作者更正北大核心

《暖通空调》2013年第8期第2页公式(1)下面"N为风机电动机的输入电功率,kW"应为"N为风机电动机的输入电功率,W";公式(2)下面"Ws为风机设计单位风量耗功率,kW/(m3/h)"应为"Ws为风机设计单位风量耗功率,     

地下工程用冷冻除湿机运行风量的模拟仿真研究

在地下工程环境参数条件下,对升温除湿机的运行效能进行了数值模拟仿真研究,综合考虑除湿和节能两方面的因素,分析了进风量对除湿量、制冷量、出风干湿球温度和单位输入功率除湿量的影响,解决了冷凝器和蒸发器的风量耦合问题,得到了地下工程用升温型冷冻除湿机的最佳风量运行情况。     

沥青搅拌设备双风机节能引风模式研究

在沥青混凝土搅拌设备中,引风机的风量调节十分重要,风量的大小不仅直接影响到搅拌设备的燃烧器能否正常燃烧和烘干筒内骨料的加热效率,而且影响着风机的运行功率。对比分析节流调节和变频调节两种风量调节方式中不同风量比下的风机驱动电机功率比,确定变频调节时节能效率较高的风量范围为额定风量的50%～80%。为提高引风机风量调节的节能性和经济性,提出双风机引风模式,并对双风机驱动电机的功率进行计算。     

国内外家用新风机检测标准对比

介绍了国内外家用新风机检测的相关标准。对比分析了不同标准的检测项目及检测设备。详细介绍了风量、风压、输入功率、有效换气率、交换效率、污染物净化效率、电气安全、环境影响因素等检测项目的检测方法。对相关标准修订提出了建议。     

风道系统单位风量耗功率实测与判定分析

节能检测中,发现按照JGJ/T177—2009《公共建筑节能检测标准》中风机单位风量耗功率的检测值不能满足GB50189—2015《公共建筑节能设计标准》中风道系统单位风量耗功率的限值要求.通过理论与实测分析,对按空调机组余压设计或带处理设备的机械通风系统,在两个标准中单位风量耗功率计算式的含义并不相同,不应直接引用....     

变风量空调系统控制策略仿真与实验研究

变风量空调系统实际运行时,风量的实时改变体现出强动态特性,各末端之间存在耦合,导致系统运行会出现不稳定状况。目前针对变风量系统的控制多是从自动控制角度出发,而根据VAV空调系统特性制定的控制策略较为缺乏。为此,提出1种改进型总风量法。从变风量系统水力特性的角度,分析末端阀位变化对风机送风量的影响,找出风管系统阻抗实时变化规律。再利用控制模块读取控制量与调节量,直接达到对风机的控制。通过全尺寸实验平台和TRNSYS模拟平台对所提策略开展不同工况下的研究得:改进型总风量法、变静压法、总风量法的评价指标平均值分别为0. 085,0. 178,0. 145,改进型总风量控制效果最好;夏季供冷工况下,对比3种控制策略的风机运行功率,在系统等风量条件下,变静压法和总风量法控制下的能耗较改进型总风量法高出5. 83%和19. 68%;改进型总风量法,为避免风机频率调节过程中调节时间长和系统振荡提供新思路,为实现较好的控制效果的同时能有效地降低风机能耗提供可靠依据。     

建筑构件耐火试验炉热工理论分析及关键部件选型

介绍了建筑构件耐火试验炉的经验计算。通过分析计算,得出燃气需求量、烧嘴功率、助燃风量、排烟风量等相关参数。     

水电站地下厂房通风排热能效测试与分析

本文根据该地下水电站功能建筑的布局和通风通道的设计,结合水电站的运行特点,在地下厂房空调系统关闭状态下,对主要通道的温湿度及风量、处于开启状态的风机的总输入功率、工作场所温度、相对湿度、风速、各风口的风量进行测试,评估自然风对厂房内部功能装置的排热能力和功能房的温湿度调节作用。结果表明,进风段洞室引入室外空气具有良好的降温效果,有助于厂房段的通风排热,并建议类似厂房可在建成初期的几年内通过自然风对厂房进行排热和温湿度调节。     

采暖通风空调系统工程建设中存在的问题及对策

许多空调工程,由于所选用空调末端设备的冷量、热量、风量、风压及功率高于或低于设计要求,而造成了空调系统能耗高或空调效果差等不良后果。风机是空调与通风系统运行的动力,如果选择不当,就有可能加大其动力和单位风量的耗功率,造成能源浪费。     

