Abstract : Upgrading ammonia refrigeration systems to achieve automatic power adjustment and liquid flow regulation for cooling supply results in significant energy savings with low investment and quick returns, making it a key step in improving the automation level of refrigeration equipment. Keywords : Compression refrigeration, liquid pump cooling, PLC, frequency converter, intelligent regulator [b]1 Introduction[/b] Many large and medium-sized state-owned enterprises, especially some older ones, lack sufficient funds for comprehensive technological upgrades, resulting in low levels of automation in their refrigeration equipment. For example, in refrigeration plants using ammonia as refrigerant, the compressor and ammonia pump are still manually started, stopped, and adjusted, failing to meet the requirements of real-time start/stop and flexible adjustment based on changes in refrigeration load. Automating the refrigeration system can reduce the untimely and inaccurate effects of manual operation, achieving automatic control, prevention of misoperation, and energy saving. Automation of ammonia refrigeration systems mainly includes automatic adjustment of liquid ammonia pump supply, automatic adjustment of evaporation temperature, automatic adjustment of condensing pressure, automatic start/stop and energy regulation of the refrigeration compressor, and automatic control of refrigeration auxiliary equipment. Regarding the development direction of refrigeration automation, one opinion favors a centralized-distributed architecture and integrated control using a central computer. This requires treating the entire refrigeration system as a multi-factor coupled regulation object; establishing a general mathematical model for the system; and developing new refrigeration automatic control components suitable for computer control. However, due to the slow progress in research on the dynamic characteristics of refrigeration equipment—a major problem—there has been no significant breakthrough to date. The author believes that, given our current lack of capability and funding for highly centralized automatic control, we should focus on the core links of system automation: the automatic start-stop and cylinder adjustment (energy regulation) of the ammonia compressor and the automatic speed regulation (flow regulation) of the liquid ammonia pump. [b][align=center]For more details, please click: Automation Retrofit of Liquid Pump-Supply Ammonia Refrigeration System[/align][/b]