Daylight performance of a microstructured prismatic window film in deep open plan offices

Journal Article · Thu Jul 28 00:00:00 EDT 2016 · Building and Environment

DOI:https://doi.org/10.1016/j.buildenv.2016.07.019· OSTI ID:1436149

McNeil, Andrew ^[1]; Lee, Eleanor S. ^[1]; Jonsson, Jacob C. ^[1]

---

1. Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Building Technologies and Urban Systems Division and Energy Technologies Area

Daylight redirecting systems with vertical windows have the potential to offset lighting energy use in deep perimeter zones. Here, a microstructured prismatic film designed for such use was characterized using goniophotometric measurements and ray tracing simulations. The synthetically-generated bidirectional scattering distribution function (BSDF) data were shown to have good agreement with limited measured data for normal incident angles (0–60°). Measured data indicated that the prismatic film was most efficient when vertical angles of incidence were between 18 and 35° and within ±45° of normal incidence to the plane of the window so maximum energy savings across the full depth of the zone occurred over the equinox to winter solstice period. Annual lighting energy use and visual comfort in a deep open plan office zone were evaluated using the Radiance three-phase method in several climates and for south and east-facing window orientations. Lighting energy savings were 39–43% for a 12 m (40 ft) deep south-facing perimeter zone compared to the same zone with no lighting controls. The prismatic film with and without a diffuser controlled glare for views parallel to the window but produced glare for seated viewpoints looking toward the window. At mature market costs, the system was projected to have a simple payback of 2–6 years. Technical challenges encountered throughout the evaluation led to improvements in measurement and modeling tools and stressed the importance of having accurate input data for product development.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office; 3M Renewable Energy Division, St. Paul, MN (United States); California Energy Commission
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1436149
• Alternate ID(s): OSTI ID: 1397731
• Journal Information: Building and Environment, Vol. 113, Issue C; ISSN 0360-1323
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
29 ENERGY PLANNING, POLICY, AND ECONOMY
Daylighting
Prismatic film
Microstructured film
Bidirectional scattering distribution function
Complex fenestration systems