Energetic and thermal comfort assessment of phase change material passively incorporated building envelope in severe hot Climate: An experimental study

Phase change materials (PCMs) can beneficially work as a successful thermal energy storage medium in different applications. PCMs have shown a remarkable enhancement in building energy-saving and thermal comfort in hot locations. In this paper, the thermal behaviour of a PCM-enhanced thermally-poor building envelope is studied experimentally. To this aim, two identical rooms, one loaded with PCM (PCM room) and the other without (reference room), are built and tested under a severe hot climate of Al Amarah city, Iraq. Previously examined parameters, such as the optimal position and thickness of the PCM layer in the roof and the best-thermally performed PCM capsules integrated concrete bricks, are considered to build the PCM room. Several energetic and thermal comfort indicators such as maximum temperature reduction (MTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL), operative temperature difference (OTD), discomfort hours reduction (DHR) and maximum heat gain reduction (MHGR) are determined and discussed to show the potential of PCM. The experimental results revealed that the incorporated PCM could remarkably improve the thermal performance of building envelope exposed to high outdoor temperatures. Amongst envelope elements and compared with the reference room, the roof and east wall of the PCM room recorded the best thermal behaviour, where the MTR difference, ATFR, DF, and TL difference reached 3.75 °C, 6.5 °C, 25.6%, 70 min for the roof, and 2.75 °C, 2.4 °C, 12.8% and 40 min for the east wall, respectively. Moreover, the PCM room shows a thermal comfort enhancement by 11.2% and 34.8%, considering the DHR and MHGR, respectively, compared with the reference one. The study highlighted that suitable ventilation means are necessary to improve the building performance and reach acceptable thermal comfort when the PCM is incorporated passively.