建筑复合开窗系统天然采光室内光环境分析方法研究

为了更有效、更快速、更精确地分析复合开窗系统(Complex Fenestration Systems,CFS)的天然采光室内光环境,本文介绍了利用双向分散分布模型(Bidirectional Scattering Distribution Function,BSDF)来模拟计算室内光环境的方法,并分析了针对不同复合开窗系统类型获得双向分散分布模型数据的3种方式。以最为复杂的微棱镜结构日光重定向系统为例,通过案例实际照度测量与模拟数据的对照分析了双向分散分布模型针对复合开窗系统天然采光模拟方法的可靠性,以及微棱镜结构日光重定向系统对天然采光室内照度均匀度与光环境质量的提升。     

高校教室天然光节能调控装置设计研究 ——以天津地区为例

为解决高校教室室内近窗处照度大、远窗处照度小的问题,通过设置天然光调控装置改变光线射入方向,以此调节室内光环境。并利用DIALux模拟软件对调控装置不同角度下室内照度分布情况进行了对比分析,从中得到了最佳的教室天然采光角度,使室内照度均匀度数值达到最高。在室内达到最佳视觉效果的同时减少了能源消耗,以期为高校建筑室内光环境节能设计提供基本方法和理论参考。     

不同光区大进深办公室室内采光与节能研究

基于ECOTECT软件,以不同光气候区大进深办公室为研究对象,在南向外窗设置水平百叶遮阳对室内光环境进行模拟,分析了不同的百叶间距对室内照度分布、照度均匀度的影响,并分析了基于天然采光的人工照明节能性。模拟结果表明:水平百叶外遮阳能改善室内的照度均匀度,提高室内光照舒适度。百叶间距增大,照度均匀度有所降低。不同光气候区天然采光结合人工照明电能节省率在30.1%~55.7%之间。     

北京天然光总照度变化趋势分析

基于北京连续54年太阳辐射数据,结合中国辐射光当量模型,获取北京天然光年总照度值和月总照度值。应用Mann—Kendall检验方法分析北京天然光年和月总照度值年际变化趋势,结果表明：北京天然光年总照度基本变化趋势为明显减少,且在1977年突变发生后其下降趋势明显增加;各月月总照度值基本年际变化趋势为明显减少,其中7月月总照度值下降幅度最大。11月月总照度值下降幅度最小;除5月在1967年发生突变外,其它月份的突变均发生在1975—1981年之间;各月天然光月总照度值年际变化在突变前为不明显波动变化趋势,突变后均为明显增加的下降趋势。云量及由大气污染所产生的气溶胶光学厚度是造成北京年与月总照度值持续下降的重要因素。     

基于纸窗的北京传统四合院天然光环境模拟溯源

为溯源北京传统四合院的天然光环境,本研究对窗纸材料进行了物理测量和模型实测校核,建立了典型的北京四合院模型,对正房和厢房的天然光进行了全年逐时动态模拟,并通过与玻璃的性能比较,梳理窗纸的光学意义。研究发现,相比玻璃窗而言,纸窗的光环境特点如下:(1)除提升了正房后墙面照度外,降低了地面、工作面、东西厢房后墙面等多数区域的照度,缩小了照度的季节性差异;(2)提高了照度均匀度;(3)除正房冬季远窗区外,降低了多数位置的眼部曝光量;(4)降低了东西厢房的眩光几率。     

整体式翅片管换热器的设计与校核计算

对比分析了应用在蒸汽压缩式制冷中的冷凝器与蒸发器的异同,针对不同形式的换热管使用Fluent模拟圆管、椭圆管和扁管的流场分布。针对不同的翅片形式的整体式翅片管建立仿真模型,并在3种不同的工况下进行实验,误差都在设计要求的范围之内,验证了所建程序满足工程精度要求。对所建模型进行不同的风速、蒸发器空气侧进口处气流分布和翅片管翅片的形式进行对比分析。     

双层玻璃幕墙运行模式的模拟与实验研究

采用建筑能耗模拟软件EnergyPlus对夏热冬冷地区自然通风双层玻璃幕墙在五种运行模式下的温度和气流速度进行模拟分析。为验证模型的准确性,对某双层玻璃幕墙实验房在全年不同运行模式下进行实验测试研究,并将实验数据与模拟结果进行对比验证,发现温度和气流速度的模拟结果吻合程度较好,模拟值与实测值的误差较小,模型可靠性较高。     

图书馆书架照明设计分析

通过对图书馆书架照明的水平面和垂直面照度进行计算分析，得出它们之间的关系式，并将垂直面照度值换算成水平面照度值。通过实地测量验证了此关系式，可供工程设计人员参考使用。     

汽车最小转弯直径测量计算模型的修正分析

针对目前汽车最小转弯直径测量方法和计算模型的不足,为提高测量精度,将测量时车身侧倾引起的误差考虑在内,提出侧倾位移误差的概念并对侧倾位移误差进行推导。对计算汽车最小转弯直径的数学模型进行修正,并通过MATLAB实验仿真的方法对修正模型进行验证。结果显示,修正后的计算模型明显减小了侧倾位移误差的影响,改善了汽车最小转弯直径测量的精度。     

