Turbine Input Research Articles

Thermodynamic analysis of a multiple energy production system based on geothermal energy for commissioning in Canada and optimization by response surface method (RSM)

The thermodynamic analysis of a geothermal-based integrated energy system to produce liquid hydrogen, cooling, hot water, and power was presented in this study. The investigated system consists geothermal subsystems, a modified organic Rankine cycle (ORC), a PEM electrolyzer, and a liquid hydrogen storage source. Different organic fluids including refrigerants R113, R123, and R134a were investigated to increase the system performance. Analysis of organic fluids showed that the best organic fluid is R123 because it helps to increase the performance of the system. The authors employed the Design-Expert software and RSM for optimum results purposes, and the objective functions were chosen to be exergy efficiency (EE) and cost rate (CR). Following introduction of design variables, the mass flow rate of input to the evaporator, the temperature of input to heat recovery vapor generator, turbine efficiency, turbine input temperature, evaporator pinch point temperature, and pump efficiency, their impact on the system's performance were investigated. The optimal values for EE and CR were ultimately found to be 43.91 % and 45.12 $/h, respectively. Also, in this research, seven regions within Canada were investigated for the launch of the proposed system. The studied cities were Victoria, Vancouver, Regina, St. John's, Dawson Creek, Whitehorse, and Port Alberni. Finally, Regina was chosen because of the system's superior performance in electricity production at a reasonable cost in that area. The environmental results showed that the presented energy system in Regina city could help to expand 5 ha of green space by producing electricity at the rate of 4993.03 MWh in one year. The findings indicated that implementing the suggested system in Regina would help prevent 1018.6 tons of CO2/MWh from being emitted into the environment yearly, only by chipping in 24445.9 $/ton of CO2 per year.

Microhydro Model of Waterfalls

This research was carried out by Lecturers Swadaya Gunung Jati University, Cirebon and in partnership with the Cimanuk Cisanggarung River Area Center, Ministry of Public Works and Public Housing the Republic of Indonesia and the Kertawirama Village Government, Kuningan Regency, West Java Province. The aim of this research is to create a microhydro model of a waterfall that will produce renewable electrical energy in branching irrigation channels and calculate the water discharge. The method used is carrying out surveys, making tools and microhydro analysis. The tool model making was carried out in the Indonesian Cihanjuang Microhydro laboratory with a TC 60 type microhydro model. The results of this research were to make a TC 60 microhydro model which was installed in a waterfall channel at the irrigation water branch. The results of the research produce: the amount of discharge in the waterfall channel is 1.50 m3/s, the amount of discharge entering the turbine is 0.012 m3/s, the difference in height of the falling water is 4 m, the amount of turbine input power is 572 watts and the output power turbine is 477 watts.

Application of the Residue Method in Steam Superheater Fault Detection

Steam superheaters experience various defects that can affect the system’s operation differently. Maintaining a constant temperature and pressure of the steam at the turbine input is crucial for optimal steam turbine running conditions. This is achieved by regulating the steam temperature in the superheater, which is divided into three parts with devices mounted at each connection point to allow for the injection of condensates to cool the steam. The steam pressure is controlled by adjusting the fuel flow command. However, controlling the output temperature can be challenging because of the transfer time delay between the points where the water is sprayed and the points where the steam temperature is measured. To address this challenge, a temperature control system was developed and tested in three different environments using an electronic simulator, the block-oriented simulation hardware BORIS, data acquisition board dSpace, and a MATLAB R2020a Simulink with a PI controller model. These simulations allowed for the study of the superheater’s function in both normal and fault conditions, with the possibility of controlling the system structure and detecting faults through the proper implementation of weighting matrices.

