ELI5: Explain Like I'm 5

Free cooling

Free cooling is a type of technology that uses cool air from outside to help cool things inside. Instead of using energy to create cool air, it uses the natural air outside that is already cool. For example, in hot weather free cooling can be used to help cool a house by bringing cool air from outside into the home to make it cooler inside. This uses less energy compared to using air conditioning systems which use energy to produce cold air.