Thermal and Flow Characteristics of Liquid-Flow Window with Different Design Configurations

Window glass occupies a great deal of the building facade, and the increase in space thermal load has given much pressure on the global environmental issues. Liquid-flow window (LFW) is an innovative concept that involves a controlled flow of liquid, just like water, within the cavity between the two glass panes. The direct solar heat transmission is weakened, whereas the visible light transmission is not affected and the indoor thermal environment is improved. In this paper, its thermal characteristics are investigated with the use of a mathematical model and numerical simulation. The effects of LFW configuration, the layer of thickness, baffler length and water flow velocity on the heat flow are analyzed. The results indicate that the design configuration and the inlet flow velocity would affect the localized water and temperature distribution. A water layer of thickness around 10 mm, glazing height-to-width ratio (GHTWR) around 0.88, baffle length-to-glazing height ratio (BLTGHR) around 0.6, and inlet flow velocity around 1.0 m/s are desirable.