变频空调与散热器采暖房间温度场对比研究

针对西安地区某一办公房间采用变频空调或散热器两种采暖方式分别进行了IMP数据采集系统实测与数值模拟的对比研究,结果表明,变频空调采暖时工作区域内温度梯度较大,为3℃左右,散热器采暖时工作区域内温度梯度为0.7℃左右.根据房间实际尺寸建立物理模型并对两种采暖方式的室内温度场和流场进行了数值模拟,模拟结果与实测结果基本吻合.通过数值模拟和分析两种采暖方式的特点及对室内热环境的影响,理论上得出散热器采暖方式的室内温度场和流场更加均匀的结果.     

完整工作日中变频房间空调器动态特性仿真

针对海信KFPR-35GW型变频房间空调器,利用SIMULINK语言建立了变频空调系统动态仿真数学模型,模拟了变频空调器在夏季完整工作日中的制冷动态运行特性,根据模拟的结果分析了变频空调系统的能耗和房间的热舒适性。比较分析显示：在完整工作日中,变频空调器的平均制冷COP为3．3,而且很好地维持了房间的温度,跟设定的室内标准温度27℃相比,空调房间的温度上下波动不超过1℃,提高了空调房间的热舒适性。     

大换气量房间冬季室内热环境实测与分析

通过对顶棚辐射、散热器与热风三种采暖方式在大换气量情况下室内热状况的实测，对其热舒适性与节能效应进行了分析和讨论，指出辐射采暖可以利用墙体的蓄热能力获得节能效果，房间空气温度垂直分布状况主要取决于通风路线而非采暖方式，因而房间设有通风系统时，顶棚辐射采暖房间的舒适性要优于另外两种采暖方式。     

地板辐射采暖双向散热舒适性研究

提出了地板辐射采暖双向散热的设计模型,双向散热与传统的地板辐射采暖相比,降低了地板表面温度,楼板平均辐射温度下降,室内空气温度分布更趋合理.同时本文采用预测平均投票指标及预期不满意百分数指标,综合评价采用普通散热器房间、地板辐射采暖房间及双向散热地板辐射采暖房间在不同室内设计温度时的PMV值及PPD值,并对其进行了分析.     

变频空调的七大特点

变频空调呈现全球化趋势 ,日本达到 95 %以上 ,欧洲从 5年前不到 5 %迅速上升到 30 %。我国增长也很快 ,据家电连锁巨头国美、苏宁等反馈 ,变频空调已占销售总量的 2 0 %以上。变频空调的主要特点有 :1、控温精确。定速空调利用开停机来调节房间温度 ,控温范围± 2℃左右 ,温度波动范围大 ,人们感觉不舒服 ,易得“空调病”。变频空调在刚开机时以高速运转 ,当房间温度达到设定温度后转为低频工作 ,温度控制精确 ,控温范围± 0 5℃ ,人们感觉舒服。2、制冷制热速度快、效果好。变频空调刚起动时以最大频率运转 ,一般在130Hz以上工作 ,制冷…     

浅论采暖通风工程中存在的问题和措施

采暖,是通过对建筑物及防寒取暖装置的设计,是建筑物内获得适当的温度。通风就是采用自然或机械方法使风没有阻碍,可以穿过,达到房间或密封的环境内,以造成卫生、安全等适宜空气环境的技术。本文就目前采暖与通风工程的设计进行解析,并就目前的现状进行分析,对其出现的缺点和不足提出改正建议和对策。     

低温热水地板辐射采暖施工

低温热水地板辐射采暖一般按分室、分区控制的原则安装,即一个房间或一个区域一个环路铺设,从而达到主要房间和区域单独调节温度的目的。主要介绍低温热水地板辐射采暖的特点、施工的工艺流程、施工的具体要求、打压的要求等。     

低温热水地板辐射采暖施工

低温热水地板辐射采暖是一种利用建筑物内部地面进行采暖的系统。既节能又具有室内温度均匀、温度梯度小、地面温度高、卫生好、热舒适性好等特点。地板辐射采暖技术在一些发达国家的应用已十分普遍。在部分国家及地区其应用面积已占全部采暖面积的80%以上。     

几种常用采暖方式比较

文章介绍了目前常见的采暖方式,城市集中热力网供热,居住区规模集中供热和分户供热。对三种采暖方式进行了比较。     

夏季与冬季变频空调房间温度场对比研究

利用IMP数据采集系统对西安地区某采用变频空调办公大楼一办公室进行夏季温度场测试,将测试数据与冬季实测数据进行比较,分析其高度方向和水平方向的温度分布。同时还分析了冬夏季送风温度的周期性变化。结果表明,夏季室内垂直温度差小,最大差值只有0.27℃;冬季室内垂直温度差较大,最大值有2.65℃。夏季与冬季相比室内温度分布有明显的分区现象。冬季送风温度呈周期性变化,而夏季周期性变化不明显。     

Gender differences in publication productivity in psychology in India

An analysis of gender differences in psychology in India provides quantitative and qualitative assessment of R&D output contributed by psychologists with the indication of the trend of growth, skewness, relatedness, co-authorship pattern of productivity.     

