There have always been improvement activities on fan design of an air-conditioner for more efficient air-flow rate, higher air static pressure and lower sound levels. In doing so, much attention has been put in the design of the fan itself while other surrounding structures, such as fan nozzle & side panels are seldom considered as important factors. This paper investigates how airflow performance of an outdoor unit of air-conditioners can be improved by changing the fan nozzle radius, depth & other surrounding structures while maintaining the fan itself In the course of the investigations, theories of fluid mechanics are being applied, and experiments are carried out to validate the hypothesis. The experiments were carried out by Design of Experiments so that the significant factors are identified through screening experiments and studied further to understand its effect towards airflow performance. It is concluded that the inlet radius of fan nozzle and the fan guard grille are most significant & airflow improvements are achieved by minimizing flow recirculation & separation.
