Application of TOPSIS method in evaluating the effects of supply vane angle of a task/ambient air conditioning system on energy utilization and thermal comfort

In subtropical area, air conditioning (A/C) is widely used to provide a suitable thermal indoor environment. During operation, many parameters or configurations may influence the performance of the A/C system. Among them, the supply vane angle is an important factor, which can influence the energy saving and thermal comfort level in the occupied zone, according to previously related studies. However, it was revealed that it was difficult to get a balance between these two aspects. Therefore, based on the previous study, this further study was conducted aiming to determine the suitable angle to achieve the best performance. Hence, the technique for order preferences by similarity to an ideal solution (TOPSIS) method was used to calculate the combined performance considering energy saving and thermal comfort. Finally, the best supply vane angle of 30°, with the energy utilization coefficient (EUC) and draft risk (DR) at the values of 1.28 and 8.89, was obtained, at which the A/C system achieved a medium energy saving performance and a lower draft risk. It's indicated that using TOPSIS method can help tackle with conflicting effects for A/C systems in buildings.