节能型低噪声卡式双吹风机盘管

介绍了节能型低噪声卡式双吹风机盘管机组采用的新型卡式双吹风结构,其特点是采用了U形单排管换热器、下置式风机组件、波浪形过滤网等部件。通过对这些部件的合理布置,大幅度降低机组能耗及噪声,保证了产品输入功率及噪声指标,解决了传统盘管在实际运行时风量小的问题,有效提高了空调房间的舒适性。     

上海地区热压通风间层通风性能的实测研究

与建筑良好结合的太阳能热压通风构造可以达到夏季防热、冬季供暖的效果,是一种十分节能的被动式技术。通风量是评价该系统运行效果的重要参数之一。目前,采用的通风量预测方法多基于理论分析与实验室研究的结果,缺乏自然条件下该系统实际通风效果的分析。通过在上海嘉定某试验房中建设热压通风间层,调整试验房的旋转机构与可调通风口,分析了当地太阳辐射、通风口尺寸、风速风向对该通风层通风性能的影响。结果表明典型工况下的实测通风量始终大于预测通风量,且偏差较大。其原因主要来自室外风场、集热墙温度的不均匀性等方面。     

基于EnergyPlus对南京地区应用夜间通风预测

为了对南京地区进行夜问通风的可行性进行预测,选取南京地区某典型办公楼,利用建筑全能耗模拟软件EnergyPlus进行了模拟研究。在典型气象条件下,分别考虑了通风时间,换气次数等因素对室内温湿度及空气比焓的影响。将室内空气焓值的变化等效为空气源热泵空调耗电量,通过对比空调的耗电量与通风风机的耗电量,得出最佳的换气次数,并进行了节能效果分析。结果表明：通风时间选择在室外温度较低的时间段内较为合适。换气次数在不同的通风时间下对应不同的临界点,当换气次数小于临界点的换气次数时,等效空调耗电量大于风机耗电量,此时具有节能效果。当通风时间为6：00～6：30时,换气次数为1-2ac／h时,等效空调的耗电量与风机的耗电量差值的绝对值最大,半小时通风的最大节能达到3．6kWh。     

水口电厂厂房通风配电系统的优化改造

水口电厂厂房通风系统经过多年的长期运行,许多设备老化,故障率高。通风系统的停运会直接影响发变电设备的运行环境,特别是遇到夏季高温天气,当无法及时恢复风机运行时,将直接导致发变电设备运行环境恶劣而造成发电设备老化加速或软故障现象,影响了设备的正常运行。经过整体优化设计,重新设计了风机控制系统,并根据设备的实际情况合理选择元器件的参数,通过对该厂的厂房通风配电系统的优化改造,大大提高了该厂厂房通风系统运行的可靠性和稳定性。     

特长隧道掘进通风系统变频能耗研究及计算

特长隧道掘进通风中,通常按照掘进通风最大需求选择风机,然而在掘进工作面较短的情况下,掘进通风机仍在最大功率下运行,造成了极大的能源浪费.根据风机的相似定律,阐述了特长隧道掘进通风的特性,详细分析了风机变频工作的能耗.研究结果表明,特长隧道掘进通风机变频工作节能效果显著,具有很好的经济效益和广泛的应用前景.     

The maximum temperature of buoyancy-driven smoke flow beneath the ceiling in tunnel fires

In order to detect a fire and provide adequate fire protection to a tunnel structure, the maximum gas temperature beneath the ceiling to which the structure is exposed needs to be estimated. Theoretical analysis of maximum gas temperature beneath a tunnel ceiling based on a plume theory is given. The heat release rate, longitudinal ventilation velocity and tunnel geometry are taken into account. Two series of model-scale experimental tests were also carried out. The results of both analysis and experiments show that the maximum excess gas temperature beneath the ceiling can be divided into two regions. When the dimensionless ventilation velocity is greater than 0.19, the maximum excess gas temperature beneath the tunnel ceiling increases linearly with the heat release rate and decreases linearly with the longitudinal ventilation velocity. When the dimensionless ventilation velocity is less than 0.19, the maximum excess gas temperature beneath the ceiling varies as the two-thirds power of the dimensionless heat release rate, independent of the longitudinal ventilation velocity. In both regions, the maximum excess gas temperature varies as the −5/3 power of the vertical distance between the fire source bottom and tunnel ceiling. The investigation presented here considers only the cases when the continuous flame region is lower than the ceiling height.     

