01681nas a2200157 4500008004100000050001500041245006800056210006700124260003600191520112500227100002501352700003401377700001401411700002401425856007401449 2001 eng d aLBNL-4754400aSimulating the Operation of Photosensor-Based Lighting Controls0 aSimulating the Operation of PhotosensorBased Lighting Controls aRio de Janeiro, Brazilc08/20013 a

Energy savings from the use of daylighting in commercial buildings are realized through implementation of photoelectric lighting controls that dim electric lights when sufficient daylight is available to provide adequate workplane illumination. The dimming level of electric lighting is based on the signal of a photosensor. Current simulation approaches for such systems are based on the questionable assumption that the signal of the photosensor is proportional to the task illuminance. This paper presents a method that simulates the performance of photosensor controls considering the acceptance angle, angular sensitivity, placement of the photosensor within a space, and color correction filter. The method is based on the multiplication of two fisheye images: one generated from the angular sensitivity of the photosensor and the other from a 180- or 360-degree fisheye image of the space as seen by the photosensor. The paper includes a detailed description of the method and its implementation, example applications, and validation results based on comparison with measurements in an actual office space.

1 aEhrlich, Charles, K.1 aPapamichael, Konstantinos, M.1 aLai, Judy1 aRevzan, Kenneth, L. uhttps://facades.lbl.gov/publications/simulating-operation-photosensor01591nas a2200121 4500008004100000050001500041245008200056210006900138490000700207520115900214100002501373856007101398 1997 eng d aLBNL-4001600aSimulating the Visual Performance of Electrochromic Glazing for Solar Control0 aSimulating the Visual Performance of Electrochromic Glazing for 0 v273 a

A new technology called electrochromic glazing promises to provide the building industry with a means to dynamically control the visual appearance and solar gain of windows. Electrochromic glazing is a technology which allows an otherwise ordinary looking piece of laminated glass to change tint with the application of a small electrical charge. Prototype electrochromic devices have been produced in sizes up to one square foot, however, manufacturers are several years away from producing glazing samples large enough to fill the aperture of a typical perimeter office. Tooling up for the production of large samples is prohibitively expensive unless some assurance of the marketability of these new electrochromic products can be demonstrated.

Electrochromic glazings defy traditional performance rating mechanisms because of the temporal dimension of their thermal and visual characteristics. Every electrochromic glazing assembly has an infinite number of states at which the thermal and visual appearance could be characterized. Furthermore, the rate at which the assembly changes between states is vital for a complete understanding.

1 aEhrlich, Charles, K. uhttps://facades.lbl.gov/publications/simulating-visual-performance