Experimental investigation of phase change material (PCM) incorporated composite flat roof for energy-saving under Iraq hot climate conditions.

The roof plays a predominant role in residential buildings' energy efficiency in hot countries as it receives a significant amount of solar radiation during the summer months. Incorporating phase change material is considered a sustainable solution to improve building energy performance. In this paper, the energy-saving earned from incorporating separate phase change material panel into a composite flat roof is investigated experimentally under hot climatic conditions of Al Amarah city, south of Iraq. Two identical small-scale rooms (with and without phase change material layer) have installed considering composite flat roof and insulated floor and walls. The roofs are composed of Isogam (as a roofing layer), concrete (as the main roof layer) and gypsum board (as a cladding layer). The maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag have been calculated and discussed. Results indicated that PCM could efficiently reduce heat transfer through the roof and contribute to building energy- saving. The maximum interior surface temperature is reduced by up to 8.75 °C in the PCM roof. Moreover, an average maximum temperature reduction, average temperature fluctuation reduction, decrement factor and time lag of respectively 10.65%, 7.68 °C, 0.522 and ∼100 min, is obtained from the modified roof compared to the reference roof. [ABSTRACT FROM AUTHOR]