Analysis of the impact of a novel cool roof on cooling performance for a low-rise prefabricated building in China

The recently proposed scalable-manufactured randomized glass-polymer hybrid metamaterial (i.e. metamaterial film) exhibits good energy-saving potential for building applications. The most convenient way to employ this metamaterial film-based radiative cooling is to integrate it with buildings as cool roofs. However, metamaterial film-based radiative cooling is more suitable for buildings with higher roof area to floor area ratios, as this accounts for its relative lower cooling power of 110 W/m² on a daily average. The prefabricated buildings in China are commonly less than two floors, which are preferable for the application of this metamaterial film-based radiative cooling. To clearly reveal the cooling performance of the metamaterial film-based cool roof (MFCR), a single-floor prefabricated building is modelled in this study, and the energy-saving potential and economic feasibility of the application of the MFCR on the prefabricated building are discussed in detail. When comparing the model in this study with buildings that have the more commonly used shingle roofs or typical white roofs, the annual cooling electricity consumption is reduced by 28.9%–43.0% and 7.8%–12.9%, respectively, for buildings with MFCRs located in five cities in China, each in a different climate zone. Furthermore, the simple payback period for the buildings with MFCRs located in all five climate zones is less than three years compared to the buildings with shingle roofs.

Practical application: A recently proposed metamaterial film exhibits good energy-saving potential for building applications. This paper explores the application of this metamaterial film as a cool roof on a low-rise prefabricated building. The analysis of the cooling performance and economic value of this low-rise prefabricated building located in all five climate zones in China provides guiding significance for the application of MFCR.