共查询到19条相似文献,搜索用时 156 毫秒
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《节能》2019,(12):92-96
利用CFD对考虑地板传热的三维建筑模型进行模拟,得出换气次数,供回水平均温度和建筑外墙的内表面温度对地板表面温度,辐射换热量和总换热量的影响,以此得出这些因素对地板辐射供冷+置换通风的复合式系统的供冷性能的影响。结果表明:换气次数每降低1h~(-1),地板表面温度升高约0.26℃,辐射换热量升高约1.07 W/m2;供回水平均温度每升高1℃,地板表面温度升高约0.65℃,辐射换热量降低约2.01 W/m~2,外墙的内表面温度每升高1℃,地板表面温度升高约0.25℃,辐射换热量升高约2.08 W/m~2;由于对流换热系数约为0.5~1.0 W/(m~2·K),地板表面的总换热量中对流换热量占比很小,这主要是置换送风时,地板附近空气的垂直温差较小导致的,所以在不考虑地板的供冷能力变化的条件下,其他形式的送风系统可能是更合适的选择。 相似文献
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《节能》2017,(8)
研究太阳直射辐射因素对地板供冷系统管内供水流速及地板表面温度的影响,给出建议的供水参数。通过谐波反应法分别计算出有无太阳直射辐射因素影响时的室内逐时冷负荷(即地板辐射供冷系统的供冷量);分析不同供回水温差下的管内供水流速以及不同供回水平均温度下的地板板面温度,并与已有研究进行对比。得到了是否考虑直射辐射影响这2种情况下的供冷量表,不同供回水温差下是否考虑直射辐射这2种情况的管内水流速表以及不同供回水平均温度及流速下的板面温度对比图。太阳直射辐射因素对地板辐射供冷系统影响较大,有太阳辐射影响的白天时间段内供回水平均温度建议选择14.5℃,可满足全天75%~80%的地板板面温度要求,无辐射影响的夜间时间段供回水平均温度建议选择16.5℃。 相似文献
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定形相变贮能式地板辐射采暖系统的实验研究 总被引:8,自引:2,他引:8
作者在北京采暖季节对相变贮能式地板辐射采暖系统进行了实验研究。该系统采用厚度为2cm,熔点和潜热分别为21.6℃和37J/g的定形相变材料。作为比较,也对普通地板采暖系统进行了对比实验研究,发现:相变贮能式地板辐射采暖系统在实验期间基本上每天开启8~10h,在维持室内温度高于对比试验的情形下,运行费用低于对比试验中的普通地板采暖系统。此外,由于相变材料具有较好的贮热能力,电加热系统的启停造成的室内温度波动较小,变化平缓;试验房间内各壁面温度较高,且波动很小,从而提高了室内的平均辐射温度,这也是地板辐射采暖舒适和节能的原因之一。 相似文献
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为了适应舒适的辐射采暖系统,降低低温地板辐射采暖系统的供水温度的需要,通过对传统热管工作原理及其结构的分析,发现传统热管应用于辐射采暖具有一定的局限性,针对传统热管用于辐射采暖的局限性,提出了一种低温地板辐射供暖用的新型热管的设计方案。该新型热管的特点在于实现了气相工质和液相工质相互独立流动,减小了流动阻力,避免了热管的携带极限、干涸极限等传热极限的发生;并且增大了蒸发段和冷凝段换热面积,使热水管道与地板层的换热量显著增加。该热管应用于低温地板辐射供暖系统可以增大换热面积、提高换热量、降低供水温度,从而达到节能的目的,同时,为太阳能等低品位能源直接应用于供暖系统的研究提供参考。 相似文献
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Performance evaluation of a radiant floor cooling system integrated with dehumidified ventilation 总被引:3,自引:0,他引:3
Doosam Song Taeyeon Kim Suwon Song Suckho Hwang Seung-Bok Leigh 《Applied Thermal Engineering》2008,28(11-12):1299-1311
The radiant floor cooling system can be used as an alternative to all-air cooling systems, using the existing Ondol system (a radiant floor heating system) in Korea to save energy and maintain indoor thermal comfort. Unfortunately, a radiant floor cooling system may cause condensation on the floor surface under hot and humid conditions during the cooling season. In addition, the radiant floor system does not respond quickly to internal load changes due to the thermal storage effect of the concrete mass, which is usually present in radiant floor cooling systems.This study proposes a radiant floor cooling system integrated with dehumidified ventilation, which cools and dehumidifies the outdoor air entering through the cooling coil in the ventilator by lowering the dew-point temperature to prevent condensation on the floor surface. Furthermore, outdoor reset control was used to modulate the temperature of chilled water supplied to the radiant floor, and indoor temperature feedback control was then used to respond to the internal load changes.To evaluate the performance of the radiant floor cooling system integrated with dehumidified ventilation, both a physical experiment in a laboratory setting and TRNSYS simulation for an apartment in Korea have been conducted. As a result, it was found that the proposed system was not only able to solve the problem of condensation on a floor surface but also to control the indoor thermal environment within the acceptable range of comfort. Furthermore, the proposed system improved the responsiveness to internal load changes. 相似文献
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《International Journal of Thermal Sciences》2003,42(3):311-316
