SciELO - Scientific Electronic Library Online

 
vol.17 issue4-7Adaptive control of paste drying in spouted bed using the GPC algorithmEnergy and capital targets for constrained heat exchanger networks author indexsubject indexarticles search
Home Pagealphabetic serial listing  

Services on Demand

Journal

Article

Indicators

Related links

Share


Brazilian Journal of Chemical Engineering

Print version ISSN 0104-6632On-line version ISSN 1678-4383

Abstract

CASTRO, M.M.; SONG, T.W.  and  PINTO, J.M.. Operational cost minimization in cooling water systems. Braz. J. Chem. Eng. [online]. 2000, vol.17, n.4-7, pp.649-658. ISSN 0104-6632.  http://dx.doi.org/10.1590/S0104-66322000000400029.

In this work, an optimization model that considers thermal and hydraulic interactions is developed for a cooling water system. It is a closed loop consisting of a cooling tower unit, circulation pump, blower and heat exchanger-pipe network. Aside from process disturbances, climatic fluctuations are considered. Model constraints include relations concerning tower performance, air flowrate requirement, make-up flowrate, circulating pump performance, heat load in each cooler, pressure drop constraints and climatic conditions. The objective function is operating cost minimization. Optimization variables are air flowrate, forced water withdrawal upstream the tower, and valve adjustment in each branch. It is found that the most significant operating cost is related to electricity. However, for cooled water temperatures lower than a specific target, there must be a forced withdrawal of circulating water and further makeup to enhance the cooling tower capacity. Additionally, the system is optimized along the months. The results corroborate the fact that the most important variable on cooling tower performance is not the air temperature itself, but its humidity.

Keywords : cooling water systems; cooling towers; nonlinear optimization; cooler network.

        · text in English

 

Creative Commons License All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License