A Study on the Extreme use of cross-ventilation as a potential energy for air-conditioning purpose

极端利用交叉通风作为空调势能的研究

• 批准号: 15360312
• 负责人: KURABUCHI Takashi
• 金额: $ 9.6万
• 依托单位: Tokyo University of Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360312/
• 关键词: Cross-ventilation; Local dynamic similarity model; Outflow openings; Computational fluid dynamics; k-epsilon two-equation model; Wind pressure coefficient; Cooling load reduction; Window operations; 通風; 格子形状; 屋根面利用; 最小化問題; システムシミュレーション; 省エネルギ

At first, Local Dynamic similarity model giving special notice on dynamic similarity of cross-ventilation was applied to the outflow openings. Cross-ventilation performance at the openings on outflow side was evaluated, and the structure of air flows around the outflow openings was studied by LES and wind tunnel experiment. It was found that LES reproduces the results of the wind tunnel experiment fairly well such as extensive increase of discharge coefficient in a small region where P_R^* value is low. The evaluation of the pressure field by LES revealed that the remainder of dynamic pressure in the air flows and the change of pressure field around the outflow openings give strong influence on discharge coefficient. Also, by identifying the configuration of the stream tube of ventilation air flow, it was found that discharge coefficient is changed depending on how the air flows go out. In general, dynamic pressure tangential to wall surface at the outflow openings is considered to be … More lower than that of the inflow side. The frequency of occurrence of P_R^* was investigated by actual-size experiment, and it was elucidated that the region of P_R^* where discharge coefficient is extensively decreased develops only very rarely.In the second place, to evaluate wind pressure distribution on a building by using CFD (computational fluid dynamics), it has been generally practiced to use k-ε models. However, it is known that the use of the standard k-ε model has disadvantages such as overestimation of wind pressure coefficient and turbulent kinetic energy on the windward surface where wind impinges on the building. To overcome these problems, various modifications of the k-ε model have been proposed. In the present study, a number of modified k-ε models and k-ω model were applied for the estimation of wind pressure distribution on the building, which was designed in parallelepiped shape, and the characteristics in each of these models were confirmed. The results of the present study suggest that the modified k-ε model incorporating Durbin's limiter (model parameter α=0.5) showed satisfactory results for the estimation of wind pressure distribution. In the overall evaluation, the modified k-ε models (incorporating Durbin's limiter (α=0.65), RNG model (renormalization group theory) and Quadratic model) provided good results.At the last, cooling load reduction by introducing cross-ventilation is estimated trough use of building simulation program, TRNSYS with COMIS. Results show the load reduction depends on the building characteristics and way of windows operation. Generally, lower reference temperature, i.e. higher internal heat gain, and lower heat loss coefficient, brings higher load reduction. Larger amount of building thermal capacity also associates the effect. For windows operation, several ways of operations are tested and compared. The reduction rate varies from 10 to 20 % for wooden detached house in suburban area in Japan, depending the way of windows operation. The cooling load is not drastically reduced solely by opening windows during occupied and waking period. Frequent window operations sensitive to ambient conditions especially during night and unoccupied period increase the effect of cross-ventilation. Less