Performance of three air distribution systems in VOC removal from an area source

Building-related health complaints and symptoms represent a significant occupational health problem. Elevated concentrations of various types of indoor pollutants, frequently associated with inadequate ventilation, have been implicated as a potential cause. The objective of this research is to model and evaluate the performance of several ventilation methods in pollutant removal from indoor environments. Pollutant sources are assumed to be at the floor level, one with a constant emission rate and the other a fast decaying source (volatile organic compound emissions from a wood stain). Three ventilation methods, namely displacement ventilation and two mixing systems using a side grille and ceiling square diffuser respectively are studied. A computer model has been applied to simulate the distributions and the time history of the pollutant concentrations in a mockup office. Experimental data of velocity, temperature, and tracer gas concentration distributions in the chamber with the displacement diffuser are obtained to validate the airflow model. Simulation results show that different ventilation methods affect the pollutant distributions within the room. When the pollutant sources are distributed on the floor and not associated with a heat source or initial momentum, displacement ventilation behaves no worse than perfect mixing ventilation at the breathing zone. Conventional “mixing” diffusers, on the other hand, could perform better or worse than a perfect mixing system. The computer model could be used for selecting appropriate ventilation systems to maximize indoor air quality for occupants.     

Theoretical and Experimental Study of Critical Velocity for Smoke Control in a Tunnel Cross-Passage

Theoretical analyses and model-scale experiments have been conducted to investigate the critical velocity in a tunnel cross-passage which is defined as the minimum ventilation velocity through the fireproof door to prevent smoke from flowing into a cross-passage. The effect of the fireproof door geometry, heat release rate, ventilation velocity and fire source location were taken into account. The critical velocity in a tunnel cross-passage varies approximately as 3/2 power of the fireproof door height, as one-third power of the heat release rate and as exponential law of the ventilation velocity, almost independent of the fireproof door width. The critical Froude Number mainly ranges from 5 to 10 and consequently as it is not a constant value it is not very suitable to predict the critical velocity in a tunnel cross-passage. A dimensionless correlation that can correlate well with the experimental data was proposed.     

Performance validation of a hybrid ventilation strategy comprising longitudinal and point ventilation by a fire experiment using a model-scale tunnel

We examined the exhaust performance of a hybrid ventilation strategy for maintaining a safe evacuation environment for tunnel users in a tunnel fire. The hybrid ventilation strategy combines the longitudinal ventilation strategy with the point ventilation strategy which is a type of transverse ventilation strategy. The model tunnel developed by this study was scaled to 1/5 the size of a full-scale tunnel. The model-scale experiment was performed taking into consideration Froude's law of similarity. Measurement items were the distribution of temperature and concentration of smoke inside the tunnel, longitudinal wind velocity, mass flow of smoke in the point ventilation duct, and the heat release rate of the fire source. The following main conclusions were obtained. The smoke height was constant even when varying the extraction rate of smoke from the ceiling vent. The backlayering length and critical velocity of the smoke flow in the hybrid strategy could be predicted by the methodology developed by using the longitudinal strategy. The hybrid strategy maintained a safe evacuation environment on both sides of the tunnel fire.     

An experimental study on the effect of ventilation velocity on burning rate in tunnel fires—heptane pool fire case

The 1/20 reduced-scale experiments using Froude scaling are conducted to investigate the effect of longitudinal ventilation velocity on the burning rate in tunnel fires. The n-heptane pool fires with heat release rate ranging from 3.71 to 15.6 kW are used in this study. A load cell is used to measure the mass loss rate of burning fuel and the temperature distributions are measured by K-type thermocouples in order to investigate smoke movement. The ventilation velocity in the reduced-scale tunnel is controlled by the wind tunnel through an inverter. The increases in ventilation velocity lead to enhance burning rate of n-heptane fuel. The reason is that the oxygen supply effect prevails rather than the cooling effect as the ventilation velocity increases. As a result, the heat release rates in experiment are larger than constant heat release rates by 4.45–11.3 times in the n-heptane pool fires. Also, it is found that non-dimensional critical ventilation velocity is proportional to one-third power of non-dimensional heat release rate.     

断面宽度对纵向通风隧道火风压影响研究

针对不同断面宽度隧道中发生火灾时的火风压变化问题,利用Fluent软件模拟隧道内发生火灾的情况,分析隧道宽度对临界风速的影响以及隧道宽度、火源功率和通风速度对火风压的影响。研究表明,火源功率较小时,宽度越小的隧道,临界风速越大;随着火源功率的增大,临界风速之间的差距减小。火风压中火区绕流阻力和热烟摩阻增量会随着风速的增大而相互作用。导致火风压会先随风速的增大而增大,到达一个峰值后会随着风速增大而减小,最后当通风速度增大到临界风速后趋于稳定的数值。随着隧道宽度的增大,通风速率对火风压的影响逐渐减弱。建立不同宽度隧道在不同通风速率和火源功率下的隧道火风压计算公式,为隧道火灾通风设计提供参考。