Abstract: Insufficient oil return in compressors can lead to reduced efficiency, increased noise, and even mechanical failures, posing a serious threat to system reliability and lifespan. Focus on the issue of insufficient oil return in compressors. It begins by thoroughly analyzing the oil return mechanism in refrigeration systems and the factors influencing compressor oil return. Based on this analysis, two improvement solutions are proposed using specific cases of insufficient oil return: optimizing refrigerant charge to improve oil temperature superheat, and adjusting startup frequency and operating platform time to establish a dynamic balance of oil circulation. Experimental validation confirms the feasibility and effectiveness of these solutions. Both approaches significantly enhance oil return performance, eliminating oil shortage periods—which previously lasted 150 seconds during cooling startup and 110 seconds during heating startup—and achieving continuous and stable oil return. However, each solution has its applicable scenarios, offering flexible choices for different engineering conditions. The research result provides a viable technical path and experimental basis for optimizing compressor oil return in refrigeration systems, offering practical reference value for improving equipment operational reliability and reducing maintenance costs.

Key words: Compressor, Oil return, Inverter air conditioner, Long connecting pipes