Fine and ultrafine particle removal efficiency of new residential HVAC filters

Particle air filters used in central residential forced‐air systems are most commonly evaluated for their size‐resolved removal efficiency for particles 0.3‐10 µm using laboratory tests. Little information exists on the removal efficiency of commercially available residential filters for particles smaller than 0.3 µm or for integral measures of mass‐based aerosol concentrations (eg, PM_2.5) or total number concentrations (eg, ultrafine particles, or UFPs) that are commonly used in regulatory monitoring and building measurements. Here, we measure the size‐resolved removal efficiency of 50 new commercially available residential HVAC filters installed in a recirculating central air‐handling unit in an unoccupied apartment unit using alternating upstream/downstream measurements with incense and NaCl as particle sources. Size‐resolved removal efficiencies are then used to estimate integral measures of PM_2.5 and total UFP removal efficiency for the filters assuming they are challenged by 201 residential indoor particle size distributions (PSDs) gathered from the literature. Total UFP and PM_2.5 removal efficiencies generally increased with manufacturer‐reported filter ratings and with filter thickness, albeit with numerous exceptions. PM_2.5 removal efficiencies were more influenced by the assumption for indoor PSD than total UFP removal efficiencies. Filters with the same ratings but from different manufacturers often had different removal efficiencies for PM_2.5 and total UFPs.     

In-situ effectiveness of residential HVAC filters

In this study, we explore different filter and contextual characteristics that influence effectiveness of high-efficiency filters in 21 residences in Toronto, Canada. The in situ effectiveness was assessed with decay tests at the beginning and the end of filter life with four different filters (MERV 8-14 from ASHRAE Standard 52.2) installed in operational HVAC systems, compared with either the system off or with no filter installed. There was considerable difference between median PM_2.5 effectiveness of the non-electret filters when compared to electret filters (16% vs. 36%) of the same nominal efficiency (MERV 8). However, median PM_2.5 effectiveness of electret filters only slightly improved (between 5% and 9% absolute increase) as MERV increased from 8 to 14. There was more variation in filter effectiveness between the same filter in different homes than there was between different filters in the same home. Variations in filter performance arose because home-specific particle loss rates (eg, ventilation rate) vary greatly in different buildings. The higher the loss rates due to non-filter factors, the lower the effectiveness of a filter. Given the relatively large variation in effectiveness for a given filter over time and in different homes, increasing system runtime may be a productive way to improve filter performance in many homes.     

Quantitative filter forensics with residential HVAC filters to assess indoor concentrations

Analysis of the dust from heating, ventilation, and air conditioning (HVAC) filters is a promising long‐term sampling method to characterize airborne particle‐bound contaminants. This filter forensics (FF) approach provides valuable insights about differences between buildings, but does not allow for an estimation of indoor concentrations. In this investigation, FF is extended to quantitative filter forensics (QFF) by using measurements of the volume of air that passes through the filter and the filter efficiency, to assess the integrated average airborne concentrations of total fungal and bacterial DNA, 36 fungal species, endotoxins, phthalates, and organophosphate esters (OPEs) based on dust extracted from HVAC filters. Filters were collected from 59 homes located in central Texas, USA, after 1 month of deployment in each summer and winter. Results showed considerable differences in the concentrations of airborne particle‐bound contaminants in studied homes. The airborne concentrations for most of the analytes are comparable with those reported in the literature. In this sample of homes, the HVAC characterization measurements varied much less between homes than the variation in the filter dust concentration of each analyte, suggesting that even in the absence of HVAC data, FF can provide insight about concentration differences for homes with similar HVAC systems.     

超低阻高中效过滤器在健康快车通风空调系统改造中的应用

通过健康快车空调系统的改造实践,提出了空调系统中空气生物污染的一种控制方法,给出了超低阻高中效过滤器的性能参数及其在健康快车通风空调系统中的应用效果.     

防治“非典”时期空调系统的应急措施

给出了全空气系统、风机盘管系统和各类窗式、柜式空调器在防治“非典”时期的应急措施和相关建议。     

舒适性空调系统的临界净化效率与最小换气次数

指出舒适性空调应同时满足健康和舒适要求，从室内空气中有害物质量平衡方程导出舒适性空调系统临界净化效率和最小换气次数，认为依靠增加新风量来改善室内空气品质的作用是有限的，在满足室内要求的基本新风量后，提高各级空气净化器效率才有助于改善空气品质，据作者的观点设计空调系统其方法将有别于传统设计。     

北京理工大学体育馆暖通空调设计

该项目为2008北京奥运会排球比赛场馆之一.介绍了暖通空调的主要设计方案,以及比赛场地风速控制的设计思路,总结了设计中的经验和体会.     

低温空调设计方法探讨

通过两则低温空调的工程实例分析低温空调系统在参数选择,设备配置等方面的一些特点,强调在设备选型方面不可贸然选用常规机型。     

Optimization of envelope and HVAC systems selection for residential buildings

In this paper, a comprehensive energy simulation environment is developed and presented to optimally select both building envelope features and heating and air conditioning system design and operation settings. The simulation environment is able to determine the building design features that minimize the life cycle costs. Three optimization algorithms are considered in the simulation environment including Genetic Algorithm, the Particle Swarm Algorithm and the Sequential Search algorithm. The robustness and the effectiveness of the three algorithms are compared to assess the performance of the simulation environment for various design applications and climatic conditions. In particular, the simulation environment has been applied to design single family homes in five US locations: Boulder, CO; Chicago, IL; Miami, FL; Phoenix, AZ; and San Francisco, CA. Optimal designs are determined to reduce life cycle costs with and without budget constraints. It is found that the optimal selection can reduce life cycle costs by 10-25% depending on the climate and type of homes.     

