Comparative evaluation of hybrid (dry/wet) cooling tower performance

The performance of hybrid cooling tower is analyzed using experiments and numerical simulations on a wide variety of working conditions. A computational model for predicting the behavior of dry, wet and hybrid cooling systems has been developed. The hybrid cooling tower model is expressed as a combination of a dry cooling model and a wet cooling model. The effectiveness-NTU equation and the Merkel equation, fundamental equation of heat transfer in dry and wet cooling towers, are presented and discussed. The cooling tower characteristics are a function of water-to-air ratio for each cooling mode. Comparison of the model tower test results with those of a computer simulation has demonstrated the validity of that simulation and its use as a design tool. Using the information presented in this paper, it will be possible to incorporate dry and wet cooling tower design, and simulation into a procedure to evaluate and optimize hybrid cooling tower performance.