行为模式对户式空气源热泵地暖系统供热性能的影响

自主调节供水温度及开关部分供暖回路阀门等行为模式对户式空气源热泵地暖系统的节能与舒适性具有重要影响。本文以一实际住宅为例,实验研究了户式空气源热泵地暖系统在不同供水温度和改变供暖回路数量下的供暖特性,对室内空气温度、地面温度及系统耗电量等参数的实测与分析显示：室外平均温度为-2.3℃,按照机组最高供水温度55℃运行时,由于地面温度过高,地板表面温度局部不满意率超过20%,相对于供水温度30℃运行结果,耗电量增加191%,客厅与书房的温差增加2.5℃以上。室外平均温度为-1.7℃,关闭次卧和客卧相应的地暖回路阀门后,主卧、客厅和书房室温比全屋供暖时分别降低了1.4、2.9、0.5℃,系统耗电量降低18.7%。     

某冰蓄冷项目运行策略分析

结合某办公建筑,对3种冰蓄冷运行策略进行对比分析.结果 显示:3种运行策略日总移峰电量分别为28575 kW·h,28395 kW·h和28215 kW·,日移高峰电量分别为16785 kW·h,21645 kW·h和17415 kW·h,单日节省电费分别为12464元,13082元和13509元;运行策略3的日总移峰...     

太阳能-空气能双源直膨式热泵系统夏季冷热电性能研究

本文设计了一种基于微热管阵列的太阳能-空气能双源集热蒸发(冷凝)器及双源直膨式热泵系统,该系统可有效降低光伏组件温度提升光伏发电效率,同时可实现制热和制冷功能,是一种多能互补可满足多种用能需求的新型建筑供能系统形式。搭建了太阳能-空气能双源直膨式热泵系统实验台,并对系统在夏季典型工况下的发电、供冷与提供生活热水性能进行实验测试与分析,结果表明,双源直膨式热泵系统制热运行时,PV/T组件工作对光伏组件起到了显著降温作用,相比于热泵不运行工况,组件光电功率提高56.43%,光电效率提升53.15%;双源直膨式热泵系统将180 L水由20℃加热至50℃的制热过程,系统平均制热COP为4.59,集热功率为3.20 kW,总发电量为1.43 kW·h,总耗电量为1.36 kW·h;由12℃冷却至7℃的制冷过程,系统平均EER为2.29。     

地源热泵运行模式对北方住宅供暖能耗的影响

在对一栋满足节能65%设计标准的住宅进行逐时能耗分析的基础上,得出间歇运行的最大热负荷约为连续运行时的3倍,但是连续运行和间歇运行的累计耗热量分别为39.4 kW·h/(m~2·a)和33.6kW·h/(m~2·a),建议地源热泵尽量采用连续运行的方式。分析实际项目的装机容量和土壤温度逐年变化情况,所调研的住宅1第一年土壤计算温降为1.81℃,实际温降为1.9℃。提出为了避免土壤温度逐年降低,可采用具有分区补热功能的跨季节蓄热空气源-土壤源复合式系统。     

空气源/污水源复合热泵系统设计与应用

基于公共浴室热水生产设备节能减排改造的需要,本文设计了可回收洗浴废水余热的空气源/污水源复合热泵热水系统,在合肥工业大学屯溪路校区建立了应用示范工程,进行了运行测试和应用研究工作。结果显示:在8℃±1.2℃的环境温度、50℃供水设定温度的运行条件下,通过预热器和污水源热泵机组进行余热回收,洗浴废水温度从30.6℃降低至15.5℃,热回收的能量约占热水生产总能量的1/3;在10℃±1℃的环境温度、45℃供水设定温度的条件下,复合热泵系统的能效比为3.45,与单独运行空气源热泵的2.96相比,能效提高16%;与传统的燃气锅炉设备、电热水器对比分析,复合热泵系统可分别节约运行费用53.3%、72.4%,节能、环保和降费的优势明显。     

纯电动汽车两种热泵空调系统的实验研究

为解决纯电动汽车采暖时采用电加热方式导致能源利用率低,降低纯电动车的续航里程这一问题,本文设计了分别采用四通阀和阀组的热泵空调系统并搭建了实验台,通过实验测试了系统的制冷量、制热量及耐振动性能。结果表明:采用四通阀的热泵空调系统与采用阀组的热泵空调系统在名义工况下制冷量和制热量约为2 kW,两套系统制冷模式时的出风温度皆为15.3℃,制热模式时的出风温度分别为41.3℃和38.2℃;两种热泵空调系统在低温工况下制热量均降至800 W左右;采用四通阀的热泵空调系统在振动状态下易出现窜气导致系统工作不稳定,损坏压缩机;采用阀组的热泵空调系统在振动状态下运行稳定。     

严寒地区空气源热泵供暖运行性能研究

基于TRNSYS软件建立空气源热泵供暖系统仿真模型,模拟空气源热泵供暖运行性能,对比分析不同供水流量、不同月份以及3个典型供暖日下的系统COP。研究结果表明:室内温度及系统COP随室外温度的升高而升高,系统耗电量随室外温度的升高而降低;当室外温度恒定时,室内温度和系统耗电量随供水流量的增大而增大,但系统COP随供水流量的增大而降低;供暖期开始和结束时,空气源热泵运行性能稳定、满足供暖热舒适需求,供暖期室外温度最低时不宜单独使用空气源热泵。研究结果可为空气源热泵供暖系统在包头地区的应用提供指导。     

热气旁通技术在纯电动客车热泵低温制热中的应用

通过将热气旁通装置加装在纯电动客车热泵上,并在低温工况(室外-15℃/室内-5℃)下进行了制热性能试验研究,得出:制热量、功率、排气温度及出风温度等系统参数均随热气旁通装置阀开度的增大而下降,该装置在一定范围内可避免低压过低引起的压机频繁启停或者低压保护停机,可使纯电动客车热泵在较低温环境中依然可以稳定运行制热,扩大热泵系统的工作范围。此外,还提出了热气旁通装置的初步控制方法。     

风机盘管/毛细管顶板联合供暖的试验研究

本文建立了风机盘管/毛细管末端系统,运用TRNSYS软件模拟了该系统冬季不同工况（流量、供水温度）下系统及房间特性。同时搭建了风机盘管/毛细管末端试验平台,进行了冬季不同工况情况下的试验研究。通过试验分析了该系统在冬季供暖时,在不同供水温度和供水水量情况下的运行特性,结果表明供水温度43℃、流量0．8m^3/h是比较合适的供水工况。同时,长时间运行的实验结果表明,系统联合运行供暖,舒适性好,响应速度快,节约能源。     

数据中心冷通道封闭对室内热环境影响的模拟研究

降低数据中心空调系统能耗对节能具有重要意义。冷通道封闭技术可以优化机房气流组织、节省数据中心空调能耗。本文利用数值模拟的方法对北京市某数据中心冷通道封闭前后机房内热环境进行分析,结果表明,冷通道封闭可以减少冷热气流的掺混及局部热点的产生,可将空调送风温度由18℃提高至22℃,每年可节能约1×10~5 kW·h。     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Instructions & Forms for Authors

Journal of Materials Sciences ＆ Technology is a monthly journal for the rapid dissemination of new, impor- rant results in material and related fields. Submission Electronic files of MS Word and PDF are acceptable. Please visit http：//www.jmst.org and submit online.