Simulation of the Impacts of Different Cooling Roofs on the Thermal Environment of Urban Blocks

The use of cooling roofing materials to alleviate the effects of urban heat islands and the energy crises brought by urbanization has always been a critical research issue in the field of urban meteorology. This paper used offline town energy balance mode (TEB) to analyze roof surface temperature and the radiant heat of urban blocks during the two-week-long heatwave during 16−30 July 2017. The study involved solar panels with a conversion efficiency of 14% and three kinds of high albedo roof materials: Aluminum foil asphalt membrane, white TPO membrane, and randomized glass-polymer hybrid metamaterial from the University of Colorado. The results show that under continuous high temperature, the super-material roof treatment and the 100% coverage of roof area with solar panels treatment had the best cooling effect, reducing daytime roof surface temperature by 18.59 K and 19.58 K, respectively. The aluminum foil asphalt membrane’s effect takes second place, reducing temperatures by 13.47 K on average. The TPO film and covering 50% of the roof area with solar panels had the worst performance, it also has a nighttime cooling effect of 1.08–4.53 K. The setting of cooling roofing materials can reduce cooling energy demand both directly and indirectly. Covering 100% of the roof area with solar panels and using super-material roofs can minimize buildings’ cooling energy consumption, and can reduce 2.1 W m⁻² and 2.16 W m⁻² per square meter, respectively. Aluminum foil asphalt film takes second place, with a reduction of 1.47 W m⁻². TPO film and 50% solar panel coverage had the smallest effect. The selected solar photovoltaic panels can generate an additional 1.84 kW h of electricity per day, and the electricity over the simulated two weeks can offset all the energy consumption of air conditioning during the same period.