Open Cycle Gas Turbine Research Articles

Storage and demand response contribution to firm capacity: Analysis of the Spanish electricity system

Provision of firm capacity will become a challenge in power systems dominated by renewable generation. This paper analyzes the competitiveness and role of battery storage, six types of pumped-hydro storage, open cycle gas turbine (OCGT), and demand response (DR) technologies in providing the firm capacity required to guarantee the security of supply in a real-size power system such as the Spanish one in horizon 2030. The paper contributes with detailed and realistic modeling of the DR capabilities. Demand is disaggregated by sector and activities and projected towards 2030, applying a growth rate by activity. The load flexibility constraints are considered to ensure the validity of the results. A generation operation planning and expansion model, SPLODER, is conveniently upgraded to properly represent the different storage alternatives addressed in the paper. The results highlight the importance of considering demand response for evaluating long-term firm capacity requirements, showing a non-negligible impact on the investment decisions on the amount of firm capacity required in the system and the optimal shares of wind and solar PV renewable generation. Results also show the dominance of cost-competitiveness of pumped hydro and OCGTs over batteries. Additionally, capacity payments are required to support firm capacity providers’ investments.

Sensitivity of transpiration cooled gas turbine cycle efficiency and coolant requirement to changes in cooling parameters

The maximum temperature at the gas turbine inlet gets restricted due to metallurgical constraints, which can be increased using blade cooling. Among different techniques for cooling blades in the gas turbine, the transpiration cooling of blades permits quite a high temperature at the turbine inlet. The objective of this study is to analyse the sensitivity of transpiration cooled gas turbine cycle performance for cooling parameterssuch as allowable blade material temperature, film cooling effectiveness, and internal cooling efficiency, so that the most important cooling parameters may be focused upon for the improvement of gas turbine cycle performance. In this study, it is found that the cycle efficiency is more sensitive to allowable blade material temperature followed by film cooling effectiveness and to internal cooling efficiency only a little bit. This study shows that with the use of cooling, for an increase in allowable blade temperature by 50 K, the gas turbine cycle efficiency increases by 0.15% . Also, the increase in film cooling effectiveness from 0.4 to 0.5 increases the cycle efficiency by 0.13% . Furthermore, with an increase in cooling efficiency from 0.7 to –0.8 the cycle efficiency increases by 0.03% only.

Numerical study of effects of solid particle erosion on compressor and engine performance

Solid particle erosion (SPE) is a major source of damage to, and cause of failure of, turbomachinery, including centrifugal and axial compressors and gas turbines. There is considerable interest within the turbomachinery industry to develop the means to enhance durability and improve prediction of likely breakdowns of machinery operating in locations and conditions where ingestion of, for example, dust and sand grains is unavoidable during operation. The present study examines the implications of degradation of the compressor on gas turbine cycle performance, caused by operating in eroding environments, linking compressor aerodynamics with the thermodynamic cycle. The research engine employed in the study comprised a fan, bypass, and two stages of the low-pressure compressor (booster). A numerical simulation using Computational Fluid Dynamics (CFD) software was performed to predict the likely erosion patterns due to solid particles (SPs) impacting on the blades of the first two stages of an axial compressor. This study introduces a method that provides the freedom to apply roughness to a particular region of the blade following the SPE patterns identified as part of the CFD simulations so as to represent the effects of the erosion spots on the overall flow field. The localised roughness method employs a perturbation of the geometry of the blade in the regions corresponding to the location predicted by the SPE model. The intensity of the perturbation, which is governed by a “fraction factor” coded in a Matlab script, was calibrated by reference to a roughness case, applied over the entire blade surface, with equivalent sand-grain roughness (ks) of 60 μm. Turbomatch, the Cranfield in-house gas turbine performance simulation software, was employed to model the degradation of engine performance. The research confirmed that SPE is linked with significant decreases in engine performance parameters such as isentropic efficiency (ηis) and pressure ratio (PR). These quantities showed, for the SPE cases considered, a drop of 8.8% and 5.2%, respectively. These findings are useful to link local SPE events to global GTE cycle performance.

