The Research of Performance Comparison of Displacement and Mixing Ventilation System in Catering Kitchen

A commercial kitchen is a complicated environment where multiple components of a ventilation system including hood exhaust, conditioned air supply, and makeup air systems work together but not always in unison. And the application of an appropriate ventilation system is extremely vital to keep the catering kitchen comfortable, which consequently promotes the productivity and gains. Application of two systems (traditional mixing ventilation system and thermal displacement ventilation system) is compared in a typical kitchen environment using computational fluid dynamics modeling which was used to investigate the difference between mixing and displacement ventilation (DV). It was reported in two parts, one on thermal comfort and the other one on indoor air quality. The results show that DV can maintain a thermally comfortable environment that has a low air velocity, a small temperature difference between the head and ankle level, and a low percentage of dissatisfied people, and may provide better IAQ in the occupied zone. So it was persuasive that using thermal displacement ventilation in kitchen environment allows for a reduction in space temperature without increasing the air-conditioning system capacity.

The Research of Performance Comparison of Displacement and Mixing Ventilation System in Catering Kitchen

A commercial kitchen is a complicated environment where multiple components of a ventilation system including hood exhaust, conditioned air supply, and makeup air systems work together but not always in unison. And the application of an appropriate ventilation system is extremely vital to keep the catering kitchen comfortable, which consequently promotes the productivity and gains. Application of two systems (traditional mixing ventilation system and thermal displacement ventilation system) is compared in a typical kitchen environment using computational fluid dynamics modeling which was used to investigate the difference between mixing and displacement ventilation (DV). It was reported in two parts, one on thermal comfort and the other one on indoor air quality. The results show that DV can maintain a thermally comfortable environment that has a low air velocity, a small temperature difference between the head and ankle level, and a low percentage of dissatisfied people, and may provide better IAQ in the occupied zone. So it was persuasive that using thermal displacement ventilation in kitchen environment allows for a reduction in space temperature without increasing the air-conditioning system capacity.

Numerical Simulation of Energy Saving Potential in Dispersing Process of Blasted Smoke in Mines

The dispersing process of the blasted smoke in underground mines by ventilation is very important for the safety of personnel,and its energy consumption is also worthy of concern. In this study,the impact of supply air flow rate on the decay process of harmful gases and fan energy,and the role of harmful gases buried by blasted pile in the smoke dispersing process is analyzed with three-dimensional numerical simulation. According to the results,air flow facilitates quick smoke dispersion and the gas emits from the blasted pile is only significant at the beginning of ventilation. It is thus recommended that large amount of air supply is taken to disperse the smoke quickly until the concentration of harmful gases reaches relevant standards,and reduce the amount of air in the remain time with frequency conversion technology to save energy. In the given study,12 m / s air flow rate is taken for dispersing smoke and 3 m / s air flow rate is taken for the waiting time. The energy consumption for ventilation is reduced by about 50%. In addition,due to the gases in the blasted pile remains very high concentration after the dispersing process,it is recommended to keep suitable amount of ventilation in the consequent process.

Comparison study of thermal comfort and energy saving under eight different ventilation modes for space heating

The relative location of inlets and outlets plays an important role in thermal comfort and energy conservation under ventilation modes for the building non-uniform indoor environment.Hence,a comparison study of thermal comfort and energy efficiency of eight widely-used ventilation modes for space heating was conducted in this study.Both subjective experiments and verified computational fluid dynamics(CFD)models were carried out.In the subjective experiments,the vote of local thermal sensation(LTS),overall thermal sensation(OTS)and draft sensation were collected.In the CFD simulations,RNG κ-ε model was applied to compare and analyze the air temperature field,turbulence intensity,ventilation effectiveness and air diffusion performance index(ADPI).The thermal comfort results showed that the air inlets are better located at the mid-height level of a wall,and the outlets are located at the same or higher height.While the results of the energy efficiency suggested that the inlets are better installed at the lower level of a wall,and the outlets should be placed far from the inlets.Since the results were conflict,the economic-comfort ratio was introduced to calculate and compare the thermal comfort and energy efficiency simultaneously.The final results concluded that it can achieve excellent thermal comfort performance without sacrificing energy efficiency when the inlets are at the height of 1.2 m of the front wall,and the outlets are at 1.2 m height of the back wall.Hence it is the best choice for the winter air distribution in northern China.This study can offer a guideline for the air terminal arrangements in non-uniform ventilation under heating mode.

