Study on the cooling performance of a radiative cooling-based ventilated roof for its application in buildings

Radiative cooling has been demonstrated as an effective way to reduce building energy consumption especially for the recently developed diurnal radiative cooling materials. The most convenient application of radiative cooling materials is configured as the cool roofs. However, cool roofs will produce cooling energy throughout the year which will lead to the increase of heating penalty in the heating season. This phenomenon will offset part of the cooling benefit from radiative cooling. The ventilated roofs are also commonly employed in buildings for achieving energy-saving by reducing the heat gain from the roof to the building. To reduce the influence of radiative cooling in the heating season, a radiative cooling-based ventilated roof (RCVR) is proposed in this study by integrating the ventilated roof with the radiative cooling-based cool roof. The process of the heat transfer through RCVR is analyzed, and the simplified heat transfer model is developed. And then the effect of RCVR configuration on the room temperature is discussed in detail through CFD simulation. Finally, the annual electricity consumption of the building with RCVR is derived using EnergyPlus. The results show that the annual comprehensive performance of RCVR is superior to the cool roof and original roof since the total annual electricity consumption of the building with RCVR can be decreased by 21.8% and 16.9% compared with that of cool roof and original roof. Practical application: A radiative cooling-based ventilated roof (RCVR) is proposed by integrating the ventilated roof with the radiative cooling-based cool roof. The results show that the annual comprehensive performance of RCVR is superior to the cool roof and original roof. This study can provide the guiding significance for the application of RCVR, in which the building energy consumption can be further decreased for the application of radiative cooling in buildings.