轻质双层纺织基太阳能空气集热器的集热性能试验研究

纺织基太阳能空气集热器作为轻质柔软的太阳能集热器,在中低温集热领域具有潜在的应用前景。文章设计了新型双层纺织基太阳能空气集热器,并进行户外试验,探究单双层结构、间隔丝密度、空气质量流量对集热器性能的影响。研究结果表明:在空气质量流量为0.023 kg/(m²·s)时,双层纺织基太阳能空气集热器热转移因子和总热损系数分别为0.97和5.87 W/(m²·℃),集热性能优于同条件下单层结构集热器;进出口空气温差和集热效率随间隔丝密度的增加而增加;集热效率随空气质量流量的增加而增加,当空气质量流量为0.037 kg/(m²·s)时,间隔丝密度为36根/cm²的集热器集热效率为0.64。     

高层住宅阳台太阳集热器系统的极值风效应

在大气边界层风洞中模拟C类地貌,对缩尺比为1∶80的高层住宅阳台太阳集热器模型进行刚性模型测压试验。首先,对集热器极值风压系数进行概率分析,结果表明太阳集热器极值风压系数的概率模型归属受面板位置、来流风向的影响较小,广义极值分布可较好地描述集热器极值风压系数的概率分布;其次,研究集热器安装倾角、楼层高度、在阳台上的相对位置等参数对集热器极值风荷载的影响规律,结果表明顶部楼层的阳台集热器表现出与中间楼层集热器不同的风荷载特性,各楼层阳台集热器的风荷载作用效应机理与阳台立面明显不同;倾斜安装于阳台立面的集热器最不利极值风压系数与安装倾角变化并不表现为单调关系;最后,基于包络法给出阳台太阳集热器的极值风压系数设计建议取值。     

Preparation and properties of MnO2–TiO2 nanotube array composite electrodes using titanium foam as the current collector

MnO₂–TiO₂ nanotube array composite electrodes were prepared through depositing MnO₂ onto TiO₂ nanotube arrays obtained by anodization of the titanium foam and the effect of morphologies of TiO₂ nanotube arrays on the performance of the electrode was investigated. Results show that the wall thickness, the tube diameter and the tightness among the nanotubes affected the performance of composite electrodes. The areal, quality and volume capacitance value of the optimized sample reached up to 436.2 mF/cm², 1470.8 mF/g and 5452.5 mF/cm³, respectively, at a current density of 0.1 mA/cm², which were significantly higher than those of the MnO₂–TiO₂ nanotube array composite electrodes using planar titanium foil as the current collector. The capacitance retention was 85.7% after 3000 cycles. In addition, the influences of the cations (Li⁺, Na⁺, K⁺, NH₄⁺) and anions (Cl^?, Br^?, I^?, CH3COO^?) in the testing electrolytes on the capacitance properties were also studied in detail.     

Thermal analysis of insulated north-wall greenhouse with solar collector under passive mode

An insulated north wall greenhouse dryer has been fabricated and tested for no-load condition under passive mode. Testing has been conducted in two different cases. Case-I is considered for solar collector kept inside the dryer and Case-II is dryer without solar collector. Convective heat transfer coefficient and various heat transfer dimensionless numbers with have been calculated for thermal analysis. The maximum convective heat transfer coefficient is found 52.18?W/m²°C at 14?h during the first day for Case-I. The difference of the highest convective heat transfer coefficient of both cases was 8.34?W/m²°C. Net heat gain inside room curves are uniform and smooth for Case-I, which shows the steady heat generation process due to presence of solar collector inside the dryer. Above results depicts the effectiveness of solar collector and insulated north wall. The selection of suitable crop for drying can be done by analysing article’s result.     

Optical performance and instantaneous efficiency calculation of linear Fresnel solar collectors

The main objective of this study is the investigation of the effect of the optical path of incident beam solar radiation on the performance of a linear Fresnel concentrating solar collector. The requirements regarding the kinematics of the reflectors are examined, allowing the effective focus of the reflected radiation on the receiver cover. A methodology for the calculation of the reflection angles of the sun rays incident on the mirrors, as well as of the incidence angles of the reflected rays on the cover, as a function of the sun position and the geometry of the collector is proposed. Specific scenarios, describing the effect of the solar radiation optical path on the collected heat, are formulated, each of them leading to a different form for the instantaneous efficiency equation. The evaluation and analysis of these scenarios, on the basis of actual operation conditions, has shown that the effect of the reflection and incidence angles throughout the modeling of the collector and the calculation of the useful thermal power cannot be neglected.     

Thermodynamic assessment of modified Organic Rankine Cycle integrated with parabolic trough collector for hydrogen production

Hydrogen is one of the most clean energy carrier and the best alternative for fossil fuels. In this study, thermodynamic analysis of modified Organic Rankine Cycle (ORC) integrated with Parabolic Trough Collector (PTC) for hydrogen production is investigated. The integrated system investigated in this study consists of a parabolic trough collector, a modified ORC, a single effect absorption cooling system and a PEM electrolyzer. By using parabolic trough collector, solar energy is converted heat energy and then produced heat energy is used in modified ORC to produce electricity. Electricity is then used for hydrogen production. The outputs of this integrated system are electricity, cooling and hydrogen. By performing a parametric study, the effects of design parameters of PTC, modified ORC and PEM electrolyzer on hydrogen production is evaluated. According to the analysis results, solar radiation is one of the most important factor affecting system exergy efficiency and hydrogen production rate. As solar radiation increases from 400?W/m² to 1000?W/m², exergy efficiency of the system increases 58%–64% and hydrogen production rate increases from 0.1016?kg/h to 0.1028?kg/h.     

细纱机集落抓管器损坏原因及解决办法

为了解决细纱机集落装置抓管器损坏频繁且数量大的问题,介绍了抓管器的作用、损坏形式与受力情况;分析了抓管器损坏的原因并提出解决办法;指出抓管器损坏的原因主要是设备维护、保养不及时或集落系统出现故障后未能及时解决造成的,应重视设备管理,以减少设备故障次数和停台率。     

ONP/OMG浮选-洗涤脱墨剂的研究

讨论了不同类型非离子表面活性剂的浮选-洗涤脱墨性能及脱墨效果最佳的HLB值.确定了以脂肪酸聚氧乙烯酯(PEE)与脂肪胺聚氧乙烯醚(PAE)为主要成分的脱墨剂的组成,并研究了促集剂和阴离子表面活性剂对脱墨效果的影响.实验结果表明,PEE和PAE具有良好的协同脱墨性能,PEE-6和PAE-2以60:40复配时脱墨效果最好;10%油酸钾作为促集剂有助于脱墨效果的提高.     

浮选脱泥选别某难选氧化锌矿试验研究

矿泥对四川某难选氧化锌矿的浮选产生严重影响。试验研究结果表明,以Yt作为浮选脱泥调整剂、Ym作为捕收剂,在适当脱泥量的前提下,可使矿泥中锌金属损失降至最少。闭路试验结果表明,采用浮选脱除15.83%细泥后能获得含锌34.15%、回收率为82.47%的合格氧化锌精矿。     

提高赛什塘铜矿选矿技术指标的试验研究及实践

赛什塘铜矿是以铜、硫为主的复杂多金属硫化矿,通过试验研究,在不改变现场生产流程的情况下,采取新的药剂制度,即以石灰为pH调整剂、复合黄药为捕收剂、A6为辅助捕收剂,在精选添加调整剂T-20,并适当降低精选作业矿浆pH值,工业应用获得了较好的技术指标,铜精矿品位年累计达到19.67%、回收率达到89.33%,为企业创造了良好的经济效益和社会效益。