Testing of Localized Ventilation Systems in a New Controlled Environment Chamber

This paper describes tests of thermal comfort and air distribution performance of two relatively new occupant-controlled localized ventilation (also called task ventilation) systems. The first is a raisd-floor distribution system providing air through grilles in the floor panels, and the second is a desk-mounted unit supplying conditioned air at desktop level. The tests were performed in a new controlled environment chamber (CEC) having unique capabilities for detailed studies of space conditioning and thermal comfort in office environments. Measurements were made in a mockup of a typical partitioned open-plan office, and the resulting temperature and air velocity distributions are reported for a variety of system- and locally controlled conditions. Comfort model predictions are presented to describe the degree of environmental control and range of occupant comfort levels produced in the workstations. The results are also compared to those produced by a conventional ceiling supply system. The tests investigated the effects of supply volume, supply location, supply vent orientation, supply/return temperature difference, heat load density, and workstation size and layout. Temperature differences in the range of 1–2.5°C were observed between adjacent workstations, and local air velocities in the vicinity of outlets could exceed 3 m/s. Such wide-ranging values could violate existing comfort standards (ASHRAE, 1981; ISO, 1984), if strictly interpreted. However since these systems put the local thermal conditions within the workstations under the direct control of their occupants, it is recommended that the standards grant exceptions to such systems.     

上海期货大厦变风量空调系统实际运行状况的分析与总结

该大厦采用变风量空调系统，对变风量空调系统新风供给的控制方式进行了分析。测试了大厦部分房间CO2浓度，比较了采用定送风温度与定回风温度两种控制方式的特点，讨论了吊顶回风、空调系统运行能耗等问题。     

空调房间不同送风方式的实验研究

本文通过对空调房间三种不同送风方式（下送风、上送风和侧送风）进行实验研究,从主、客观两方面进行评价,实验结果表明：在保证相同的室内环境参数下,下送风通风空调系统优于上送风和侧送风两种传统送风方式,能够获得较好的舒适度和空气品质。     

Mixing characteristics in a ventilated room with non-isothermal ceiling air supply

A two-dimensional turbulence k–ε model is used to predict distribution of air velocity, temperature and turbulence kinetic energy in an air-conditioned room using ceiling air supply. Mixing characteristics of the airflow are analyzed under different air supply velocities and temperatures. A modified Archimedes number is correlated with the parameters characterizing heat transfer, ventilation system, and turbulence kinetic energy of room air flow. Significant correlations have been shown. It is found that the linear ceiling air supply air-conditioning system with a high level return air provides excellent air mixing across a wide range of Archimedes numbers. The results are useful for air-conditioning design and thermal comfort study.     

冷却吊顶供水方式对系统运行能耗的影响

通过对冷却吊项运行能耗的计算机动态模拟，分析了供水方式、新风系统形式、冷却塔供冷、制冷机冷水温差等因素对系统能耗的影响，认为采用冷却吊项水系统与新风系统独立的水系统形式，并结合冷却塔自然供冷，节能效果最好。建议生产厂家开发小温差、大流量、低流动阻力的冷水机组，以推动冷却吊项的应用。     

大空间建筑室内气流组织数值模拟与舒适性分析

分别对采用百叶侧送侧回、喷口侧送侧回、散流器顶送下回、分层空调、置换通风方式的大空间建筑空调室内气流的速度场和温度场进行了数值模拟,并对其结果进行了实验验证。根据ADPI指标对这几种送回风方式进行了热舒适性评价.结果表明,分层空调和置换通风是大空间建筑中较好的气流组织方式。     

上置置换通风-顶板辐射供冷室内热环境研究

利用计算流体力学(CFD)方法,对上置置换通风-顶板辐射供冷复合空调办公建筑室内采用不同气流组织方式的通风效果进行了模拟研究,分析比较了气流组织特性指标--温度不均匀系数k1、速度不均匀系数ku空气分布特性指数ADPI及温度效率ηt等,给出了送、排风口适宜的上置安装位置.并从舒适性、供冷情况、竖直温度梯度以及温度、速度场分布等方面与传统置换通风.顶板辐射供冷复合空调系统进行了比较,指明了这种新型空调模式可行性、优点及不足.     

