Miniature vapor-compression refrigeration system with capillary evaporator for portable cooling devices

With the rapid development of portable electronic devices, efficient and compact cooling solutions have become increasingly important. This study designs and fabricates a miniature vapor-compression refrigeration system (MVCRS) incorporating a novel capillary evaporator with a diameter of 3 mm, which offers enhanced flexibility and deformability of the evaporator. This structural innovation enables the evaporator to be bent into various shapes to adapt to complex surfaces, making it suitable for application in the compactness and light-weight electronic components, such as wearable device, robotics, and battery thermal management. Several evaporator structures (viz. serial, parallel, double-serial, and double-parallel evaporators) were proposed and systematically evaluated, which confirm that the throttling effect and flow resistance caused by the capillary evaporator can be effectively mitigated by optimizing the evaporator structure, thereby improving the system's coefficient of performance (COP). With a double-parallel evaporator, this system can achieve a cooling capacity of up to 281 W and a maximum COP of 5.06, respectively. The proposed MVCRS exhibits strong potential for cooling portable electronic devices and provides a novel structural strategy for developing efficient miniature cooling systems capable of operating in complex and compact heat dissipation structures. Owing to its high cooling performance and energy efficiency, this system is promising for application in automotive, medical, military, aerospace, and electronics sectors.