住宅户式中央空调及独立机械通风系统设计

介绍了绵阳市某住宅户式中央空调及独立机械通风系统的设计,住宅的空调方式选用风冷式（冷热水型）户式中央空调系统,同时设置独立机械通风系统,有利于改善室内空气品质,并对投资及运行费用进行分析,认为该空调及通风方式完全可以推广应用。     

Application of multicriteria analysis in designing HVAC systems

The present paper discusses a study which aims to develop a method for choosing and managing in the best possible way heating, ventilating and air conditioning (HVAC) systems in new and existing buildings. The method utilises a combination of two analysis’ tools, the multicriteria decision-making and the building simulation towards the direction of a holistic assessment of HVAC systems. In order to evaluate the method, a series of HVAC systems are considered for installing in an office building and the multicriteria method Electre III is applied for their selection. The results show that the proposed model allows the classification of alternative technical solutions concerning the HVAC's design, taking into consideration economic, energy and environmental criteria as well as criteria of users’ satisfaction. Finally, the study also indicates that when applying the sustainability concept in the building sector, and especially in the HVAC systems, this should concern the overall socioeconomic costs.     

日本住宅的空调方式与设备

介绍了日本住宅建设的状况、住宅中空调设备与系统的主要方式及住宅用能源的消耗量和CO2的排放量。同时对近年来住宅环境设备的新动向和住宅空调设备的新技术作了介绍。     

沈阳奥体中心体育场暖通空调节能设计

介绍了沈阳奥体中心体育场暖通空调系统设计,围绕节能主题,在供暖系统、冷热水大温差、等径环管水系统、一次泵变流量水系统、新风调节和利用新风供冷、空调自动控制、排烟系统管路等多方面采取了节能措施.     

铝箔车间暖通空调设计

介绍了该车间各工段环境品质的要求和各工段的供暖、空调和通风系统的设计。总结了设计体会。     

户式中央空调在太原市场的发展及应用

介绍了小型户式中央空调的三种主要形式,分析了各自的特点并对三种主要类型的中央空调进行了综合比较,提出了户式中央空调在设计、施工及验收过程中存在的一些问题,经分析得出风冷冷热水机组为太原空调市场的推荐应用形式。     

暖通空调系统几项重点节能设计措施探讨

详细探讨了暖通空调系统的几项重点节能设计措施,主要包括:室内设计计算温度取值、冷热负荷计算、供暖系统设计、风系统设计、空调水系统设计、冷热源选择、补水定压、保温及水力平衡、室温调控与冷热量计量,以供专业人员在工程设计中参考。     

上海智能楼宇空调系统对室内生态环境的影响

在对上海7栋智能建筑的实测和调研中发现,对室内环境品质的主观问卷调查与客观实测数据之间没有明显的相关性,有的甚至大相径庭。分析表明,这些大楼空调系统的设计、安装和运行对室内环境品质的主观调查结果有很大的影响,主要影响因素有：室内设定参数,室内气流分布,新风供给方式,窗是否能开启,空气龄,楼宇自控理念等。提出了改善室内生态环境的建议。     

Real-time measurements of PM2.5 and ozone to assess the effectiveness of residential indoor air filtration in Shanghai homes

Portable air cleaners are increasingly used in polluted areas in an attempt to reduce human exposure; however, there has been limited work characterizing their effectiveness at reducing exposure. With this in mind, we recruited forty-three children with asthma from suburban Shanghai and deployed air cleaners (with HEPA and activated carbon filters) in their bedrooms. During both 2-week filtration and non-filtration periods, low-cost PM_2.5 and O₃ air monitors were used to measure pollutants indoors, outdoors, and for personal exposure. Indoor PM_2.5 concentrations were reduced substantially with the use of air cleaners, from 34 ± 17 to 10 ± 8 µg/m³, with roughly 80% of indoor PM_2.5 estimated to come from outdoor sources. Personal exposure to PM_2.5 was reduced from 40 ± 17 to 25 ± 14 µg/m³. The more modest reductions in personal exposure and high contribution of outdoor PM_2.5 to indoor concentrations highlight the need to reduce outdoor PM_2.5 and/or to clean indoor air in multiple locations. Indoor O₃ concentrations were generally low (mean = 8±4 ppb), and no significant difference was seen by filtration status. The concentrations of pollutants and the air cleaner effectiveness were highly variable over time and across homes, highlighting the usefulness of real-time air monitors for understanding individual exposure reduction strategies.     

Combined simulation of central HVAC systems with a whole-building hygrothermal model

Due to the lack of building simulation programs that can simulate in details the combined heat, vapor and liquid transfer in porous elements and the HVAC systems, a generic and flexible computational algorithm has been elaborated in order to integrate models for both HVAC systems and multizone building hygrothermal model.     

Membrane heat exchanger in HVAC energy recovery systems, systems energy analysis

The thermal performance of an enthalpy/membrane heat exchanger is experimentally investigated. The heat exchanger utilizes a 60gsm Kraft paper as the heat and moisture transfer surface for HVAC energy recovery. The heat exchanger sensible, latent and total effectiveness have been determined through temperature and moisture content measurements. The annual energy consumption of an air conditioner coupled with an enthalpy/membrane heat exchanger is also studied and compared with a conventional air conditioning cycle using in-house modified HPRate software. The heat exchanger effectiveness are used as thermal performance indicators and incorporated in the modified software. Energy analysis showed that an air conditioning system coupled with a membrane heat exchanger consumes less energy than a conventional air conditioning system in hot and humid climates where the latent load is high. It has been shown that in humid climate a saving of up to 8% in annual energy consumption can be achieved when membrane heat exchanger is used instead of a conventional HVAC system.