The influence of the selective ventilation in the thermal performance of modern naturally-ventilated houses in Goiânia – Brazil

The aim of this paper is to investigate the influence of the selective ventilation in the thermal performance of modern naturally-ventilated houses built in the 1950’s and 1960’s in Goiânia, located in middle-west of Brazil. The selective ventilation is one of the passive thermal conditioning strategies recommended for buildings located in this city, in the summer. This study allows the analysis how much important is the selective ventilation as a bioclimatic strategy in the studied cases, considering the application of this strategy before the establishment of contemporary concepts as “zero energy building”, helping us to reflect on the future from a historical perspective. Seven rooms in two houses were selected for in situ measurements and simulations. Indoor and outdoor air temperatures and relative air humidity were measured with data loggers HT-500, during 91 days in three different months in 2011: June (low air temperatures and low relative humidity); September (high air temperatures and low relative humidity); and December (medium air temperatures and medium relative humidity). The measured dates are used to calibrate the virtual model of the dynamic simulations. Based on this calibrated model, a reference model for computer simulations was defined in the EnergyPlus building energy simulation program, used also to solve the energy balances and to evaluate the thermal performance of the cases. Variations in the ventilation were carried out and hourly air temperature and relative air humidity were the output data for the same thermal zones studied in each measured case. By imputing such data in the Analysis Bio Computer Programme, the percentage of discomfort hours in the models was obtained. Correlations among the results were investigated considering different variables in the time and the space, allowing the comparison among different buildings and comfort zones, periods of the day and seasons. The main conclusion is that it is possible to verify the sensibility of the technical solutions applied in the cases in relation to the selective ventilation, demonstrating its importance in the building thermal performance and identifying important variables to improve the thermal performance of modern naturally-ventilated houses.