Transient discharge performance of high-temperature latent storage system integrated with supercritical CO2 Brayton cycle: A combined analytical and numerical study

In this article, a generalized robust analytical model is developed to evaluate the discharge performance of a high-temperature latent heat storage (HT-LHS) system coupled with the supercritical CO2 (sCO2) recompression Brayton cycle. During discharging, the release of thermal energy from metallic phase change medium (PCM) based HT-LHS is the input to the sCO2 cycle. The thermal efficiency of sCO2 recompression cycle is observed to be significantly larger (> 50 %) than the conventional Rankine cycle at higher operating temperature (700–750 °C). The thermal efficiency increases with turbine input temperature for all split ratios and is maximized at a split ratio of 0.75. Turbine inlet pressure and air temperature are identified as the most and least sensitive parameters to affect the cycle efficiency. The average effectiveness of the LHS considering only conduction is compared with combined conduction and convection in PCM during discharging. The combined effect increases the average effectiveness of LHS maximum by 26.8 %. The analytical model is developed by eliminating two traditional assumptions considered so far in deriving analytical model. The derived dimensionless governing equations are solved using a Python routine to obtain the discharge performance (ε = 0.61,Q = 797.48 kW, ro = 138.61 mm) of LHS.

Single-Flow Supercritical CO2 Brayton Cycles: A Performance Comparison of the Different Layouts

Supercritical CO2 Brayton cycle (sCO2-BC) has been frequently used in power generation applications in recent years due to its high efficiency, compact size, and low-cost advantages. In this study, performances of different configurations of single-flow sCO2-BCs, such as recuperation, intercooling, reheating, pre-compression, inter-recuperation, and split expansion, are examined. Firstly, thermodynamic analyzes of six different single-flow sCO2-BCs were conducted. Secondly, parametric analyses based on the system performance-influencing parameters, such as turbine input temperature, turbine inlet pressure, and compressor inlet pressure, were carried out. Engineering Equation Solver (EES) computer software was used in the analysis. According to the initially accepted design parameters, the highest energy efficiency was calculated as 39.25 % in the reheating cycle, and the lowest efficiency was found as 29.62 % in the split expansion BC. Moreover, it has been determined that the energy and exergy efficiencies of cycles increase with rising turbine input temperature and turbine input pressure.

Design and Assessment of the Solar Energy Based Direct Steam Generation Supercritical CO2 Brayton Cycle

The aim of this study is to examine the performance of the supercritical CO2 Brayton cycle (sCO2-BC)with intercooling and reheating for low-temperature solar energy application. The heat required for the sCO2-BC is supplied from an evacuated tube solar collector. Energy and exergy analyses of the solar energy-assisted sCO2-BCwith intercooling and reheating are investigated. In addition, the effects of operating parameters like solar radiation, collector number, compressor, and turbine input pressure on system performance are examined parametrically.According to the findings of the analysis, the net power production is found to be 0.2687 kW. In addition, the solar energy-based sCO2-BC's energy and exergy efficiencies are found to be 3.68% and 3.95%, respectively. Moreover, it has been determined that the sCO2-BC's energy and exergy efficiencies reduce with the increase of solar irradiation, the collector number, and the compressor inlet pressure, while the system's energy and exergy efficiencies rise with the increase of the turbine input pressure.

A transient study on a solar-assisted combined gas power cycle for sustainable multi-generation in hot and cold climates: Case studies of Dubai and Toronto

Efficiently managing heat losses continues to be a prominent obstacle within gas-fired power plants. The discharge of high-temperature gases from turbines and the considerable pressure generated by compressors present compelling opportunities for augmenting both power generation and overall efficiency. The present study analyzes a gas-fired power plant with two additional Rankine cycles and a concentrated solar power system to enhance efficiency and output power. Clean power generation and distilled water were the outputs of the proposed system. This study also sought to reduce greenhouse gas (GHG) emissions by using solar energy and diminishing the consumption of fossil fuels (CH4) in the combustion chamber. The proposed system was implemented in hot and cold climates. The Brayton cycle of the system was validated through data of a real-life power cycle on the southern coasts of Iran. Furthermore, a transient evaluation was conducted to explore the effects of climatic parameters on the power and desalination system. The contributions of solar irradiance, wind speed, and ambient temperature to the proposed system in a hot climate (Dubai, UAE) and a cold climate (Toronto, Canada) were evaluated. It was found that gas turbine efficiency, compression ratio, and gas turbine input temperature had the greatest effects on the system. Exergy analysis revealed that the combustion chamber, heliostats, the solar receiver, the multi-effect distillation (MED) unit, gas turbine 1, and the thermoelectric generator accounted for the largest portion of the exergy destruction. The case study indicated that the system would work best in climates like Toronto. The findings can be useful to investors and governments in such climates. The proposed system demonstrates its adaptability to regions sharing a climate resembling that of Toronto, making it a viable solution for a wide range of geographical areas. The design and functionality of the system have been meticulously crafted to accommodate the specific environmental conditions present in Toronto and its comparable regions. Gas-fired power plants across numerous countries widely employ the Brayton cycle as their primary operational framework. In this context, the proposed system presents a compelling opportunity to unlock valuable outcomes and advancements.

