PATH: Video-based assessment of advanced light redirecting components in windows and luminaires to optimize lighting in buildings

摘要提案编号0533269：对窗户和灯具中的先进光重定向组件进行基于视频的评估，以优化建筑物中的照明技术注意事项为了有效地控制房屋中的视觉舒适度并减少加热和冷却负荷，建筑物中照明的优化使用和分布仍然是先进开窗系统（例如新型太阳能百叶窗）的主要目标，新的玻璃或涂层材料和日光转向装置，以及节能灯具。它们的方向性光学特性由双向透射（或反射）分布函数（Bidirectional Transmission（or Reflection）Distribution Functions，简称BT（R）DF）描述，该函数表示给定入射方向的出射光通量分布，其准确评估需要适当的实验设备。为了满足这一需求，研究人员和她的同事们开发了一种新的测量设备，能够实现涂层或材料的真正高效的双向测量。这种创新的双向测角光度计，也可转换为全自动heliodon，用于比例模型的定性研究，收集半反射半椭圆体上分析组件发出的光通量，并将其重定向到配备鱼眼透镜的校准数码相机。因此，仅需要在不同积分间隔拍摄的一组图像来实现出射光分布的完整和连续的可视化，这与传统的逐点测角光度计相比是独特的特征。这项研究的其他主要创新是提供了一个波长依赖的调查，并在整个太阳光谱。将双向功能的适用性扩展到近红外光谱范围为管理和控制太阳能增益开辟了新的视角，并导致建筑物热质量位置的改进。日光照明，或更普遍的照明，不仅要充分满足我们对视觉舒适和健康环境的需求，而且还可以大大减少建筑物对环境的影响，因为它们占总能源使用量的三分之一，而今天40%的能源通常用于照明。精心规划的照明策略还可以通过增加冬季的太阳能增益和减少夏季的太阳能增益来显着减少住房的供暖和制冷需求。与此同时，许多科学研究已经证明了日光的可用性对人类生产力和福祉的强烈积极影响。为了回应设计更适合日光照明的建筑物的日益增长的动力，研究人员和她的同事开发了一种原创的，领先的和时间效率高的测量设备，用于研究光线在被先进的日光收集和重定向系统或灯具组件重定向或改变后在空间内的分布情况。该仪器依靠数字成像技术将测量时间减少到最低限度，同时提供整个太阳光谱的波长相关分析，将材料的研究扩展到太阳辐射的热方面。对于想要快速开发和优化其产品的制造商来说，获得这样的详细信息是至关重要的，对于建筑师来说，在项目的设计水平上明智地选择合适的窗户和照明组件是至关重要的，对于日光模拟工具开发人员来说，通过包括与热控制相关的先进光重定向系统来扩展此类软件的功能是至关重要的。尽管其结果的复杂性，评估过程仍然在这里快速和廉价，以有效地促进更健康和可持续的设计

ABSTRACTProposal No. 0533269 : Video-based assessment of advanced light redirecting components in windows and luminaires to optimize lighting in buildingsTechnical descriptionTo efficiently control visual comfort in housing and reduce heating and cooling loads, an optimized use and distribution of lighting in buildings remains a major objective for advanced fenestration systems such as novel solar blinds, new glazing or coating materials and daylight-redirecting devices, as well as for energy-efficient luminaires. Their directional optical properties are described by Bidirectional Transmission (or Reflection) Distribution Functions, abbreviated BT(R)DF, that express the emerging light flux distribution for a given incident direction.Their accurate assessment requires an appropriate experimental equipment. To answer this need, the investigator and her colleagues develop a new measurement device, able to achieve truly time-efficient bidirectional measurements of coatings or materials. This innovative bidirectional goniophotometer, also convertible into a fully automated heliodon for qualitative studies on scale models, collects the light flux emitted by the analyzed component on a half-mirrored hemi-ellipsoid and redirects it towards a calibrated digital camera equipped with a fish-eye lens. Only one set of images taken at different integration intervals is therefore needed to achieve a complete and continuous visualization of the emerging light distribution, which is a unique feature compared to conventional, point-per-point goniophotometers. The other major innovations of this research are to offer a wavelength-dependent investigation and to do this over the full solar spectrum. Extending the applicability of bidirectional functions to the near-IR spectral range opens new perspectives in managing and controlling solar gains, and leads to refinements in the location of the building's thermal mass. Non-technical descriptionDaylighting, or more generally lighting, not only has to adequately respond to our needs for visual comfort and for a healthy environment, it can also greatly contribute to reduce the environmental impact of buildings, considering that they represent about a third of the total energy use and that 40% of this energy today is generally dedicated to lighting. A carefully planned lighting strategy can also significantly reduce heating and cooling needs for housing by increasing solar gains in the winter and decreasing them in the summer. At the same time, numerous scientific studies have demonstrated the strongly positive impact of daylight availability on human productivity and well-being. To answer the consequential increasing incentive to design buildings more adapted to daylighting, the investigator and her colleagues develop an original, leading-edge and time-efficient measurement device for investigating how light is distributed inside a space after being redirected or altered by advanced daylight collection and redirecting systems or luminaires components. The instrument relies on digital imaging techniques to reduce the measurement time to a minimum, while offering a wavelength-dependent analysis over the whole solar spectrum to extend the materials' investigation to the thermal aspects of solar radiation. Having access to such a detailed information is critical for manufacturers that want to quickly develop and optimize their products, for architects to get guidelines in the judicious selection of the proper window and lighting components already at the project's design level, and for daylighting simulation tool developers to extend the capabilities of such software by including advanced light redirecting systems in connection with thermal control. Despite the complexity of its outcomes, the assessment process remains here rapid and cheap to efficiently promote more healthy and sustainable design