Air-cooled heat exchangers rough rating

Select an overall from Tables 5 and 6 in the Heat Transfer Coefficients section (based on finned area). Arbitrarily use /2 -flns, 9 to the inch for determining U,. 

Calculate approximate air temperature rise from where 

ATa = Air side temperature rise, °F Ux = Overall coefficient based on finned area, Btu/hr ft °F 

Typical Section Width, ft Typical Tube Length, ft 

APF= Extended area ff/ft of tube = 3.80 AR= Extended area/bare area - 14.5 APSE = Extended area/bundle face area = No. tube rows (22.8) 

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If exchanger shell diameter is in doubt, see Chapter 2, Heat Exchangers, the Shell Diameter section. In addition, this book provides a rough rating method for air-cooled heat exchangers. 

The preceding information will suffice to rough rate shell and tube units. For air-cooled heat exchangers, more is involved in rough rating. A suggested procedure is as follows 2 3... 

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