试论空调系统节能优化的问题与对策

空调系统能耗占整个建筑能耗的70%左右.随着节能技术的日臻完善,空调如何在保证舒适性要求的前提下以提高能源利用率来实现节能是本文研究的重点.文章指出了目前空调系统节能优化中存在的主要问题,同时提出空调系统节能优化的一些措施.     

冷、热风幕气幕式空调伞的实验研究和对比分析

介绍了一种营造局域舒适性环境的新型空调设备--气幕式空调伞,借助实验手段比较了两种空调伞的流场、温度场以及最佳高径比,并对有效空调区和舒适性进行了分析和比较.     

玻璃幕墙建筑的遮阳与节能

1 前言 玻璃的发明为建筑提供的另一个更广阔的设计发展空间。20世纪,世界建筑科学技术突色猛进,发达国家建筑围护结构的保温隔热性能和气密性大有提高,采暖、空调和遮阳的设备与技术日益进步,人们可以在越来越更为优裕利舒适的室内环境中生活与工作。从经典型建筑珍品到粗糙的乡土建筑,建筑遮阳无不得到充分重视。     

宝马5系轿车中铝合金散热器的自动空调故障诊断与排除

空调系统是舒适性装置,汽车内部温度是舒适性的重要指标。自动空调能够依据车厢温度自动调节出风温度,具有平滑柔顺性,温控调节精细。单从上述结构看,现代汽车的自动空调就比传统空调复杂得多。有些轿车的自动空调还装有红外温度传感器,专门探测乘员面额部的表面皮肤温度。当传感器检测到人体皮肤温度时也反馈到IHKA。这样,IHKA有多种传感器的温度数据输入,就能更精确地控制空调。乘员只要操作旋钮或按键,设置所需温度及风机转速,以后一切事情都由自动空调控制系统办理了。本文主要介绍宝马5系自动空调系统故障诊断与排除的方法与技巧。     

上海国际体操中心比赛大厅的设计

体育馆在空间建筑范畴,它的设计不同于一般建筑,要求空调控制范围大,录烽性高,以满足多功能使用要求。本文对比赛大厅的空调设计做了比较详细的介绍和探讨。     

遮阳系统在建筑中的灵活应用

世界建筑科学技术突飞猛进,房屋建筑快速发展,建筑围护结构的保温隔热和气密性能大有提高,采暖、空调和照明的设备与技术日益进步,使人们能够在更为优裕和舒适的室内环境中生活与工作,人类建筑文明取得了前所未有的成就.在此同时,人们也不得不面对着资源枯竭、环境恶化、生态破坏、气候变暖等一系列严峻问题.强调节能、低污染、低耗能的绿色建筑顺应时代的要求而生.     

赣南地区低温地板辐射采暖效果研究

赣南地区属于夏热冬冷地区, 被列为非采暖区, 冬季室内热舒适性较差.由于各方面的原因, 人们对居住环境的要求越来越高, 迫切需要改善室内热舒适性.结合赣南地区冬季气候及地域特点, 研究低温地板辐射采暖的效果, 并与空调采暖进行对比.利用CFD理论分别对该采暖室在2种采暖方式下的室内热环境进行数值模拟, 分析室内空气温度场、湿度场, 并用PMV-PPD评价指标对室内热环境进行评定.研究表明, 与空调采暖相比低温地板辐射采暖:室内热环境更加舒适; 室内设计温度可降低2~3℃, 能节约15%的能量, 有利于节能环保.      

低能耗技术在重庆绿色建筑中的应用

以绿色建筑工程-中冶赛迪研发中心项目为例,简要介绍了在设计中应用的低能耗技术。由于空调系统的能耗占建筑总能耗的比例很高,文章主要从空调系统方面作详细分析,包括地源热泵与低温热水地板辐射联合运行的采暖系统、地源热泵与热-湿分控空调末端联合运行的空调系统,以期对在重庆地区建筑中应用类似的低能耗技术有一定指导和示范作用,并推动低能耗技术在重庆地区建筑中的应用。     

大面积建筑空调系统方式探讨

从实用的角度出发．提出了大面积建筑空调系统可供选择的3种方式，介绍了不同方式的优缺点．并以实例说明吊顶柜式空调加新风方式是满足大面积建筑租售、使用、管理的最佳选择。     

对智能化楼宇中空调设计的探讨

通过介绍现代化办公楼的使用、建筑特点、空调负荷特点,提出了对空调的看法和观点。     

Detached Eddy Simulation Investigation of Turbulence at a Circular Pier with Scour Hole

