置换通风—地板供冷复合空调系统热舒适性研究

通过实验和CFD模拟相结合,分析了不同工况下的置换通风—地板供冷复合空调系统的热舒适性,得到了不同的送风风速、不同的地板表面温度以及提高送风温度对室内的速度场和温度场的影响。对实验室进行建模,利用CFD的后处理软件对复合系统的速度场和温度场进行分析,对其热舒适性给予了评价。研究结果表明,在良好设计的前提下,置换通风—地板供冷复合式空调系统充分发挥了两者的优点,可弥补各自不足,具有节能、舒适和空气品质良好的特点。     

不同的通风方式对打印室空气环境影响的模拟研究

以打印室为例,通过模拟置换通风、顶棚送风以及传统的中央空调送风形式,得到不同送风方式下的温度场、速度场和污染物浓度场,分析结果表明,置换通风方式并不适宜用在此类房间中(污染物密度比空气大的房间);在相同的能量消耗情况下,传统的中央空调送风形式不能提供良好的热环境,顶棚送风可以获得相对较好的室内空气环境。     

置换通风空调系统的节能分析

本文从送风量、新风量、送风温度和室内温度分布几方面分析了置换通风的节能特性,归纳了置换通风系统和冷却顶板或其他冷源结合的节能措施.研究表明:在合理应用的情况下,置换通风空调系统具有明显的节能性.本文通过分析为置换通风空调系统的节能设计提供参考.     

风口侧上置置换通风的热舒适性实验研究

以小型办公室为实验模型,采用了5组对比工况进行了实验,并将实验值与模拟值进行了比较,结果二者吻合较好。分析了侧墙上置风口置换通风的热舒适性。结果表明风口侧上置置换通风在各设计工况下,其负荷承担能力要大于传统置换通风,并且不论是吹风感、吹风温度还是室内头脚垂直温差都满足人体热舒适。这也证实风口上置置换通风与传统置换通风一样,可以在室内形成良好的热力分层现象,并且其能很好地满足人体的热舒适性需求,具有置换通风系统的特性。     

置换通风与混合送风供冷季运行能耗比较

根据置换通风和混合送风设计及运行的特点，以DeST为模拟工具，分析了北京某写字楼分别采用置换通风和混合送风方式供冷季空调系统的运行情况，讨论了两种送风方式在定风量或变风量运行时系统的逐时能耗及在室外新风利用上的特点。结果表明，置换通风比混合送风节省10％以上的运行费用。     

基于方柱面贴附空气幕式送风模式气流组织特性研究

提出了一种适用于大空间建筑通风空调系统的方柱面贴附空气幕式送风模式。采用数值模拟方法,研究了多柱组合送风模式下各柱体间气流组织特性的对称性,分析了送风速度、温度和热流密度3个特性参数对房间速度场和温度场分布的影响,并对工作区人员热舒适性进行了评价。研究表明,该送风模式能够在房间下部工作区形成类似于置换通风的空气湖状速度及温度分布,人员热舒适性较强,承担的室内负荷较传统置换通风模式大,而且上置送风口便于布置,是一种通风效率较高、工作区空气品质较好的气流组织形式。     

上置风口置换通风方式的讨论

针对传统置换通风系统中存在的不足,提出了上置风口置换通风方式,介绍了该通风方式的工作原理,并将其与传统置换通风进行了比较分析,指出上置风口置换通风具有热舒适性好、高效节能的特性,发展前景广阔。     

山西大剧院空调系统设计

介绍了山西大剧院的空调系统,并以主剧场为例着重阐述了观众厅座椅送风方案,通过对置换通风和空调系统下送风的方式进行分析,总结了该工程观众厅气流组织的设计和计算方法,对同类工程具有借鉴作用。     

剧场座椅送风气流组织数值模拟

座椅送风是置换通风的一种具体形式,不同于传统置换通风的侧送风形式,我国在这方面设计规范也相应较少,又鉴于座椅送风初投资昂贵,在设计时有必要对其气流组织、舒适性等加以模拟预测。本文采用FLUENT软件对其空调系统的气流组织进行模拟研究,运用座椅送风的简化模型,模拟各种送风形式下的温度场和速度场,对比了各种送风形式的温度、速度、风量等因素,为大空间建筑空调系统优化设计、模拟气流组织提供了方法及理论依据。     

办公建筑中旋流风口地板送风系统的设计及实验研究

基于地板送风与置换通风原理的相似性,参考办公室中置换通风的设计方法,结合旋流风口地板送风系统的特性,提出旋流风口地板送风系统的设计方法。通过实验对设计方法进行了验证,并对室内热舒适性进行了评价。     

风口上置置换通风的实验研究

对风口上置置换通风系统进行实验研究,得出此种通风方式下送风口的速度分布,室内的温度分布,O.1m处的风速等实验数据.通过分析实验数据得出,风口上置置换通风在满足室内热舒适性的前提下,能够提高房间的负荷承担能力,与混合通风相比能够得出较高的通风效率;另外,阶梯形的风口较普通的送风口能较少的卷吸上区品质差的空气,能更好地满足上置置换通风的风口特性要求.     

