Delafield, Wis.-based Envelop LLC announced it was issued United States patent No. 8,910,453, titled “Vacuum Insulated Glass Units System.”

According to a release from Envelop, glass curtainwall vacuum systems covered by the patent comprise “large structural vacuum insulated glass (VIG) units that are connected by tubing to each other and to a pumping station that establishes and maintains service vacuum pressures within a façade by removing the gas load from permeation and outgassing.”

“These types of façades can have area weighted average façade U-values as low as 0.23 W/m2K or 0.04 Btu/hr °F ft2 with a window-to-wall ratio of 100 percent, accompanied by very long service lives,” says Robert Jones, managing member of Envelop. “At these U-values, net-zero energy buildings with all glass façades become practical in climates with a high number of heating degree days. The technology stands out not just because of its high thermal, mechanical, and structural performance but also because of its feasibility.”