Flexible CO2 capture for open-cycle gas turbines via vacuum-pressure swing adsorption: A model-based assessment

As energy systems require flexible and responsive power generators to combat network imbalances, CO2 post-combustion capture (PCC) technologies need to be capable of transient operation. However, currently only amine absorption has been investigated for its efficacy in Flexible-PCC.Within this study we develop and validate a vacuum-pressure swing adsorption (VPSA) process model, capable of processing 33.8 kg/s of exhaust flow from a small-scale open-cycle gas turbine (OCGT). The Flexible response scenario is based on realistic load changes of OCGTs during a 5-h period. To handle the size of flow the system is split into two identical two bed four step VPSA processes, both using Zeolite 13X as the adsorbent material. Included in the Flexible-VPSA operation is the start-up, ramping, and shutdown procedures. Flexible-VPSA showed minute deviations in CO2 purity and recovery rate, and despite the specific energy demand increasing, results show no technical limitations to transient operation. The Flexible VPSA simulations are compared against the benchmark MEA solvent, with both technologies performing similarly when processing highly transient flue gas flowrate. Thus, VPSA is potentially an attractive alternative technology for Flexible-PCC.

Effect of Heavy Fuel Combustion in a Gas Power Plant on Turbine Performance: A Review

The current review focuses on the utilization of heavy fuel in operating gas turbine and their effect on the power plant performance. The literature survey includes a comparison of the different studies to reveal the effect of the fuel property on the combustion efficiency and fuel consumption. the most important of which is the generation of electric power by heavy fuels in power stations that use turbines. Gas turbine is becoming increasingly widespread in electric power generation and other branches of industry. It is known that the thermal efficiency of an open gas turbine cycle varies according to the type of fuel used in the plant. Gas turbines are particularly suitable for fuels with materials that have physical and chemical properties that help in continuous combustion and therefore the ease inherent in Fuel injection and mixture preparation.

Techno-Environmental Evaluation of a Liquefied Natural Gas-Fuelled Combined Gas Turbine with Steam Cycles for Large Container Ship Propulsion Systems

Restrictions on emissions are being imposed by regional and international shipping organisations, which raise the question of which marine fuel and technology can most effectively replace heavy fuel oil and diesel engines. The aim of this study is to find appropriate advanced combined gas and steam turbine cycles for marine propulsion systems in a large container ship with respect to the evolving maritime environmental regulations. The selection criteria are the thermodynamic performance, emissions, size, and weight of advanced combined gas and steam turbine cycles in a large container ship. Two baselines are used: a diesel engine using marine diesel oil and a combined gas and steam turbine system using liquefied natural gas and marine diesel oil. Then, liquefied natural gas cycles are examined based on fuel replacement and enhanced to assess the benefits of liquefied natural gas over marine diesel oil. The results show that the enhanced liquefied natural gas combined gas and steam turbine cycles are the most efficient, at up to 1.6% higher than the other cycles. Regarding the size and weight, the combined gas and steam turbine propulsion system is approximately 24.7% lighter than the original diesel engine propulsion system.

Firming merchant renewable generators in Australia’s National Electricity Market

Global decarbonisation is driving investments in intermittent renewable generation, with most plant entering the market by way of a Power Purchase Agreement. In Australia’s National Electricity Market, a surprising number of renewable generators have entered on a merchant basis. To maintain tractable revenues some minimum level of hedging is required, but in an energy-only electricity market with a very high market price cap, merchant intermittent generators require some level of associated firming capacity to ensure spot price exposures can be adequately managed. This article uses unit commitment, battery arbitrage and stochastic discounted cashflow valuation models to compare an Open Cycle Gas Turbine and a battery as firming options for a hypothetical wind farm in the South Australian region of the NEM. Using historic market data from 2010–2020, we find OCGT firming capacity helps the wind farm to generate consistent net cash flows, allowing it to withstand the highs and lows of spot market prices whilst covering required contract-for-difference payments associated with hedging. When battery firming is deployed, the wind farm/ battery portfolio generated higher cash flows at specific times, reflecting participation in price arbitrage under low spot price scenarios. However, battery performance was constrained by costly storage capacity.