New optimized configuration for a hybrid PVT solar/electrolyzer/absorption chiller system utilizing the response surface method as a machine learning technique and multi-objective optimization

The presented study examined the multigenerational power, cooling, heating, and hydrogen systems in coastal areas using thermodynamic and economic modeling and multiobjective optimization tools. The organic Rankine cycle (ORC), water heater, proton-exchange membrane (PEM) electrolyzer, absorption chiller, and photovoltaic (PV/T) panel were all included in a case study that was carried out in four different regions. In the EES, the suggested system was thermodynamically modeled. By utilizing the surface response (RSM) methodology, multi-objective optimization was carried out to identify the ideal PV/T area, turbine efficiency, evaporator pinch point, pump efficiency, and turbine input temperature. The ideal cost rate and exergy efficiency were 1.299 USD/h and 19.100%, respectively. The feasibility of the suggested module was studied in coastal areas of San Francisco (America), Dubai (Asia), Barcelona (Europe), and Melbourne (Oceania). Finally, the system's effectiveness in providing the power, cooling, and heating demands of a two-floor two-unit building during the year was evaluated.

Simulink modelling of Combined Cycle Gas Turbine (CCGT) power plant for performance analysis

A gas-fired plant and a steam-fired plant make up a combined cycle power station. The purpose of this research is to build a CCGT power plant and investigate the interaction between fuel and airflow using a simulink model. A mathematical model is used to predict how the CCGT power plant system will react. The goal of a turbine is to extract as much energy as possible from the working fluid and convert it into usable work. A large amount of heat energy from the gas turbine exhaust is wasted but has a lot of potential energy. The term total energy approach describes a system's capacity to use all of the energy at its disposal. To generate as little energy waste as possible, every watt of heat energy in a power system is supposed to be used to produce work, steam, or heat air or water. The creation of a mixed-cycle power plant is the most efficient and cost-effective way to accomplish this objective. The concept and early development of the mixed cycle were centred on the utilisation of thermal power plant waste heat. The temperature of the gas turbine exhaust can vary from 450°C to 650°C depending on the pressure ratio and turbine input temperature. It is wasteful to discard this energy into the environment. This wasted heat energy could be used to generate steam in the steam heat recovery generator (HRSG). By employing the Rankine cycle to expand the steam generated by the HRSG in a steam turbine, additional power may be created. One name for this configuration is a gas/steam mixed-cycle power plant. A gas turbine's exhaust temperature must be higher than 570°c. For the steam cycle to function properly and for the combined cycle efficiency to remain high.

Comparative assessment of the various split flow supercritical CO2 Brayton cycles for Marine gas turbine waste heat recovery

Supercritical CO2 Brayton cycle (sCO2 BC) can become easily utilized in marine gas turbine waste heat recovery applications due to their high efficiency, compact size, and low-cost advantages. In this study, the performance of the three different split flow sCO2 BCs, including turbine split flow-1 (TSF-1), turbine split flow-2 (TSF-2), and turbine split-3 (TSF-3), for the recovery of marine gas turbine waste heat is compared. The Engineering Equation Solver (EES) application is used to compare the three different split flow sCO2 BCs' performances. Moreover, to investigate the influence of important thermodynamic parameters on cycle performance, a parametric analysis is carried out. The effect of variable exhaust gas temperature, turbine input pressure, and compressor inlet pressure on net power, the energy efficiency of the system, system's exergy efficiency, and exergy destruction are examined. The results suggest that the energy efficiencies of the TSF-1 sCO2 BC, the TSF-2 sCO2 BC, and the TSF-3 sCO2 BC are calculated by 28.71%, 34.5%, and 29.42%, respectively. The TSF-2 sCO2 BC has more advantages in efficiency among all the cycle layouts while the TSF-3 sCO2 BC layout has better performance in the net power. In addition, the TSF-3 sCO2 BC has the highest exergy destruction at 99.71 kW, followed by the TSF-1 sCO2 BC at 91.83 kW and the TSF-2 sCO2 BC at 41.75 kW. It has been determined that the cycle's net power increases with rising exhaust gas temperature and turbine input pressure and decreases with compressor input pressure. Exhaust gas temperature and turbine inlet pressure have a positive effect on the performance of all split flow sCO2 BCs.

