Evaporative cooling has been used for a long time, as a low-cost way to provide cooling in hot and dry climates (ASHRAE Climate Zones 1B, 2B, 3C). The adverse impact of direct evaporative cooling is an increase in humidity content within the supply air stream. The Coolerado system uses a speciazlied evaporative cooling heat exchanger to deliver cooled air, without any change in absolute humidity. The system is capable of cooling air to the outdoor air dewpoint temperature. The Department of Energy has evaluated the Coolerado system as having an EER of over 40, approximately 4 times higher than the minimum efficiency requirements for small split DX systems.
We recommend discussing applications of the Coolerado system carefully with a building owner. Some care is needed to properly shut-off the system for the winter, to prevent water from affecting the unit's heat exchanger. Unit fans are not capable of a significant amount of static pressure capability. Application support is more limited than that provided by major HVAC equipment manufacturers, but is improving.