Techno-economic assessment for a pumped thermal energy storage integrated with open cycle gas turbine and chemical looping technology

Pumped thermal energy storage offers a high energy density, potentially resulting in a relatively low cost per unit of energy stored. In this study, two novel energy storage systems were developed. The first system was developed by integrating pumped thermal energy storage and chemical looping technologies, whereas the second was formed by merging the first system with an open cycle gas turbine. Both systems used an oxygen depleted stream as a working fluid and iron-based oxygen carriers from a chemical looping water splitting process storage material for the pumped thermal energy storage system. In addition, hydrogen from the chemical looping process was employed for the gas turbine in the second system. Both systems were evaluated thermodynamically via the determination of the roundtrip efficiency. The results presented here indicate that the roundtrip efficiency of both systems developed was 77%. Furthermore, the capital requirements, operating costs, and daily profits from electricity generation were calculated for both systems over several days within the year. The capital and operating costs for the several days that were simulated for the integrated pumped thermal energy storage system were lower than that of a gas turbine based system. Consequently, the daily profit was estimated and found to be between 4.9% and 72.9% higher for the integrated pumped storage relative to the gas turbine based system. Moreover, an economic sensitivity analysis was performed to identify the factors that strongly affect the daily profits of the gas turbine system relative to the pumped storage system. Based on the analysis, the optimal hydrogen fuel percentage fed to the open cycle gas turbine was calculated for the days simulated. Finally, the impact of % error on the estimated capital and fuel production costs on daily profits were investigated. The outcome revealed a higher impact of computational errors on the fuel costs relative to the costs of the capital.

Methodology for the evaluation of low-frequency environmental noise: a case-study

Industrial sources like open-cycle gas turbines, boilers, forced and induced draft fans, shakers on hoppers, vibratory screens, and compressors are just some of the possible sources of low-frequency environmental noise, as well as wind farms or surface transport infrastructures. However, unlike the latter, industrial sources are characterized by a so large variability of the components that constitute them to require specific studies on the modalities of emission and on the effects induced to the receptors.In the near future, the evaluation and control of low-frequency noise sources will become a key factor in environmental management, which requires specific knowledge, investigation strategies, and proper measurement techniques.In this paper an industrial plant held liable for low-frequency noise annoyance is analyzed, focusing on the benefits achievable by adopting an investigation strategy combining simultaneous indoor and outdoor noise measurements carried out along with vibration and weather data acquisition. The specific investigation methodology applied to the case study analyzed highlighted the importance of validating the acoustic data through a thorough analysis of the meteorological data, focusing on effects on sound pressure level variation due to strong wind (gusts). The role of preliminary structured interviews to people claiming to be annoyed and the importance of their written notes during unattended monitoring sessions are also addressed.

Combined effect of variable parameters on the performance of gas turbine cycles

The gas turbine cycle is the key solution for the power generation system from the last decade. several types of research are going to enhance the overall system efficiency of the gas turbine cycle. In the present study, six sets have been investigated parametrically for energy and exergy. Thermodynamic assessments have been effectively achieved for the compressor pressure ratio from 4 to 14, turbine inlet temperature (TIT) from 1000K to 1500K, and ambient temperature 250C to 450C. Results show that for every 100 rises in ambient temperature the maximum decrease in peak output and peak thermal efficiency is 6.2% and 5% respectively at 1000K and 3.6% and 1.9% respectively at 1500K. The exergy loss by exhaust gases of set 4 and set 5 increased by 107% whereas set 6 is decreased by 85.5% as compared to set 1 under the conditions when the exergy loss by exhaust gases of set 1 is minimum at TIT 1000K. The total exergy destruction of set 3, set 4, set 5, and set 6 is increased by 102%, 32.6%, 133.3%, and 102% respectively as compared to set 1 under the conditions when the total exergy destruction of set1 is minimum at TIT 1000K. Regenerative Gas Turbine cycle is the best in terms of the ratio of net output to exergy destruction of the plant as well as initial, operational, and maintenance costs.

Blade Roughness Effects on Compressor and Engine Performance—A CFD and Thermodynamic Study

Degradation of compressors is a common concern for operators of gas turbine engines (GTEs). Surface roughness, due to erosion or fouling, is considered one of the major factors of the degradation phenomenon in compressors that can negatively affect the designed pressure rise, efficiency, and, therefore, the engine aero/thermodynamic performance. The understanding of the aerodynamic implications of varying the blade surface roughness plays a significant role in establishing the magnitude of performance degradation. The present work investigates the implications due to the degradation of the compressor caused by the operation in eroding environments on the gas turbine cycle performance linking, thereby, the compressor aerodynamics with a thermodynamic cycle. At the core of the present study is the numerical assessment of the effect of surface roughness on compressor performance employing the Computational Fluid Dynamics (CFD) tools. The research engine test case employed in the study comprised a fan, bypass, and two stages of the low pressure compressor (booster). Three operating conditions on the 100% speed-line, including the design point, were investigated. Five roughness cases, in addition to the smooth case, with equivalent sand-grain roughness (ks) of 15, 30, 45, 60, and 150 µm were simulated. Turbomatch the Cranfield in-house gas turbine performance simulation software, was employed to model the degraded engine performance. The study showed that the increase in the uniform roughness is associated with sizable drops in efficiency, booster pressure ratio (PR), non-dimensional mass flow (NDMF), and overall engine pressure ratio (EPR) together with rises in turbine entry temperature (TET) and specific fuel consumption (SFC). The performance degradation evaluation employed variables such as isentropic efficiency (ηis), low pressure compressor (LPC) PR, NDMF, TET, SFC, andEPR. The variation in these quantities showed, for the maximum blade surface degradation case, drops of 7.68%, 2.62% and 3.53%, rises of 1.14% and 0.69%, and a drop of 0.86%, respectively.