Potential of Natural Ventilation in Mexico According to Its Hours of Hygrothermal Comfort

This work shows, through monthly maps, the potential of natural ventilation in order to cool down buildings in the different climatic regions of Mexico. By using the method of energy evaluation of buildings in Brazil applied to Mexico, a monthly electric-power saving factor is calculated to use natural ventilation for the forty-three biggest cities of the country according to their hours of hygrothermal comfort. Then, with the Geographical Information System Map Maker, monthly maps were created from the potentials of saving for the Mexican territory. Then, energetic, economic and environmental benefits were estimated for year 2006, in comparison to the realistic energy consumption in the same year.

Performance Comparison and Analysis of Heating and Ventilation of Two Kinds of Roof Solar Collectors

Two roof solar collectors (RSCs), conventional single pass RSC and new double pass RSC, were compared. The new roof solar collector, which is formed by integrating a double pass solar air collector with the roof of the building, can be operated more efficiently for space heating in winter, and for natural ventilation in other seasons. To evaluate the performances of the two RSCs for both space heating and natural ventilation, a single traditional Chinese style house, on which the two RSCs will be mounted, was developed. The efficiency of solar energy conversion for the new RSC is higher than that of the single pass one by 10% on average, and the ventilation rate contributed by natural ventilation for the new RSC can be improved to a great extent for most cases, indicating that the new RSC is superior to the single pass one from the viewpoint of both space heating and natural ventilation. The new RSC is more potential for improving indoor thermal environment and energy saving of buildings.

基于Ventsim的王家塔煤矿通风系统优化研究

针对王家塔煤矿存在的多煤层、多盘区、供风线路长和通风阻力分布不协调等特点,尤其是随着4^(#)煤开拓和3^(#)煤3盘区的准备,通风系统的不合理性更加凸显。在获取可靠通风基础参数的基础上,利用Ventsim建立王家塔煤矿全矿井三维可视化模型并完成仿真模拟,按照调风操作可行、简单、可靠的原则,提出优化调整方案并模拟分析了调风效果。调风实践表明,优化后的通风系统稳定性增强,通风总阻力降低,阻力分布趋于合理,既实现了企业通风的节能降耗和成本开支,又全面提升了矿井的通风管理水平及决策能力,对矿井通风管理有较好的指导作用。

超长电力电缆隧道冬季温度分布特征及通风节能潜力

为了解冬季通风时隧道内的换热情况和节能潜力,对冬季室外气温为4~12℃时超长通风区间特高压电力隧道内的温度分布特征进行数值模拟研究。采用ANSYS Fluent 19.2软件,通过用户自定义程序完成电力隧道全长的模拟。对冬季隧道的传热特征和通风节能潜力进行分析,定义并给出了冬季能实现最大节能效果的临界通风量。结果表明:具有超长通风区间的电力隧道存在通过降低通风量从而实现节能的潜力;冬季电力隧道前段土壤放热、后段土壤吸热,土壤放热量占比受室外气温影响,而土壤吸热量占比受室外空气温度和通风量影响;冬季室外气温越低,临界通风量越小,通风节能潜力越大,当冬季室外气温为4~12℃时,最大可能节能率为91%。

