Simulation of a GEF5 Gas Turbine Power Plant Using Fog Advanced Cycle and a Systematic Approach to Calculate Critical Relative Humidity

Document Type: Original Article


1 Department of Energy, Materials & Energy Research Center (MERC), Tehran, Iran

2 Department of Mechanical Engineering, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran


The ambient conditions have a significant effect on the generated power and efficiency of gas turbines [1]. These variations considerably affect power generation, fuel consumption, power plant emissions, and plant incomes. However, cooling the compressor inlet air has been widely used to reduce this deficiency [2]. In this paper, by simulating a specific gas unit in Thermoflow software, the effect of the FOG system on it was studied. Considering the error in determining the capacity of cooling systems based on the average values of dry and wet bulb temperatures, or even considering the worst possible temperature and humidity conditions, it is advisable to use ECDH or Evaporation cooling Degree Hours. Accordingly, by calculating ECDH under at ambient temperatures above 15 °C and changing the conditions of the model, the total production increase of the unit was estimated to be 4.7×106 kWh. In addition, the effect of relative humidity on payback time was examined, which illustrated the critical relative humidity for a gas unit would depend on the price of fuel, the purchase price of electricity, the design parameters of the unit and the expected payback time. For this gas unit, critical relative humidity was monitored based on expected payback time and electricity purchase price. Results showed that for a certain electricity price, at the shorter PBT, the critical RH is lower; therefore, the temperature drop and power enhancement will be greater. In addition, at a certain PBT, as the electricity price increases, the critical RH for the same PBT will be higher.


