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System Performance | System Description | Case Study |
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System Performance
Velux Skylights with SageGlass are individual unit skylights that are installed and flashed into independent structural roof systems as specified by design. SageGlass provides the skylight’s Insulating Glass Unit (IGU) with electrochromic glass. Materials for architectural electrochromic uses must provide an optical response that enables high transmittance in the bleached state and high attenuation in the colored state. The coating is switched via a very low voltage (1-2 V). In its clear state the system performs as a transparent IGU (62% light transmission), and in its blue tinted state (3.5 % light transmission) the system minimizes solar gains, reduces glare and provides privacy while allowing visibility through it. The voltage is only needed during the coloration and bleaching processes. Switching speed (for ITO coated plastic) is 10 to 20 seconds to bleach, and 1 to 2 min to color (for a small piece). For a standard window, most of the tinting occurs in 3 to 5 minutes, depending on glass size and temperature of the glass. Faster tinting can occur in smaller panes and/or for warmer temperatures. For a more advanced lighting analysis and project specific results, we recommend using the Lightsolve program (under development).
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Performance data for all systems in the same category. Comparison to systems in other categories, selected through the matrix filtering process.
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| System Description
SageGlass first sputter-coats panes of float glass with multiple layers of all-ceramic thin films onto the #2 surface. The glass is then assembled into an industry-standard IGU and tested before being shipped to Velux, who manufactures the skylights with wood, metal, silicone and gaskets as is common in the fenestration industry. The glass unit is sealed into the skylight for durable weather tightness and connected to a power supply by a small low voltage wire either inside the venting electric skylights or separately with the fixed skylights. The coating changes from a clear state to a darkened state and back via either the control system or manually by the owner. Velux model VSE skylights with SageGlass are available in 6 standard sizes ranging from 21 ½” x 27 3/8” up to 44 ¾” x 46 ¼”, and require a minimum pitch of 15 degrees but may be installed on a flat roof via a contractor built curb that puts the skylights on at least a 15 degree pitch. Wind, UV radiation, temperature, humidity and resistance to chemical aggression affect the size of the device and the lifetime of the system. The expected energy savings come from reductions in cooling and electric lighting needs. |
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