The heat transfer effect of a sectioned wall made of five volumes filled with a phase change material (PCM) coupled to an air cavity is presented. The analysis system was equipped with a heat source next to the sectioned wall and an opposite isothermal wall. The experimental study was carried out by measuring the temperature of the five PCM volumes, likewise in four profiles along the air cavity. For the numerical formulation of the phase change of the PCM wall, the enthalpy method was used. With the validated model, the temperature fields, velocity contours, liquid fraction contours, and heat transfer coefficients are presented and discussed. The comparison between the numerical model and the experimental data presented a general average percentage difference in the range of 3.8–7% for the temperature of the air profiles, while for the PCM was 0.9–3.2%. The numerical results showed that the amount of liquid PCM in the enclosure can be reduced by dividing the wall into segments. Additionally, the heat transfer mechanism of conduction was noted between PCM volumes due to the union of these.