Study of refrigerant flow consistency and tolerance control of a distributor for air conditioner

Abstract

In the residential air-conditioning system, a refrigerant distributor is a device that connects the outlet of an expansion valve to each evaporator coil circuit when paired with a multi-circuit evaporator. The efficiency of the heat exchanger is significantly impacted by the two-phase refrigerant’s distribution. Only when the distributor has consistent performance can the heat exchanger be utilized efficiently. Hence, the aim of this study is to identify the impact of manufacturing tolerance of the distributor for air conditioner on the flow consistency. Preliminary analysis for different rules of factors such as the installation angle, barrel diameter and branching angle are studied through Computational Fluid Dynamics (CFD) simulation to analyze the parameter sensitivity. Based on the mean value of the standard deviation of the mass flow rate and quality at each path, the distributor’s performance is evaluated. It is found that the tolerance control on barrel diameter and installation angle will give significant impact on the flow performance, this is because the evaluation of standard deviation for mass flow rate and quality for these conditions are above average, that are 0.443 and 0.0161 respectively. On the contrary, a minimal influence is seen when the branching angle can be controlled within 1 degree tolerance. The following parameters’ effect on flow consistency are presented in order of largest to smallest: barrel diameter, installation angle and branch angle. A thorough study on the performance for the existing distributor is conducted and the tolerance of the important geometrical parameters (i.e., barrel diameter and branch angle) and working condition (i.e., installation angle) are identified.