Comparison of gas turbine inlet air cooling systems for several climates in Iran using energy, exergy, economic, and environmental (4E) analyses

The effects are investigated of using absorption chiller, heat pump, and inlet fogging systems for cooling the inlet air of a gas turbine power plant for four cities in Iran representative of different climatic conditions, namely Yazd (hot-arid), Bandar Abbas (hot-humid), Ardabil (cold-humid) and Sari (humid subtropical). Gas turbine functional parameters, quantities of emitted pollutants, prices of generated electricity and capital cost payback periods are determined. The rates of pollutants produced and fuel consumption are considered per unit of electricity generated. The results show that the best cooling system for cities with hot climates is the absorption chiller; it improves gas turbine net power by 18% in Bandar Abbas and 14% in Yazd, the energy efficiency by 5.8% in Bandar Abbas and 5.5% in Yazd, and the exergy efficiency by 2.5% in Bandar Abbas and 1.5% in Yazd. Inlet air cooling reduces NOx pollutant emissions by 60% in Bandar Abbas and 53% in Yazd and reduces electricity generated costs by 6.5% and 6.0% in Bandar Abbas and Yazd respectively. The inlet fogging system performs well only in arid regions. The most appropriate type of cooling system must be selected based on specific objectives (such as increasing power or reducing fuel consumption or reducing pollutants). In cold regions such as Ardabil, where cooling system is used only for a limited period, the heat pump system is suitable because of its low initial investment cost.