An evaporative device for cooling a stream of air for cooling a space into which the air is discharged. The device includes psychrometric sensors installed in the air stream which provide signals to either an analog or a digital microprocessor control device. The stream of air is cooled by one or more mist nozzles in the incoming air stream, the flow of water to which is controlled through analog or digital control devices, enabling cooling of the stream of air to the maximum permitted by psychrometric relationships without unnecessarily high humidity.

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