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4. General Information
Adiabatic Cooling
Adiabatic cooling uses evaporation to cool air before it passes through a finned heat exchanger. During adiabatic cooling, a
wetted pad is used to cool the entering airstream. The pads are specially designed to retain water on the surface to ensure that
it does not carry over to the finned coil, minimizing the risk of coil damage. The finned heat exchanger stays dry, protecting
surfaces from scale and corrosion.
The use of a small amount of water to pre-cool the air entering the heat exchanger lowers the required airflow and fan power
compared to air-cooled units, while also lowering the fluid temperature back to the system. In the most efficient adiabatic
systems, the air is cooled close to the wet-bulb temperature. Such substantial depression of the air temperature results in a
significant increase in dry cooling capacity and energy efficiency compared to dry-only designs. Once the ambient temperature
begins to approach freezing, or during times of reduced load, the unit can be switched to operate in a dry-only mode, thus
decreasing water usage.
Adiabatic heat rejection system controls are designed to be flexible, intelligent, and customer friendly, taking full advantage of
the dual operating modes. At a customer-selected design point, such as a cooler ambient dry bulb and a lower heat load, the
unit can turn off the recirculating water and switch to operation in dry mode. Additionally, the low volume recirculating water
sump automatically drains when freezing temperatures are experienced, negating the need for sump heaters.
The recirculating design of an adiabatic heat rejection system consumes less water than an evaporative cooling tower and an
adiabatic cooler with a "once through" design that sends water directly to the drain.
TrilliumSeries™ Adiabatic Cooler - TRF Operation & Maintenance Manual – General Information
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