Construction-Efficient Air Cooled Heat Exchanger in Outdoors Service

Date of Submission: 09/16/2015
Status: Provisional
Jurisdiction: USA
Equipment Type: Air Cooled Heat Exchanger
Docket Number: HOL-104

Abstract: The most common example of a large Air cooled heat exchanger is the so-called “Air Cooled Condenser” (ACC) used to condense a power plant’s sub-atmospheric exhaust steam using ambient air. Another example is the “Air Blast Chiller” or ABC (Holtec patent application number 62207674) explained in the Holtec Technical Bulletin HTB-34 (attached). Both the ABC and ACC are typically large installations with footprints that may well exceed 100,000 square feet, often much more. Figure 1 illustrates a typical “Cell” of an ACC. The “Cell” typically consists of a set of A-frame (inverted V-shaped) tube bundles made of a single row of tubes, served by a large blower which delivers ambient air in the so-called “forced flow” configuration to the bundles. The tube bundles emanate from a header at the apex of the ACC and slope down to two headers at the bottom. The exhaust steam, delivered to the top header condenses as it traverses down the length of the bundles. The bottom headers serve as the repository of the condensate. The blower is typically quite large, as much as 40 feet in diameter. To avoid excessive amount of parasitic power expenditure, the tube Bundle is typically made only one row deep with each tube made of an obround shape with the long flat sides (Figure 1) equipped with tall fins to serve as the dissipaters of the latent heat of the exhaust steam to the air coursing across the bundle (Figure 2). V-shaped bundles with the blower located above the bundle drawing the air in the so-called “induced” flow are also used.