Performance evaluation of multifunctional windows for commercial buildings under hot-humid climatic environments

The Multifunctional Window (MFW) is a novel solution for solar radiation optimal utilization in commercial buildings. The present work aims to evaluate the performance of the Multifunctional Window consisting of multi-glazed window, liquid-absorbing filter, and traditional photovoltaic for use in near-zero-energy commercial buildings. Fulfilling this goal, a simulation model using CFD code was developed to predict the effect of design parameters such as absorbing filter liquid types (Pure water-polyethylene glycol–water/Ag Nanofluid), liquid filter thickness (2–10 mm), and air gap thickness (5–15 mm) on window performance characteristics and building energy savings under hot and humid climates. Results showed that the water/Ag Nanofluid (NF) minimize the PV surface temperatures by up to 3.2 °C and increase the power saving by about 6.4–9.8 % in comparison to other tested fluids i.e., NF is the best liquid filter from viewpoint of total power saving. As the thickness of the liquid filter increases, the transmitted indoor visible light radiation reduces by 43.6% and the average room load decreases by 47.6%. The average interior window surface temperature and room load of MFW are 4.1% and 60.7% lower than Window with PV only, respectively. The proposed MFW has the highest energy performance compared to typically adopted glazing systems.