Daylighting design is the controlled admission of natural light into a building to reduce the need for artificial lighting and save energy, balanced with the need to optimize user comfort by mitigating glare and direct sunlight. Diffuse daylight allows for maximum productive usage of the building floor plate, since there are no “hot spots” or areas of discomfort at the perimeter.
Panelite’s proprietary ClearShade™ technology is an “angular selective” technology that redirects light rays, providing high diffuse light transmission while reflecting direct solar rays from entering the building.
This ray redirection technology provides two critical advantages:
- MORE LIGHT. ClearShade™ provides up to 70% light transmission depending on the insert and glass types specified; few energy performance glazing solutions maintain such high levels of natural daylight while controlling solar heat.
- BETTER LIGHT. ClearShade diffuses light rays, eliminating glare and improving user comfort and productivity.
An MIT daylighting lab study shows ClearShade light diffusion (center) vs. glare from a transparent IGU (left).
WHAT IS ANGULAR SELECTIVE GLAZING?
ClearShade™ is an angular selective technology whose honeycomb structure performs like a series of very small louvers, but in cellular rather than linear form. This structure combined with a proprietary polymer composition provides the unique advantage of dynamic performance – increased solar heat protection at peak hours – without the dramatic reduction invisible light that occurs with other dynamic technologies such as switchable glass.
ANGULAR SELECTIVE GLAZING vs. LOW-E ONLY vs. DYNAMIC GLAZING
Angular selective glazings are designed to attenuate direct solar radiation, the main source of solar heat gains and glare, while transmitting a significant amount of diffuse skylight.
Glazings that use low-e films to achieve solar heat control often do so at the expense of visible light, and this performance is static throughout the day, blocking daylight even when the sun is not at its peak.
Dynamic glazings vary over the course of the day to reduce solar heat at peak hours. Technologies such as electro-chromic glass do this by darkening to nearly opaque, blocking both visible light and solar heat.
ClearShadeTM is an angular selective technology whose patented honeycomb structure and polymer composition ensure consistent, diffuse daylight throughout the day and the highest level of solar heat control at peak hours.
ClearShade™ is now integrated with Lawrence Berkeley National Lab (LBNL)/Dept. of Energy’s Window 7, Energy Plus and Radiance software for DAYLIGHTING and ENERGY ANALYSIS of ANGULAR SELECTIVE glazing solutions.
For more, see our TECH FOCUS on Performance Analysis and integration with Lawrence Berkeley National Laboratory’s suite of analysis tools.
A FIELD STUDY OF CLEARSHADE SKYLIGHTS AT THE PARRISH ART MUSEUM
- Energy-savings of 89%
- Museum quality daylight
Panelite ClearShade™ skylight glazing was specified by architects Herzog & de Meuron and daylighting engineers ARUP to achieve their goal of providing a naturally daylight environment, similar to that of artists’ studios, for viewing the collection at the Parrish Art Museum in Water Mill, New York.
NYSERDA (NY State Energy and Research Development Authority) funded a research project to evaluate the potential energy savings for New York State of ClearShade honeycomb glazing technology. Under the grant, Lighting Research Center at Rensselaer Polytechnic Institute conducted a field study of ClearShade skylights at the Parrish Art Museum by Herzog & de Meuron Architects.
- 81% of the time the museum was open in spring, electric lights were not needed. The remainder of the time electric lights were dimmed from full output. Compared to the museum’s allowable power density, the skylights and use of lighting controls saved 89% in lighting energy.
- Energy savings also resulted in reduced air pollution: 4.6 lbs of SO2, 5.2 lbs of NOx, and 6,219 lbs of CO2.
- 73% of visitors considered the illumination of the Parrish galleries to be better than other museums.