An investigation of thermal comfort, IAQ, and energy saving in UFAD systems using a combination of Taguchi optimization algorithm and CFD

ABSTRACT The present study investigates underfloor air distribution (UFAD) systems by using the combination of computational fluid dynamics (CFD) and the Taguchi optimization algorithm. A multi-objective optimization approach is used to analyze the efficiency of UFAD systems from the viewpoints of thermal comfort, indoor air quality (IAQ), and energy consumption. The supply air temperature, the air change rate per hour (ACH), and the height of the return air vent factors are considered in order to achieve the optimum operating condition. First, numerical validation has been done for an office room model, and then optimization has been performed for this space. The optimization results state that setting the supply air temperature and ACH at 19°C and 4.0, respectively, and placing the return air vent at the height of 1.6 m would lead to the optimum state. The CFD simulation results for this condition show that the thermal comfort in the occupied zone and the desirable IAQ in the breathing zone are established, corresponding to the predicted mean vote (PMV) and mean age of air (MAA) values equal to 0.13 and 640 s, respectively. Furthermore, energy consumption has a considerable reduction of 21.5%, compared to the conventional mixing ventilation (MV) systems.