Abstract: Heat exchange units are disclosed for exchanging heat between at least one fluid, for example water, and a gas, for example air, comprising at least one battery of heat exchange tubes which are parallel to each other and extend generally vertically and in which circulates one of the fluids. The gas, such as air, passes between the tubes of the battery generally transversely of the heat exchange tubes, and means are provided for selectively spraying a liquid on the heat exchanger tubes. The heat exchange units may be employed in atmospheric natural draft, or forced draft coolers, or cooling towers, or combinations of such draft-producing means may be employed in a single cooling tower.