A device or structure used to condense steam or reduce the temperature of water used as a cooling medium in a process for reuse. Cooling towers are either natural draught or forced draught in design and operation. Natural-draft cooling towers are large structures that contain packing material with a high specific surface area down which the water to be cooled trickles and cascades, contacting with cool air that is drawn up through the packing by convection. The cooled water collects at the bottom of the tower and is returned to the process for reuse and a make-up of water is added to account for loss by evaporation. Forced-draft cooling towers use fans to pass the cooled air through the packing. Although they have a higher operating cost, they are comparatively smaller and more compact than natural-draught cooling towers. In mechanical-draft cross-flow cooling towers, the air flows horizontally across the downward-flowing water. They therefore have a shorter path for the air to flow and allow a greater flow of air for the same power demand as counter-flow forced-draft cooling towers.