Metrology in Chemistry in Germany

The system for Metrology in Chemistry in Germany is described. At the national standards level, a network of high-level chemistry institutes coordinated by the national metrology institute, PTB, provides the primary references for chemical measurements. A dissemination mechanism employs chemical calibration laboratories accredited within the framework of the German Calibration Service (DKD). They act as “multipliers” between the national standards level and the user level by providing the user with calibration means which are traceable to the SI via national standards. Traceability structures in clinical chemistry, electrochemistry, elemental analysis and gas analysis are described     

Natural radioactivity in drinking water in private wells in Finland

Radiation Protection Dosimetry     

Natural radioactivity in drinking water in private wells in Finland

Natural radioactivity in drinking water was determined in population-based random study of 472 private wells. The mean concentrations of (222)Rn, (226)Ra, (234)U, (238)U, (210)Pb and (210)Po in drilled wells were 460, 0.05, 0.35, 0.26, 0.04 and 0.05 Bq l(-1), and in wells dug in the soil were 50, 0.016, 0.02, 0.015, 0.013 and 0.007 Bq l(-1), respectively. Approximately 10% of the drilled wells exceeded a radon concentration of 1000 Bq l(-1) and 18% a uranium concentration of 15 microg l(-1). The mean annual effective dose from natural radionuclides for a drilled well user was 0.4 mSv and 0.05 mSv for a user of a well dug in the soil. The effective dose arising from (222)Rn was 75% of the total of all natural radionuclides for drilled well users. As regards long-lived radionuclides, (210)Po and (210)Pb caused the largest portion of the effective dose. The dose arising from (238)U, (234)U and (226)Ra was only 8% of the total of all natural radionuclides.     

Trends in alcohol-impaired driving in Canada

While a general decreasing trend in the number of persons killed in a traffic crash involving a drinking driver has occurred in Canada since the 1980s, it is evident that much of this decrease occurred in the 1990s. Since 2002, less progress has been made as the number of persons killed in crashes involving drinking drivers remains high. To better understand the current situation, this paper describes trends in drinking and driving in Canada from 1998 to 2011 using multiple indicators based on data collected for the Traffic Injury Research Foundation's (TIRF) Road Safety Monitor (RSM), the National Opinion Poll on Drinking and Driving, and trends in alcohol-related crashes based on data collected for TIRF's national Fatality Database in Canada. There has been a continued and consistent decrease in the number of fatalities involving a drinking driver in Canada. This remains true when looking at the number of fatalities involving a drinking driver per 100,000 population and per 100,000 licensed drivers. This decreasing trend is also still apparent when considering the percentage of persons killed in a traffic crash in Canada involving a drinking driver although less pronounced. Data from the RSM further show that the percentage of those who reported driving after they thought they were over the legal limit has also declined. However, regardless of the apparent decreasing trend in drinking driving fatalities and behaviour, reductions have been relatively modest, and fatalities in crashes involving drivers who have consumed alcohol remain high at unacceptable levels.     

Radioactivity in building materials in Iraq

Activity concentrations of (226)Ra, (232)Th and (40)K in 45 samples of different building materials used in Iraq were measured using gamma-spectroscopy system based on high-purity germanium detector with an efficiency of 40 %. Radium equivalent activity, air-absorbed dose rate, annual effective dose, external and internal hazard indices and alpha index due to radon inhalation originating from building materials were measured to assess the potential radiological hazard associated with these building materials. The activity concentrations of the natural radionuclides (226)Ra, (232)Th and 40K were found to range from below detection limit (BDL) to 223.7 ± 9, BDL to 93.0 ± 3 and BDL to 343.1 ± 12, respectively. Values of average radium equivalent activity, air-absorbed dose rate, indoor and outdoor annual effective doses, external and internal hazard indices and alpha index ranged from 6.5 to 124.9, 16.2 to 89.5 (nGy h(-1)), 0.08 to 0.44 mSv, 0.02-0.11 mSv, 0.09 to 0.53, 0.13 to 0.69 and 0.03 to 0.62, respectively. These values indicate a low dose. Therefore, the building materials used in the current study are quite safe to be used as building materials.