宁波南苑饭店扩建工程空调设计

介绍了风系统和水系统的设计。商务套房采用空气源热泵作为冷热源，为便于分户计量，装设了集中空调计费系统，以每台风机盘管上安装的采样器采集到的时间当量为计费依据。大会议厅采用自动调节型条缝风口吊顶送风，风口截面大小可随送风温度自动调节。为防止室内游泳馆窗玻璃结露，在窗子上方设条缝型风口沿玻璃面送热风。     

办公建筑中吊顶辐射空调系统夏季工况性能测试研究

以办公建筑中实际使用的一套金属吊顶辐射板+新风的空调系统为研究对象,对夏季运行工况进行了测试研究。分别对比分析了高温和高湿气象条件下办公建筑室内的温湿度分布,比较了不同高度和不同位置处的温湿度场,在测试条件下,室内有良好的热舒适性。     

深圳文化中心音乐厅空调送风方案比较

对顶棚上送下回，局部椅背送风、主体上送风，椅脚送风三种送风方式进行了比较。介绍了置换通风系统在音乐厅的应用。     

中城赛特购物中心空调通风设计

该购物中心冷源为两台离心式冷水机组和1台螺杆式机组，水系统为一次泵系统，垂直同程、水平异程方式；为解决空调系统与层高的问题，充分利用了建筑角落布置空调间，分层分区设置空气处理机，选用部分高排数空调箱，以加大处理焓差，提高冷风比，缩小空调问面积；介绍了空调、通风、人防及防排烟系统设计和工程使用效果，并总结了设计体会。     

中国大唐电力集团公司生产调度指挥中心空调设计

介绍了该工程的基本情况。为降低运行费用、提高空调舒适度,工程采用冰蓄冷、大温差供水的低温变风量系统加独立的新风系统。采用冰蓄冷系统充分利用峰谷电价差,可节省系统的运行费用;采用低温变风量系统可以减少末端设备的送风量,减小管道尺寸,降低输送能耗,同时由于低温送风降低了室内空气相对湿度,使环境舒适度得以改善。     

棉花HVI检验恒温恒湿环境室设计探讨

根据棉花HVI检验恒温恒湿环境室的要求,提出了恒温恒湿系统方案及温湿度分体设置和单路分控的设计思想。结合现有建筑物实际结构情况,采用了上送下侧回风的气流组织方式。通过两个多月的运行和有关部门的现场检测,实际效果优于规定的要求。     

On the bidirectional flow across an atrium ceiling vent

Sizing of horizontal ceiling vent in a tall atrium is usually based on vent flow models with unidirectional flow. This is only good for natural vents with large pressure differences between inside and outside. For low pressure differential across the horizontal ceiling vent as experienced in some atrium fires, bidirectional smoke flow rates were observed. The extraction rate through the vent would be reduced, giving poor performance of the smoke exhaust system.     

变风量空调系统温度模糊PID控制

将模糊PID控制应用于变风量空调系统中,任务是将送风温度和空调房间内的温度（回风温度）控制在各自的设定目标值附近。分别设计了变风量空调系统的送风温度模糊PID控制系统和室内温度（视为回风温度）模糊PID控制系统,通过调节冷冻水阀门的开度来控制送风温度,通过调节变频风机的转速来控制室内温度。应用所设计的模糊PID控制器对送风温度和空调房间的温度（即回风温度）进行了实时在线控制,控制结果表明模糊PID控制器设计合理,控制效果良好。     

