置换通风的原理及应用

在过去的十多年中，置换通风系统在北欧国家得到了大量应用并显示出极大的优势。本文介绍了置换通风的原理及其在工业民用建筑中的应用实例，用通风效率、换气效率和热舒适性指标比较了置换通风与混合式通风的优缺点，最后指出置换通风系统在控制污染物、改善空气品质方面极强的生命力。     

置换通风的通风效果及其节能评价

本文简要介绍了置换通风的原理和特性，从评价气流分布性能的各项指标及能耗出发，分析了置换通风与传统通风相比表现出的优势，指出置换通风应该在我国工程中得到更广泛的应用和推广。     

上海体育馆置换通风系统设计研究

介绍了上海体育馆置换通风设计,采用相同的原始数据与设计参数,按照现行的暖通规范与混合通风设计作了比较。计算显示出置换通风在室内空气品质和节能上的优势及其在应用场所上的局限性。     

轿车车身车间空调通风技术的探讨——置换通风的应用

在对多个车身车间的不同类型空调通风系统运行情况对比分析后，提出置换通风空调的送风模式有利于提高车间空气品质和舒适度，并在减少通风空调系统对车间空间占用、方便工艺设备布置和变更方面有较大优势。     

地板送风与置换通风的差异

探讨了地板送风和置换通风两种下送风方式在概念、机理、主要功能、特性及应用等诸多方面的差异与联系，分析比较了各自的优越性及局限性，提出了地板送风和置换通风各自的适用范围。地板送风作为一种节能空调系统应同时处理好通风换气和温度控制功能；置换通风由于加热和除湿问题，其应用在一定程度上受到了限制，但只要将其应用在恰到好处的场合，也可发挥出优势。     

从置换通风的设计原理及运行工况析其节能特性

通过对置换通风设计原理及运行状况特性的分析，来比较置换通风和混合通风的能耗，并认为置换通风整体上是节能的。     

置换通风的发展及研究现状

基于置换通风舒适、健康和节能的显著特点，本文回顾了置换通风的发展历程，从室内空气品质和节能等方面阐述了国内外置换通风的研究现状。气流组织、热舒适性和污染物分布是影响置换通风室内空气品质的主要因素，因而论文主要从置换通风的两个显著特性：热力分层和垂直温度梯度的角度讨论了室内热舒适性影响因素和研究现状，从颗粒和气体污染物的分布情况论述污染物对室内空气品质的影响，根据置换通风的气流特性，提出可以把室内污染物分为热源和冷源污染物进行研究；最后简要介绍了置换通风节能的情况和优势。     

置换通风与CFD数值模拟

为了降低空调通风系统的能耗,提高通风效率,改善热舒适性,对于建筑在夏季工况下,可采用置换通风方式来满足室内空气品质和热舒适性的要求.通过分析置换通风的运行原理,借助计算流体力学的理论和方法,利用CFD(Fluent)软件,采用了低Re数湍流模型,模拟了夏季工况下的室内温度场和速度场.     

初论置换通风在纺织厂的应用

从置换通风的基本理论出发，结合纺织厂的具体情况，分析了置换通风在纺织厂应用的优势和可能存在的问题；并通过计算和数值模拟，研究了纺织厂各车间的能源消耗、气流组织、温度分布等问题。结果表明：在纺织厂使用置换通风系统有较为明显的节能效果。此外，还针对纺织厂各车间的不同具体情况，就粉尘控制问题做了讨论。     

夏季湿热地区置换通风和冷却顶板复合系统节能潜力研究

根据上海一办公楼置换通风和冷却顶板复合系统的设计及运行特点,应用EnergyPlus软件模拟了采用转轮除湿方式的复合系统的供冷季能耗,并分别模拟了采用冷却除湿方式的复合系统、带热回收装置的混合通风系统和置换通风系统的供冷季能耗以进行对比。结果表明,在湿热地区采用转轮除湿方式可比冷却除湿方式节约制冷机冷量,空调季总能源费用比混合通风系统节约30%左右。     

A combined system of chilled ceiling,displacement ventilation and desiccant dehumidification

Different types of heating, ventilation, and air-conditioning (HVAC) systems consume different amounts of energy yet they deliver similar levels of acceptable indoor air quality (IAQ) and thermal comfort. It is desirable to provide buildings with an optimal HVAC system to create the best IAQ and thermal comfort with minimum energy consumption. In this paper, a combined system of chilled ceiling, displacement ventilation and desiccant dehumidification is designed and applied for space conditioning in a hot and humid climate. IAQ, thermal comfort, and energy saving potential of the combined system are estimated using a mathematical model of the system described in this paper. To confirm the feasibility of the combined system in a hot and humid climate, like China, and to evaluate the system performance, the mathematical model simulates an office building in Beijing and estimates IAQ, thermal comfort and energy consumption. We conclude that in comparison with a conventional all-air system the combined system saves 8.2% of total primary energy consumption in addition to achieving better IAQ and thermal comfort. Chilled ceiling, displacement ventilation and desiccant dehumidification respond consistently to cooling source demand and complement each other on indoor comfort and air quality. It is feasible to combine the three technologies for space conditioning of office building in a hot and humid climate.     