Distribution ratio of radiation heat on each inside surface of building enclosure of a room has an important effect on the accurate calculation of air conditioning loads. Cooling loads are calculated and analyzed under different distribution ratios on the building enclosure of a room with underfloor air conditioning system and with different constructions. It is found that the previous approximate methods of distribution ratio will result in serious errors when calculating the cooling loads accurately formed by radiant heat gains from indoor heat sources. The accurate method should be calculating the loads based on the actual distribution ratio to each of the inside surfaces of the room. Factors affecting the ratio of radiant heat sent out by indoor heat sources are analyzed. And some regular results are concluded with the ratio calculated under different conditions. The results can supply reference to the people concerned. 相似文献
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本文阐述了低温热水地板辐射采暖分户热计量系统是一种易控、易调、节能的采暖系统,讨论了地板辐射供暖方式与其他方式在房间内人体热舒适方面的差异,并通过对其综合节能效果的考察,分析了地板辐射供暖系统不稳定供暖过程的数学模型,用数值计算的方法分析了间歇供暖条件下,达到室内要求温度所需的预热量与预热时间的关系。 相似文献
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冷辐射地板系统的实验研究 总被引:1,自引:0,他引:1
为了研究冷辐射地板系统的热工性能,测试了地板辐射供冷系统的运行工况,得到了地板表面的最低温度、室内的实感温度、热流密度等参数,并初步探讨地板辐射供冷系统结露现象及防治措施,通过实验分析指出这是一种舒适、节能的供冷方式。 相似文献
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An experiment has been performed to investigate the cooling performance of a thermoelectric ceiling cooling panel (TE‐CCP). The TE‐CCP was composed of 36 TE modules. The cold side of the TE modules was fixed to an aluminum ceiling panel to cool a test chamber of 4.5 m3 volume, while a copper heat exchanger with circulating cooling water at the hot side of the TE modules was used for heat release. Tests were conducted using various system parameters. It was found that the cooling performance of the system depended on the electrical supply, cooling water temperature and flow rate through the heat exchanger. A suitable condition occurred at 1.5 A of current flow with a corresponding cooling capacity of 289.4 W which gives the coefficient of performance (COP) of 0.75 with an average indoor temperature of 27°C. Using thermal comfort test data in literature for small air movements under radiant cooling ceilings, results from the experiments show that thermal comfort could be obtained with the TE‐CCP system. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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对地板辐射和风机盘管两种采暖方式进行了实验研究和理论分析,提出了围护结构临界热阻临的概念,推导出了两个采暖系统的热舒适性随围护结构热阻和冷风渗透量波动的变化关系。实验验证了地板辐射采暖既改善了室内热环境又显示较好的节能效果。 相似文献
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Very low temperature radiant heating/cooling indoor end system for efficient use of renewable energies 总被引:2,自引:0,他引:2
Solar or solar-assisted space heating systems are becoming more and more popular. The solar energy utilization efficiency is high when the collector is coupled with indoor radiant heating suppliers, since in principle, lower supply temperature means lower demand temperature and then the system heat loss is less. A new type radiant end system is put forward for even lower supply temperature compared to the conventional radiant floor heating systems. A three dimensional model was established to investigate its energy supply capacities. Simulation results show that 50 W per meter length tube can be achieved with the medium temperature of 30 °C for heating and 15 °C for cooling. The predicted results agree well with the actual data from a demonstration building. Furthermore, it is demonstrated that a supply temperature of 22 °C in winter and of 17 °C in summer already met the indoor requirements. The new end system has good prospects for effective use of local renewable resources. 相似文献