Exploring the competitiveness of hydrogen-fueled gas turbines in future energy systems

Hydrogen is currently receiving attention as a possible cross-sectoral energy carrier with the potential to enable emission reductions in several sectors, including hard-to-abate sectors. In this work, a techno-economic optimization model is used to evaluate the competitiveness of time-shifting of electricity generation using electrolyzers, hydrogen storage and gas turbines fueled with hydrogen as part of the transition from the current electricity system to future electricity systems in Years 2030, 2040 and 2050. The model incorporates an emissions cap to ensure a gradual decline in carbon dioxide (CO2) levels, targeting near-zero CO2 emissions by Year 2050, and this includes 15 European countries.The results show that hydrogen gas turbines have an important role to play in shifting electricity generation and providing capacity when carbon emissions are constrained to very low levels in Year 2050. The level of competitiveness is, however, considerably lower in energy systems that still allow significant levels of CO2 emissions, e.g., in Year 2030. For Years 2040 and 2050, the results indicate investments mainly in gas turbines that are partly fueled with hydrogen, with 30–77 vol.-% hydrogen in biogas, although some investments in exclusively hydrogen-fueled gas turbines are also envisioned. Both open cycle and combined cycle gas turbines (CCGT) receive investments, and the operational patterns show that also CCGTs have a frequent cyclical operation, whereby most of the start-stop cycles are less than 20 h in duration.

An evaluation of power conversion systems for land-based nuclear microreactors: Can aeroderivative engines facilitate near-term deployment?

Power conversion cycles (Subcritical Steam, Supercritical Steam, Open Air Brayton, Recuperated Air Brayton, Combined Cycle, Closed Brayton Supercritical CO2 (sCO2), and Stirling) are evaluated for land-based nuclear microreactors based on technical maturity, system efficiency, size, cost and maintainability, safety implications, and siting considerations. Based upon these criteria, Air Brayton systems were selected for further evaluation. A brief history of the development and applications of Brayton power systems is given, followed by a description of how these thermal-to-electrical energy conversion systems might be integrated with a nuclear microreactor. Modeling is performed for optimized cycles operating at 3 MW(e) with turbine inlet temperatures of 500 °C, 650 °C and 850 °C, corresponding to: a) sodium fast, b) molten salt or heat pipe, and c) helium or sodium thermal reactors, coupled with three types of Brayton power conversion units (PCUs): 1) simple open-cycle gas turbine, 2) recuperated open-cycle gas turbine, and 3) recuperated and intercooled open-cycle gas turbine. Aeroderivative turboshaft engines employing the simple Brayton cycle and two industrial gas turbine engines employing recuperated air Brayton cycles are also analyzed. These engines offer mature technology that can facilitate near-term deployment with a modest improvement in efficiency.

Sound propagation through elevated, heated jets in cooler cross-flow: An experimental study.

Sound propagation through hot exhaust plumes with cooler cross-winds is present in many real world systems. One particular example is the sound propagation from exhaust stacks attached to open cycle gas turbine power stations. The research presented in this paper investigates the sound propagation from a reduced-scale exhaust stack, with a cross-flow from experiments conducted in a wind tunnel. Experimental measurements of the flow and temperature fields provide insight into the complex sound radiation characteristics. Results from the acoustic measurements show the change in the sound directivity arising from the inclusion of the hot exhaust plume, leading to non-axisymmetric sound directivity and a concentration of sound downwind of the exhaust stack outlet. In certain cross-flow conditions, the hot exhaust plume can increase the sound observed downwind by up to 11 dB when compared to the scenario of sound propagation from an exhaust stack in the absence of a heated jet or cross-flow. This paper describes the acoustic directivity at various radial distances from the exhaust stack, acoustic frequencies, jet temperatures, and cross-flow free-stream velocity. The results from this paper emphasise the importance of taking into consideration the hot exhaust plume with cooler cross-flow when estimating sound levels downwind of the stack.

