Dry Cooling Towers

Abstract

The chapter presents a technical summary of the power-plant cooling problem, outlining generic possibilities, and the associated environmental impacts, in the categories of hydrosphere, atmosphere, noise, and aesthetics. General ideas of economic optimization are given, and the conventional alternatives are described. Limitations under current regulations and possible future restrictions are mentioned. The chapter studies the problem to minimize simultaneously tower size and heat-exchanger size. An analysis of the internal aerodynamics of dry towers, which leads to a criterion for minimum tower size, is presented. The chapter considers the heat exchanger and shows that small heat-exchanger size and small tower size are simultaneously achieved by use of a fine, shallow heat exchanger, in principle. The chapter presents particular types of heat exchangers as potentially practical examples and examines how the basic design features of the cooling tower depend on various given or assumed parameters. These relationships are organized in forms of a power-law correlation, which will be useful for future economic optimization studies. The results are related to data from real towers. The chapter concludes with a brief survey of questions requiring further study; among these are the interesting possibility of very low natural-draft towers and related problems of aerodynamic loss and weather modification, the relation between draft and noise production, possibilities for “cold storage” to level the effects of temperature change, and the possibilities for innovative heat transfer device.