Optimal thermohydraulic design of the indoor unit of a split-type air conditioner

Abstract

A CFD-based optimization process was used to design an air supply casing shape for the indoor unit (IDU) of a split-type air conditioner (SAC). The aim was to enhance the IDU performance, including the volume flow rate and total cooling capacity. To this end, the numerical results, including the pressure, velocity, temperature, and humidity ratio distribution, were used to evaluate the IDU performance. For the CFD-based optimal design, a 3D printer was used to manufacture an optimized casing in combination with four IDU geometric parameters. The optimal tongue gap, rear wall gap, and radii of curvature for the first and second segments were 2.2, 8.4, 56.7, and 98.8 mm, respectively. As a result, the measured and predicted volume flow rate and total cooling capacity of the optimized IDU increased by nearly 20% and 27%, respectively, compared with those of the original IDU. Moreover, the predicted and measured volume flow rates and total cooling capacities agreed well, with the relative errors of the IDU performance being less than 1% and 5%, respectively. In addition, the measured power consumption of the cross-flow fan of the optimized IDU was reduced by 19.4% compared with that of the original IDU.