Chilled Coil Performance Control and Application to Turbine Inlet Air Cooling

Abstract

The Absorption Refrigeration Cycle Turbine Inlet Conditioning (ARCTIC) system can chill the inlet air of the turbine to maintain optimum turbine performance at all ambient temperatures. However, turbine characteristics and bell-mouth icing concerns impose a minimum temperature limitation on the chilled air. Performance guarantees may also require maintaining the inlet air temperature within a narrow range throughout the year. These considerations require accurate prediction of the chilling coil performance over a wide range of operating conditions and the development of a robust controls strategy. A modified wet-surface model is used to model the chilling coil performance. The application of the model to a 2110[Formula: see text]kW (600 RT) ARCTIC providing inlet air chilling for a MARS 100 turbine is considered. A control strategy is developed to maintain the inlet air temperature at the desired set point with varying ambient temperatures and chilling loads. The TIAC controls help maintain the inlet air temperature at 7.22∘C to maximize turbine capacity and efficiency during most of the hot/warm days and accommodates 100% turndown. Additional safety measures are incorporated to prevent bell-mouth icing.