Comparing CO2 emissions impacts of electricity storage across applications and energy systems

Summary Electricity storage systems can support the decarbonization of energy systems. However, the effect of electricity storage use on greenhouse gas emissions is complex because of roundtrip efficiency losses of the storage and its effects on the dispatch of different electricity-generation technologies. The limited literature examining this issue focus on individual electricity storage applications and the geographies where they are applied. Here, we systematically compare the effects of electricity storage on CO2 emissions across four applications in electricity systems resembling seven European countries. Our findings reveal large emission impact differences between applications and countries. Among other findings, we find that when compared with wholesale arbitrage, storing electricity in other applications exhibits much lower effects on CO2 emissions. We also investigate different policy options to reduce CO2 emissions from storing electricity. We find that although a higher carbon price can have a substantial effect on reducing the CO2 emissions from wholesale arbitrage, other applications require alternative approaches.

Techno-economic optimisation of battery storage for grid-level energy services using curtailed energy from wind

The increasing integration of renewable energy sources makes balancing an electricity grid challenging due to their intermittency. Renewable energy can be curtailed especially when production exceeds demand or when there are transmission and/or distribution network congestions within a grid. However, curtailment would become unnecessary with battery storage, provided the battery storage has enough available storage capacity, which can store energy during the time of excess generation and in turn discharge it to the grid once the demand is high during peak times. Hence, stored energy from batteries can potentially offset supply from expensive and environmentally harmful peak plants e.g. open/combined cycle gas turbine. We investigated the techno-economic prospects of the utilisation of curtailed energy from the wind with bulk battery storage to replace open and combined cycle gas turbine power plants, by taking the UK as a case study. A techno-economic model to size and optimise a Li-ion type battery was developed. The optimisation aimed to determine at what cost and size the storage can be commercially viable for grid-level energy applications. Results show that under base case assumptions of a 15% day to day curtailment from wind and £200/kWh battery cost, an optimised battery size of 1.25 GWh could supply 285 GWh peak demand per annum and its corresponding net present value of £22.4m, internal rate of return of 1.7% and a payback period of 14 years could be achieved. However, to achieve the internal rate of return of 8%, a minimum hurdle rate for investment, the cost of battery would need to be below £150/kWh. Sensitivity analysis with parameters such as curtailed wind, depth of discharge, battery efficiency, and cost and income of battery shows that all techno-economic parameters considered in this research have a significant impact on the commercial viability of battery storage for grid applications.

Enhancing dispatch efficiency of the Nigerian power system: Assessment of benefits

Although developing countries typically deal with the challenge of mobilizing investments for adding new generation and transmission capacity to cope with high demand growth, there are often opportunities to enhance operation of existing generators and extract significant cost reduction as well as the ability to meet greater demand. This is particularly relevant for the Nigerian power system that has 13 GW of installed capacity but could meet only 5.2 GW of peak demand in 2018 at an average capacity utilization of 27% of its thermal (mostly gas) generation fleet. There are simple steps that can be adopted to restore merit-order based dispatch that can immediately yield an operational cost reduction. Increased plant availability, gas supply to power plants, and removal of uneconomic take-or-pay obligation are increasingly onerous tasks, but with commensurate significantly higher payoffs.We have used a dispatch analysis model to show that merit-order based dispatch within the current constraints can yield an annual benefit of $29 million or 4% of variable costs. With the removal of physical availability constraints around plants and gas supply, benefits increase by an order of magnitude to $309 million, or 19% of total annual costs. If it is possible to get rid of the uneconomic take-or-pay obligations, benefits would further increase to $579 million or over 30% of total annual costs. These are major findings especially if we consider these in the context of tremendous financial stress in the power sector. Although we do not estimate the cost of implementing these measures, there are very little hard investments needed in some of these cases such as establishing a strict merit-order based dispatch or enhancing operational practices to improve plant and gas availability. There are indeed difficult commercial and institutional issues when it comes to renegotiating take-or-pay contracts, albeit the massive benefits in excess of half a billion dollar per year should make it a worthwhile undertaking.Removal of operational and commercial constraints could also allow the Nigerian power system to meet increased demand to the benefit of unserved residents or businesses, and pave the way towards increased penetration of variable renewable energy (VRE) resources. We have shown that an addition of 500 MW solar capacity in the current system will earn reasonable return on investment between 4% and 9% and help to meet increased demand. However, an important precondition for adding large-scale solar is to raise the spinning reserve capability in the system through additional investments in flexible resources, namely, open cycle gas turbines (OCGT), pumped storage hydro or battery storage systems.

