Cooling towers originated in the 19th century through the development of condensers for use with the steam engine.[5] Condensers use relatively cool water, via various means, to condense the steam coming out of the cylinders or turbines. This reduces the back pressure, which in turn reduces the steam consumption, and thus the fuel consumption, while at the same time increasing power and recycling boiler water.[6] However, the condensers require an ample supply of cooling water, without which they are impractical.[7][8] While water usage is not an issue with marine engines, it forms a significant limitation for many land-based systems.[citation needed]
By the turn of the 20th century, several evaporative methods of recycling cooling water were in use in areas lacking an established water supply, as well as in urban locations where municipal water mains may not be of sufficient supply, reliable in times of high demand, or otherwise adequate to meet cooling needs.[5][8] In areas with available land, the systems took the form of cooling ponds; in areas with limited land, such as in cities, they took the form of cooling towers.[7][9]
These early towers were positioned either on the rooftops of buildings or as free-standing structures, supplied with air by fans or relying on natural airflow.[7][9] An American engineering textbook from 1911 described one design as “a circular or rectangular shell of light plate—in effect, a chimney stack much shortened vertically (20 to 40 ft. high) and very much enlarged laterally. At the top is a set of distributing troughs, to which the water from the condenser must be pumped; from these it trickles down over ‘mats’ made of wooden slats or woven wire screens, which fill the space within the tower