A hybrid cooling tower model for plume abatement and performance analysis

Abstract

A one-dimensional model of a hybrid cooling tower and its atmospheric plume is presented with the aim of studying plume abatement, water consumption and cooling performance. To achieve this goal, a counter-flow wet cooling tower model is integrated with an effectiveness-NTU model for the dry cooling section, and, a turbulent plume model. To estimate fan power requirements, a draft equation is also included to predict the pressure drop and damper requirements in the dry and wet sections. The proposed model is used to study the effect of environmental and operating conditions on hybrid cooling tower plume visibility and cooling performance. In particular, and for the hybrid cooling tower examined in this study, a visible plume can be suppressed by approximately 10%–40% and 80%–90% hybridization, i.e., dry section to total air flow rate ratio, when the ambient air temperature is 5°C and −20°C, respectively. Results highlight the inherent trade-offs between cooling capacity, plume abatement, water consumption and fan power. Parametric studies identify the range of operating conditions for which satisfying outlet water temperature and plume abatement requirements may prove especially challenging.