Solar Pond Window Technology for Energy-Efficient Retrofitting of Buildings: An Experimental and Numerical Investigation

Windows are responsible for an important proportion of heat loss from building envelope due to inadequate insulative characteristics of traditional glazing products. In this respect, advanced glazing solutions are of vital importance to mitigate energy demand of buildings, thus to reduce carbon emissions. Therefore, in this research, a novel glazing technology called solar pond window is introduced, and it is numerically and experimentally investigated for different design configurations. The optimum design of this novel glazing covers four 5-mm-thick glass panes, two 20-mm-thick water layers, and one 20-mm-thick Krypton layer in the middle. The average heat transfer coefficient (U-value) of the optimum case is found to be about 0.40 W/m 2 K. If air is used as insulative gas in the interlayer, the U-value of the glazing is determined to be around 0.90 W/m 2 K, which is still competitive with the U-value range of argon-filled triple-glazed windows with low-e coatings. The fabrication cost of the optimum design of solar pond window is around €120/m 2. Overall, solar pond window technology is a cost-effective and energy-efficient glazing, which has a great potential to be the future of fenestration products as well as being capable of meeting the latest building fabric standards.