PDC齿破岩仿真模型与全钻头实验研究

针对PDC全钻头设计方法单一和实验工作量大的问题,提出了一种PDC单齿切削力学计算模型,并通过有限元数值模拟对计算模型的结果进行对比,讨论了PDC切削齿前倾角、侧倾角、齿径及切深与切削力的关系。结果表明:PDC单齿力学计算模型与有限元模拟结果比较接近,验证了该模型的正确性。在单齿力学计算模型的基础上建立全钻头力学计算模型,并对PDC全钻头扭矩和钻压进行计算,结合有限元仿真和全钻头实验结果,将3种计算结果进行对比分析,结果显示当PDC全钻头破碎砂岩时,力学模型计算出的扭矩值与实验测试的误差为2.11%,与有限元模拟结果的误差为1.51%;而计算的钻压值与实验结果的误差为1.25%,与有限元模拟结果的误差为6.79%,同时,该钻头计算模型的计算效率也大大提高,说明了PDC全钻头力学计算模型的准确性和可行性,为PDC钻头的评价与设计提供了技术支持。     

A field study of illuminance reduction

Many offices are illuminated at levels much higher than necessary for office tasks. Lowering ambient illuminance, while maintaining task illuminance, i.e., task-ambient lighting, can save energy without impairing visual performance. A downside of task-ambient lighting is rooms appear dark and gloomy. Maintaining brightness perception is the key to success in task-ambient lighting. To examine the practicality of brightness-enhanced task-ambient lighting for illuminance reduction a field study was conducted in a modern office setting. This study examined office workers’ responses to approximately one-third lower ambient illuminance than the initial illuminance and two measures designed to enhance brightness perception: higher correlated color temperature lamps (6500 K) and sparkle elements. Surveys showed that after an initial adaptation period, office workers were generally satisfied with the lower level of ambient lighting. They did increase their use of task lighting at their desks but this had little impact on overall energy consumption. The 6500 K lamp was effective at increasing perceptions of brightness in offices with the lower ambient light level. Over a longer period, the sparkle elements used did not significantly change workers’ perceptions of gloom.     

A design tool for predicting the performances of light pipes

Light pipes are simple means of directing daylight (diffuse and direct light) into interior spaces. Previous work by the authors described the initial work on a luminous flux and illuminance predictive model for straight light pipes, using a basic equation for illuminance distribution as a function of horizontal distance. Further work has now produced a model that uses the cosine law of illuminance to describe the distribution of light from the light pipe diffuser as well as takes into account pipe elbow pieces or bends. The resulting illuminance model can be described as a quartic cosine model. By producing a “luxplot” prediction for any given light pipe application, it is possible to maximise the potential of these daylight providers and design their configuration to suit any given need. As part of this study, wide-ranging illuminance and luminous flux data were collected both for the formulation of this model (as the formula is semi-empirical) and its validation.     

Optimal sun-shading design for enhanced daylight illumination of subtropical classrooms

This study investigates the feasibility of fitting windows with sun-shadings in order to minimize the lighting power costs in daylight-illuminated classrooms lit from a single side in subtropical regions. An IES-CPC model is created of a representative classroom in Taiwan, and a series of simulations is performed to determine the average illuminance value and the uniformity of the illuminance distribution in the classroom under various lighting conditions with no sun-shadings fitted to the window. The numerical results are found to be in good agreement with the experimental measurements obtained using an array of nine-channel photometers. Having confirmed the validity of the simulation scheme, the illumination properties of four different sun-shading designs are considered. The results show that a double-layered sun-shading represents the optimal sun-shading design in terms of achieving a uniform illumination distribution within the classroom. Given appropriate physical dimensions, this daylight access device achieves the minimum illuminance requirement of 500 lx and improves the lighting uniformity ratio from 0.25–0.35 to 0.40–0.42. Furthermore, using this sun-shading device, the required illuminance ratio of 0.5 can be obtained simply by switching on one of the three rows of lights in the classroom. Accordingly, the daylight access device not only improves the illuminance conditions within the classroom, but also reduces the lighting power cost by 71.5% compared to the case where all of the lights are turned on.     

Sky model blends for predicting internal illuminance: a comparison founded on the BRE-IDMP dataset

The BRE-IDMP validation dataset contains simultaneous measurements of sky luminance patterns and internal illuminances in two full-size office spaces. This benchmark dataset has been applied previously to test the illuminance predictions from a lighting simulation program under real sky conditions. Sky luminance patterns were mapped into the lighting simulation so that the absolute accuracy of the program could be evaluated without the uncertainties that are introduced when sky models are used. For this follow-on study, the BRE-IDMP dataset is now used to quantify the divergence between the sky model generated luminance patterns and the actually occurring conditions based on the resulting internal daylight illuminances. The internal illuminances were predicted using three ‘narrow-range’ models (CIE overcast, CIE clear and intermediate) and the Perez All-Weather model. Predictions from the narrow-range models were used to investigate formulations for sky model blends. The illuminance effect of arbitrary sky model blends is reproduced in a post-process of the illuminance predictions from the ‘narrow-range’ sky model types. The determination of an optimum sky model blend is described. The findings show that relatively simple blends of just two pure sky models (e.g. CIE overcast and intermediate) may be adequate for the prediction of time-varying illuminances founded on climatic test reference year data.     

