@article {12172, title = {Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems}, journal = {Building and Environment}, volume = {46}, year = {2011}, month = {03/2011}, pages = {747-757}, chapter = {747}, abstract = {

Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90\% of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system.

}, keywords = {automated roller shade systems, daylight responsive dimming systems, daylighting, Integrated systems, photoelectric controls}, doi = {10.1016/j.buildenv.2010.10.007}, author = {Byoung-Chul Park and An-Seop Choi and Jae-Weon Jeong and Eleanor S. Lee} } @article {58228, title = {Field Measurements of Innovative Indoor Shading Systems in a Full-Scale Office Testbed}, journal = {ASHRAE Transactions}, volume = {115}, year = {2009}, month = {10/2009}, pages = {706-728}, chapter = {706}, abstract = {

The development of spectrally selective low-e glass with its superior solar control and high daylight admission has led to widespread use of large-area, "transparent" or visually clear glass windows in commercial building facades. This type of fa{\c c}ade can provide significant inherent daylighting potential (ability to offset lighting energy use) and move us closer to the goal of achieving zero energy buildings, if not for the unmitigated glare that results from the unshaded glazing. Conventional shading systems result in a significant loss of daylight and view. Can innovative shading solutions successfully balance the tradeoffs between daylight, solar heat gains, discomfort glare, and view?

To investigate this issue, a six-month solstice-to-solstice field study was conducted in a sunny climate to measure the thermal and daylighting performance of a south-facing, full- scale, office testbed with large-area windows and a variety of innovative indoor shading systems. Indoor shading systems included manually-operated and automated roller shades, Venetian blinds, daylight-redirecting blinds, and a static translucent diffusing panel placed inboard of the window glazing. These innovative systems were compared to a reference shade lowered to block direct sun.

With continuous dimming controls, all shading systems yielded lighting energy savings between 43-69\% compared to a non-dimming case, but only the automated systems were able to meet visual comfort criteria throughout the entire monitored period. Cooling loads due to solar and thermal loads from the window were increased by 2-10\% while peak cooling loads were decreased by up to 14\%. The results from this experiment illustrate that some indoor shading systems can preserve daylight potential while meeting comfort requirements. Trends will differ significantly depending on application.

}, author = {Eleanor S. Lee and Dennis L. DiBartolomeo and Joseph H. Klems and Robert D. Clear and Kyle S. Konis and Mehry Yazdanian and Byoung-Chul Park} }