Efficiency control in a commercial counter flow wet cooling tower

This paper presents open and closed-loop analyses of a counter flow wet cooling tower. The closed-loop system analysis was based on a comparative evaluation of three control strategies. The first and second comprised a split-range control of the cooling water temperature and an index of thermal performance (efficiency), respectively, and the third strategy comprised a combination of override and split-range control in order to control two performance indexes (efficiency and effectiveness). In this case, a SISO (Single-Input Single-Output) loop for each controlled variable is considered. In each case the water loss through evaporation and the energy consumption in the cooling tower (pump and fans) were estimated in order to analyze its eco-efficiency. All the simulation tests were carried out considering the same regulatory problem and the results show a notable improvement in the tower's performance when compared to open-loop operation, thus attesting the potential benefits of the use of an efficient control strategy for such equipment. (C) 2009 Elsevier Ltd. All rights reserved.