Thermodynamic Analysis of a Gas Turbine Power Plant Modelled with an Evaporative Cooler

Abstract

In this paper the performance enhancement of gas turbine power plants by cooling the compressor intake air with an evaporative cooler is studied. This study investigated the effect of inlet air cooling system on the performance of an existing gas turbine power plant in Nigeria. The results show that for each 5 o C decrease of inlet air temperature, net output power increases around 5-10% and the thermal efficiency increases around 2-5%. It is shown that the amount of this increase is higher when the pressure ratio is high and turbine inlet temperature is low. The results of this study shows that retrofitting of the existing gas turbine plant with inlet air cooling system gives a better system performance and may prove to be an attractive investment opportunity to the Nigeria government and stakeholders of the plant.

Climate Effects on Cooling Degree-Hours and Evaporative Cooling of Gas Turbine

“…Moreover, turbine inlet temperature is also limited by metallurgical property used by the manufacturer, hence, the maximum requirement temperature for this system was limited to1514 [K] as shown in Table I. The results obtained correspond to the result of Anoor and S. Oyedepo in reference [13] and [14]. Evaporative cooling of gas turbine decreases the compression work of the compressor and increases the efficiency of the system,that means compressor effectivenss is also another factor to be consider on simulations Fig.…”

“…The mass flow rate of the fuel, specific fuel consumption and air fuel ratio are computed in equation (13) to (14), the mass of air entering turbine is 40 % of the air leaving compressor.…”

Thermodynamic Analysis of Gas Turbine Power Plant

“…Oyedepo and Kilanko [5] carried out a study on the thermodynamic analysis of a gas turbine power plant fitted with an evaporative cooler based in Nigeria. They concluded that power output increased by 5-10% and thermal efficiency by around 2-5% on decreasing the inlet air temperature by 5°C.…”

Modelling and Assessment of Effect of Operation Parameters on Gas Turbine Power Plant Performance using First and Second Laws of Thermodynamics

“…Gas turbines are ideal for this application as they can be started and stopped quickly, enabling them to be brought into service as required to meet energy demand peaks (Jaber et al, 2007). However, due to availability of natural gas at relatively cheap prices compared to distillate fuels, many countries around the world, e.g Nigeria, use large conventional GTs as base load units (Oyedepo and Kilanko, 2014).…”

“…Power rating can drop by as much as 20 to 30%, with respect to International Standard Organization (ISO) design conditions, when ambient temperature reaches 35 to 45°C (Mahmoudi et al, 2009;Guinee, 2001). One way of restoring operating conditions is to add an air cooler at the compressor inlet (Sadrameli and Goswami, 2007; (Oyedepo and Kilanko, 2014). The air cooling system serves to raise the gas turbine performance to peak power levels during the warmer months when the high atmospheric temperature causes the turbine to work at off-design conditions with reduced power output (Kakaras et al, 2004;Kamal and Zubair, 2006;Khaliq et al, 2009).…”