Abstract: A heat exchange system and particularly a water cooling tower wherein water is sprayed from an upper level thereof to be cooled by rising air currents. A rotatable vertical shaft coaxial with the tower, has a multiplicity of arms or blades extending radially therefrom along the length thereof. The blades are of generally triangular cross-section, having upper surfaces which slope downward and lower surfaces which slope upward from leading portions thereof, whereby water drops falling from above and air currents rising from below both impart vectors of force toward the leading portion to rotate the shaft. An air impeller at the lower end of the shaft is thus rotated to augment air flow.

Abstract: A heat transfer system for cooling water, comprising a relatively large air duct which is open to ambient air at the upstream end, where there is situated an annular, coaxial nozzle to jet hot water through a venturi tube toward the downstream end of the air duct. The high velocity stream of water draws air into the low pressure zone to intermix with the finely divided water droplets moving downstream. The water is cooled by transfer of heat of vaporization as well as by transfer from the air itself, whereby water drawn from the downstream end of the air duct is cool enough for recycling.