Indirect Evaporative Cooling is one of the most significant energy efficiency technologies we research.


Indirect evaporative cooling operates by the same fundamental concept as evaporative cooling (evaporating water to cool the air), except that cooling is achieved without adding moisture to the supply air stream. Various formats are available for indirect evaporative coolers, many of which are capable of cooling well beyond the wet bulb temperature—the temperature one feels when one’s skin is wet and is exposed to moving air. These systems can be installed as the primary cooling equipment in residential or small commercial buildings, or as ventilation air pre-coolers for conventional vapor compression systems with high outside air load and tight supply temperature tolerances.


WCEC sees indirect evaporative cooling as one of the primary energy efficient ways to cool hot, dry air typical of Western climates. In order to further advance the technology into the marketplace, WCEC works to answer these questions:


  • Can we model indirect evaporative coolers to help create solid, baseline savings measurements that can be utilized by utilities to create incentive programs?
  • How well do these indirect evaporative systems hold up over time? What parts need to be maintained or serviced regularly?
  • How effective are indirect evaporative stand-alone units within specific climate zones?
  • How much savings can be estimated for stand-alone indirect evaporative cooling systems and hybrid systems within specific climate zones?


WCEC is field testing hybrid-indirect evaporative systems through the Western Cooling Challenge and is looking to test other indirect evaporative systems through demonstration programs.