Towards sustainable smart window design: Life cycle assessment of innovative electrochromic devices

Among window design innovations, electrochromic (EC) devices are gaining popularity due to their capacity to dynamically manage daylight and solar energy accessing buildings. An advanced EC window technology dynamically modulates transparency while controlling infrared solar heat gains. This study examined the production phase of a new solid-state, low-emissive EC device to assess whether its production phase performance comes at acceptable environmental performance burdens. A cradle-to-gate energy and emissions (environmental profile) comparison was conducted between a new solid-state EC (NEW_EC), developed by some of the authors, and a reference commercial EC device (REF_EC). The inventory was created using input from the Ecoinvent database in OpenLCA software with the Ecoinvent 3 database to evaluate multiple environmental impact categories including Global Warming Potential (GWP), Cumulative Energy Demand (CED), and ReCiPe indicators. Results demonstrate significant environmental improvements with the NEW_EC design, including a 26% reduction in CED (34.65 MJ-eq versus 46.24 MJ-eq), 24.9% decrease in GWP (2.44 kg CO 2 -eq versus 3.25 kg CO 2 -eq), and substantial reductions across ReCiPe impact categories (25% for human health, 27% for ecosystem quality, and 29% for resource depletion). Material composition analysis revealed that the elimination of lithium perchloride which contributed to 51% of GWP and 69% of human health impacts in the REF_EC device and the reduction to a single glass panel were primary drivers of improved environmental performance. The simplified architecture of the NEW_EC device, fabricated at room temperature with a single-substrate design, offers both functional and environmental advantages.