Thermofluid-dynamic analysis of ventilated facades

Ventilated facades can be used in cases of renovation of existing buildings and new buildings to improve both the thermal performance of building, and external architectural skin. The energy advantage provided by the ventilated facades during the summer is the reduction of the heat load due to the combined effect of the shading of the external wall and the air flow caused by natural convection into the heated duct. The evaluation of ventilated facade performance requires a complete thermofluid-dynamic analysis of a ventilated air duct and an accurate knowledge of heat transfer coefficients, friction factors and thermo-physical properties of the materials. The Authors have used the computer code "Fluent" to investigate the thermal behaviour of three different typologies of ventilated facades. The aim of this research is to show an analytical method for design applications able to provide all the useful criteria for choosing the most suitable ventilated facades both in case of forced convection, due to the action of a fan, and natural convection due to stack effect.