建筑自然通风与置换通风的适用性分析

通过阐述建筑自然通风和置换通风的基本原理,结合人们越来越关注的空气环境和室内空气品质等问题,分析总结了自然通风和置换通风各自优缺点和适用环境。     

Ventilation rates in schools

Research shows that poor indoor air quality (IAQ) in school buildings can cause a reduction in the students’ performance assessed by short-term computer-based tests; whereas good air quality in classrooms can enhance children's concentration and also teachers’ productivity. Investigation of air quality in classrooms helps us to characterise pollutant levels and implement corrective measures. Outdoor pollution, ventilation equipment, furnishings, and human activities affect IAQ. In school classrooms, the occupancy density is high (1.8–2.4 m²/person) compared to offices (10 m²/person). Ventilation systems expend energy and there is a trend to save energy by reducing ventilation rates. We need to establish the minimum acceptable level of fresh air required for the health of the occupants. This paper describes a project, which will aim to investigate the effect of IAQ and ventilation rates on pupils’ performance and health using psychological tests. The aim is to recommend suitable ventilation rates for classrooms and examine the suitability of the air quality guidelines for classrooms. The air quality, ventilation rates and pupils’ performance in classrooms will be evaluated in parallel measurements. In addition, Visual Analogue Scales will be used to assess subjective perception of the classroom environment and SBS symptoms. Pupil performance will be measured with Computerised Assessment Tests (CAT), and Pen and Paper Performance Tasks while physical parameters of the classroom environment will be recorded using an advanced data logging system. A total number of 20 primary schools in the Reading area are expected to participate in the present investigation, and the pupils participating in this study will be within the age group of 9–11 years. On completion of the project, based on the overall data recommendations for suitable ventilation rates for schools will be formulated.     

通风道沉淀问题的研究

通风道内有沉淀物是由于空气中的微粒在靠近通风道壁的边层出现扩散而引起的。作者从通风道的清理、清理的重要性以及沉淀速度等三方面,来说明正常清理才能保持通风器的运转。     

太阳能通风式屋顶强化通风性能的研究

利用热网络分析法建立了太阳能通风式屋顶的传热模型,并就室外气象参数与结构尺寸对其通风性能的影响进行了理论分析,结果表明:采用太阳能通风式屋顶来强化高温地区室内的通风是完全可行的;就结构设计而言,采用多个尺寸较短的屋顶进行组合对加强通风与排热有利,其倾角与绝热层厚度可根据具体情况分别控制在30～60°与0.1～0.3m范围内;至于截面形状,采用宽厚比小的截面可获得较大的单位面积通风量与排热量;但在具体结构设计时要配合建筑设计,依据当地气候条件、建筑用途及经济性来灵活决定。     

Field Measurements of Ventilation and Ventilation Effectiveness in an Office/Library Building

Mechanical ventalation system performance involves the provision of adequate amuunts of outdoor air, uniform distribution of ventilation air within the occupied space, and the maintenance of thermal comfort. Standard measurement techniques exist to evaluate thermal comfort and air change rates in mechanically ventilated buildings; procedures to evaluate air distribution or ventilation effectiveness in the field are still being developed. This paper presents measuremetlts of air change rates and ventilation effectivenes in an office/library building in Washington, DC. The tracer gas decay technique was used to measure whole building air change rates. The air change rates during the measurement period were essentially constant at about 0.8 air changes per hour, somewhat below the design specification and above the minimum recmmmded in ASHRAE Standard 62-1989. Ventilation effectiveness was investigated at several locations within the building through the measurement of local tracer gas decay rate and mean local age of air. The ventilation effectiveness measurements serve as an investigation of the applicability of the m e a s u r r n procedures employed, providing insight into the measurement issue of establishing initial conditions, the spatial variation in test results within a building, and the repeatabildy between tests. The results of the ventilation effectiveness meusurements are consistent with good distrhtion of the outdoor air by the ventilation system and good mixing within the occupied space.     

侧墙上置送风口置换通风流场及通风效果评价

针对设置侧墙上置送风口置换通风系统的房间,采用CFD软件对室内空气速度场、温度场进行模拟。根据模拟结果,分析贴附射流、冲击射流的发展过程,评价侧墙上置送风口置换通风系统的通风效果。     

通风效率性能参数在通风设计中应用的探讨

采用CFD的方法对不同通风方式的典型的办公室内污染物的去除进行了模拟,介绍并比较了换气效率和通风效率作为有效的室内空气品质参数在通风设计和实地测量中的应用：总共进行了3个不同的数值模拟计算,总结实验结果得出：在不知道室内污染源时,采用换气效率比较评价室内通风设计方案;而对于已知室内污染源及释放率的情况,采用通风效率作为评价标准将更准确,以便能详细地给出污染物排除情况。基于本文的研究,空调系统设计者可以根据特定的情况选择适当的参数来指导空调通风系统的设计。     

重庆地区通风舒适区及通风季节划分的探讨

本文以适应性模型为基础,根据人体热舒适及人体卫生学的要求,探讨了重庆地区通风环境下室内舒适温度、舒适风速、相对湿度,结合有效温度,综合考虑了它们之间的相互影响,绘制了重庆地区的通风舒适区.同时与ASHRAE舒适区相比较,划分了重庆地区的通风季节.     

Ventilation of small factory units

Ventilation rates have been measured using tracer gas techniques in a number of modern factory units with no mechanical ventilation. Wind direction remained fairly constant throughout the tests on individual units, enabling the variation of ventilation rate with wind speed to be determined. In the second phase of the work, measurements were made on a single building under a wide range of weather conditions. Although no correlation with wind direction was apparent, it was shown that the ventilation rate varied not only with wind speed, but also with the difference between the internal and external temperatures, i.e. the “stack effect”.     