This paper uses results from detached eddy simulation to reveal the dynamics of large-scale coherent eddies in the flow around a circular pier with an equilibrium scour hole. This is important for the sediment transport because the local scour process is controlled to a large extent by the large-scale coherent structures present in the near-bed region. The present paper investigates the dynamics of these coherent structures, their interactions and their role in entraining sediment in the later stages of the scour process when the horseshoe vortex system is stabilized by the presence of a large scour hole. The pier Reynolds number was 2.06×105, outside the range of well-resolved large-eddy simulation (LES). Additionally, scale effects are investigated based on comparison with LES results obtained at a much lower Reynolds number of 16,000 in a previous investigation. The paper provides a detailed study of the dynamics of the main necklace vortices of the horseshoe vortex system, including an investigation of the bimodal oscillations, their effect on the amplification of the turbulence within the scour hole and the interactions of the necklace vortices with the downflow. Several mechanisms for the growth of the downstream part of the scour hole in the later stages of the scour process are discussed. Similar to the low-Reynolds-number simulation, and consistent with experimental observations, the presence of strong upwelling motions near the symmetry plane resulted in the suppression of the large-scale vortex shedding in the wake. The fact that the nondimensional values of the turbulent kinetic energy and pressure RMS fluctuations in the higher Reynolds number simulation were consistently lower inside the regions of high turbulence amplification associated with the main necklace vortex, the separated shear layers and the near-wake shows that changes in the flow and turbulence due to the Reynolds number and scour hole geometry can be quantitatively significant over Reynolds numbers between 104 and 105.     

Seismic Response of Isolated Bridges

The seismic response of bridges seismically isolated by lead-rubber bearings (L-RB) to bidirectional earthquake excitation (i.e., two horizontal components) is presented in this paper. The force-deformation behavior of L-RB is considered as bilinear, and the interaction between the restoring forces in two orthogonal horizontal directions is duly considered in the response analysis. The specific purpose of the study is to assess the effects of seismic isolation on the peak response of the bridges, and to investigate the effects of the bidirectional interaction of restoring forces of isolation bearings. The seismic response of the lumped mass model of continuous span isolated bridges is obtained by solving the governing equations of motion in the incremental form using an iterative step-by-step method. To study the effectiveness of L-RB, the seismic response of isolated bridges is compared with the response of corresponding nonisolated bridges (i.e., bridges without isolation devices). A comparison of the response of the isolated bridges obtained by considering and ignoring the bidirectional interaction of bearing forces is made under important parametric variation. The important parameters included are the flexibility of the bridge piers and the stiffness and yield strength of the L-RB. The results show that the bidirectional interaction of the restoring forces of the L-RB has considerable effects on the seismic response of the isolated bridges. If these interaction effects are ignored, then the peak bearing displacements are underestimated, which can be crucial from the design point of view.     

柳钢4号高炉侧壁温度升高与侵蚀状态分析

为了进一步明确柳钢4号高炉炉缸侧壁温度升高原因和炉缸侵蚀状态,通过对柳钢4号高炉炉缸结构设计、原燃料质量和生产参数进行调研分析,结合炉缸侧壁温度的变化规律和炭砖残厚的计算,分析了炉缸侧壁温度升高原因及侵蚀状态。结果表明,4号高炉炉缸冷却能力和炉缸侧壁温度监测仍有待加强;除侧壁炭砖侵蚀外,原燃料质量波动和冶炼强度增大等也是炉缸侧壁温度上升的重要原因;炉缸侵蚀最为严重的部位在铁口中心线以下1.9 m的位置,表现为“象脚”侵蚀。     

Prediction of Rainfall for Short Term Irrigation Planning and Scheduling—Case Study in Victoria, Australia

In the short-term planning (7–14?days) and operation of complex irrigation systems, an estimate of irrigation water demand (IWD) is of a fundamental concern. To predict the IWD, a reliable estimate of the expected rainfall during any irrigation period is of fundamental importance. Rainfall is generally predicted with a certain probability of exceedance. However, the standard flood flow-frequency distributions cannot be used for prediction of rainfall of such short durations because these rainfall series in general consist of zero values. Two methods, the total probability theorem (TPT) with three normalizing transformations (i.e., power, log, and square root), and the leaky law (LL) were used to predict the rainfall of short durations (7–14?days, depending upon the number of irrigations per season) in the Goulburn irrigation area (GIA) of Victoria, Australia. Investigations indicated that the TPT using the power transformation (TPTP) was more effective in modeling the short-term data series than the log (TPTL) and square-root transformations (TPTS). Although the overall fitting of the short-term rainfall data series by the LL method was significantly (99%) better than the TPT method, some series could not be fitted by the LL method. This revealed that the LL method could not model all short-term rainfall data series. Results showed that although both the TPT and LL were quite satisfactory in predicting short-term seasonal rainfall of short durations in the study area, none of them was individually able to model all the short-term rainfall series. Hence, the joint use of TPT and LL methods was recommended for short-term rainfall prediction of the study area.     

