Use of natural ventilation in reducing building energy consumption in single-family housing in Brazil

This paper presents the analysis of thermal comfort in single-family housing in Brazil, by quantifying the heat loss due to the use of natural ventilation. Thus, it was investigated the relationship of thermal comfort with the possibility of reducing the energy consumption of active conditioning systems. The method comprises the computer simulation of a 63m² single-family housing construction, using the software EnergyPlus. The simulated model has no active conditioning system. Natural ventilation was simulated with EnergyPlus through the algorithm, AirflowNetwork, a model of ventilation network, where mass flows through openings and loss of thermal load due to pressure differences in building are estimated. The condition for opening the window depends on external temperature and a prescribed maximum internal temperature, which supposes the use of natural ventilation only as daytime passive cooling tool. For the study two cases were simulated by varying the thermal properties of the constituent components of the roofing and of vertical components. Variations studied represent the application of different constructive elements of practice in the construction market in the country. The options described were also simulated for three Brazilian cities with different climates, in the situations ventilated and unventilated, totaling 12 different simulations. The comparative analysis was performed by checking the comfort hours and simultaneously quantifying the sensible heat loss due to the use of natural ventilation, for each simulated event. Results indicate the importance of natural ventilation combined with the use of adaptive models for thermal comfort and the possibility of significant reduction in energy consumption resulting from this design strategy.