Waste Heat Disposal to Air with Mechanical and Natural Draft—Some Analytical Design Considerations

There is a growing acceptance of the future necessity of dry and wet/dry cooling tower systems for large power stations in spite of their economic penalty compared with once-through cooling, cooling ponds, and evaporative cooling towers. If technological improvements succeed in reducing the current costs of dry cooling towers, their future applications will be accelerated. The main objective of this work is to quantify the factors that reduce the overall size and cost of the tower and the associated heat transfer system and to provide a basis for establishing the conditions that result in dry cooling tower cost reductions. As a first-step, the design equations for forced-and natural-draft dry cooling towers are derived in close form to give explicit relations for salient design variables. Subsequently, these equations are used to establish a set of influence coefficients for quantifying the effects of various key design variables on the design of forced- and natural-draft cooling towers.