Evaporative condensers employ cooling coils instead of packing. Downcoming drops of water cascade over a closed system of coils, counter-current to the flow of air induced by the fan system. 

Evaporation of the circulating water removes heat from the fluid passing through the coils. Water drops to the pan, where it collects and flows to the spray pump for recirculatlon.

Pump horsepower needs are much lower than for an equivalent cooling tower due to shorter piping runs and less water recirculation.

Evaporative condensers have some special advantages over cooling towers. Fluid cooled is in a closed system where it can't be contaminated and much less water is lost than from a conventional mechanical draft tower. 

The unit can be installed indoors or out, but hot discharge from indoor units must be ducted outside.