It doesn't? What does it do?
Here's my understanding of how a car A/C works. The refrigerant expands adiabatically from its compressed state, rapidly cooling. The cold refrigerant passes through a heat exchanger where it absorbs heat from the car's warm interior air. The refrigerant gets compressed & heats up even more, then passes through another exchanger to give off some of its heat to the outside air, and then back to the expansion valve again.
I.e., it moves heat from the interior car air to the outside air.
My home AC unit has a big honkin' fan surrounded by lots of cooling fins. This is where the coolant dumps its heat into the atmosphere.
Now, if you're talking about home use, geothermal is the way to go! Constant ground temperatures; run it one way and heat the house, run it the other way and cool the house. Very nice.