Evaporative Cooling 101

What is evaporative cooling?

From the perspiration on your skin, to the transpiration from the pores on trees, evaporative cooling is found throughout the world; remember those misting fans everyone loved in the 90’s? That’s evaporative cooling too.

Evaporative cooling is the process in which the evaporation of water removes heat from a system.

Application in cooling towers

Cooling and HVAC units typically use evaporative cooling through either counterflow or crossflow systems, this can be further broken down to direct and indirect evaporative cooling.


In counterflow systems, water is dispersed evenly over the fill while air is drawn directly upwards into it. The uniform dispersal of water is vital for even, effective cooling; EVAPCO designed and uses specialized nozzles and a pressurized water distribution system to facilitate this.


In crossflow systems, the air is drawn perpendicularly across falling water. In this system, no pressurized nozzles are necessary to facilitate the falling water, instead passing through a distribution basin.

Direct evaporative cooling

Direct evaporative cooling systems put the process fluid, typically water, into direct contact with air. Water flows through fill as a fan draws air across it, facilitating the transfer of heat from the warm water to the cooler air. This is the system used in open-air cooling towers, such as EVAPCO’s factory assembled cooling towers.

Indirect evaporative cooling

Indirect evaporative cooling systems keep the process fluid out of direct contact with air. Instead, it is pumped through coils, with water flowing across the coils. Water absorbs heat from the process fluid through sensible heat transfer from the coil or piping. This process minimizes the potential for contamination and reduces overall maintenance on the cooling unit. EVAPCO’s closed circuit coolers and evaporative condensers utilize this form of cooling.

EVAPCO’s numerous trend-setting technologies demonstrate our tireless pursuit of innovation; we are constantly investing in research and development to improve our products and the experience each of our customers has with our cooling solutions. Choosing EVAPCO is choosing progress.