Fluid Glass Façade Elements: Influences of dyeable Liquids within the Fluid Glass Façade

In this paper a glass façade system is proposed, which controls the energy flows within the transparent building envelope [1]. Yearly energy consumptions of an office space are calculated in Munich and Dubai [2]. The office space is calculated with a theoretical glazing share of 100% within the south-west oriented façade area. A standard solar-control glazing unit (SCGU) is adopted as benchmark for the fluid glass. Three fluid glass scenarios are considered: two with adjustable transparency (dyed) and one with constant properties of a clear fluid. One of the adjustable scenarios is simulated with white glass (low iron). The cooling demand is strongly connected to the g-value of the glass unit. Without coloring the fluid, the cooling demand with fluid glass is approximately 39% higher than with SCGU in Munich, and approximately 25% higher in Dubai. While colored fluid glass nearly halves the cooling demand compared to the SCGU. Colored fluid glass show an overall saving in the energy demand of approximately 23% in Munich, and approximately 44% in Dubai, compared to the SCGU. Thus, using dye to control the solar transmission is crucial for successful implementation of the fluid glass concept. By coloring the outer liquid layer, a huge fraction of the solar radiation is absorbed in the fluid. As a result, the temperature of the liquid layer rises, but not the room temperature. To optimize the fluid glass system, white glass (low iron) is investigated. The visual transmission of the clear fluid glass rises by 38% compared to standard glass panes, the solar transmission even by 84%. Contrary to expectations the energy demand of the office space in Munich rises by around 70%, which is due to the poor absorption behaviour within the near infrared spectrum of the actual used dye. The current study showed the high potential of fluid glass façades for reducing the energy demand of an office space, mainly for cooling purposes. An important function of the fluid glass façade is the dyeing of the liquid with to actively control the solar transmittance. Further investigations are required to optimize the spectral transmission behaviour of the fluid glass system.