39(12):1427-1434
A model is developed to analyze the thermal performance of a room applying a new kind of under-floor electric heating system with shape-stabilized phase change material (PCM) plates, which is verified by our experimental data. This system can charge heat by using cheap nighttime electricity and discharge the heat stored at daytime. The thermal performance of the heating system and the effects of various factors on it are analyzed through simulation. The results show that the heating system can be used in various climates if its structure is properly designed. The model and the discussion are helpful to design such kind of under-floor electric heating systems. 相似文献
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J. Koo 《Energy and Buildings》2011,43(8):1947-1951
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. 相似文献