  1. N. Shokati, F. Ranjbar, and F. Mohammadkhani, “Comparison of single-stage and two-stage tubular sofc-gt hybrid cycles: energy and exergy viewpoints”, International Journal of Engineering, Transactions A: Basics, Vol. 28, No. 4, (2015), 618-626, doi: 10.5829/idosi.ije.2015.28.04a.17.
  2. S. M. Arabi, M. Aminy, H. Ghadamian, H. A. Ozgoli, and B. Ahmadi, “Thermo-Economic Analysis of Applying Cooling System Using Fog on GE-F5 Gas Turbines (Case Study)”, Journal of Heat and Mass Transfer Research, Vol. 4, No. 2, (2017), 73-81, doi: 10.22075/JHMTR.2017.1613.1106.
  3. A. M. Al-Ibrahim, and A. Varnham, “A review of inlet air-cooling technologies for enhancing the performance of combustion turbines in Saudi Arabia”, Applied Thermal Engineering, Vol. 30, No. 14-15, (2010), 1879-1888, doi: 10.1016/j.applthermaleng.2010.04.025.
  4. A. P. Santos, and C. R. Andrade, “Analysis of gas turbine performance with inlet air cooling techniques applied to Brazilian sites”, Journal of Aerospace Technology and Management, Volume 4, No. 3, (2012), 341-353, doi: 10.5028/jatm.2012.04032012.
  5. S. Baakeem, J. Orfi, S. Alaqel, and H. Al-Ansary, “Impact of Ambient Conditions of Arab Gulf Countries on the Performance of Gas Turbines Using Energy and Exergy Analysis”, Entropy, Vol. 19, No. 1, (2017), 32, doi: 10.3390/e19010032.
  6. D. C. Sue, and C. C. Chuang, “Engineering design and exergy analyses for combustion gas turbine based power generation system”, Energy, Vol. 29, No. 8, (2004), 1183-1205, doi: 10.1016/
  7. R. Chacartegui, F. Jimenez-Espadafor, D. Sanchez, and T. Sanchez, “Analysis of combustion turbine inlet air cooling systems applied to an operating cogeneration power plant”, Energy Conversion and Management, Vol. 49, No. 8, (2008), 2130-2141, doi: 10.1016/j.enconman.2008.02.023.
  8. M. Farzaneh-Gord, and M. Deymi-Dashtebayaz, “Effect of various inlet air cooling methods on gas turbine performance”, Energy, Vol. 36, No. 2, (2011), 1196-1205, doi: 10.1016/
  9. Y. S. Najjar, A. M. Abubaker, and A. F. El-Khalil, “Novel inlet air cooling with gas turbine engines using cascaded waste-heat recovery for green sustainable energy”, Energy, Vol. 93, No. 1, (2015), 770-785, doi: 10.1016/
  10. A. Noroozian, and M. Bidi, “An applicable method for gas turbine efficiency improvement. Case study: Montazar Ghaem power plant, Iran”, Journal of Natural Gas Science and Engineering, Vol. 28, No. 1, (2016), 95-105, doi: 10.1016/j.jngse.2015.11.032.
  11. M. Ameri, and S. H. Hejazi, “The study of capacity enhancement of the Chabahar gas turbine installation using an absorption chiller”. Applied Thermal Engineering, Vol. 24, No. 1, (2004), 59-68, doi: 10.1016/S1359-4311(03)00239-4.
  12. X. Shi, B. Agnew, D. Che, and J. Gao, “Performance enhancement of conventional combined cycle power plant by inlet air cooling, inter-cooling and LNG cold energy utilization”, Applied Thermal Engineering, Vol. 30, No. 14-15, (2010), 2003-2010, doi: 10.1016/j.applthermaleng.2010.05.005.
  13. T. K. Ibrahim, M. M. Rahman, and  A. N. Abdalla, “Improvement of gas turbine performance based on inlet air cooling systems: A technical review”, International Journal of Physical Sciences, Vol. 6, No. 4, (2011), 620-627, doi: 10.5897/IJPS10.563.
  14. M. A. Ehyaei, A. Mozafari, and M. H. Alibiglou, “Exergy, economic & environmental (3E) analysis of inlet fogging for gas turbine power plant”, Energy, Vol. 36, No. 12, (2011), 6851-6861, doi: 10.1016/
  15. S. Sanaye, and M. Tahani, “Analysis of gas turbine operating parameters with inlet fogging and wet compression processes”, Applied Thermal Engineering, Vol. 30, No. 2-3, (2010), 234-244, doi: 10.1016/j.applthermaleng.2009.08.011.
  16. M. A. Ehyaei, M. Tahani, P. Ahmadi, and M. Esfandiari, “Optimization of fog inlet air cooling system for combined cycle power plants using genetic algorithm”, Applied Thermal Engineering, Vol. 76, No. 1, (2015), 449-461, doi: 10.1016/j.applthermaleng.2014.11.032.
  17. R. Gareta, L. M. Romeo, and A. Gil, “Methodology for the economic evaluation of gas turbine air cooling systems in combined cycle applications”, Energy, Vol. 29, No. 11, (2004), 1805-1818, doi: 10.1016/
  18. H. H. Erdem, “Thermodynamic and economic assessments of gas turbine inlet air-cooling by evaporative technique”, International Journal of Exergy, Vol. 6, No. 5, (2009), 605-619, doi: 10.1504/IJEX.2009.027492.
  19. M. De Lucia, E. Carnevale, M. Falchetti, and A. Tesei, “Performance improvements of a natural gas injection station using gas turbine inlet air cooling”. In ASME 1997 International Gas Turbine and Aeroengine Congress and Exhibition, American Society of Mechanical Engineers, (1997), V002T07A001-V002T07A001, doi: 10.1115/97-GT-508.
  20. M. Chaker, and C. B. Meher-Homji, “Inlet fogging of gas turbine engines: climatic analysis of gas turbine evaporative cooling potential of international locations”, In ASME Turbo Expo 2002: Power for Land, Sea, and Air, American Society of Mechanical Engineers, (2002), 371-386, doi: 10.1115/GT2002-30559.
  21. J. D. McNeilly, “Application of Evaporative Coolers for Gas Turbine Power Plants”, ASME Turbo Expo 2000: Power for Land, Sea, and Air, American Society of Mechanical Engineers, (2000), V003T03A005, doi: 10.1115/2000-GT-0303.