@article {3185, title = {Discomfort Glare: What Do We Actually Know?}, journal = {Lighting Research and Technology}, volume = {April 2012}, year = {2012}, month = {05/2012}, abstract = {

Glare models were reviewed with an eye for missing conditions or inconsistencies. We found ambiguities as to when to use small source versus large source models, and as to what constitutes a glare source in a complex scene. We also found surprisingly little information validating the assumed independence of the factors driving glare.

A barrier to progress in glare research is the lack of a standardized dependent measure of glare. We inverted the glare models to predict luminance, and compared model predictions against the 1949 Luckiesh \& Guth data that form the basis of many of them. The models perform surprisingly poorly, particularly with regards to the luminance-size relationship and additivity. Evaluating glare in complex scenes may require fundamental changes to form of the glare models.

}, doi = {10.1177/1477153512444527}, author = {Robert D. Clear} } @techreport {58303, title = {Daylighting the New York Times Headquarters Building: Final Report: Commissioning Daylighting Systems and Estimation of Demand Response}, year = {2007}, month = {08/2007}, address = {Berkeley}, abstract = {

The technical energy-savings potential for smart integrated window-daylighting systems is excellent and can yield significant reductions in US commercial building energy use if adopted by a significant percentage of the market. However, conventional automated shades and daylighting controls have been commercially available for over two decades with less than 1-2\% market penetration in the US. As with many innovations, the problem with accelerating market adoption is one of demonstrating real performance and decreasing risk and cost. The New York Times considered use of such daylighting systems for their new 139,426 m2 (1.5 Mft2) headquarters building in downtown Manhattan.

In the initial phase of work, The New York Times employed a unique approach to create a competitive marketplace for daylighting systems and to address their concerns about risk by building a full-scale daylighting mockup and evaluating commercially-available products. This field test formed the strategic cornerstone for accelerating an industry response to the building owners{\textquoteright} challenge to a sleepy market. A procurement specification was produced and bids were received that met The Times cost-effective criteria. The Times decided to proceed with using these innovative systems in their new building.

This next phase of work consisted of two distinct tasks: 1) to develop and use commissioning tools and procedures to insure that the automated shade and daylighting control systems operate as intended prior to occupancy; and 2) to estimate the peak demand savings resulting from different levels of demand response (DR) control strategies (from moderate to severe load curtailment) and then determine the financial implications given various DR programs offered by the local utility and New York Independent System Operator in the area.

Commissioning daylighting control systems is mandatory to insure that design intent is met, that the systems are tuned to optimal performance, and to eliminate problems and errors before occupants move in. Commissioning tools were developed and procedures were defined and then used to verify that the daylighting systems operated according to the technical specifications. For both lighting control and shading systems, the Times and the manufacturers were able to resolve most of the bugs and fine-tune the systems prior to occupancy.

The demand response (DR) strategies at the New York Times building involve unique state-of-the-art systems with dimmable ballasts, movable shades on the glass facade, and underfloor air HVAC. The process to develop the demand response strategies, the results of the EnergyPlus model, the activities to implement the DR strategies in the controls design at the New York Times Headquarters building and the evaluation of economics of participating in DR programs are presented and discussed. The DR simulation iv efforts for this building design are novel, with an innovative building owner evaluating DR and future DR program participation strategies during the design and construction phase using advanced simulation tools.

}, keywords = {automated daylighting controls, automated window shades, daylighting, demand response, energy-efficiency, visual comfort}, author = {Eleanor S. Lee and Glenn D. Hughes and Robert D. Clear and Luis L. Fernandes and Sila Kiliccote and Mary Ann Piette and Francis M. Rubinstein and Stephen E. Selkowitz} } @techreport {1264, title = {A Design Guide for Early-Market Electrochromic Windows}, year = {2006}, abstract = {

Switchable variable-tint electrochromic windows preserve the view out while modulating transmitted light, glare, and solar heat gains and can reduce energy use and peak demand. To provide designers objective information on the risks and benefits of this technology, this study offers data from simulations, laboratory tests, and a 2.5-year field test of prototype large-area electrochromic windows evaluated under outdoor sun and sky conditions. The study characterized the prototypes in terms of transmittance range, coloring uniformity, switching speed, and control accuracy. It also integrated the windows with a daylighting control system and then used sensors and algorithms to balance energy efficiency and visual comfort, demonstrating the importance of intelligent design and control strategies to provide the best performance. Compared to an efficient low-e window with the same daylighting control system, the electrochromic window showed annual peak cooling load reductions from control of solar heat gains of 19-26\% and lighting energy use savings of 48-67\% when controlled for visual comfort. Subjects strongly preferred the electrochromic window over the reference window, with preferences related to perceived reductions in glare, reflections on the computer monitor, and window luminance. The EC windows provide provided the benefit of greater access to view year-round. Though not definitive, findings can be of great value to building professionals.