一种卷烟厂高架库空调系统气流组织的优化的探索

以杭州地区某一高架库为例,基于高架库的负荷分布特点以及平面布局,提出较好地满足高架库室内参数均匀性要求的气流组织形式:下部侧送+上部顶送、车间中部和上部回风,然后根据负荷分布位置的不同来分配送风量。采用CFD手段对上下层不同风量比例时的气流组织进行模拟分析,分析表明,上下层风管的设计送风量比例为:夏季为1.783:1,冬季为3.178:1,可以很好地满足室内设计要求。     

Air Change Effectiveness and Pollutant Removal Efficiency during Adverse Mixing Conditions

Abstract The air change effectiveness (ACE), an indicator of the indoor airflow pattern, was measured in twenty-six laboratory experiments. Ventilation air was supplied through induction-type diffusers located in the ceiling and removed through a ceiling mounted return grille. The tracer-gas step-up measurement procedure was employed. In five of the experiments, pollutant removal efficiencies were also measured for simulated pollutant emissions from the floor covering and for simulated emissions from occupants. In experiments with heated supply air, supply airflow rates typical of the minimum supply flow rates of VAV ventilation systems, and 100% outside air, the ACE ranged from 0.69 to 0.89. These results indicate that significant short-circuiting of ventilation air between the supply air diffuser and return air grille does occur under these adverse conditions. Mechanical recirculation of air, so that the supply air contained approximately 50% outside air, increased the ACE by about 0.05. When the supply air was cooled, the ACE ranged from 0.99 to 1.15, adding to existing evidence that short-circuiting is rarely a problem when the building is being cooled. The pollutant removal efficiency for simulated pollutant emissions from the floor covering (PRE_floor) was strongly correlated with ACE (R²= 0.98) and the values of PRE_floor were within approximately 0.1 of the values of ACE. The pollutant removal efficiency for simulated pollutant emissions by occupants varied between workstations and was not as well correlated with the ACE.     

Determination of particle concentration in the breathing zone for four different types of office ventilation systems

Many factors affect the airflow patterns, thermal comfort, contaminant removal efficiency and indoor air quality at individual workstations in office buildings. In this study, four ventilation systems were used in a test chamber designed to represent an area of a typical office building floor and reproduce the real characteristics of a modern office space. Measurements of particle concentration and thermal parameters (temperature and velocity) were carried out for each of the following types of ventilation systems: (a) conventional air distribution system with ceiling supply and return; (b) conventional air distribution system with ceiling supply and return near the floor; (c) underfloor air distribution system; and (d) split system. The measurements aimed to analyse the particle removal efficiency in the breathing zone and the impact of particle concentration on an individual at the workstation. The efficiency of the ventilation system was analysed by measuring particle size and concentration, ventilation effectiveness and the indoor/outdoor ratio. Each ventilation system showed different airflow patterns and the efficiency of each ventilation system in the removal of the particles in the breathing zone showed no correlation with particle size and the various methods of analyses used.     

Performance of combined displacement ventilation and cooled ceiling liquid desiccant membrane system in Beirut climate

The performance of the chilled ceiling (CC) displacement ventilation (DV) systems is constrained by latent load removal capacity and cost of supply air dehumidification to prevent condensation on the ceiling. In this study, a liquid desiccant dehumidification membrane cycle (LDMC) is mathematically modelled to replace the CC and remove directly latent and sensible load from indoor space through the membrane. The desiccant system is coupled with the DV system. An optimized operational strategy is adopted while allowing ceiling temperature to drop to lower values than conventional CC/DV. The optimized LDMC-C/DV system was implemented in an office space in Beirut climate. It was found that decreasing the membrane liquid desiccant temperature resulted in a significant decrease in the total cooling energy of the system, while increasing the solar heating energy of the desiccant regeneration. At optimal set points, a decrease of 49% in energy consumption was observed compared to the conventional CC/DV system.     

通仓交融手术室空调系统设计

介绍了通仓交融手术室概况及平面布置。阐述了通仓交融手术室空调系统设计参数、送回风及气流组织方案、送回风量平衡、温湿度独立控制、手术室洁净级别转换装置与措施,并对该设计方案进行了CFD模拟。