地铁站环控系统控制方案的节能对比研究

为明确常见的地铁车站环控系统控制方案的用能表现和节能潜力,为地铁车站节能降碳提供参考和指导,以北京、上海和广州分别作为寒冷、夏热冬冷和夏热冬暖地区的代表性城市,在TRNSYS软件中搭建屏蔽门地铁站模型,探究增设自控系统和优化时刻表控制这2种优化方案相比于当前常规的时刻表控制方案在站内环境控制、节能潜力、改造成本方面的表现。结果显示,采用2种优化方案均可有效提高站内空调控制温度,实现类似的站内温度控制效果。用能方面,相比于当前的时刻表控制方案,增设自控系统可为各气候区地铁站环控系统降低41%~49%的年能耗,优化时刻表控制方案可降低38%~48%的年能耗。改造成本方面,优化时刻表控制方案仅需要提高管理水平,无需增加设备和系统,而增设自控系统方案的设备成本和后期运维管理成本较高。因此,综合考虑站内环境控制效果、能耗情况和改造成本,建议地铁站采用优化时刻表控制方案进行节能运行优化,以实现节能目标。

医疗建筑医用气体机房及其通风系统高效运行策略研究

目前医疗建筑医用气体机房设备、设施用能管理意识不强,安全与节能管理工作存在割裂情况。在保证医用气体系统安全可靠的基础上,从影响气体机房效能变化的各类直接和间接因素入手,深入剖析气体机房设备设施的运行状况和需求特征。对医用气体系统的工艺设计、运维管理、机房空间环境保障等环节进行探究,多维度挖掘节能降耗的潜力和路径,通过对医用气体系统设备设施的配置优化、运维管理措施优化以及机房通风系统分级管控等措施,可大幅提升气体机房设备设施的能源使用效率,进而构建一个安全可靠、节能高效的医用气体机房。

EnergyPlus软件在置换通风设计中的应用研究

介绍了EnergyPlus软件中的置换通风模型,采用EnergyPlus辅助某办公室置换通风系统设计,并采用CFD软件模拟了室内温度分布,结果表明,EnergyPlus可以精确地预测置换通风系统负荷,系统设计能满足热舒适要求。

探究供热通风与空调工程的施工技术要点与节能控制措施

在当代,低能耗、低污染及低排放是建筑工程施工的必然要求,同时也对其性能提出了更高的要求,如对环境友好、绿色和高效。暖通工程在绿色建筑中的运用是非常关键的一步,只有适时地转变高强度、高环境污染的施工方式,重视空调工程品质的提高,才能取得较好的节能和环境保护成效,促进企业的环保和节能。同时,在通风空调装置的安装过程中,要提高对有关施工的掌控程度,按照施工技术应用要求和通风空调装置的结构进行工程施工,确保建筑通风空调工程质量的提升。供热通风和空调工程施工水平已成为衡量施工部门资质的有效依据,为满足现阶段行业发展需求,施工团队需要进一步规范施工,严格依照建筑物施工方案与安装标准,严格制定现场施工管理策略,提升施工人员技术水平,确保各施工环节的科学性、合理性。

基于三维仿真的四季气候变化对矿井通风影响规律研究

四季气候变化影响着矿井内自然风压的大小和方向,若将自然风压作为动力合理运用,有益于矿井通风系统节能减排。眼前山铁矿井下通风系统在初期设计中对自然风压的利用较少,且风机选型方面未将四季气候变化的因素考虑其中。本文对眼前山地区四季气候变化对矿井通风的影响规律进行研究,并以此规律指导井下基站风机进行优化。通过三维仿真系统建立井下通风系统模型,模拟眼前山地区一年四季气候条件,通过风流模拟计算进风井口处的自然风压大小和方向,结果表明眼前山地区夏季日间,1号主进风井、2号主进风井处会出现与矿井通风方向反向的自然风压,其余季节进风井处自然风压均有利于通风,其中,冬季自然风压可利用价值最大,且冬季风机风压较夏季风机风压显著增大,使得冬季总进风量增加4.46%;建议针对主机站2-3基站、2-4基站的K-8-19型风机和主机站2-15基站、2-16基站的K-8-23型风机进行工况点调节,在冬季时期将主扇叶片安装角由35°调整至30°;根据眼前山地区的四季气候变化规律适时调整主要通风机工况点,对自然风压有效利用,解决了矿井通风系统冬季风量过剩的问题,实现了以更加节能的方式满足矿井通风需要。

