Air-Cooled Condensing Units in Thermal Engineering (Review)

Data testifying growth in the number and capacity of power plants that use atmospheric air for heat-removal purposes are presented. The basic schemes for removing heat from turbines involving air-cooled units are considered, and the ratios of their technical indicators, such as heat-transfer surface areas and power consumption for driving the pumps and fans, are illustrated. The heat-removal scheme most rational for using it in practice is substantiated. Different kinds of finning heat-transfer tubes that allow cooling system performance features to be taken into account are presented. Their design features, characteristics, and application fields are considered. Promising lines of constructing efficient heat-transfer surfaces are shown. The basic design schemes of air-cooled condensing units (ACCs), their classification, and specific features of their layout solutions are presented. The important structural components, including a largediameter steam line, fans, and heat-exchanging modules, are described. The basic requirements for the ACC's fan units are formulated. Their design versions, main components, and layout solutions are described. It is shown why the fan test results differ from the actual operation conditions. The basic kinds of heatexchanging modules and their assemblies, which depend on the technological capabilities of the manufacturers and thermal-hydraulic parameters, are presented. The specific features relating to startup, shutdown, and operation of ACCs at low outdoor air temperatures are considered along with the design and technological measures taken to secure their trouble-free operation. The importance of cleaning the ACC's finned surface is noted, and methods for cleaning it in the course of operation are pointed out. Specific features relating to the occurrence of corrosion and erosion of the ACC's heat-transfer surface are described. The influence of wind and air recirculation on the ACC's operation is shown, and the designs of devices for usefully utilizing the wind energy aimed at achieving more efficient operation of ACCs are suggested.