Abstract: The thermal expansion valve is still widely used in the commercial air conditioning field due to its advantages of automatic flow regulation, easy installation and maintenance. It is crucial to make the best use of its key role. This article studies the influence of adjusting the thermal expansion valve of the air conditioning unit on system performance and other parameters during refrigeration operation. It is found that there is an optimal static superheat of -1.5 K during the matching test between the thermal expansion valve and the whole machine, which maximizes the performance of the system. At this time, the superheat degree at the outlet of the evaporator is 3.7 ℃, the low pressure of the system is 0.81 ℃, and the outlet air temperature reaches a minimum of 14.2 ℃, achieving good user comfort, the highest energy efficiency, and achieving the goal of energy conservation and emission reduction.

Key words: Thermal expansion valve, Air conditioner, Experimental study, Refrigeration system