Thermal Management by PCM in a Room Wall CFD Simulation

Description

Thermal Management by PCM in a Room Wall CFD Simulation, ANSYS Fluent Tutorial

Description

A Phase Change Material is a material that releases or absorbs sufficient energy during melting and freezing. They melt and solidify at specific temperatures, making them suitable for controlling the temperature. PCM can absorb significant heat energy during the melting and give out the heat absorbed when it solidifies.

PCMs have many applications where energy storage and stable temperatures are required. It Includes heating pads, cooling for telephone switching boxes and fabrics available for bedding and clothing.

This project modeled a square-shaped room with a wall consisting of 3 layers of different materials. The wall layers are Brick, Trimethylolethane/water (PCM), and Concrete from the outer to the inner layer. The outer surface of the Brick is exposed to 100 w/m² heat flux. Brick, Trimethylolethane/water, and Concrete have a low thermal conductivity so that the room temperature would resist any rapid thermal change.

The geometry of the solution is a 3D square domain of 3 meters in addition to 3 layers, and each one has a 10cm thickness. Plus, Design Modeler software is used to create the geometry. Ansys Meshing software is used for generating structured mesh grids, and the number of them is 193,500.

This CFD project is the 4th episode of the ANSYS Fluent General Training Course.

Methodology: thermal management by PCM in a room wall

The Solidification and Melting model is used to simulate the Phase Change Material loading. The pressure-based solver has been employed due to the incompressibility of the fluid. Also, the simulation depends on Time, so it has been performed in a Transient form. Moreover, the gravitational effects are ignored.

Conclusion

At the end of the solution process, two-dimensional contours and vectors related to water pressure, temperature, turbulence kinetic energy, and velocity are obtained. As depicted, it’d take about 6 days to make the volume fraction equal to 1. It means all the Phase Change Material(Trimethylolethane/water) melts completely. it shows the time the material needs to store the energy it gets from radiation.

Also, the temperature increases inside the house very slowly which is due to the low conductivity of the wall components(Brick, Trimethylolethane/water, Concrete).

this simulation confirms the ability of the PCM in storing the energy and then use them at a proper time, resulting in lower energy and power consumption.