A simplified method for modelling the effect of blinds on window thermal performance

An approximate method is presented for predicting the effect of a louvered blind on the centre‐glass thermal performance of a fenestration. The method combines a one‐dimensional heat transfer model with data from a numerical simulation of the window and blind. Sample results for a blind mounted on the indoor surface of a window show the effect of blind slat angle on heat transmission. Both summer and winter conditions are considered. The results show that a louvered blind can improve the U‐value of a standard double‐glazed window by up to 37%. Also, the radiation heat exchange with the room can be dramatically reduced (by up to 60%), which will improve the level of occupant comfort. However, there was found to be a trade‐off between U‐value and occupant comfort; placing the blind closer to the window improves the U‐value, but increases the radiation heat exchange with the room. The predictions from the present simplified method compare well with results from a full two‐dimensional computational fluid dynamics solution of the conjugate blind/window interaction. Copyright © 2005 John Wiley & Sons, Ltd.     

Adaptive actions on shading devices in response to local visual stimuli

Based on 6 years of continuous measurements, we have analysed in detail the occupancy, thermal and visual parameters influencing actions on shading devices in order to derive an accurate model for the prediction of their usage in office buildings. This article begins by presenting some of the key findings from these analyses. Informed by other developments in the literature, we go on to propose an approach for a comprehensive stochastic model for simulating blind usage. This model is based on a Markov process taking rigorously selected predictors (initial blind status, indoor and outdoor illuminance) as input variables to predict lowering and raising actions performed by occupants. A separate sub-model then predicts the chosen shaded fraction. An assessment of the predictive accuracy of simulations is then presented for several modelling variants using our measured data, from which the best performing model variant is selected.     

Efficient calculation of daylight coefficients for rooms with dissimilar complex fenestration systems

The daylight coefficient (DC) method is a powerful and efficient method to perform annual daylight illuminance simulation. A set of coefficients are calculated for a given room space and static fenestration systems prior to simulation start. Time series of indoor daylight illuminances are obtained by only knowing the sky luminance. However, for rooms with dissimilar dynamic complex fenestration systems (such as windows with movable shadings) whose optical behaviour (transmission, reflection and scattering) may change during simulation, the efficiency of the DC method may be compromised as another whole set of coefficients must be re-calculated. This study presents the development of a new methodology to compute the DC set for rooms with dissimilar complex fenestration components only once prior to simulation start. A validation study is carried out, in which the daylight illuminances in an office space equipped with a clear window and internal Venetian blinds are compared using predictions from the present model, the Radiance program, as a benchmark model employing detailed optical model of Venetian blinds, and the Daysim program employing a simple engineering blinds model. Findings from the validation study show that the present model yields overall accurate results when compared with the benchmark model for any window orientation, although some local illuminance differences are observed in areas under direct sunlight exposure.     

外火箱矩形竖窑进火孔的改进与施工

介绍了外火箱矩形竖窑进火孔改造前的使用情况以及改造的必要性 ;阐述了进火孔改造的设计施工和试验情况 ,并在 15 0 0～ 16 0 0℃时对物料的烧结作了成功的尝试 ,解决了因进火孔堵塞影响窑炉寿命和产品质量的问题。     

Bi-directional transmission properties of Venetian blinds: experimental assessment compared to ray-tracing calculations

An accurate evaluation of daylight distribution through advanced fenestration systems (complex glazing, solar shading systems) requires the knowledge of their Bidirectional light Transmission (Reflection) Distribution Function BT(R)DF. An innovative equipment for the experimental assessment of these bi-directional functions has been developed, based on a digital imaging detection system. An extensive set of BTDF measurements was performed with this goniophotometer on Venetian blinds presenting curved slats with a mirror coating on the upper side.In this paper, the measured data are compared with ray-tracing results achieved with a virtual copy of the device, that was constructed with a commercial ray-tracing software. The model of the blind was created by implementing the measured reflection properties of the slats coatings in the ray-tracing calculations. These comparisons represent an original and objective validation methodology for detailed bi-directional properties for a complex system; the good agreement between the two methods, yet presenting very different parameters and assessment methodologies, places reliance both on the digital-imaging detection system and calibration, and on the potentiality of a flexible calculation method combining ray-tracing simulations with simple components measurements.     

Impact of window blinds on daylight-linked dimming and automatic on/off lighting controls

This paper presents the field-measured performance of two commercial photocontrolled lighting systems, continuous dimming and automatic on/off, as a function of various configurations of manual and photocontrolled automatic venetian blinds. The performance indicators considered were the space illumination and the electric lighting consumption as a function of blind slat angle and retraction area. The results showed that under clear sky and without blinds both lighting control systems reduced the lighting energy consumption on average by 50–60% when compared to lights fully on from 6 AM to 6 PM. These savings, however, dropped by 5–45% for the dimming system, and by 5–80% for the automatic on/off system with the introduction of various static window blind configurations. The savings in lighting energy were more significant when the lighting control systems were used with photocontrolled blinds. This was due to the capability of the blinds to adjust their position automatically in direct response to the variable daylight levels.     

在棉型织机上生产粘/涤仿毛织物的生产实践

介绍了以棉型粘胶与涤纶为原料,在棉型织机上生产粘,涤混纺仿毛织物的生产技术。以涤粘直贡缎为例,着重讨论了织造生产过程中存在的问题及解决方法,给出了织造工艺参数及关键技术措施。     

Control of visual conditions for open-plan offices

This paper reports insights about energy savings in buildings dedicated to tertiary activity. The goal is to employ as much as possible natural light flows to minimize the artificial light source consumption. Although the solar energy is power-efficient to light and heat a room, this natural source remains complex to manage and can generate inconveniences related to occupants visual comfort. The authors propose a global solution to deal with visual comfort by controlling the daylight contribution to the indoor light atmosphere. This control structure is based on the use of an innovative sensor of light conditions and it was implemented within an experimental room equipped with classic Venetian blinds. This paper focuses on the control laws to apply in order to meet visual needs for current tasks performed in offices.     

南京地区活动式建筑外遮阳设施对室内热环境影响

针对活动式铝合金的外遮阳百叶帘和卷帘,对夏季和过渡季节南京地区建筑室内的热环境的影响进行了计算和分析研究,指出在该地区两种活动式建筑外遮阳设施在夏季能有效改善空调房间室内热环境,但对过渡季节自然通风房间室内热环境的影响正相反。     

CNC冲床上的百叶窗精密模具设计与制造

介绍了CNC冲床结构特点，阐述CNC冲床模具结构设计与制造工艺特点，特别是数控冲床的成形模具结构要求合理、简单。模具材料的选择及热处理工艺要求正确。上下模刃口间隙要合理，针对典型的百叶窗模具给出了一种实用的高效率的模具结构设计及其制造工艺。