Research PaperImproving quick cooling performance of a R410A split air conditioner during startup by actively controlling refrigerant mass migration

- The refrigerant distribution inside the air conditioner is measured.
- The dynamic characteristics of the air conditioner after startup are investigated.
- Active control strategies are proposed to improve quick cooling performance.
- Increasing the refrigerant mass in the condenser can improve cooling performance.

This paper presents experimental investigations on the transient refrigerant migration during the start-up and shut-down of a R410A split air conditioner. The refrigerant distribution inside the main components of the air conditioner is measured by using “quick-closing valves” technique in which the components are isolated and the refrigerant is removed to be weighed. Results indicate that the refrigerant distribution rapidly changes within 300 s during start-up and becomes gently after 300 s. On the other hand, the refrigerant distribution rapidly changes within 60 s during shut-down and becomes gently after 60 s. In addition, the dynamic characteristics of the air conditioner after startup are also investigated at the standard cooling capacity rating condition. Several active control strategies for refrigerant mass migration during on-off cycling are proposed to improve quick cooling performance during startup. And it is verified that increasing the refrigerant mass in the condenser can improve cooling performance during startup.