变电所通风设计浅析

分析了变电所设备间设备发热量大、设备布置紧凑、电压等级高等特点。结合工程实例，介绍了变电所通风设计的方法、原则和应注意的问题。     

通风的有效性与室内空气品质

指出了通风有效性对改善室内空气品质的重要性,比较了不同送风方式的换气与通风效率,分析了通风效率与室内污染度的关系,最后提出了关于如何提高通风效率的建议。     

地下车库诱导式通风与风管式通风系统的数值模拟分析

诱导式通风和风管式通风作为2种常用的通风系统,在地下车库通风设计中得到了广泛的应用.本文以某地下车库为载体,首先对诱导式通风系统和风管式通风系统进行了数值模拟计算.而后从气流组织、污染物浓度分布和经济性方面对2种通风方式进行分析评价,得出诱导式通风系统在气流分布方面虽不如风管式通风系统均匀,扰动较大,但有利于污染物的排放;同时,该系统运行经济,节省费用可观,综合考虑可知诱导式通风系统拥有较大的优势,具有很好的推广前景.     

室内环境与自然通风

通风的目的是保证室内良好的空气品质,采用自然通风方式是生态建筑设计的重要内容,通过良好的自然通风组织减少对空调的利用,并及时将污染物排出,改善室内空气品质。在热舒适方面,自然通风形成的室内热环境有利于人体舒适性。分析了生态建筑中自然通风对室内空气品质与室内热环境产生的影响,探讨了利用自然通风来改善建筑的室内环境的效果和策略,并提出了相应的设计方法。研究结果表明:组织合理的自然通风,可以有效地改善室内的空气品质和室内热环境。     

建筑的自然通风设计浅析

自然通风是节能建筑中广泛采用的一项技术手段。根据自然通风的实现原理不同可分为：利用风压实现的自然通风、利用热压实现的自然通风、风压与热压相结合的自然通风以及机械辅助通风等几种形式,着重从自然通风的实现方法着手,结合具体实例,分析其原理,并对双层维护结构和高层建筑的自然通风问题进行了初步的分析。     

Ventilation system with spiral recuperator

A new kind of longitudinal flow spiral recuperator for the heat recovery in ventilation systems of buildings was studied experimentally and analytically.The aim of this work is to analyze the possibility of using air handling units with new type of spiral recuperator in order to recover heat in ventilation systems of buildings. For the reason that the air flows are parallel to the symmetry axis of the longitudinal flow spiral recuperator, in this unit pressure drops are smaller than in commonly known spiral exchangers. Because of the counter flow, a greater value of thermal effectiveness ? is reached for the same value of the number of transfer units in comparison to cross-flow recuperators.The exploitation of the new type of spiral recuperator in winter periods brings significant savings. The results obtained from computations are very encouraging for a widespread use of these devices.     

利用竖井自然通风辅助机械通风的关键参数研究

为了解决长大隧道中如何有效利用竖井自然通风辅助机械通风,提高通风效果、节约能耗,以锦州地下储油洞库群和官田隧道的施工通风为依托,采用理论分析、数值模拟及现场测试对竖井自然通风效应的影响参数进行了研究。研究结果表明,在特定的气温条件下,竖井进行自然通风会对机械通风有辅助的效果;竖井的直径变化对通风的作用影响是比较有限,当竖井的深度在250 m以前时,竖井通风效应随竖井深度的增大而增强。当竖井深度达到250 m后,继续增加深度,其通风效应无显著变化。温差越大,竖井自然通风效果相对越好,冬季利用竖井出风的通风效果要好于夏季利用竖井进风的通风方式;该竖井进风方案的要点在于如何将新鲜的风引入到主洞室,在距竖井的中线5 m处布置风机比较科学合理。     

热压自然通风网络模型及通风量计算方法

基于多区域通风网络模型,根据热压作用下的自然通风原理,建立了热压自然通风网络模型,探讨了基本数学方程.结合算例,分析了某别墅建筑热压自然通风量的计算过程.     

机械通风是解决住宅室内通风问题的适宜方法

新鲜清洁的空气是人们身体健康和生活品质的基础。本文通过对北京和上海普通民宅的测试调查，指出伴随着建筑节能的深化而引起的门窗密闭性的提高，自然通风无法满足住宅的新风需求。通过总结北京，上海住宅室内通风的系统型式，提出了机械通风在解决住宅室内通风问题时应该采取的方式和方法。     

厨房通风量计算分析及风系统布局建议

本文对厨房排风量及新风量计算各方法进行介绍,提出各方法的优缺点和适用范围。对厨房排风系统和新风系统进行了详细介绍,结合实际工程情况分析了各系统的优缺点。厨房采用空调风时,结合工程实际情况提出了新型的“三管制”新风系统,已达到节能和经济合理的要求。     

纵向通风下隧道长度对临界风速的影响分析

临界风速可有效控制烟气蔓延,是隧道防灾通风重要参数。为分析隧道长度对临界风速的影响,采用量纲分析法构建临界风速与隧道长度关系公式,并分别在5 MW和30 MW火源热释放速率下,对不同长度隧道的火灾进行数值模拟以量化研究隧道长度对临界风速的影响。结果表明,隧道长度对临界风速具有影响,且不同火源释放速率时影响也有所不同:无量纲火源热释放速率小于0.15时,临界风速随隧道长度增大呈现1/41次方增长关系;无量纲火源热释放速率高于0.15时,临界风速随隧道长度增大呈现1/25次方增长关系。进而建立了考虑隧道长度的无量纲临界风速计算公式。