DEVELOPMENT OF A SYSTEM FOR COOLING INLET AIR FOR GAS TURBINE USING CHILLED WATER

The strong influence of climate on gas turbine behavior is well known. The output of
gas turbine falls to a value that is less than the rated output under high temperature
conditions that often occur during the daylight. In Malaysia, during daylight ambient
temperature varies from 23°C to 38°C. This temperature is relatively high. Cooling of
the turbine air intake can increase output power substantially. This is because cooled air
is denser, giving the turbine higher mass flow rate and resulting in decreasing
compressor specific work and specific fuel consumption.
In order to maintain inlet air at constant low temperature, an air cooling system is
required to be developed at the air intake of gas turbine. A lot of researches have been
done proved that by cooling the air at inlet gas turbine will increase the efficiency of gas
turbine. The gas turbine engine at Gas District Cooling Plant (GOC) plant in Universiti
Teknologi PETRONAS (UTP) has an advantage due to availability of a chilled water
system that is produced by cogeneration plant. Heat from gas turbine exhaust is
recovered to produce chilled water by the steam absorption chiller (SAC). The chilled
water is then distributed to the academic building at a temperature of 6°C by pipeline
into the air handling unit (AHU) in every building at UTP for air conditioning purpose
and return back to GDC at a temperature of l3°C.
This study analyzed the power requirement by the cooling system, the material used,
sizing and feasibility of new cooling system. Mathematical equations have been
developed. The air cooling system consist of 83 units of copper tubes 19.05 mm outer
diameter and 77.26 m length for each tube. A 0.35 kW pumping power is required to
circulate 11.72 kgls mass flowrate of chilled water through the system to cool 19 kgls
mass flowrate of air from variable high temperature to 20°C.