Influence of dirt on windows on the energy performance of buildings: case study in three Brazilian cities

estudo de caso em três cidades brasileiras

Abstract

Considering the wide variety of glass available on the market, it is essential to select those that have properties compatible with the energy requirements of the building, since their characteristics can significantly influence energy consumption. Dirt on glass surfaces is an important factor to be considered as it can affect the transmission of energy through the glass, impacting daylight and solar heat gain in the environment, and consequently influencing the building's thermal load and energy consumption for air-conditioning. Through computational simulation using the EnergyPlus software, this study analysed the energy consumption of air-conditioning in three Brazilian cities (Florianópolis, Porto Alegre, and Cuiabá) considering four types of glass with different solar transmittance and varied levels of dirt. The results showed that, for the three cities, an increase in dirt led to a reduction in energy consumption due to a decrease in solar transmittance, resulting in lower heat transmission through the glass and a reduction in thermal load. Furthermore, the higher the solar transmittance of the glass, the greater the difference in energy consumption between the clean glass scenario and the very dirty environment scenario. The clear glass scenario had the highest reduction in energy consumption in very dirty environments, with a decrease of 8.26% in Florianópolis, 6.47% in Porto Alegre, and 5.28% in Cuiabá.