Four layers of materials comprise GLASSXcrystal: an exterior layer of tempered safety glass, two layers of tempered low-E safety glass, and an interior layer of tempered safety glass with ceramic silk-screen printing. In between the two layers closest to a building’s interior, a plate filled with salt hydrate phase change material (PCM) captures and stores solar heat. Initially in a crystallized form, the PCM melts as it absorbs solar heat. The heat is then released overnight as the PCM recrystalizes. glassx.ch; +41 (0)44 389 10 60.