ENHANCING GAS-TURBINE PERFORMANCE BY INTAKE AIR COOLING USING AN ABSORPTION CHILLER

The performance of gas turbines, operated either as a simple cycle or a combined cycle, is critically constrained by the prevailing ambient temperature, particularly in arid and tropical climates. This paper in vestigates the option of cooling the intake air to the compressor of t he gas-turbine system using an absorption chiller in order to increase the gas turbine capacity. High-temperature waste heat from the exhaus t gas may be utilized to produce steam in a recovery boiler. Part of t he steam produced could then be used to drive a lithium-bromide double -effect absorption chiller which in turn could cool the incoming air. An analysis carried out by taking the weather data of Bangkok (Thailan d) indicates that reducing the temperature from ambient condition to 1 5-degrees-C could help to increase the instantaneous power output betw een 8 and 13%. As an outcome, as much as 11% additional electricity co uld be generated from the same gas turbine power plant. A simple econo mic assessment indicates that the proposed scheme will require a minim al investment as compared to the commissioning cost of a new gas turbi ne unit to meet the corresponding capacity increment. The latter will need nearly four times higher intial cost than the amount estimated fo r the proposed scheme. Thus, implementation of such a system would sig nificantly abate the negative impact of the ambient temperature, while providing an economically and environmentally attractive option for e nergy producers in most developing nations of the world which are loca ted in arid and tropical zones.