Optimization of a liquid desiccant based dedicated outdoor air-chilled ceiling system serving multi-zone spaces

A liquid desiccant based dedicated outdoor air-chilled ceiling (DOAS-CC) system is proposed to serve a multi-zone space. The outdoor airflow rate and the supply air humidity ratio are two crucial variables in such a system, which significantly influence indoor thermal comfort, indoor air quality and energy consumption. Two strategies are presented to optimize these two variables in the study. They are the demand-controlled ventilation (DCV) strategy and the supply air humidity ratio set-point reset strategy. To evaluate the performances of these two strategies, a basic control strategy, i.e., the strategy adopting constant ventilation flow rate and constant supply air humidity ratio, is selected as the benchmark. Performances of the two strategies in terms of indoor air temperature, relative humidity and CO₂ concentration as well as energy consumption are analyzed using simulation tests. The results show that the supply air humidity ratio set-point reset strategy is effective for the indoor air humidity control. It can save about 19.4% of total energy consumption during the whole year. The DCV-based ventilation strategy can further reduce about 10.0% of energy consumption.     

Ventilation and energy performance of partitioned indoor spaces under mixing and displacement ventilation

Large variation in indoor air quality (IAQ) and thermal comfort can occur in partitioned office spaces due to heterogeneous air mixing. However, few published studies examined IAQ, thermal comfort, and energy performance of partitioned occupied spaces, which are commonly found in today’s buildings. The objective of this study is to evaluate indoor environmental quality and air conditioning performance of a partitioned room under two typical ventilation modes: (1) mixing ventilation and (2) displacement ventilation. For a total of six representative air-conditioning scenarios, three-dimensional computational fluid dynamics (CFD) simulations are performed to examine temperature distribution, ventilation effectiveness, energy consumption, and local thermal comfort for two partitioned spaces. Simulation results indicate that temperature distribution in a partitioned room is a strong function of ventilation strategy (mixing vs. displacement), but marginally affected by diffuser arrangements. Local age-of-air (air freshness) significantly varies with both diffuser arrangement and ventilation strategy. Regarding energy consumption, displacement ventilation can achieve an indoor set-point temperature in the partitioned spaces about two times faster than mixing ventilation. Under mixing ventilation, the time to achieve a set-point temperature was notably reduced when each partitioned space is served by its own diffuser. For the same supply airflow rate, displacement ventilation can generate local draft risk at ankle level, while mixing ventilation may result in a draft sensation in wider areas around an occupant. Overall, the results suggest that mixing ventilation system can save energy if each partitioned zone is served by its own diffuser such as a multi-split air conditioning. However, when multiple partitioned zones are served by only one diffuser, displacement ventilation is more energy-efficient and can achieve higher ventilation effectiveness than mixing ventilation.     

暖通空调低碳节能技术应用的案例分析

本文以某项目为例,探讨了在其空调系统中应用的低碳节能技术。从空调冷热源系统、变频调速、热回收、置换式通风、多元通风、可再生能源利用等方面,对其节能技术进行了具体的研究与分析。并对该项目的室内空气质量、能耗情况进行了分析,证明了其节能效果比较显著。     

能量回收转轮及高能离子净化系统在大型公建中的应用

介绍在车库排风、排烟及空调新风、排风系统中利用能量回收转轮这一新技术收到较大的节能效果。高能离子净化装置在新风、排风系统中的应用,解决和改善了VOC、微小可吸入颗粒对室内环境品质的影响。     

Numerical investigation on the ingress of particulate matter from ambient air into the inlet of a building air handling unit

The transportation of ambient particulate matter (PM) from outdoor air into the inlet of a mechanical building ventilation system is poorly understood. No studies have examined the effect commonly used commercial air handling unit (AHU) inlet designs have upon the migration of PM from the ambient environment into the building ventilation system, and implications of this on energy consumption and indoor air quality (IAQ). Through the numerical analysis of commercial AHU inlets, the differences in concentration of PM in ambient air and that within AHUs were determined, more commonly referred to as Aspiration Efficiency (AE %). A 20–50% difference in particle concentrations between ambient air and the in-AHU concentration was observed between forward and rear-facing AHUs relative to ambient wind direction and speed, and at the maximum ventilation flow rate. Furthermore, a decrease in the ventilation flow rates resulted in a significant reduction in PM concentrations entering the rear-facing AHU. Increasing the Stoke number led to lower AE as a continuous decrease was observed for both rear-facing inlets. The findings of this paper show that AHU inlet design has significant implications on IAQ and building energy consumption, and scope exists to design these inlets to impact both aspects positively.     

置换通风在办公建筑中的应用与分析

利用计算流体力学(CFD)方法，对使用置换通风的办公建筑进行计算机数值模拟对室内空气的速度场、温度场进行分析，认为置换通风在提高空内空气品质和节能方面具有一定的效果。     

高大空间四种气流组织的比较

高大空间建筑常采用的空调方式有四种,即分层空调、置换通风、地板送风以及碰撞射流。本文以一航站楼为工程案例,借助FLUENT软件,对这四种室内气流组织进行模拟计算,比较各自的气流分布特性及送风能耗,为高大空间空调系统室内热环境的改善和节能提供依据。     

Energy analysis for workshops with floor–supply displacement ventilation under the U.S. climates

Many studies have shown that floor–supply displacement ventilation systems are better than mixing ventilation systems. The benefits include indoor air quality, thermal comfort and reduced energy use. The energy benefits depend on the climate conditions. This research compared the energy use of a floor–supply displacement ventilation system in a large industrial workshop with that of a mixing ventilation system for five U.S. climate regions. It was found that the energy use and the system performance vary with the locations. The displacement ventilation system may use more fan and boiler energy but less chiller energy than the mixing ventilation system. The total energy used is slightly less with displacement ventilation, although the ventilation rate was increased in order to handle the high cooling loads found in U.S. buildings. Thus, the displacement ventilation system can save some energy in cooling mode. However, displacement ventilation system has a lower capacity of dehumidification. This system alone, thus, is not suggested for use in humid regions.