【作者】 张宁波；

【导师】 亢燕铭；

【作者基本信息】 东华大学 ， 供热、供燃气、通风及空调工程， 2014， 博士

【摘要】 庭院式建筑(即围合式建筑)是一种具有悠久历史的建筑布局形式。因其围合空间具有较好的自然通风利用潜力,并易于营造相对独立的户外微气候,因而被越来越多地应用在城市现代建筑结构中。许多公共建筑中的庭院被当成中心或主要公共活动场所。经过几十年的不断优化,很多庭院建筑已经能够与当地气候特征进行有机结合以实现充分利用能源和节能的目的。如在北方地区,利用庭院作为防风建筑以及吸收太阳能；而南方气候下,庭院式建筑则可以减少太阳辐射并有效地降低庭院内和室内平均气温。然而,在冬季寒冷气候条件下,围合式建筑所具有的自然通风优势是否会造成冬季室内通风热损失过大；在为人们户外活动需求营造出良好庭院微气候的同时,是否有足够的能力移走内部污染物。这些问题是围合式建筑的节能效应能否充分发挥的关键。为此本文针对围合式建筑室内外空气环境特征展开了实测与数值模拟研究,同时对非围合式建筑(行列式布局)也进行了对比实测与数值计算分析。本文先针对具有高人员密度特征的高校宿舍建筑,对非围合式建筑的冬季和夏季室内空气品质和热舒适状况进行了长时间现场实测和调查。在这一基础上,分别对围合式建筑与非围合式建筑的室内空气环境进行了对比测量。结果表明,相同室外气象条件下,围合式建筑的房间通风量大于非围合式建筑,因而降低了围合式建筑冬季非供暖房间对太阳能的利用效果；但在高人员密度房间中,这虽然导致了较低的室内气温,但另一方面却改善了室内空气品质。通过对不同的围合式庭院空气环境的实测分析发现,若围合式建筑中设置有空调系统,则空调房间在夏、冬两季渗透出的冷空气或热空气对庭院空气环境和通风量的影响明显。特别是供暖季节,即使在微风情况下,本文实测结果均表明,热浮力诱导的庭院通风量大约相当于室外背景风速为4.5～5.9m/s时形成的风压通风量,因此,可以有效地避免污染物在庭院内的滞留和积聚；同时,由于庭院内气温高于环境空气温度,可使实测建筑的围护结构热损失减少11%～20%。自然通风对庭院热环境的影响在不同的窗户开闭和太阳辐射条件下效果不同,合理控制窗户开启状态可有效改善庭院内热环境的舒适性。根据围合式建筑的结构特点,本文利用数值方法对建筑庭院内的气流流动和污染物浓度分布进行了不稳态和稳态数值模拟,以考查其基本规律和特征,并以行列式建筑为基准,分析和比较了不同风向时,围合式建筑形式对污染物扩散的影响。结果表明,对于不稳态过程,污染源散发期间,围合式建筑比行列式建筑附近污染物浓度高,但污染物停止散发后,前者迅速衰减而后者衰减较慢。不同于行列式布局,围合式建筑庭院内污染物浓度对背景风向的变化不敏感。稳态条件下,大多数风向时,庭院下部区域的排污能力与行列式布局基本相当,且庭院上部空间的排污能力好于行列式布局；降低庭院进口的开口高度对庭院内2m以下空间空气品质的影响较小。由于减小庭院进口面积可使庭院微气候的独立性更好,因此,庭院建筑采用高度较低的进口(即交通口),比高开口更易与当地气候特征相结合,缓解庭院微气候独立性与空气品质对通风量要求恰好相反的矛盾；同时发现,庭院迎风面开口的高度对庭院内污染物浓度随建筑高度增大的幅度并无实质性影响。更多还原

