Patent Application
20050006050
The following invention relates to methods and devices for directing the flow of air in the suction area formed by the chamber below air-cooled condenser systems that are mounted on support structures and are comprised of air-cooled condensation installations consisting mainly of one vertical plane with air flowing through and of a plane consisting of condenser modules with cooling elements, preferably in the form of roof panels for cooling process and turbine exhaust. The cooling elements may also be arranged even with the surface.
Air-cooled condenser systems for cooling turbine or process exhaust are generally comprised of identical modules arranged in several parallel rows, adjacent to and behind one another, arranged essentially in a single plane, in a checkerboard pattern. These systems are normally raised on a supporting structure, forming a suction area in the space below. Each module is equipped with a ventilator, which sucks in the cooling air flowing beneath the supporting structure, and forces it essentially vertically through the cooling elements. To enable undisrupted operation, it is necessary for all the ventilators to supply equal quantities of air in order to maintain the basic condensation output. For this reason the modules are placed on a support structure so that it is possible to achieve an even flow of cooling air from all sides.
In the case of a crosswind, air preferably flows toward the condenser system from one direction and thus disrupts the flow field in the suction area beneath the module. As a result, one can observe a subsiding of the quantity of cooling air in parts of the system which in turn will lead to a reduction in condensation output. Experience has shown that the outer windward modules are especially unfavorably affected as the greatest flow rates of the cooling area occur there. As a result, the air-cooled condensers often can no longer ensure the necessary vacuum pressure at the outlet to the turbines, which leads to losses in the efficiency of the power plant. Under unfavorable conditions, the exhaust pressure increases to such a level that to protect the turbines an emergency shut-off must be initiated. Neither a reduction in output nor a complete shut-off of the power plant is acceptable to operators.
To avoid this problem, current technology utilizes wind deflection panels, blocking panels or fine-meshed screens around the periphery or outside the condensation system. These are intended to block wind flow and to ensure an undisrupted airflow field beneath the condensation module. The disadvantage of these solutions is their high cost and the increase in flow resistance for the cooling air, which only can be compensated by an increase in energy consumption by the cooling ventilators. Furthermore, in many cases local features do not allow building modifications to condenser facilities.
The purpose of the invention consists in eliminating or at least largely minimizing the negative effects of crosswind while avoiding the above-discussed disadvantages. This is solved in accordance with the invention by installing baffle plates in the space that forms a suction area beneath the condenser system that is mounted on the supporting structure. Panels designed to direct flow, so-called wind deflection panels, are used as baffle plates.
In relation to the clearance below the steel structure, the wind deflection panel in the case “A” between 1/(N−1) and 1/N, wherein “N”=the number of modules that lie one behind the other in the direction of the wind, blocks off the height. With six or more modules, as in the case of the wind deflection panel “B”, the blockade increases to 1/(N−2).
With respect to the outer ventilators, panels “A” and “B” have the effect of collecting the flow of air below the cooling air intake of the ventilators, thus improving the supply of air. The advantage is thus that even the kinetic energy contained in the wind is utilized. Surprisingly, tests have shown that the optimized arrangement of the wind deflection panels generates no additional drop in pressure for the ventilators; but, in contrast, a tendency towards improved supply to the modules is ensured. Because the wind deflection panels only block approximately that portion of the cross-section of the flow of cooling air that corresponds to the portion of the flow of cooling air that corresponds to the modules, the modules that lie behind the blocking panels are not affected, or are only slightly affected.
In another favored design, additional wind deflection panels “C” are installed at a height slightly above the base. These panels serve to ensure an improved bombardment with air of the modules that lie directly behind the upper dividing panels “A” and “B”. The height of these wind deflection panels “C” installed near the base preferably amounts to 1/N, a maximum of ¼ of the clearance height of the supporting structure. The preferred ground clearance is approximately 1 m, but if the system is large enough this can also be increased to approximately 2 m to allow easier access to the system. These base panels “C” give an advantageous upward component to the cooling air flowing beneath the modules. The use of such wind deflection panels near the base is dependent upon local conditions, especially main wind direction.
The wind deflection panels “A”, “B”, and “C” can be made of steel; however, other materials such as canvas, plastics, or wood are also suitable for use. The panels can be designed to be static or movable, e.g. in the form of roll-up panels or venetian blinds. The movable design for the wind deflection panels enables adjustment to current wind conditions, especially wind direction, and wind speed.
Adjustment of such movable panels can be automatic or manual. Advantageously, the wind deflection panels according to the invention can be made of sound-absorbing materials, allowing the noise emissions from the air-cooled condenser system to be further reduced.
Advantageously, the wind deflection panels according to the invention can be integrated not only into newly constructed air-cooled condenser facilities; but, a modernization of already existing condenser facilities is also possible.
| Number | Date | Country | Kind |
|---|---|---|---|
| 03015751.5 | Jul 2003 | EP | regional |
