Positive energy schools with cool materials and passive strategies: scenarios and perspectives for the Brazilian context
Educational Buildings, Energy Efficiency, Building Design, Building Energy Simulation
Standardized public buildings replicated in different climatic contexts associated with high urban temperatures can cause thermal discomfort to occupants and increase energy consumption by air conditioning, especially in very hot climates. Currently, passive climate control strategies and specially supercool materials are highly effective solutions in these cases. Therefore, this study aims to evaluate a current model of a standardized Brazilian public school and identify optimal passive solutions to provide thermal comfort without active air conditioning systems through optimization simulations with EnergyPlus and JEA Algorithm. Different combinations of passive strategies and cool materials for each bioclimatic zone allow a maximum discomfort of 10% due to heat or cold according to the ASHRAE 55 adaptive model, with 80% acceptability during the occupancy period in all regions of Brazil. Among the opaque envelope materials, thermal mass flat roofs and insulated walls provide adequate heat balance for both cooling and heating dominated zones. The optimal combinations of passive strategies are: supercool material on roofs and walls, as well as window shading and 24/7 95% aperture natural ventilation for extreme cooling-dominated zones; cool roofs, medium reflectivity walls, and 5% aperture ventilation for coolingdominated zones and thermochromic roof and dark walls with 5% aperture ventilation for heating-dominated zones. Cities with greater discomfort, whether due to heat or cold, also require extra solution for the external floor (reflectivity of 90% and 30%, respectively).