Analysis of Fresh Air Volume of Air-conditioning System for Railway Vehicles

The relevant standard requirements both in domestic and abroad provide the basis for designing air-conditioning system of railway vehicles present. However, there are great differences in the fresh air volume indicators among different standards requirements, and the requirements of each vehicle procurement contracts are also different. The design of air-conditioning become difficult above these. In this paper, the fresh air volume of different type railway vehicles is analyzed from health and equipment electricity consumption according to the railway vehicles air-conditioning system standard requirements in domestic and abroad. Some advises for designing air-conditioning system of railway vehicles through the fresh air volume calculation and comparison for domestic air-conditioning system of railway vehicles was provided.

Air-void parameters measurement of fresh concrete and hardened concrete

Air content, spacing factor and specific surface of fresh concrete and hardened concrete with different air contents, slumps and mineral admixtures (fly ash, slag, fly ash + slag, fly ash + slag + silica fume composite) were studied by the air-void analyzer (AVA) method and the microscopical method. The correlations between the test results obtained from different methods were analyzed. The results show that, there is a close correlation of air content and spacing factor between the fresh concrete and the hardened concrete, but the specific surface correlation is weak. The air content of concrete measured by the AVA method is smaller than that of the pressure method and the microscopical method, because AVA device captures only the air voids with the size smaller than 3 mm. Spacing factor of the fresh concrete measured by the AVA method is greater than that of the hardened concrete measured by the microscopical method, while the specific surface is smaller. When the criterion of 4%-7% air content measured by the pressure method and microscopical method is acceptable for concrete freezing-thawing (F-T) durability in cold weather, the air content measured by the AVA method should be 2.4%-4.6%. For the concrete F-T durability, when the criterion of the spacing factor measured by the microscopical method is 300 μm, the spacing factor measured by the AVA method should be 360 μm.

Air-void Parameters Measurement of Fresh Concrete

To explore the method to evaluate air-void parameters of fresh concrete rapidly, the spacing factor and specific surface of freshly mixed concrete of different air contents, different slumps and different mineral admixtures （fly ash, fly ash-slag, fly ash-slag-silica fume composite） are studied by air-void analyzer （AVA）, and the correlation between the air content measured by AVA and air content determinator is compared. The results show that the spacing factor of the fresh concrete decreases firstly and then increases with the increase of air content, however the specific surface has the opposite rule. When the air content is more than 8%, the spacing factor of fresh concrete increases and the specific surface decreases. For the fresh concrete samples with similar air content, the specific surface increases firstly and then decreases with the increase of slump, but the spacing factor decreases firstly and then increases. Mineral admixalre can reduce the spacing factor of fresh concrete and increase the specific surface to some degree. There is a good correlation between the air content measured by two methods, and the air content measured by AVA is about 70% of the air content measured by the air content determinator.

Response of IAP/LASG GOALS Model to the Coupling of Air-Sea Fresh Water Exchange

The process of air—sea fresh water exchange is included successfully in the Global— Ocean—Atmosphere Land—System model developed at the State Key Laboratory of Atmospheric Sciences and Geophysical Fluid Dynamics (LASG). The results of the coupled integration show that the climate drift has been controlled successfully. Analyses on the responses of ocean circulation to the changes of surface fresh water or salinity forcing show that the ocean spin-up stage under flux condition for salinity is the key to the implementation of air-sea fresh water flux coupling. This study also demonstrates that the Modified—Monthly—Flux—Anomaly coupling scheme (MMFA) brought forward by Yu and Zhang (1998) is suitable not only for daily air—sea heat flux coupling but also for daily fresh water flux coupling. Key words Fresh water flux - Air-sea coupling - Thermohaline circulation This work was co-supported by the National Key Project (Grant No.96-908-02-03), the Excellent National Key Laboratory Research Project (Grant No.49823002) and Chinese Academy of Sciences (CAS) under grant “ Bai Ren Ji Hua? for “Validation of Coupled Climate Models”.

