An experimental study of the thermal behavior of bricks integrated with PCM-capsules in building walls

Buildings are the major energy users and by 2035, they will be the fourth largest source of greenhouse gas emissions. Phase change materials (PCMs) are applied to shift the peak-load to the off-peak-load, positively effecting the efficiency of the building. In this paper, an experimental embedding of PCM (Paraffin) with bricks in conventional wall layers is carried out. The effect of this on the thermal diffusion of the inner surface of the wall is studied. Capsules are manufactured to fit the size of the holes inside the bricks and they are filled with Paraffin (147 kJ/kg latent heat, 38oC solidified and 43oC liquidised) and closed in a way that prevents leakage. Each brick contained two rows of holes (5 holes per row). Capsules are placed in the holes at a rate of 5 capsules per brick and 10 capsules per brick. Three wall samples are experimentally tested: traditional wall, wall containing 5 capsules/brick and a wall containing 10 capsules/brick. The indoor test with light intensity has been fixed on 900 W/m2 during the heating period for 4 hours and the remaining period of cooling. The temperature measured and recorded for the internal, external surfaces and the middle of the wall using K-type thermocouples and datalogger. The results indicated that, bricks wall with 10 PCM- capsules per brick reduced the heat flux by 34.17% compared with traditional wall sample, and energy stored 50% more than a wall with 5PCM-capsules per brick. The lowest temperature of the internal wall surface of sample 10 capsules per brick is recorded compared to the reference wall where the difference is more than 3°C.