HVAC system that pulls-in cold air from outside?
There is an optional add-on part for HVAC systems called an economizer.


  An HVAC economizer is a dampered vent designed to save energy and give the cooling system a break. Sensors within the economizer compare the outdoor temperature and humidity with that inside the building. –Google


When you call for cooling, the unit decides if it needs to run the AC or just open the economizer to pull in outside air.