scope:

introduction

For thermal power plants, only part of the primary energy may be transformed into electrical energy. Generally, the rest of the energy is released as waste heat. This is done by emitting the heat into surface water or, by means of coohng towers, into the atmo sphere.

There are to types of coohng towers, natural-draft and fan-type (i.e., mechanical-draft) cooling towers; the former is either for wet or for dry cooling, the latter for wet and dry cooling. Nowadays, for large thermal power plants, natural draft cooling towers Up to 170 m are used.

The physical processes occurring in the cooling tower and in the surrounding area are sufficiently wellknown, as far as they are relevant for this GuideUne (see Section 2 as well as [1 ; 3 ; 5]). The statements which are given in this Guideline refer to Single cool¬ ing towers that are about 80 m to 170 m high and have a wast heat power in the ränge of 1000 MW and 2500 MW, the towers being located on flat terrain (without any special orographic conditions) and in the Central European climate.

The physical impact of coohng tower emissions is described in Sections 4 and 5.