Optimization of a near-zero-emission energy system for the production of desalinated water and cooling using waste energy of fuel cells

In the present study, a biomass-based multi-purpose energy system that can generate power, desalinated water, hydrogen, and ammonia is presented. The gasification cycle, gas turbine, Rankine cycle, PEM electrolyzer, ammonia production cycle using the Haber-Bosch process, and MSF water desalination cycle are the primary subsystems of this power plant. On the suggested system, a thorough thermodynamic and thermoeconomic evaluation has been conducted. For the analysis, the system is first modeled and investigated from an energy point of view, after which it is similarly studied from an exergy point of view before the system is subjected to economic analysis (exergoeconomic analysis). The system is evaluated and modeled using artificial intelligence to aid in the system optimization process after energy, exergy, and economic modeling and analysis. The resulting model is then optimized using a genetic algorithm to maximize system efficiency and reduce system expenses. EES software does the first analysis. After that, it sends the data to MATLAB program for optimization and to see how operational factors affect thermodynamic performance and overall cost rate. To find the best solution with the maximum energy efficiency and lowest total cost, multi-objective optimization is used. In order to shorten computation time and speed up optimization, the artificial neural network acts as a middleman in the process. In order to identify the energy system's optimal point, the link between the objective function and the choice factors has been examined. The results show that increasing the flow of biomass enhances efficiency, output, and cost while raising the temperature of the gas turbine's input decreases cost while simultaneously boosting efficiency. Additionally, according to the system's optimization results, the power plant's cost and energy efficiency are 37% and 0.3950$/s, respectively, at the ideal point. The cycle's output is estimated at 18900 kW at this stage.

Study on output power oscillation characteristics of a doubly-fed unit when operating parameters change

To study the power propagation of wind turbines in the doubly-fed unit and the output power oscillation characteristics of the doubly-fed unit after transformation. Firstly, the damping of the doubly-fed unit was changed when the wind velocity was lower than the rated wind velocity and higher than the rated wind velocity respectively, considering the tower shadow effect and wind shear, and the oscillation characteristics of the output power of the doubly-fed unit were studied. Finally, modeling and simulation were carried out on PSCAD/EMTDC platform. Through the analysis of power fluctuation and spectrum change of the unit, it is concluded that when the wind turbine input wind velocity is greater than or less than the rated wind velocity of the unit, the wind turbine power through the doubly-fed unit has different effects on the output power oscillation characteristics of the unit. The output power oscillation characteristics of doubly-fed units are different with and without the tower shadow effect and wind shear. When the doubly-fed unit is negatively damped and the tower shadow effect and wind shear are taken into account, the output power of the unit contains both low-frequency and sub-synchronous oscillations, and the magnitude and frequency of the oscillation components are related to the control parameters of the unit.

A novel comparison of energy-exergy, and sustainability analysis for biomass-fueled solid oxide fuel cell integrated gas turbine hybrid configuration

Conventional gas turbines (GT) are working with limited fuels and exhibit thermal efficiency between 30 and 40%. This restriction with the fuels and its efficiency range can be improved by adding an electrochemical fuel cell, i.e; a Solid Oxide Fuel Cell (SOFC). This paper proposes three different types of biomasses, including pine sawdust, poplar sawdust, and almond shell, which may all be used to power the novel biomass-fueled solid oxide fuel cell gas turbine (SOFC-GT) presented herein. MATLAB based simulation is used to validate the results of this fuel cell based hybrid cycle performance. Three performance parameters are considered namely, current density (id), turbine input temperature (TIT), and pressure ratio (rp) to evaluate the performance of the proposed system. For this, energy-exergy approaches based on the first and second law of thermodynamics are used to assess each cycle component as well as the entire system. The sustainability index and environmental impact factor of each component are evaluated using dimensionless modified exergy indicators. With all three of the suggested biomass fuels, the SOFC-GT hybrid system runs most effectively at pressure-ratio of 6 and TIT 1250 K. Pine sawdust (Case-1) exhibits the largest levels of exergy destruction (2653.14 kW), environmental effect (0.91), and the lowest sustainability index (2.09) but it also has the highest levels of thermal efficiency (63.12%).

