Design Guidelines for Thermal Comfort and Energy Consumption of Triple Glazed Fluidic Windows on Building Level

There has been a growing trend for buildings with large glazing size. As a trade-off, this comes with enhanced solar heat input and/or reduced thermal insulation. Several approaches are being followed to reduce the energy consumption in these buildings, including the prolific field of smart windows. In a previous report, a fluidic window device for thermal harvesting and air-conditioning was introduced. Using this example, the impact of a building’s window-to-wall ratio on the triple glazed fluidic window’s energy consumption and user thermal comfort is evaluated, providing design guidelines for large-scale implementation of such smart windows with real-world buildings. The analysis shows that the proposed window design reduces the primary energy demand as compared to using a conventional air-conditioning system. Building simulation results indicate that the system enables satisfying thermal comfort for buildings with different windowto-wall ratios. Although a higher window-to-wall ratio improves the heat pump efficiency, it requires more heating and cooling energy. On-device photovoltaic modules may be used for changing this relationship. In this case, the proposed device may become self-sufficient once the transfer efficiency is high enough. It is argued that similar considerations should be applied to other types of smart window technologies.