Optimizing building surface retro-reflectivity to reduce energy load and CO2 emissions of an enclosed teaching building

Building surface reflectivity determines the amount of reflected solar radiation, which indirectly affects the cooling and heating load of a building. Therefore, optimizing building surface retro-reflectivity is an effective method to reduce energy load and CO2 emissions of buildings. To analyse the optimization potential of building surface retro-reflectivity, the effect of surface reflectivity on daily, monthly and yearly energy load, as well as CO2 emissions of an educational building were simulated based on the Energyplus software. The numerical results showed that for daily energy load in four typical seasons, there was a positive correlation between the daily energy load and building surface reflectivities in January, April and October and a negative correlation in July. For monthly energy load, the building cooling and heating loads were the highest in January and August, respectively. For annual energy load, the higher the reflectivity, the lower the cooling load and the higher the heating load. When the building surface reflectivity was 0.7, the annual energy load was the least, with a value of 148.23 kWh/m2. In addition, the CO2 emission was also the lowest, with a value of 24.79 kg/m2. According to the relation between building surface reflectivities and retro-reflectivities, the optimal retro-reflectivity was 0.47.