Research on the flow characteristics identification of steam turbine valve based on FCM-LSSVM

Due to aging and deformation of the through-flow path and system modifications, the flow characteristics of the turbine inlet valve often deviate from the design value, which affects the unit load control accuracy and operational stability. In order to obtain the actual valve flow characteristics of the turbine and thus improve the FM performance, an FCMLSSVM model is proposed in this paper to identify the valve flow characteristics. First, FCM clustering is proposed to classify the historical operating data of the plant and obtain a wide range of variable operating conditions. Then, using least squares support vector machine (LSSVM), the relationship between turbine input and output variables was modeled in each condition cluster, with integrated valve position command, speed, and real power generated as input variables and actual steam inlet flow as output variables. Using a 330 MW turbine unit as an application example, the established FCM-LSSVM model was validated for the valve flow characteristics of the turbine. The results show that the model can obtain accurate valve flow characteristics without conducting tests on the turbine. The method can save a lot of labor and material resources in doing the characteristic test, and after comparison, the proposed method can identify the flow characteristics more accurately among the existing neural network identification methods, which can provide technical support to improve the unit frequency regulation characteristics and improve the accuracy of valve operation.

An innovative compressed air energy storage (CAES) using hydrogen energy integrated with geothermal and solar energy technologies: A comprehensive techno-economic analysis - different climate areas- using artificial intelligent (AI)

The present study evaluates the optimal design of a renewable system based on solar and geothermal energy for power generation and cooling based on a solar cycle with thermal energy storage and an electrolyzer to produce hydrogen fuel for the combustion chamber. The subsystems include solar collectors, gas turbines, an electrolyzer, an absorption chiller, and compressed air energy storage. The solar collector surface area, geothermal source temperature, steam turbine input pressure, and evaporator input temperature were found to be major determinants. The economic analysis of the system showed that the solar subsystem, steam Rankine cycle, and compressed air energy storage accounted for the largest portions of the cost rate. The exergy analysis of the system demonstrated that the solar subsystem and SRC had the highest contributions to total exergy destruction. A comparative case study was conducted on Isfahan, Bandar Abbas, Mashhad, Semnan, and Zanjan in Iran to evaluate the performance of the proposed system at different ambient temperatures and irradiance levels during the year. To optimize the system and find the optimal objective functions, the NSGA-II algorithm was employed. The contradictory objective functions of the system included exergy efficiency maximization and cost rate minimization. The optimal Exergy round trip efficiency and cost rate were found to be 29.25% and 714.25 ($/h), respectively.

Güneş Enerjisi Kaynaklı Farklı Transkritik CO2 Rankine Çevrimlerinin Karşılaştırılması

In this study, different transcritical CO2 Rankine (tCO2-RC) cycles with vacuum tube solar collectors are examined. In this context, the transcritical CO2 Rankine cycle in different configurations, such as simple, regenerator, reheat, regenerator, and reheat, which is widely used in the literature, has been chosen. First, the energy and exergy efficiencies of the cycles were founded by performing thermodynamic analyzes of four various tCO2-RCs under certain operating parameters. Moreover, parametric studies were carried out according to the factors affecting the system performance, like turbine input temperature and input pressure of the turbine. Both analyzes and parametric studies were conducted utilizing the Engineering Equation Solver (EES) computer program. As outcomes of analyzes, the highest thermal efficiency was founded for the tCO2-RC with reheat and regenerator by 11.8%, and the lowest energy efficiency was calculated for the simple tCO2-RC and tCO2-RC with reheat by approximately 6.6%. While all tCO2-RCs' energy and exergy efficiencies increased with the rise of the turbine’s input pressure, the energy and exergy efficiency of all tCO2-RCs decreased with the rise of the pump’s input pressure.

