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Techno-Economic Comparison of Different Gas Turbine Inlet Cooling Techniques

Shayan, Mahdi | 2024

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56995 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Hakkaki Fard, Ali
  7. Abstract:
  8. Inlet air cooling is a simple and economical method to increase the power output of gas turbines. High-pressure fogging systems and mechanical chillers are two common methods. High water consumption, damage to compressor blades by water droplets, and inefficiency in humid climates are disadvantages of high-pressure fogging systems. Mechanical chillers have high electricity consumption and initial costs. In this research, an earth-to-air heat exchanger (EAHE) is introduced as a new method for inlet air cooling of gas turbines and is technically and economically compared with the two common methods in the long term in the climate of Tehran city. Temperature distribution in the ground is obtained using the finite difference method in computational fluid dynamics (CFD), infinite line source (ILS) method and the Duhamel theorem. The results of EAHE are validated against two experimental researches. The variables used in the optimal design of the EAHE are diameter, length, depth, number of rows, and spacing between pipes. Due to the large number of variables in the EAHE, the Taguchi method is used for optimization. The objective function of optimization is to minimize the levelized cost of electricity (LCOE). The results show that the EAHE has less ability to reduce air temperature and increase turbine power output compared to the other two systems. The LCOE in the optimized high-pressure fogging, EAHE, and mechanical chiller systems are 17.2, 23.9, and 29.6 USD per Megawatt-hour of electricity generated, respectively. The discounted payback period (DPP) in the high-pressure fogging, EAHE, and mechanical chiller systems are 1.78, 3.48, and 3.48 years, respectively. The net present value (NPV) of these three systems after 30 years is calculated as 11.32, 2.82, and 7.38 M$, respectively. It is finally shown that using the EAHE reduces the unit of pollutant gases emissions compared to the case without cooling, but the positive impact of the other two common systems in this area is more
  9. Keywords:
  10. Gas Turbines ; Inlet Cooling ; Earth to Air Heat Exchanger ; Fogging System ; Economic and Technical Study ; Mechanical Chiller ; High Pressure Fogging System

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