Fresh air evaporative coolers generally refer to devices that use the principle of water evaporation to absorb heat and cool fresh air (outdoor air). Their classification is mainly based on the contact method between air and water and the number of system stages.
Classification by Cooling Method:
Direct Evaporative Cooling (DEC): Fresh air comes into direct contact with water, achieving adiabatic cooling and humidification. The maximum temperature can reach the wet-bulb temperature of the air.
Common forms include: Cold mist type (such as high-pressure micro-mist type, air-water mixture type)
Cool air type (such as evaporative air conditioners/cooling fans, window-type evaporative cooling air conditioners)
Indirect evaporative cooling (IEC) involves avoiding direct contact between fresh air and water. Sensible heat is exchanged through a heat exchanger, achieving isohumidity cooling. The maximum temperature can reach the air's dew point.Common types include plate-fin and tube-type indirect evaporative coolers.
Composite/Multi-Stage Evaporative Cooling
Combining direct and indirect methods to improve cooling efficiency:
Two-Stage System: Indirect pre-cooling followed by direct evaporative cooling
Three-Stage System: Such as cooling tower pre-cooling → indirect evaporation → direct evaporation