Evaluating the commercial airliner cabin environment with different air distribution systems

Ventilation systems for commercial airliner cabins are important in reducing contaminant transport and maintaining thermal comfort. To evaluate the performance of a personalized displacement ventilation system, a conventional displacement ventilation system, and a mixing ventilation system, this study first used the Wells‐Riley equation integrated with CFD to obtain the SARS quanta value based on a specific SARS outbreak on a flight. This investigation then compared the three ventilation systems in a seven‐row section of a fully occupied, economy‐class cabin in Boeing 737 and Boeing 767 airplanes. The SARS quanta generation rate obtained for the index patient could be used in future studies. For all the assumed source locations, the passengers’ infection risk by air in the two planes was the highest with the mixing ventilation system, while the conventional displacement ventilation system produced the lowest risk. The personalized ventilation system performed the best in maintaining cabin thermal comfort and can also reduce the infection risk. This system is recommended for airplane cabins.     

Theoretical and experimental investigation of impinging jet ventilation and comparison with wall displacement ventilation

This paper focuses on evaluating the performance of a new impinging jet ventilation system and compares its performance with a wall displacement ventilation system. Experimental data for an impinging jet in a room are presented and non-dimensional expressions for the decay of maximum velocity over the floor are derived. In addition, the ventilation efficiency, local mean age of air and other characteristic parameters were experimentally and numerically obtained for a mock-up classroom ventilated with the two systems. The internal heat loads from 25 person-simulators and lighting were used in the measurements and simulations to provide a severe test for the two types of ventilation systems. In addition to a large number of experimental data CFD simulations were used to study certain parameters in more detail. The results presented here are part of a larger research programme to develop alternative and efficient systems for room ventilation.     

某报告厅空调系统的设计及其能耗分析

介绍了西安某办公楼报告厅空调系统的设计。分别应用置换通风与混合通风两种通风方式，在室外和室内设计参数相同的情况下，充分比较了它们在送风量、新风量、能耗以及室内空气品质的不同。结果表明在某些应用场合，置换通风在空气品质提高和能耗降低上有明显的优势，同时这种优势不以牺牲热舒适性为代价，因此建议使用置换通风系统。     

Floor-supply displacement ventilation for workshops

This paper reported the investigation of the performance of floor-supply displacement ventilation with swirl diffusers or perforated panels under a high cooling load (nearly 90 W/m²). The experiment was carried out in a full-scale environmental chamber to obtain reliable data on the floor-supply displacement ventilation for the validation of a computational-fluid-dynamics (CFD) program. Numerical simulations using CFD program were to evaluate the performance of the system for a large workshop. The impacts of several parameters, such as the air change rate, number of diffusers, diffuser location, occupant location, furniture arrangement, partition location, and arrangement of exhausts, on the indoor environment were investigated based on the thermal comfort level and indoor air quality. This study ranked the impacts of these parameters on indoor environment.     

Comparison of annual energy performances with different ventilation methods for temperature and humidity control

Stratum ventilation has been proposed to accommodate elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling loads, sensible and latent, as well as system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Desiccant dehumidification with and without solar assistance is utilized for the air treatment under displacement ventilation and stratum ventilation, while simple reheating is adopted under mixed ventilation. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following five factors: the reduction in ventilation, dehumidification and transmission loads, prolonged free cooling period and increased the COP of the chillers. For the office, the year-round energy saving is found to be substantial at 20% and 40% without the need for solar energy provision when compared with displacement ventilation and mixing ventilation respectively. For the classroom and retail shop, the year-round energy saving is at about 25% and at least 37% with the aid of solar energy provision when compared with displacement ventilation and mixing ventilation respectively.     

Comparison of annual energy performances with different ventilation methods for cooling

Stratum ventilation has been proposed to cope for elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling load and system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following three factors: the reduction in ventilation and transmission loads and increased COP of chillers. The year-round energy saving is found to be substantial at 25% and 44% at least when compared with displacement ventilation and mixing ventilation, respectively.     

建筑自然通风之温度效应

采用自然通风系统因有助于减少空调的使用,既节省能源又有利于人们的身心健康而得到提倡.建筑的自然通风系统由于动力的不同而分为风压通风系统和热压通风系统.与风压通风系统相比,热压通风系统更能适应常变的外部风环境.对热压通风的原理、可实现热压通风系统的建筑空间形式进行了分析探讨,同时列举了在此方面堪称典范的实例,以作为热压通风系统设计的参考.     

地板个性化送风系统动态能耗分析

地板个性化送风能够改善工作区微环境的空气品质和热舒适性,其送风温度较传统空调系统高,有较大的节能潜力。对送风采用冷冻除湿和转轮除湿时,节能与否或者节能程度大小分别取决于再热量和再生热量及再生风机能耗。本文中,利用能耗模拟分析软件Energyplus分别模拟计算了在中国各气候区使用混合通风、冷冻除湿的地板个性化送风及转轮除湿的地板个性化送风系统时,各系统的年能耗,并进行了比较分析,得出地板个性化送风系统在中国各气候区的能耗特性。