Enhanced energy efficiency in dual-evaporator refrigerators: experimental insights into parallel cooling cycle optimization

Abstract

This study systematically investigates the optimization of the cooling cycle for a bottom-mounted freezer (BMF) refrigerator equipped with dual evaporators dedicated to fridge and freezer compartments. Unlike prior research focused on theoretical models or generalized designs, this work emphasizes a comprehensive, step-by-step experimental approach. The optimization involved transitioning the cooling cycle from a serial evaporator configuration to a parallel configuration, facilitated by a 3-way valve enabling independent refrigerant flow control to each evaporator. The transition addressed critical technical challenges, including refrigerant starvation in the fridge evaporator, through iterative modifications to algorithms and hardware. The performance was rigorously evaluated according to the IEC 62552 standard, measuring key metrics such as energy efficiency, energy consumption, energy class, and temperature distribution. The findings reveal a 7.2 % improvement in energy efficiency alongside enhanced cooling performance, achieved through innovative design and operational adjustments. Notable outcomes include a reduction in compressor frequency, enhanced defrosting efficiency, and improved refrigerant flow management. The research highlights the importance of experimental validation and iterative testing for optimizing complex refrigeration systems, addressing both energy savings and environmental sustainability.