Increasing the thermal inertia of building walls when using phase change materials

The influence of a thin layer of phase change material (PCM) on the thermal characteristics of the outer wall of a building made of lightweight thermal insulation material was studied numerically. Changes in temperature and heat flux density were analyzed for various locations of a PCM layer in the wall. It is shown that the use of a thin paraffin layer 4 mm thick in a wall made of foamed polyurethane 100 mm thick can reduce the amplitude of heat flux fluctuations on the inner surface of the wall in the summer from 2 to 13 times, depending on the PCM location. The greatest reduction is achieved when installing the PCM in the central area of the wall. Calculations show that when using a PCM in the walls of buildings made of light thermal insulation materials, a positive effect, associated with a 6–8 hour delay in the maximum heat flux entering the room relative to the maximum daily value of the outside air temperature, is observed in the summer.