TABLE OF CONTENTS In the presence of an atmospheric temperature inversion, the performance of an air-cooled heat exchanger and of a cooling tower is reduced. This is because the potential driving force or pressure differential is less and the effective temperature of the air entering the cooling system is higher than during conditions when the adiabatic lapse rate prevails. In 1925, Merkel mentioned that temperature inversions might be the cause of apparent inconsistencies in cooling tower performance predictions.
Normally, cooling tower acceptance tests should not be performed during periods of inversions according to Lauraine, Lemmens, and Monjoie. During a temperature inversion, the moist air in the plume of a wet-cooling tower may be trapped in the inversion, and plume dispersion is greatly reduced. This may lead to fog formation and precipitation. In extreme cases, it can lead to the formation of ice. An indication of the nature and frequency of inversions is presented by Tesche. Exceptionally strong inversions have been observed in arid and desert areas where dry-cooling towers are most likely to be erected.
Buxmann tries to quantify the influence that an inversion has on the performance of a natural-draft, dry-cooling tower. Employing the temperatures measured 1.2 m above ground level and at the tower top, he assumes a linear profile between the two. According to his model, the effective air inlet temperature is the average of the two values. This approach enables him to obtain an improved estimate of the air inlet temperature. It also allows quantifying the effect...