}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Robert D. Clear and Dennis L. DiBartolomeo and Joseph H. Klems and Luis L. Fernandes and Gregory J. Ward and Vorapat Inkarojrit and Mehry Yazdanian} } @techreport {58284, title = {Daylighting the New York Times Headquarters Building: Final Report}, year = {2005}, month = {06/2005}, abstract = {

The technical energy-savings potential for smart integrated window-daylighting systems is excellent and can yield significant reductions in US commercial building energy use if adopted by a significant percentage of the market. However, conventional automated shades and daylighting controls have been commercially available for over two decades with less than 1-2\% market penetration in the US. As with all innovations, the problem with accelerating market adoption is one of decreasing risk. As the building owner researches technology options, the usual questions surface that concern the purchase of any new product: how will it work for my application, are the vendor claims valid, what risks are incurred, and will the performance benefits be sustained over the life of the installation? In their effort to create an environment that "enhances the way we work" in their new 139 km2 (1.5 Mft2) headquarters building in downtown Manhattan, The New York Times employed a unique approach to create a competitive marketplace for daylighting systems. A monitored field test formed the strategic cornerstone for accelerating an industry response to the building owners{\textquoteright} challenge to a sleepy market (i.e., US automated shading and daylighting control products have had few major technical advances over the past 10 years). Energy, control system, and environmental quality performance of commercially-available automated roller shade and daylighting control systems were evaluated. Procurement specifications were produced. Bids were received that met The Times cost-effective criteria. The Times will proceed with the use of these systems in their final building. Competitively-priced new products have been developed as a result of this research and are now available on the market.

}, keywords = {automated daylighting controls, automated window shades, daylighting, energy-efficiency, visual comfort}, author = {Eleanor S. Lee and Stephen E. Selkowitz and Glenn D. Hughes and Robert D. Clear and Gregory J. Ward and John Mardaljevic and Judy Lai and Mehlika Inanici and Vorapat Inkarojrit} } @conference {11745, title = {Development of Trade-Off Equations for EnergyStar Windows}, booktitle = {SimBuild 2004}, year = {2004}, month = {08/2004}, address = {Boulder, CO}, abstract = {

The authors explore the feasibility of adding a performance option to DOE{\textquoteright}s EnergyStar{\textcopyright} Windows program whereby windows of differing U-factors and SHGCs can qualify so long as they have equivalent annual energy performance. An iterative simulation procedure is used to calculate trade-off equations giving the change in SHGC needed to compensate for a change in U-factor. Of the four EnergyStar{\textcopyright} Window climate zones, trade-off equations are possible only in the Northern and Southern zones. In the North/Central and South/Central zones, equations are not possible either because of large intrazone climate variations or the current SHGC requirements are already near optimum.

}, author = {Yu Joe Huang and Robin Mitchell and Stephen E. Selkowitz and Dariush K. Arasteh and Robert D. Clear} } @conference {11671, title = {A Database of Window Annual Energy Use in Typical North American Residences}, booktitle = {2000 ASHRAE Winter Meeting}, year = {1999}, month = {02/2000}, address = {Dallas, Texas}, abstract = {

This paper documents efforts by the National Fenestration Rating Council to develop a database on annual energy impacts of windows in a typical new, single family, single story residence in various U.S. and Canadian climates. The result is a database of space heating and space cooling energies for 14 typical windows in 52 North American climates. (Future efforts will address the effects of skylights.) This paper describes how this database was created, documents the assumptions used in creating this database, elaborates on assumptions, which need further research, examines the results, and describes the possible uses of the database.

}, author = {Dariush K. Arasteh and Yu Joe Huang and Robin Mitchell and Robert D. Clear and Christian Kohler} }