Construction aspects of hybrid water-filled building envelopes

Water-filled building envelopes are hybrid constructions with a solid and a fluid component, typically a glass or steel shell filled with water. The paper introduces the challenges of developing a water-filled façade structure and evaluates the possibility to utilise it as a viable construction system on a building scale. Water-filled glass (WFG) has been researched in the past and it was presented as an independent window element of a conventional building, where energy savings are achieved by using the absorption of the water layer for energy management of the building envelope. The results suggest that WFG’s efficiency could be improved further if the system is assembled as a united building envelope in which the fluid can flow between panels and building parts. The paper presents two experimental ‘water house’ buildings with these design parameters, designed and constructed by the author. The importance of these buildings is that a connected water-filled envelope is built for the first time. The discussion presents two construction methods for water-filled façades, evaluates their viability for different climates, introduces the design-construction aspects of the technology, and offers a comparison with existing construction methods. A fluid-solid building envelope provides significant savings for both operational and embodied energy, by lowering cooling load, reusing absorbed heat, balancing thermal differences between parts of the envelope and the rest of the building, while making additional construction elements (e.g. external shadings) obsolete.