Temperature Moderation in a Structure by Solidification of a Phase-change Material

The current numerical study focuses on the feasibility of temperature moderation in a structure located at mid-storey in a multi-storey building, by using a phase-changing paraffin wax stored on an aluminum tray under the floor tile. Inside the building, at each level, walls are exposed to the ambient. In winter the walls are cooled, and the paraffin wax serves as the heat source, by solidifying in day-time, and melting at night. The numerical model relates to day-time temperature variations, outside and inside the structure. The heat conduction from the paraffin wax is coupled with the free convection of air in the space, radiation between the inside surfaces, heat conduction across the walls and accumulation in the walls. The dimensions of the analyzed structure are: 8m long, 8m wide and 2.5m high. Effects of wax layer thickness and of fins along the tray, on the rate of solidification are parametrically investigated. The simulations are performed for the structure using Fluent 6.3 software.