How air condition system is closed loop control system?

Air conditioner system senses the room temperature and then decides how much cooling has to be provided to room as per the setting. Say u need only 20 degree Celsius only.

To elaborate, in a closed loop system, the output in some way shape or form is fed back into the input of the control system. With an air conditioning system, the output is temperature. This temperature is read, and fed back into the control system to determine if additional cooling is needed or not.

An example of an open loop system would be if you programmed the air conditioning to turn on from 11AM to 5PM, then turn off. The output of the system (temperature) doesn't effect the input (when the system runs).