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Photograph: Photograph: FIGURE 4. The air is induced in the base of the tower by the fan, flows upward though the fill material and interfaces counter-currently with the falling hot water. This is a counterflow type
Photograph: Photograph: FIGURE 5. The fans are located in the air outlet to induce air flow though the air inlets. This is a crossflow type
Photograph: Photograph: FIGURE 6. The concrete version of the natural-draft tower features large chimney heights and diameters
From the dawn of mankind, the need for ridding ourselves of excess heat has existed. Until the industrial revolution, however, perspiration and surface water were sufficient to serve this need.
The need for cooling towers became imperative after the U.S. Civil War. Two factors that contributed to this change were the harnessing of electricity and the movement of great masses of people to the cities. With this influx of people came the necessity of preserving fresh food. The poor ice-producing winters of 1888 and 1889 created a great need for ice-making plants.
The first a.c. electrical system was installed at Greensburg, Pa. in 1886. The demand for this new energy led to the construction of 410 power stations by 1888. The 1896 development of high-tension lines made the extended delivery of electricity possible. Manufacturing of ice and electricity resulted in waste heat. Thus, there was a requirement for more-efficient means of heat removal.
The first type of cooling used was via spray ponds. They were easy to build and maintain at low cost. However, they required large areas, were inefficient, and created major entrained-droplet problems. Ponds and spray ponds are still in use today, primarily by utility plants that have adequate land to accommodate them. The original cost of earth-moving for current large heat loads is expensive, so an available valley or river bend may be utilized to cut costs.
The early towers
In 1898 an immigrant from Germany, George Stocker, answered the...