办公建筑的照度测量及分析

针对某些建筑后期装修与前期照明设计差异很大的问题,笔者通过对某办公建筑的两个典型房间进行实例照度分析,在对照度值和照明功率密度的对比分析中找出后期装修中存在的问题,并提出相应的对策.以期达到合理进行照度装修设计,节约能源的目的.     

Using field measurements of desktop illuminance in European offices to investigate its dependence on outdoor conditions and its effect on occupant satisfaction,and the use of lights and blinds

Adequate indoor illuminance is accepted as one important determinant of conditions for comfort and productivity in offices. This paper uses the results of field surveys in 26 offices in five European countries (France, Greece, Portugal, Sweden and the UK) to investigate what illuminance levels are actually achieved on office desks, what light level is considered ‘best’ by occupants, and how this is affected by outdoor sky conditions and illuminance. The paper also explores how blinds and lights are used by occupants to modify light levels at their desks. The office workers show a remarkable degree of adaptation to different light intensities. They use controls to modify the light level at their desks to almost the same mean level irrespective of the sky conditions outside. There is a small but significant effect of lighting on self-reported productivity which seems to be higher when offices are daylit.     

Applicability of daylighting computer modeling in real case studies: comparison between measured and simulated daylight availability and lighting consumption

The objective of this work is to investigate the accuracy of the Adeline lighting software in simulating the illuminance distribution from daylighting and the electrical lighting consumption of an existing atrium building. The case study is an enclosed atrium space equipped with an automatic on/off lighting control system and roofed by a skylight made of several glazing systems. Field monitoring of the atrium space was conducted during summer and winter and included measurements of horizontal indoor and outdoor illuminance, solar radiation and electrical lighting system time-of-use. The computer simulation included the creation of one simple and one complex computer model used to simulate the daylighting performance of the atrium space. The software accuracy was evaluated based on comparisons between the predicted and the on-site measured illuminance distribution and lighting energy consumption.     

Artificial neural networks to predict daylight illuminance in office buildings

A prediction model was developed to determine daylight illuminance for the office buildings by using artificial neural networks (ANNs). Illuminance data were collected for 3 months by applying a field measuring method. Utilizing weather data from the local weather station and building parameters from the architectural drawings, a three-layer ANN model of feed-forward type (with one output node) was constructed. Two variables for time (date, hour), 5 weather determinants (outdoor temperature, solar radiation, humidity, UV index and UV dose) and 6 building parameters (distance to windows, number of windows, orientation of rooms, floor identification, room dimensions and point identification) were considered as input variables. Illuminance was used as the output variable. In ANN modeling, the data were divided into two groups; the first 80 of these data sets were used for training and the remaining 20 for testing. Microsoft Excel Solver used simplex optimization method for the optimal weights. The model's performance was then measured by using the illuminance percentage error. As the prediction power of the model was almost 98%, predicted data had close matches with the measured data. The prediction results were successful within the sample measurements. The model was then subjected to sensitivity analysis to determine the relationship between the input and output variables. NeuroSolutions Software by NeuroDimensions Inc., was adopted for this application. Researchers and designers will benefit from this model in daylighting performance assessment of buildings by making predictions and comparisons and in the daylighting design process by determining illuminance.     

气凝胶玻璃在东北地区建筑应用的采光及能耗模拟研究

采用Ecotect Analysis 2015和DeST软件,探究气凝胶玻璃作为围护结构对东北地区建筑的采光及建筑能耗的影响,模拟地址选取沈阳,模拟时间为1年,模拟模型为普通二层办公建筑。结果显示,光学性能方面,气凝胶玻璃应用后的可见光照度均能达到标准最低要求495lx,室内最低也达到540lx,天棚玻璃光线直射处的可见光照度降低了1419.3lx,避免了眩光;热学性能方面,相较于同样厚度的传统中空玻璃系统,使用气凝胶玻璃模拟的室内全年冷负荷量降低了10.65个百分点。研究发现,气凝胶玻璃作为建筑外围护结构时,可保证建筑应有的采光效果,在提高采光舒适度的前提下还能有效降低建筑能耗。     

Occupant preferences and satisfaction with the luminous environment and control systems in daylit offices: a literature review

This paper presents an overview of peer-reviewed investigations of subjective issues linked to the use of daylighting in office buildings, particularly studies of preferred physical and luminous conditions in daylit office environments, and studies of occupant satisfaction and acceptance of electric lighting and window shading controls. The literature shows a consistent strong preference for daylight and a wide distribution between individuals in relation to the preferred illuminance levels in daylit offices. Existing knowledge about how people respond to daylight-linked lighting and shading controls in the workplace is very limited; therefore, this paper presents a summary of knowledge gaps in the field of daylighting and its interaction with the occupants. The resulting key directions for future research highlight issues for which a better understanding is required for the development of lighting and window shading control systems that are both energy efficient and suitable for the office occupants.