Heat and Mass Transfer Model for Cooling Tower and LiBr Regenerator in Turbine Inlet Chilling System

A gas turbine normally suffers significant penalties in power output and heat rate during hot days. Turbine inlet chilling is an effective approach to reduce these penalties. Reducing the inlet air temperature increases the density of turbine inlet air and as a result, more air mass flow enters the compressor, resulting in more power produced. Cooling towers and liquid desiccant (Lithium Bromide, LiBr) regenerators are important components in a turbine inlet chilling system. Understanding of their heat and mass transfer performance, particularly the performance of LiBr regenerators, is of importance for system design and integration. 1-dimensional finite difference heat and mass transfer models were developed in this study to simulate the cooling capability of cooling towers and the efficiency of water removal of LiBr regenerators. The models were used to perform sensitivity analysis on the performance of the regenerator to understand the effects of major parameters such as Lewis factor (Le_f), the ratio of the air to solution mass flow and the temperature of the LiBr solution at the inlet. The simulation results show that the performance is insensitive to Le. Reducing the ratio of the air to solution mass flow or increasing the temperature of the solution at the inlet increases the thermal efficiency of the regenerator.