绿色低碳城轨通风空调节能措施探讨

城市轨道交通在优化城市功能配置、解决交通拥堵问题、提升居民出行环境等方面发挥着重要作用,但同时,作为“用能大户”城市轨道交通需要耗费大量能源。近年来,随着“碳达峰”“碳中和”目标的提出,发展绿色低碳城轨成为人们的共识。地铁通风空调系统能耗约占地铁车站运营能耗的50%~60%,其节能措施研究对提高能源利用效率及绿色低碳城轨具有重要意义。结合工程设计经验,分析了目前城市轨道交通中通风空调系统运行现状及存在的问题,结合大系统、小系统、多联机系统及空调水系统的具体节能设计方案,从设备和系统配置方面探讨了主要节能措施和节能技术发展方向。

ANSI/ASHRAE/ASHE standard 170-2021《医疗设施通风》修订内容简介

对ANSI/ASHRAE/ASHE standard 170-2021《医疗设施通风》的主要修订内容进行了分析,包括:修改医用房间名称,将有较高设计要求的房间与其他房间分开并提出细化指标;增加值班状态,为医疗建筑节能运行提供方法依据;进一步明确各类医疗用房排风过滤效率。此外,对ASHRAE 170发展趋势进行了简要介绍,对未来发展进行了展望,以期为我国医疗建筑相关标准规范的制订/修订提供参考。

建筑节能工程中的供暖通风节能设计

能源问题逐渐成为世界各国都非常重视的问题,随着各国工业化进程的发展,地球中目前可以供人们使用的燃料资源越来越少。在工业不断发展背景下,能源消耗在不断增加,尤其是建筑能耗已经达到各种能源消耗的1/3。另外,我国幅员辽阔,很多地区居民都要靠采暖应对严寒,但是采暖燃煤会污染大气。在人们生活水平不断提高的背景下,节能建筑逐渐成为建筑发展的重点。基于此,对建筑节能工程中供暖通风节能设计进行研究。

矿井通风系统节能技术的应用与实践

煤矿生产中,随着工作面的推进,出现了通风阻力增大、风量不足、能耗增大以及设备运行效率低等综合问题。为了解决这些问题,结合生产实践对通风系统的现状进行了分析,在对通风阻力、通风机运行性能参数等进行测定的基础上,结合现场条件提出了相应的优化改造措施。最后通过生产实践验证了优化改造的节能效果和整体优化效果。

供热通风与空调工程关键安装技术分析

作为建筑工程的一部分,供热通风空调工程又称暖通空调工程,其安装和施工质量直接影响到人民群众的生产生活。供热通风空调的安装是一项非常重要的工作,不仅能够改善建筑物的内部环境,还能够保证建筑物的安全。因此,施工企业应该特别注意这一方面的质量,并且严格遵守相关的行业标准,以确保安装的完整性和可靠性。供热通风与空调工程的核心特点之一便是其复杂的技术要求,在实施过程中,必须解决各种关键的技术难题,以确保其质量。基于此,该文主要围绕供热通风与空调工程关键安装技术展开分析,并提出具体的技术措施,以供参考。

基于气候条件的地铁站通风空调系统节能运行研究

节能降耗、绿色发展是当前地铁运营单位积极探索的发展之路,该文基于贵阳市良好的气候条件,结合贵阳地铁1、2号线客流特征,对车站公共区通风空调系统开展节能运行研究,选取25座车站作为试点开展实践论证。数据表明,车站公共区通风空调系统节能运行方案可行,在保证候车环境质量前提下,还能实现企业节能减排和降本增效的目的。