Power decoupling control of DFIG rotor‐side PWM converter based on auto‐disturbance rejection control

AbstractIn this paper, double PWM converter AC excitation system of the variable speed constant frequency doubly fed induction generator (DFIG) for wind power generation is taken as the research object. At present, most vector control systems of rotor‐side PWM converter adopt feedforward compensation to realize the purpose of power decoupling control. The decoupling effect is greatly affected by the power changes. A power decoupling control strategy based on auto‐disturbance rejection control (ADRC) is proposed. The decoupling control between active power and reactive power is realized by observing the coupling term and the total disturbance of the d‐axis and q‐axis components of the stator current and the stator voltage with the extended state observer and compensating. Simulation analysis and experimental test show that, on the basis of vector transformation, the rotor‐side PWM converter power decoupling control based on ADRC has a small overshoot and fast dynamic response when tracking the change of wind turbine input power, which can achieve the decoupling control between active power and reactive power well. The system has strong robustness and adaptability.

Development of a novel combined energy plant for multigeneration with hydrogen and ammonia production

In order to meet the energy and fuel needs of societies in a sustainable way and hence preserve the environment, there is a strong need for clean, efficient and low-emission energy systems. In this regard, it is aimed to generate cleaner energy outputs, such as electricity, hydrogen and ammonia as well as some additional useful commodities by utilizing both methane gas and the waste heat of an integrated unit to the whole system. In this paper, a novel multi-generation plant is proposed to generate power, hydrogen and ammonia as a chemical fuel, drying, freshwater, heating, and cooling. For this reason, the Brayton cycle as prime unit using methane gas is integrated into the s-CO2 power cycle, organic Rankine cycle, PEM electrolyzer, freshwater production unit, cooling cycle and dryer unit. In order then to evaluate the designed integrated multigeneration system, thermodynamic analyses and parametric studies are performed, revealing that the energy and exergy efficiencies of the whole plant are found to be 69.08% and 65.42%. In addition, ammonia and hydrogen production rates have been found to be 0.2462 kg/s and 0.0631 kg/s for the methane fuel mass flow rate of 1.51 kg/s. Also, the effects of the reference temperature, pinch point temperature of superheater, combustion chamber temperature, gas turbine input pressure, and mass flow rate of fuel on numerous parameters and performance of the plant are investigated.

Development and analysis of VAWT offgrid in ducting system

Horizontal Axis Wind Turbine (HAWT) had been widely used in Malaysia, however, research concluded that the power produced is still low which approximately 0.02% from the wind turbine input is. The average wind speed in Penang, Malaysia, is recorded between 1.0 m/s to 2.5 m/s whereby to produce 2.7 kW of power by HAWT, 12.0 m/s of average wind speed is needed. Therefore, the main objective in this project is to develop and analyse the suitability on the Vertical Axis Wind Turbine (VAWT) to be used for power generation with the wind speed in between 0.5 m/s to 3.0 m/s. Ducting system is chosen rather than the open air since commercial buildings used Heat Ventilation Air Conditioning (HVAC) system. Arduino microcontroller and LabVIEW is used as interfaced to setup two types of sensors that is temperature sensor and anemometer.

Simulation Study on Dynamics of Hydraulic Turbines Used in Drilling Engineering

Hydroturbines have a very wide range of applications, which are commonly found in wind turbines, water turbines, aero engines, etc. This paper provided a detailed turbine design and a design method of turbine blade shape. Using the CFD (computational fluid dynamics) method, based on the realizable k-ɛ turbulence model and Euler multiphase flow model, the effects of different external loads, blade numbers, blade installation angles, and flow rates on the force condition of turbine and the influence of different solid contents, particle sizes, and densities on turbine performance were studied. The simulation results show that, under the action of fluid, when the starting torque of turbine is larger than the external load, the turbine starts to move, the angular velocity increases until it remains constant, the absolute value of impact force decreases, and the impact torque decreases until it is equal to the external load; while the starting torque of turbine is smaller than the external load, the turbine stays still. The increase of the particle size, content, and density of the solid phase will lead to an increase in the torque and pressure drop of the turbine and ultimately leads to the increase of turbine input, output power, and efficiency.