Hybrid Cooling System

Abstract

The invention is a hybrid cooling system for condensing the exhaust steam of a steam turbine (10), which cooling system comprises a dry cooling circuit (11), a dry air-cooled unit (12) performing heat dissipation of cooling water flowing therein, and a wet cooling circuit (14) and a wet cooled unit (15) performing heat dissipation of the cooling water flowing therein. According to the invention, the cooling water flowing in the dry cooling circuit (11) is separated from the cooling water flowing in the wet cooling circuit (14), and the dry and wet cooling circuits (11, 14) are connected to a common condenser.

Description

TECHNICAL FIELD[0001]The present invention relates to water-saving dry / wet cooling systems, i.e. to hybrid cooling systems for use in power plants and in other industrial cyclical processes.BACKGROUND ART[0002]In prior art, the most widely used power plant and industrial cooling system is the so-called wet cooling system, in which the cooling water is allowed to evaporate freely to the environment. The application of this system—in addition to the extra cost of required additional water—entails environmental problems, like, for example, the negative impact of the emitted high volume of vapour on the microclimate, icing of the roads nearby in winter-time, as well as the deposition of the water saturated with contaminations that must be drained from the cooling water circuit. At the same time, there are known dry or in other words air cooling systems, which absolutely eliminate water consumption and the associated environmental damage, in which the cooling water is circulating in a cl...

AI Technical Summary

Benefits of technology

The solution presented in this patent is to use separate water circuits for wet and dry cooling, with a common condenser. This allows for the use of a more efficient air cooler material in the dry cooling circuit and eliminates deposits within the air cooler tubes. Additionally, water-water heat exchangers can be used to further improve operational flexibility and cooling capacity. These are cheaper and can change cooling capacity quickly as needed.

Problems solved by technology

The application of this system—in addition to the extra cost of required additional water—entails environmental problems, like, for example, the negative impact of the emitted high volume of vapour on the microclimate, icing of the roads nearby in winter-time, as well as the deposition of the water saturated with contaminations that must be drained from the cooling water circuit.

These systems require a much higher investment cost and their application is limited by the lower summer output.

One such frequently applied hybrid system is the plume abatement hybrid cooling, which eliminates the disadvantages of wet cooling systems regarding the intensive emission of vapour, although it has a low water-saving ability.

However, due to the single circuit solution, the same cooling water is circulated in the dry air-cooled tubes as taken on the wet cooler fill, which is considered as being contaminated from the aspect of air-cooled heat exchangers.

It is a further disadvantage that the extended number and length of tubes in the air cooler make their cleaning difficult.

Using the known hybrid cooling system, all this also limits the ability of accomplishing a substantial water-saving by increasing the air cooler surface.

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