Experimental study of a multi-evaporator refrigeration system applying mechanical subcooling and high efficiency distributor

• An improved rectifier nozzle-type distributor was designed. • A mechanical subcooling unit was incorporated to enhance refrigerant distribution. • The cooling rate, distribution unevenness, energy efficiency ratio parameters were analyzed. • The system’s energy efficiency ratio improved by 20% To improve heat exchange performance in multi-evaporator refrigeration systems under varying operating conditions, this study proposes an improved rectifier nozzle-type distributor (IRND) as a replacement for the rectifier nozzle-type distributor (RND). Additionally, a dedicated mechanical subcooling unit is introduced to further enhance refrigerant distribution and system efficiency. A multi-evaporator refrigeration system with a mechanical subcooling unit was constructed to analyze cooling rate, superheat unevenness across branches, cooling capacity unevenness, pressure loss in the distributor, and the system’s coefficient of performance. Results showed that within the 6–26 °C subcooling range, the system using IRND achieved a 64.0 % increase in cooling rate, a 20 % improvement in COP , a 36.9 % reduction in superheat unevenness, and a 26.5 % reduction in cooling capacity unevenness. Under experimental conditions, the IRND system demonstrated significantly lower unevenness compared to both RND and centrifugal distributor (CD) systems. This study demonstrates the feasibility of IRND structural improvements, offering a new approach to enhancing refrigerant distribution and system efficiency in multi-evaporator refrigeration systems using mechanical subcooling.