Simulation of a ventilated cavity to enhance the effectiveness of PCM wallboards for summer thermal comfort in buildings

•Air circulation between walls and PCM wallboards can enhance the PCM effectiveness.•A simulated case study is presented with the aim of quantifying such enhancement.•This set-up can double the thermal energy storage potential in the PCM wallboards.•Therefore, the average room temperature is reduced of about 0.4 °C.•Further improvements are expected if optimizing cavity size and ventilation time.

The present paper proposes and evaluates a novel solution for increasing the effectiveness of phase change materials (PCMs) micro-encapsulated in thin wallboards, in order to improve summer thermal comfort in buildings. The unique feature of this solution consists in realizing a narrow cavity between the wallboards containing the PCM and the partition wall. Here, fresh air might circulate according to appropriate control logics, thus boosting the rate of heat flux exchanged by the PCM, and enhancing its solidification process. This set-up should increase the PCM storage efficiency and the average thermal comfort perceived by the occupants.After introducing a mathematical model to identify the temperature distribution along the ventilated cavity, its actual efficiency is evaluated through a case study, based on simulations performed with EnergyPlus. The evaluation is accomplished by means of newly-introduced indicators that allow a thorough description of the PCM behaviour and its relation with thermal comfort in the room.