Comparative Analysis Between a Capillary Tube and an Electronic Expansion Valve in a Household Refrigerator

This study compares the performance characteristics of a household refrigerator equipped with an Electronic Expansion Valve (EEV) with those with a capillary tube. A 513-liter top-mount refrigerator, originally equipped with a capillary tube, was retrofitted with a Pulse Width Modulated (PWM) expansion valve and extensively tested. Comparative analyses were performed based on standardized pull-down and energy consumption tests, carried out at three ambient temperatures (18°C, 32°C and 43°C) and with three compressor speeds (2000 rpm, 3600 rpm and 4500 rpm). It was shown that the EEV system showed better performance in terms of energy consumption, as compared with the capillary tube system, only at high cooling loads (ambient temperature of 43C) and at low cooling capacities (compressor speed of 2000 rpm). For a wide range of operating conditions the pull-down times of both systems were kept within a difference band of ± 3%.