Solar chimney geometry for stack ventilation in a warm humid climate

Natural ventilation is a well known strategy to improve indoor air velocity and reduce indoor temperature. It is the main criterion to achieve thermal comfort in terraced housing in Malaysia. In hot and humid climates, one drawback to single sided ventilation is that the wind effect is not well captured, which in turn, increases the use of mechanical cooling. Therefore, it is important to understand and consider the use of the solar chimney as a stack induced ventilation strategy for a single sided ventilated room. This study investigates solar chimney geometry to improve indoor air velocity and to reduce temperature in order to achieve comfort ventilation in hot and humid climates. An experiment was carried out to measure the natural ventilation rate of a single master bedroom in a typical single storey terrace house. The investigation was assisted using FloVent 5.1, a computational fluid dynamic simulation program which was first validated by comparing simulated results with field measurements taken on site. The results of the experiment showed that an optimum solar chimney geometry model of 3.5 m height, 3.5 m length and 1 m width gap could increase the indoor air velocity by more than 30% when compared with the standard field study model. This effect is significant towards improving air velocity for thermal comfort performance in conventional terraced housing through passive natural ventilation. In conclusion, optimisation and modification of solar chimney geometry can further improve the air velocity for increased ventilation and thermal comfort.