Nondeformability of Ventilated and Mortar-Embedded Marble Facade Panels

It is known that in historical buildings as well as new buildings, facade claddings consisting of marble panels, are prone to damage patterns such as softening, crack formation, and bowing. The degree of damage is apparently dependent on the location of the building, the external climatic conditions, and the type of fastening of the facade panels. In this article, it is examined by means of nonstationary thermal simulation, to which extent the temperature fields, which develop in the facade panel, have an effect on the damage of the panel. It is shown that the diurnal and annual amplitude of the panel temperature induced by solar flux, external air temperature fluctuations, and long-wave input radiation and irradiation have a substantial influence on the damage process. On the example of the simulation of the thermal behavior of a facade panel for the building locations in Athens, Greece, Vienna, Austria, and Helsinki, Finland, it is shown that the observed increase of the susceptibility of marble facades to damages can be explained with the increase of the geographical latitude through the differences in the external climatic conditions. It is strongly recommended that architects and restorers install specific marble facade panels (like carrara marble) in close thermal contact with the wall behind, since this reduces the susceptibility of the facade to damage.     

包钢薄板坯连铸机结晶器振动台机构分析

应用机械原理、理论力学的基本理论,对薄板坯连铸连轧厂连铸机的结晶器振动台进行机构的分析转化和运动学分析,得出振幅的调整方法和结晶器的位移和速度函数,并进行推理和定量分析.     

挤压和锻造工艺对铍青铜棒材组织和性能的影响

文章以铍青铜半连续铸锭为原料,研究了挤压、锻造及锻造＋挤压工艺对铍青铜棒材组织和性能的影响。研究结果表明：由于挤压时铸锭内外层变形不均匀,导致沿断面上棒材的组织不均匀;在加工率相同条件下,锻造棒材的微观组织比挤压组织均匀,抗拉强度比挤压工艺的略低,但延伸率较高,而锻造＋挤压工艺对棒材组织改善最为明显,微观组织细小均匀,综合力学性能和内部组织最好。     

Simulation of Shield Tunneling Behavior along a Curved Alignment in a Multilayered Ground

The kinematic shield model has been proposed to simulate shield behavior during excavation based on equilibrium condition, taking into account ground displacement around the shield. The model has been validated by the simulation of an earth pressure balanced shield behavior in a straight alignment for a single ground layer. To verify the model performance for shield tunnel excavation at curved alignment in multilayered ground, the slurry shield behavior is simulated in this study using the in situ data, and the immediate ground movements around the shield are computed by three-dimensional FEM employing the enforced displacement, which is obtained from the shield behavior simulation. As a result, it is found that the simulated shield behavior and the computed immediate ground movements around the shield during shield tunneling are in good agreement with the observations. Furthermore, the results reveal that the excavated area including the area generated by copy cutter is a predominant factor affecting the shield behavior, and the ground displacement, at the excavated surface plays an important role in the surrounding ground movements during shield tunneling.     

首秦公司燃气资源梯级利用研究与实践

通过对首秦公司天然气消耗情况对标分析,得出减少钢包、中间包以及鱼雷罐等设备烘烤使用天然气,是降低天然气消耗的重要手段。通过理论计算及工艺试验,证明低热值转炉煤气可以替代天然气进行工艺烘烤,保证用能设备内衬温度均衡、稳定。同时通过回收试验获得最佳的转炉煤气回收区间,提高转炉煤气回收水平,确保钢包、中间包、鱼雷罐等设备的转炉煤气烘烤用量需求,达到停用天然气烘烤的目的。燃气资源的梯级利用,有效降低了首秦公司天然气消耗水平,提高了转炉煤气回收利用率,降低了能源成本,减少了环境污染,对国内同类型钢铁企业燃气资源梯级利用具有一定的借鉴意义。     

I-35W Bridge Collapse

The I-35W bridge over the Mississippi River in Minneapolis, Minnesota, collapsed suddenly on August 1, 2007. This note briefly summarizes an analysis based on original design drawings, an investigation of material evidence provided by the National Transportation Safety Board (NTSB), and a full-scale load rating of the bridge superstructure. The results of the investigation and conclusions of the analysis include. (i) The thickness of gusset and the thickness of the side wall of the upper chords were designed proportional to the bending moment solution of a one-dimensional influence line analysis. This fact reveals that the NTSB-disclosed undersized gusset plates are the consequence of a bias toward a “one-dimensional model” in the original design that did not give sufficient consideration to the effects of the forces from diagonal truss members. (ii) Although the bridge’s truss-cell structure was appropriately designed, the design of the node that connected the floor members to the main truss-frame was inadequate to effectively distribute live and dead loads. Consequently, the local redundancy provided by the truss-cells was significantly reduced. (iii) A three-dimensional, nonlinear, finite-element, computation-based load rating indicates that some of the gusset plates had almost reached their yield limit when the bridge experienced the design load condition. The bridge was sustained by the additional safety margin provided by the ultimate strength of the ductile steel that comprised the gusset plates.