Abstract: A system cools a space toward target conditions using an air conditioning process based on a bank of different cooling device types. Some device types consume relatively less energy and are suitable for mild environmental conditions, others consume more energy and are needed for extreme conditions, while others may fill a middle ground. To help save energy, the system alters the air conditioning process by selecting one or a mix of cooling device types expected to be sufficient for current conditions. Current conditions corresponds to a supply air position on a psychrometric chart. Selection of the appropriate cooling device type(s) is made according to the location of the supply air position relative to a dew point, which is determined from the target conditions set by a user.