Heat transfer performance of fresh-air handing device using earth energy

In order to reduce the fresh-air handing energy consumption,a fresh-air handing device using earth energy was presented. The major part is a double pipe soil-air heat exchanger. Its performance was tested in summer and winter. The results show that while the volume of the treated fresh-air is 125 m3/h,in summer,at the outlet of the device,the air temperature is 21.5-24.0 ℃,the air humidity ratio is about 17 g/kg,the greatest temperature drop is about 9 ℃ ,and the largest dehydration quantity is about 6 g/kg. In winter,at the outlet of the device,the air temperature is 15-17 ℃,the air humidity ratio is about 11 g/kg,the largest temperature rise is about 11 ℃,and the largest humidification quantity is about 6 g/kg. Therefore,the application of this new fresh-air handing device can take full advantage of the natural energy,thus effectively reduce the traditional energy consumption for fresh-air handing.

Research on the Phase Change Solar Energy Fresh Air Thermal Storage System

In this article, a new kind of solar fresh air system is designed in order to realize the improvement of thermal efficiency by the integrated application of the PCMs and heat pipe technology. Under the adequate sunshine condition, the fresh air is directly delivered into the indoor environment after being heated by the solar collector. When the sun radiation is reduced, the heated air temperature can not satisfy the need of supply of air temperature.The main heat source is changed to phase change heat storage equipment instead of solar energy. The system adopt heat pipe for a high-efficiency and isothermal heat transfer which recover the shortcomings of PCMs such as： low coefficient of thermal conductivity and poor thermal efficiency. This article establishes the physical model of phase change solar energy fresh air thermal storage system and creates the mathematical model of its unsteady heat transfer to simulate and analyse the operation process by using Fluent software. The results of the study show that, compared to normal fresh air system, the phase change solar energy fresh air thermal storage system has a significant improvement in energy saving and indoor comfort level and will play an important role in the energy sustainable development.

How to Get A Breath of Fresh Air

Heavy smog shrouded China＇s central and eastern regions for days this past January, and experts are advising citizens to stay inside. But how much safer is our indoor air？ The U.S. Environmental Protection Agency＇s research shows that 24 million people in the world die every year as a result of poor indoor air quality, said Song Guangsheng, Secretary General of China＇s Indoor Environment Test Center （CIETC）.

基于Airpak的幼儿园生活单元空气质量模拟分析

通过对幼儿园生活单元建立物理数学模型,基于Airpak模拟分析了排风量、新风量、新风口位置以及室外风速对室内空气品质的影响。结果表明,门窗关闭的室内,仅设置排风并不能有效降低室内CO_(2)平均浓度;引入新风对降低室内CO_(2)平均浓度效果显著;新风口距离人员越近,并非越有利于降低室内CO_(2)平均浓度;过渡季节,开启门窗室内CO_(2)平均浓度水平明显降低。

Design of Control Scheme for Variable Air Volume Air- conditioning System

The air quantity of variable air volume system for the rooms and the total air quantity of the system changes with the change of room load. Combined with the system composition in the laboratory, the paper determines the control scheme of the variable air volume system, that is, indoor temperature-control, indoor positive pressure control, air distribution static pressure control, air-supply temperature control and new air volume control. The dotted lines with arrows mean the output signals from the control unit to actuator, and the solid lines with arrows represent the input signals from the actuator to the control unit.

Analysis of the Influence of Different Drying Methods on the Active Ingredients of Fresh Medicine