Effects of market and climatic conditions over a gas turbine combined cycle integrated with a Heat Pump for inlet cooling

The growing need of dispatchable units, capable to balance the variable renewable energy electrical production leads to the development of strategies aimed at increasing power plants operational flexibility and global efficiency in part-load operation. A highly efficient heat pump (integrated in a conventional natural gas combined cycle is here proposed as a flexibility enhancement solution. Such concept, applied to power oriented combined cycle, allows to modify the compressor intake temperature with a consequent increase of the power production. While this operation for open cycle gas turbine is beneficial also to electric efficiency, combined cycles’ efficiency is less sensitive to the temperature variation and thus more influenced by the auxiliary consumption. The selection of the proper heat pump size for the proposed layout was based on an optimization process considering both combined cycle and heat pump off-design performance. After a statistical analysis of climatic data and their correlations with energy market condition for the six Italian price zones, the models developed were applied to assess the thermoeconomic potential of the proposed layout. This work highlights how a proper optimization process influences both revenues and size optimization and to highlight how such integrated system can be selected at its best considering typical market and climatic frames. The ratio between the air-cooled heat pump electrical consumption and the electrical combined cycle capacity that maximize power production increase was found to be 1/100. This finding can be extended to the others world Humid subtropical climate and Mediterranean hot summer climates zones. It is underlined how electrical market conditions could jeopardize the installation profits even under favourable climatic potential reducing the optimal economic heat pump size. Using off-design curves and optimization algorithm in performing coupling analysis appears to be more effective, with respect to simplified calculations under unfavourable economic and climate conditions.

Parametric Study on the Performance of Combined Power Plant of Steam and Gas Turbines

Abstract This paper deals with aspects of the combined power and power (CPP) plants. Such plants consist of two major parts: the steam turbine and gas turbine plants. This study investigates the efficiency of CPP under the effect of several factors. CPP plants including an open cycle gas turbine and a bottoming cycle steam turbine can achieve the highest thermal efficiency obtained with turbomachinery up to date. In this cycle, the anticipated waste thermal energy of the exhaust of gas turbine is used to generate high-pressure steam to empower the steam turbine in the steam cycle. By systematically varying the main design parameters, their influence on the CPP plant can be revealed. A comprehensive parametric study was conducted to measure the influence of the main parameter of the gas and steam cycles on the performance of CPP. The results exhibit that the overall plant thermal efficiency is significantly greater than that of either of the two turbines. Due to the high thermal efficiency, a significant reduction in the greenhouse effect can be achieved. It is found that the regenerative steam cycle will reduce the overall efficiency of the combined cycle. On the other hand, using the reheat steam cycle in the CPP plant will lead to an increase in both the thermal efficiency of the plant and the dryness factor of steam at the exit of the steam turbine.

SFC Optimization of Gas Turbine Cycle Using Air Pre-cooling Unit: Performance Improvement

A critical issue concerning the gas turbine cycle of combined cycle power station is the reduction in net power output considerably with increasing ambient air temperature. The present simulation study aims to improve the performance of gas turbine cycle of combined cycle power station through use the fresh air handling units of mechanical chiller. To obtains the influence of use the mechanical chiller as pre-cooling units on a performance of gas turbine cycle, the thermodynamic analysis are used to simulate the performance of gas turbine cycle for three different operating loads (66.67, 83.33, and 100% full load). Based on results of the simulation analysis, the mechanical chiller which is inserted as a pre-cooling unit can; (i) increase the average monthly net power output by values varying between 7.33-18.17 MW compared to the original case without pre-cooling units; (ii) the rate of improvement in the average monthly net power output varies between 4.6-11% compared to the case without pre-cooling units; (iii) reduce the specific fuel consumption (SFC) by a rate varying between 5.21-10.81 kgfuel /MWh compared to the original case without pre-cooling units; and (iv) the saving in SFC reached to 4.4% compared to the original case without pre-cooling units.