Energy consumption of water-filled glass (WFG) hybrid building envelope

The thermal properties of building envelopes have a major effect on energy consumption and indoor comfort, which is even more significant for glass buildings. The current solutions for mitigating this is either improving U-value and solar heat gain coefficient (SHGC) with additional layers, utilizing shading device or changing the transparency of the glazing system with adjustable properties. These solutions address the problem of energy consumption to a certain extent but cannot effectively manage and take advantage of the solar radiation effectively. Moreover, shading solutions obstruct the view to the outside and have negative impact on daylighting. This paper introduces Water-filled glass (WFG) technology, a transparent glazing system that utilizes water infill to improve thermal performance of the building envelope. The impact of WFG on cooling and heating energy demand is evaluated by studying different glazing configurations for WFG in different climates. Besides, the overall performance of WFG is compared with conventional double glazing with Low-E as base-case (with and without shading). The significance of this evaluation is that a comprehensive climate-based assessment considering absorption and insulation-based options for WFG is presented here for the first time: the paper evaluates different options of glazing system in combination with active systems in building via advance dynamic simulation over a typical year for all major Köppen-Geiger climates (13 cities). Additionally, as a novel approach, the simulation results presented here identify climates where improving SHGC is more ideal for thermal performance than improving U-value even if it occurs by compromising the latter and distinguishes absorption-based and insulation-based scenarios respectively. The results show that absorption-based energy model is a viable option, which results in energy savings between 3 and 84% in value of US$0.99-24.25/m².a depending on climate. The discussion includes simulation and comparison with identical spaces using standard technology that follows the local building code and conventions. The climate-based evaluation of water-filled glass can improve energy consumption of buildings and offer a sustainable strategy for glass envelopes by absorbing and reusing heat where transparency becomes an asset instead of being a liability.