Solar Chimney for a Room HVAC, CFD Simulation Tutorial

Description

The problem is simulating the HVAC inside the room considering a solar chimney by ANSYS Fluent software. The present model consists of two main parts, including the interior of the room and a sloping solar chimney on the room’s ceiling.

The solar chimney consists of glass plates on its side surfaces that are in contact with the environment. As a transparent medium, it receives solar energy and has a plate on its back as a heat-absorbing surface. It is assumed that the adsorbent surface behind the chimney has a constant temperature of 335.15 K.

In contrast, the glass surface in contact with the external environment has convective heat transfer with its surroundings. The ambient air temperature is 308.15 K, and the convection heat transfer coefficient is 8 W/m2K.

It is also assumed that the heat received from sunlight inside the chimney creates a constant heat source inside the chimney, equivalent to 15000 W/m3.

Solar Chimney Methodology

The 2-D geometry of the present model is carried out using Design Modeler software. The model’s geometry consists of two parts, including a room measuring 2 m⨯3 m and a solar chimney with a length of 2 m, a slope of 45 degrees to the room’s ceiling and a width of 0.15 m.

The meshing of the present model has been done using ANSYS Meshing software. The mesh type is structured, and the element number is 42846.

Solar Chimney Conclusion

After the solution process is completed, two-dimensional contours of pressure, temperature, and velocity, as well as pathlines and velocity vectors, are obtained.

Also, the diagram of temperature distribution in the transverse direction at a point in the middle of the solar chimney (at a distance of 1 meter from the inlet and outlet) and the graph of velocity changes in the transverse direction in the chimney outlet section is obtained.

The airflow from the inlet section at the bottom of the room has a pressure-inlet boundary condition; In this way, this incoming airflow at a temperature of 308.15 K is sucked into the room by the heat of the solar chimney and is transferred to the environment outside the room.

The temperature profile at a point in the solar chimney at a distance of 1 m from the chimney inlet with a thickness of 0.15 m has been obtained and compared with the temperature profile of the same case in a paper.