EXTENDING COOLING-TOWER THERMAL PERFORMANCE PREDICTION USING A LIQUID-SIDE FILM RESISTANCE MODEL

Current models used to analyze the thermal performance of cooling towers assume that the air/water interfacial temperature is equivalent to the bulk temperature of the water, or, in other words, that the liquid-side film resistance is negligible. This assumption is a possible source of the dependence on inlet hot water temperatures found in cooling tower packing heat and mass transfer correlations derived from these models. For applications in which the water temperatures exceed the limits of experimental data used in developing such correlations, a resulting high level of uncertainty exists. This article describes a method by which one-dimensional cooling tower model equations can be corrected to account for liquid-side film resistance. The use of these corrected equations in the development of temperature-independent heat and mass transfer correlations for tower packings is also described.