Façades and office buildings in São Paulo (Brazil): aiming for thermal comfort and natural ventilation

This work focused on office buildings in the city of Sao Paulo, Brazil, aiming to identify facades' design solutions which provide internal thermal comfort conditions for at least 80% of the occupied hours during the year without use of air conditioning. Two building models were proposed. Annual dynamic thermal simulation of sixty four scenarios of office buildings with different configurations (building form, layout and orientation) and ventilation conditions (stack effect and wind effect) were carried out with TAS. The operative temperature was adopted as thermal comfort criteria. The relationship between the ventilation rate and the heat gain in the office through the facade was identified for each case study. The results of the thermal performance were tested against ASHRAE 55 (2004) and CEN EN 15251 (2007). The results provided inputs for the design of possible facades' solutions for the cases of office buildings which fulfilled the criterion of 80% of the annual occupied hours in comfort. The study showed: (i) the extent to which the choice of comfort criteria can impact building design and performance; (ii) it is possible to keep efficient natural ventilation and provide adequate thermal comfort conditions for the office building in Sao Paulo in a wide variety of architectural and ventilation scenarios; (iii) following the proposed design method several combinations of materials and aperture types are possible for the facades of diverse cases, depending on the relationship "heat gains versus ventilation rates".