In the Indirect Evaporative cooling stage(IEC) the water and hot air travel in different channels. Water and hot air do not come in direct contact with each other. That's why it is called Indirect Evaporative cooling. Dual-stage combined is also called the Indirect Direct Evaporative Cooling system. It additionally uses a heat exchanger called DAMA.
Jaipur, Appliances, INDIRECT EVAPORATIVE COOLING