Experimental evaluation of the optimal position of a macroencapsulated phase change material incorporated composite roof under hot climate conditions

Abstract

This paper experimentally investigates the optimal position of a phase change material (PCM) incorporated composite roof under Iraq climatic conditions. The roof composed of Isogam (4 mm), concrete (50 mm) and gypsum board (8 mm) which is an Iraqi popular roof combination. Four models are installed and tested; one represented the reference roof (Model A) and the others incorporated with PCM. The PCM placed between Isogam and concrete (Model B), in the middle of concrete (Model C), and between the concrete and gypsum board (Model D). Set of indicators are introduced to compare among models considering the test room temperature, outside and inside roof surface temperatures. These indicators are the room maximum temperature reduction (RMTR), average temperature fluctuation reduction (ATFR), decrement factor (DF), time lag (TL) and heat flux reduction (HFR). Results showed that Model B verified the best thermal performance, and the PCM was effectively working at high outside temperatures. The maximum room temperature of PCM models was reduced by up to 9 °C compared with the reference model. Moreover, a maximum of 12.9%, 8.4–9.5 °C, 0.44–0.49, 140–180 min, 47.9–64.6% of respectively RMTR, ATFR, DF, TL, and HFR, are obtained for Model B under high outside temperatures.