Feasibility Study of Turbine Inlet Air Cooling using Mechanical Chillers in Malaysia Climate

Abstract

The performance of a gas turbine is dependent on the ambient air temperature. The gas turbine’s power output is reduced and heat rate is increased as a result of higher air temperature. The warm and humid climate in Malaysia, with its high ambient air temperature, has an adverse effect on the performance of gas turbine generators. Turbine Inlet Air Cooling is a power augmentation technology for gas turbines, which reduces the turbine inlet air temperature thereby improving the power output and heat rate of the machine. In this paper the effect of Turbine Inlet Air Cooling using electric chillers, on the performance of the LM6000PD Gas Turbine Generator (43.5MW ISO rating) is evaluated in the context of the Malaysian climate. GT Pro software is used to evaluate the performance of the gas turbine generator with ambient air temperature cooled to 12°C. The ambient design points used for the sizing of the chillers are the 0.4% Evaporative (Design Point A) and the 0.4% Cooling (Design Point B) design points for Sitiawan, Perak as published by ASHRAE. It is observed that Design Point A results in a chiller capacity of 1950RT which is sufficient to satisfy the cooling demand of the Turbine Inlet Air Cooling system for approximately 98% of the operating hours in a year, while Design Point B yields a smaller chiller size of 1700RT which is capable of meeting the Turbine Inlet Air Cooling requirement for approximately 72% of the annual operating hours. In terms of Gas Turbine performance, the net power output is increased by 27.5% and 32.11% while the net heat rate is reduced by 2.8% and 3.74% for Design Points A and B respectively. The substantial improvement in gas turbine net power output and heat rate as predicted by the GT Pro demonstrate that Turbine Inlet Air Cooling using electric chillers is effective as a power augmentation technology in Malaysia.