The air conditioning (AC) system in your vehicle relies on a special compound called refrigerant that readily absorbs heat from the environment and helps the system to provide cool air to you and your passengers. The refrigerant can function in both a gaseous and liquid state. In fact, depending on what part of the system the refrigerant is occupying at any given moment, it will be one or the other.
An AC system evacuate and recharge is a two-stage procedure aimed at allowing a technician to service AC components. It is illegal to vent refrigerants into the atmosphere. Therefore, a specially trained and certified technician must follow certain procedures and use special equipment to perform an AC system evacuation and recharge.
During the procedure, refrigerant is removed from your AC system and captured in an approved container or machine. Once repairs to the system have been completed, refrigerant is added back (recharged) to the system.