The heating area of the material is large and the thermal efficiency is high,but it is n ecessary to control the suitable drying temperature ofdiffere nt medici nal materials to preserve the effective in gredients.D iff ere nt kinds of Chinese medicine need different drying conditions to fulfill good drying requirements.Natural drying in the shade is one of the traditional drying methods,which takes a long time and is easily affected by the weather.The water volatilizes slowly.It is prone to mildew and discoloration during the drying process.However,it can better preserve the volatile oil components of Chinese medicine.The hot-air drying machine has lower requirements.The medicinal materials have a large heating area and high thermal efficiency,but it is necessary to control the appropriate drying temperature of different medicinal materials in order to preserve the active ingredients of the medicinal materials;it is not suitable for medicinal materials that stick and bind easily.The microwave drying method possesses superiority in drying some valuable medicinal materials such as Ren she n(Radix et Rhizoma Ginseng)and Lurong(Co「nu Cervi Pantotrichum),and the effective ingredients are preserved at a high degree;it can also achieve the purpose of killing enzymes and protecting glycosides and have a good bactericidal effect,but it is not suitable for Chinese medicines containing heat-sensitive ingredients,because it will destroy most of the proteins,amino acids,and peptides of Chinese medicine and result in the loss of efficacy.The far-infrared drying method is suitable for drying thin-layer medicinal materials and is friendly to the environment.Freeze-drying can preserve the active ingredients very well and greatly retain the efficacy,but it has obvious limitations in preserving some Chinese medicinal materials that need to kill enzymes and protect glycosides;besides,the cost is relatively high and the drying time is long.

鲜食玉米收获机高净度清选智能测产装置研究

为改善国内小区鲜食玉米育种测产机械装备缺乏、小区鲜食玉米种子清选和测产过程完全依靠人工的现状,设计一种小区鲜食玉米种子高净度清选智能测产装置。该装置采用双层网筛、风力清选、智能测产流程完成高净度清选及测产作业,实现种子高净度清选和智能测产的作业要求。以上筛夹角、下筛夹角和螺旋分离装置入口风速为试验因素,以作业时千克籽粒含杂率为试验指标进行正交试验,建立因素与指标的响应面数学模型,并进行试验验证。结果表明:上筛夹角为14.0°,下筛夹角为4.0°,螺旋清选装置入口风速为27.0 m/s时为最佳作业组合,此参数组合下,鲜食玉米籽粒千克籽粒含杂率为1.2%,籽粒残留清理合格率为99.69%,测产平均误差为0.412%,籽粒含水率测量平均误差为3.57%,玉米种子千粒质量测量平均误差为0.276%。为小区鲜食玉米种子的高净度清选以及智能测产提供研究基础。

一种新型溶液除湿空调系统能耗及应用分析

传统空调系统通常采用温湿度联合处理的方式,该方式存在舒适性差、能源消耗大等问题。针对以上问题,提出一种利用复合直接蒸发冷却制冷水的溶液除湿空调系统,该系统可以有效节省功耗,符合节能减排的发展趋势。在研究过程中,以某办公楼为研究对象,利用TRNSYS仿真软件建立该系统,研究其在制冷季7—9月的能耗,分析其节能性及适用性。结果表明:当空调新风系统使用太阳能热水作为再生热源时,总供热能耗为6.1×10^(5)kW·h,总耗功为8.73×10^(4)kW·h。相比于传统空调系统,节能率达到55.2%,为降低空调系统能耗提供了新思路。

严寒地区超低能耗教学建筑新风系统适用性分析

目的 解决严寒地区超低能耗建筑中人员密集场所供暖期新风系统的适用性问题。方法 以沈阳市某小学教学楼中三种典型教室为例,应用Designbuilder软件建立能耗模型,分析自然通风、有无热回收的定(变)风量机械通风五种工况下超低能耗建筑的各项能耗、相对节能率和本体节能率,以及室内CO_(2)体积分数变化。结果 无热回收的变风量、有热回收的定(变)风量与无热回收的定风量机械通风相比,节能率分别为12%~30%、32%~46%、38%~57%;有热回收的变风量机械通风总能耗最低,且接近自然通风工况;五种工况室内CO_(2)体积分数均小于0.09%。结论 人员密集场所中有热回收的定(变)风量机械通风节能效果显著;建筑气密性的提高导致机械通风系统新风能耗增加,经济性和节能性下降。

