TY - JOUR T1 - End User Impacts of Automated Electrochromic Windows in a Pilot Retrofit Application JF - Energy and Buildings Y1 - 2012/04// SP - 267 EP - 284 A1 - Eleanor S. Lee A1 - Erin S. Claybaugh A1 - Marc LaFrance KW - buildings energy efficiency KW - control systems KW - daylighting KW - Electrochromic windows KW - Integrated systems KW - Intelligent buildings AB - Automated electrochromic (EC) windows, advanced thermally-improved window frames, and a dimmable lighting system were installed in a single, west-facing conference room in Washington DC. The EC windows were commercially-available, tungsten-oxide switchable devices, modulated automatically between either fully clear or fully tinted transparent states to control solar gains, daylight, and discomfort glare. Occupants were permitted to manually override the automated EC controls. The system was monitored over a 15-month period under normal occupied conditions. The last six months were used in the analysis. Manual override data were analyzed to assess the EC control system design and user satisfaction with EC operations. Energy and comfort were evaluated using both monitored data and simulations.Of the 328 meetings that occurred over the six month period, the automatic system was manually overridden on 14 or 4% of the meetings for reasons other than demonstration purposes. When overridden, occupants appeared to have switched the individual zones with deliberation, using a combination of clear and tinted zones and the interior Venetian blinds to produce the desired interior environment. Monitored weekday lighting energy savings were 91% compared to the existing lighting system, which was less efficient, had a higher illuminance setpoint, and no controls. Annual performance was estimated using EnergyPlus, where the existing condition met the ASHRAE 90.1-2007 prescriptive requirements except for a higher window U-value. Annual energy savings were 48% while peak demand savings were 35%. VL - 47 IS - April 2012 U2 - LBNL-6027E DO - 10.1016/j.enbuild.2011.12.003 ER - TY - JOUR T1 - Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems JF - Building and Environment Y1 - 2011/03// SP - 747 EP - 757 A1 - Byoung-Chul Park A1 - An-Seop Choi A1 - Jae-Weon Jeong A1 - Eleanor S. Lee KW - automated roller shade systems KW - daylight responsive dimming systems KW - daylighting KW - Integrated systems KW - photoelectric controls AB - 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. VL - 46 IS - 3 U1 -

Windows and Daylighting Group

U2 - LBNL-4418E DO - 10.1016/j.buildenv.2010.10.007 ER -