In cold winters, heating our homes uses a lot of energy. But what if our windows could help warm the house for free? A Supply Air Ventilated Window is a special kind of window that does just that. It acts like a small solar panel, catching the sun’s warmth and using it to heat up the fresh air coming into a room. While normal windows often lose heat, these smart windows have a space between the glass panes where air can flow. This design uses sunlight to pre-heat the cold outside air, which helps lower heating bills and brings fresh air into the building at the same time. This clever idea involves complex heat movement that is best understood using powerful computer tools like Computational Fluid Dynamics (CFD). A Solar Effect on Supply Air Ventilated Window CFD simulation lets us see exactly how the window works, helping engineers design even better systems for saving energy.

Based on the reference paper “A CFD-Based Parametric Thermal Performance Analysis of Supply Air Ventilated Windows”, the present CFD study is executed.

• Reference [1]: Najaf Khosravi, Shiva, and Ardeshir Mahdavi. “A CFD-based parametric thermal performance analysis of supply air ventilated windows.” Energies9 (2021): 2420.

Figure 1: Schematic of a Supply Air Ventilated Window CFD model, illustrating the airflow path for passive solar heating [1].

Simulation Process: Modeling Heat and Airflow with DO Radiation

To create our Supply Air Ventilated Window Fluent simulation, we first used Design Modeler to draw the window’s shape, just like the one in the reference paper [1]. Then, using Ansys Meshing, we filled this shape with a grid of small boxes. We made the grid much finer near the glass panes because this is where the most important heat transfer happens. To correctly simulate the sun’s energy, we turned on a powerful tool in ANSYS Fluent called the Discrete Ordinates (DO) radiation model. This DO Radiation Fluent model is perfect for capturing the Solar Effect CFD analysis. We also told the computer to consider how air density changes with temperature (using the Boussinesq model), which is essential for seeing how warm air naturally rises.

Figure 2: The geometry used for the Solar Effect on Supply Air Ventilated Window Fluent simulation.

Post-processing: CFD Analysis of Temperature and Natural Air Movement

The simulation results paint a vivid picture of the window working as a natural heater. The temperature map in Figure 3 tells the first part of the story. On the right side, a bright red strip shows where the sun’s energy has warmed the inner glass to a pleasant _25.18°C_. Right next to it, the deep blue region shows the freezing outside air at _-7.10°C_. This creates a very large temperature difference of over _32°C_ within the window itself. This sharp contrast between hot and cold is the engine that drives the entire heating process, and our model captured this stable temperature profile perfectly.

Figure 3: Static temperature contour from the Ventilated Window CFD analysis, showing the strong thermal gradient created by the solar effect.

This difference in temperature then makes the air inside the window begin to move all on its own. Figure 4 shows how this invisible dance happens. The cold air entering the window gets warmed by the hot glass, which makes it lighter and causes it to rise. This creates a gentle upward river of air, seen as a greenish-blue streak flowing at nearly _0.25 m/s_. As this warm air travels, it heats the fresh air supply for the room. The 3D view shows beautiful horizontal layers of heat, with warmer orange layers (_around 20-25°C_) neatly separating from the cooler blue bands (_about -3°C_). The most important achievement of this Solar Effect on Supply Air Ventilated Window CFD simulation is the successful and accurate modeling of the entire passive heating process—from the solar radiation absorption to the final natural convection airflow. This validated model proves that CFD can be trusted to predict the real-world thermal performance of these advanced windows, allowing architects to design more energy-efficient buildings with confidence.

Figure 4: Velocity contour from the Solar Effect Window CFD simulation, displaying the natural convection patterns that drive the passive heating system.