Get the light & keep the warmth - A highly insulating, translucent aerogel glass brick for building envelopes

Silica aerogels are thermal superinsulation materials that have found increasing application in the building sector in the last ten to fifteen years. While the most common material types are opaque insulating blankets and renders, in its monolithic form silica aerogel can be almost transparent, allowing for composite translucent insulating building system. Here, we developed and characterized a novel modular, translucent and thermally insulating building component based on silica aerogel granules, the aerogel glass brick. Both thermal and mechanical properties were tested and the former were compared to a 3D simulation of the heat transfer through the brick. The glass brick has a measured thermal conductivity of 53 mW/(m·K), corresponding well to the simulation results of 51 mW/(m·K), and a compressive strength of almost 45 MPa. This makes the glass brick the insulating brick with the highest insulation performance reported in literature or available on the market, and at the same time adds the feature of light transmission. The aerogel glass brick is suitable when the requirements combine daylighting, glare protection and the need to protect privacy, e.g. offices, libraries, museums; an analysis of the materials costs indicates that the insulating glass brick can be competitive in such applications. The glass brick provides architecture with new design opportunities to increase daylight inside buildings.