A popular type of air conditioning system uses an outdoor condensing unit coupled with an indoor evaporator coil. The coil is mounted downstream of a furnace located in a closet or attic. Split-system heat pumps are similar, but they incorporate a blower to move the air instead of a furnace.
In a properly operating residential system, the air from the home is forced across the evaporator and cooled to below its dewpoint. Moisture is literally squeezed from the air like water from a sponge. The combination of cooling and dehumidification produces (hopefully) very comfortable results.