Plants on the roofs known as “green roofs” are a passive technique to reduce the energy consumption in buildings and improve the quality of the air around them. This is made possible by heat preservation in winter and sunlight prevention and providing shades and coolness in the summer.
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Water management and control, energy saving, reduction of heat island effect in urban areas and appropriate lifetime of the roof coverings are the main things required to keep green roofs; but they do not have a big impact on energy consumption because there is not any possibility of absorbing the chill at night to use it during the day and vice versa. That’s why there is a need for materials that can save the energy for long periods of time, and PCMs are one of them. They can store latent heat and use it to improve the performance of green roofs.
Green roofs minimize the heat loss in winter, providing shades and using evaporative cooling during the summer; thus, they lead to a reduction of the required thermal load in the building and the inclusion of PCMs in the inner structure will have a positive impact on its performance.