Experimental study on the optimum design of the flow-path system for a low noise indoor package air-conditioner

This study was carried out with the Taguchi method to find the optimum design condition of an indoor package air-conditioner (PAC) to minimize noise of operation. The goal of this study is to identify the optimum set of the control factors forming the flow-path system of an indoor PAC. The sound of operation and the number of revolutions of the fan of an indoor PAC were measured according to an orthogonal array of L-18(2(3)x3(4)) and used to find the smaller-the-better quality characteristic among the static characteristic analyses. As a result, the optimum condition of an indoor PAC for a low noise of operation is a set of aOE (c) G1 A2 B1 C1 D1 E3 F1 >, with the judgment criterion of the optimum set based on the sound of operation, the number of revolutions and the cost of production. The sound performance of an indoor PAC operating under optimum conditions improved 1.8 dBA compared to that of the standard condition, and resulted in a reduction of about 45 RPM in the number of revolutions for the target flow-rate of 18.5 m3/min.