【Abstract】 A courtyard form, i.e. one enclosed building, is a very common architectural pattern throughout many periods of history. Its enclosed space has been thought to offer great potential for utilizing natural ventilation and creating a relatively independent outdoor microclimate. The courtyard form is widely used by modern unban building structures. Many public buildings contain some form of courtyard, often as a central core circulation space. It has been developed during the last periods through the process of trial and error to a general climatic satisfying state within the available resources. In northern climates courtyards are used as wind shelters and sun-traps and in southern climates for shelter from the sun and the reduction of courtyard and indoor mean temperatures.Nevertheless, some key issues on whether the energy saving effect of an enclosed building can be sufficiently utilized are still unknown. For example, whether the natural ventilation advantage of an enclosed building will lead to excessive room ventilation heat loss in the cold northern climate, whether an enclosed building is effective enough to remove the internal pollutant while providing a good microclimate in the courtyard for people’ outdoor activities. Therefore, in this paper, field measurements and numerical simulations on the air environment characteristics of the indoor and outdoor spaces of enclosed buildings were conducted, and the indoor and outdoor air environment characteristics for the non-enclosed building form (i.e. the regularly aligned building layout) were also investigated.Field measurement and questionnaire survey on the indoor air quality and thermal comfort in high occupant density dormitory buildings, which are non-enclosed buildings, were firstly conducted in winter and in summer. Then, the indoor air environment of enclosed buildings and non-enclosed buildings were tested simultaneously for comparison. The results show that the room ventilation of an enclosed building is greater than that of a non-enclosed building under the same outdoor climate conditions. It reduces the utilization of solar radiation for an unheated room of an enclosed building, resulting in that though the indoor air temperature of a high occupant density room is low, the indoor air quality of such a room is improved.The air environment in courtyards with different enclosing forms were investigated. The results show that the cold and warm air infiltration from an air-conditioned room of an enclosed building in summer and winter, respectively, has significant impact on the ventilation and air environment of the courtyard. Particularly, even under the calm wind conditions, the courtyard ventilation induced by thermal forces when the building is heated is approximately equivalent to that induced by wind forces when the ambient wind speed is4.5～5.9m/s, and is effective enough to prevent the pollutant retention and accumulation in the courtyard. Meanwhile, the air temperature in the courtyard is higher than the ambient air temperature, thus the building envelope heat loss of the tested courtyard building is reduced by11%～20%. In addition, the effect of natural ventilation on the thermal environment in the courtyard depends on the conditions of solar radiation and opening/closing of the windows. The thermal comfort in the courtyard can be effectively improved if the windows are opened suitably.Based on the structural characteristics of an enclosed building, the steady and unsteady air flow and pollutant concentration distribution in a courtyard were numerically simulated to explore its fundamental features, and that for a regularly aligned building layout was also calculated for providing a baseline for comparison. The effect of the enclosed building layout on the pollutant dispersion under different wind directions was analyzed. The results show that the pollutant concentration in the vicinity of an enclosed building is higher than that for a regularly aligned building when the pollutant source keeps emitting, however, the pollutant concentration of the former decays rapidly while the pollutant concentration for the latter decays slowly when the pollutant stops emitting. Different from a regularly aligned building, the pollutant concentration in the courtyard of an enclosed building is not sensitive to the ambient wind directions.Under steady-state conditions, the pollutant removal capability of the lower zone of the courtyard is almost equivalent to that of a regularly aligned building layout, and the pollutant removal capability of the upper zone of the courtyard is more effective than that of a regularly aligned building layout. Lowering the opening height of the courtyard entrance only have a minimal impact on the air quality within the space below the height of2m in the courtyard. Reducing the opening area of the courtyard entrance is beneficial to the independence of the courtyard microclimate, thus a courtyard with a lower entrance opening height can interact with the local climate better than a courtyard with a higher entrance opening height. This method offers the potential for mitigating the contradictory ventilation demands on the independence of the courtyard microclimate and the air quality in the courtyard. Meanwhile, the height of the windward opening seems to have no substantial impact on the extent of the pollutant concentration in the courtyard increases with the increased building height.更多还原