首先，将跨通风的动态相似性特别通知局部动态相似性模型应用于出口开口。评估了出口侧开口处的交叉通风性能，并通过LES和Wind Tunnel实验研究了出口开口周围的空气流量。发现LES可以很好地重现风洞实验的结果，例如在P_R^*值低的小区域中，放电系数的大量增加。 LES对压力场的评估表明，空气流中的其余动态压力和出口开口周围的压力场的变化对放电系数产生了强大的影响。同样，通过识别通风气流的溪流管的配置，发现排放芯的变化取决于空气流的方式。通常，在出口开口处与壁表面切线的动态压力被认为是……低于流入侧。通过实际尺寸实验研究了P_R^*的发生频率，并阐明了P_R^*的区域广泛降低临界物的发展仅很少。然而，众所周知，标准K-ε模型的使用具有缺点，例如高估了风压系数和湍流的动能在迎风表面上撞击了建筑物上的风。为了克服这些问题，已经提出了K-ε模型的各种修改。在本研究中，应用了许多修改的K-ε模型和K-ω模型，以估算建筑物上的风压分布，该建筑物的设计是平行静止的，并确认了这些模型中的每个模型的特性。本研究的结果表明，修改后的K-ε模型融合了Durbin的限制器（模型参数α= 0.5）显示出对风压分布估计的满意厂结果。在总体评估中，修改的K-ε模型（结合了Durbin的限制器（α= 0.65），RNG模型（重新归一化组理论）和二次模型）提供了良好的结果。在最后一次，通过引入交叉审查是通过估计的估计造成的降低冷却负载，这是构建模拟程序的麻烦使用，TRNS与COMIS进行了TRNS。结果表明，减少负载取决于建筑物特征和Windows操作的方式。通常，参考温度较低，即更高的内部热增益和较低的热量损耗系数会带来较高的负载降低。大量的建筑热容量也可以关联效果。对于Windows操作，测试和比较了几种操作方法。根据窗户操作的方式，日本郊区木制独立房屋的降低率从10％到20％不等。在占用和清醒期间，通过打开窗户，冷却负载并不能大大减少。频繁的窗户操作对环境条件敏感，尤其是在夜晚和空闲期间，会增加交叉换气的影响。较少的

项目成果

佐藤林太郎, 倉渕隆, 他: "流出開口部の通風性能評価に関する基礎的研究"空気調和・衛生工学会学術講演会講演論文集. 1381-1384 (2003)

佐藤伦太郎、仓渊隆等：“流出口通风性能评价的基础研究”日本空调卫生学会学术会议论文集1381-1384（2003年）。

Study on the Numerical Predictive Accuracy of Wind Pressure Distribution and Air Flow Characteristics Part3 Improvement Effects to the Predictive Accuracy by Refinement of Mesh

风压分布与气流特性数值预报精度研究第3部分网格细化对预报精度的提高效果

• 期刊: SUMMARIES OF TECHNICAL PAPERS OF ANNUAL MEETING ARCHITECTURAL INSTITUTE OF JAPAN, ENVIRONMENTAL ENGINEERING (Now Printing)
• 作者: Tomoyuki ENDO;Takashi KURABUCHI et al.
• 通讯作者: Takashi KURABUCHI et al.

CFDによる建物風圧係数分布の予測制度に関する研究 その2複雑な形状の建物の風圧係数予測制度の検討

基于CFD的建筑风压系数分布预测系统研究第2部分复杂形状建筑风压系数预测系统研究

• 发表时间: 2005
• 期刊: 日本建築学会大会学術講演梗概集 D・2
• 作者: 石井端樹;倉渕隆;遠藤智行;丸山榮蔵;澤地孝男
• 通讯作者: 澤地孝男

Study on the numerical predictive accuracy of wind pressure distributions and air flow characteristics Part 2 Prediction accuracy of wind pressure distribution of various shaped building

风压分布及气流特性数值预测精度研究 第2部分 各种形状建筑风压分布预测精度

• 发表时间: 2005
• 期刊: PASSIVE AND LOW ENERGY COOLING FOR THE BUILT ENVIRONMENT (PALENC 2005) Proceedings I
• 作者: M.Ishii;T.Kurabuchi et al.
• 通讯作者: T.Kurabuchi et al.

長井達夫: "住宅における通風・冷房のスケジューリング-積算負荷を対象とした予備的検討-"空気調和・衛生工学会学術講演会講演論文集. 1325-1328 (2003)

Tatsuo Nagai：“住宅建筑的通风和冷却调度 - 针对累积负荷的初步研究 -”日本空调和卫生工程师学会学术会议记录 1325-1328（2003）。