A study on axial flow fan design parameters of air conditioner outdoor unit and the performance improvement

An axial flow fan has been generally used for an outdoor unit of a split type room air conditioner because of the larger flow rate characteristics than the other types of fans, so that there have been many researches on flow noise reduction to provide more comfort to users. As the product size is getting smaller and energy efficiency regulation is getting stricter, it is necessary to develop a high efficiency fan as well as a low noise one. Moreover, the fan must be developed to have good performance not only the fan itself but also when it runs at an operating condition in the outdoor unit. In this paper, experimental parametric study results on the performance and its design parameters of an axial flow fan for an air conditioner outdoor unit are presented. Several axial flow fans were fabricated according to DOE(design of experiment) and experiments were carried out to verify the effects to fan performance -PQ characteristics and their efficiencies. As a result, a new combination of design parameters for high performance could be achieved and the performance of the newly designed fan had the maximum static efficiency higher by 3%, and the maximum static pressure coefficient higher by 6% than old one. At the operating condition in the outdoor unit, static efficiency had increased by 3% and static pressure coefficient had increased by 15%. Consequently the outdoor unit became less energy consuming and less noisy by 2.5 dB(A) in terms of airborne noise produced by the axial flow.