室内空气调节系统的研究与设计

车间环境中,生产活动可导致空气质量恶化,极大影响员工身体健康。文章提出了一种空气调节系统,用于监测室内空气粉尘和VOC污染物浓度,适时开启换气系统,使空气参数保持在较高的水平。该系统集成多组粉尘和VOC检测模块和双向换气装置,根据发生空气质量恶化区域自适应调整空气流动路径,有针对性的净化空气。车间外设置风向传感器,根据自然风的风向调整室内换气方向,提高换气效率。各个监测点和执行点利用WiFi实现自组网,点与点之间密切配合,提高系统换气效率。验证试验表明:监测器能够稳定运行,点与点之间配合良好,高效率、针对性实现空气净化,大大改善了车间生产环境。

空调及换气系统运行对室内PM_(2.5)净化效果的影响

为了研究室内空调与换气系统运行时空气净化器对室内空气的净化效果,采用试验研究和CFD模拟相结合的方法,研究了空调与换气系统运行对净化器将室内PM_(2.5)净化到ASHRAE规定的可接受室内空气质量的限值15μg/m^(3)的净化时间的影响。结果表明,净化器外加空调净化时间相比净化器单独运行时间缩短15.2%;净化器外加换气系统净化时间相比净化器单独运行时缩短了30.4%;三系统联合运行时的净化时间相比净化器单独运行时间缩短32.6%。结果可为研究空调与换气系统对空气净化器净化效果的贡献及室内空气净化方式提供参考。

基于智能新风系统的旧实验楼宇改造的探索

以同济大学化学馆整体改造建设项目为例,介绍了基于智能新风排风联动系统的化学馆楼宇整体改造的各项措施,包含在设计中融入EHS体系、依据通风要求分等级分区设计、各项节能措施以及长效运行机制等。在项目改造过程中,以EHS理念为指导,以节能长效为目标,完成了旧楼改造的既定目标,师生满意度达到99%。本案例作为化学类老旧实验楼宇改造领域的有益探索,为旧实验楼改造和提升提供了一个典型范例,为后续工作积累了经验。

风机盘管加新风系统室内微循环热舒适性研究

随着人们生活水平的提高,医院在提升治疗服务的同时迫切需要改善患者就医环境和医护人员的工作环境。目前,医院建筑中特别是病房广泛应用的风机盘管加新风系统存在温度分布不均匀、吹风感较强、噪音大等问题,导致了患者的室内热舒适性无法得到保障。因此,针对医院病房,探索研究风机盘管加除湿置换新风空调系统,在实际搭建的实验平台基础上建立CFD数值模拟模型,将模拟结果与实验数据相对比,论证了模型的准确性之后,通过CFD模拟的方式,在保证对流换热可以达到室内设定温度的前提下,找到一种新的气流组织形式,这样不仅有效降低室内人员的吹风感和噪音,而且避免了传统置换通风容易出现温度分层、垂直温差过大的问题。

BIPV/T–DSF与新风一体化系统性能模拟研究

为提高光伏光热建筑一体化技术中光伏组件发电效率,充分利用其光热能量,同时满足室内人员对新风的需求,本研究将光伏光热建筑一体化技术与双层皮玻璃幕墙相结合,组成BIPV/T–DSF与新风一体化系统。以沈阳市一间30 m2的卧室为研究对象,通过实地测量室内污染物浓度并进行系统仿真模拟,对室内空气质量状况进行评估,并对系统的热电性能、空气通道内流场的流动特性进行研究。结果表明:系统运行时,冬季热效率达到0.22,电效率达到0.178;夏季电效率由原来的0.151提高到0.156。新风对于室内甲醛浓度有较好的净化效果,系统通风运行20 min后,甲醛浓度即可稳定在0.033 mg/m3。

自适应PID在太阳能-新风系统温度控制中的应用

太阳能-新风系统是将太阳能热利用与新风系统相结合,用于室内进行通风换气的新型辅助供暖系统。太阳能-新风系统具有大惯性、滞后、非线性的特点,其数学模型难以精确建立,常规PID控制很难使新风温度保持平稳状态。为解决这一问题,设计了用于太阳能-新风系统的自适应PID控制器,通过在线调整PID控制器的参数来精准控制新风温度,以期为实现太阳能-新风系统温度控制提供另一种思路。