Paper Conference

ASHRAE & IBPSA-USA SimBuild 2016: Building Performance Modeling Conference


A New Polynomial Based Model for Determining Cooling Tower Evaporation Water Loss

Aaron Powers
Johnson Controls, Inc., Memphis, TN

Abstract: Water conservation has become a critical issue in recent years. Evaporation in cooling towers can be a significant source of water consumption in commercial buildings; however, most cooling tower models used in whole building simulation programs are either prohibitively time-consuming or overly simplistic with respect to water consumption. Therefore, it is difficult to determine the effects of control strategies on water consumption using these models. This paper presents a new polynomial based model which defines the water loss by evaporation as a function of tower inlet conditions. The polynomial coefficients have been derived through a multi-variable regression performed on data generated by a detailed finite difference model. Test cases show improved agreement with the detailed finite difference model compared to several other existing models. In addition, the execution time of the new model has been found to be much faster than the detailed model and comparable to those of other simplified models.
Pages: 9 - 16