Development and experimental study of the characteristics of a prototype miniature vapor compression refrigerator

This paper develops a practical miniature and portable vapor compression refrigerator. The dimensions of the refrigerator are 190 mm × 190 mm × 100 mm and its weight is 2.75 kg. It integrates a miniature variable speed rotary compressor with a miniature electronic expansion valve (EXV) operating in pulse width modulation (PWM) mode. Besides, a new type of miniature microchannel plate-fin evaporator is developed with vacuum bonding technology and a brazed aluminum parallel flow microchannel condenser is applied. Experiments are conducted to explore the operating performance of the prototype miniature refrigerator, especially the effects of EXV duty cycle and working conditions on the cooling performance. Experiments find that the operation of the system is smooth and reliable; the results show that it has a cooling capacity of 260 W which is high enough for cooling one person with moderate working load, where the ambient temperature is as high as 50 °C and the inlet cold water temperature of the evaporator is 24 °C, respectively. Under these operation conditions, the system COP can reach 1.62 and the reversible efficiency is 0.324.