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In the evolving landscape of sustainable energy, optimizing geothermal power systems presents a critical challenge. This study explores the energy and exergy efficiencies of a power production system utilizing a single‐flash geothermal cycle integrated with a trans‐critical CO2 cycle. The study's methodology involves a detailed examination of key performance parameters—separator pressure, CO2 turbine intake pressure, and steam turbine output pressure. Utilizing the EES software environment, the study innovatively employs a combination of Genetic Algorithm (GA), Nelder–Mead Simplex (NMS) method, and Direct algorithm (DA). When using GA, NMS and DA, the system's exergy efficiency increases from 32.46% in the default operating mode to 39.21%, 36.16%, and 38.82%, respectively. One of the notable outcomes is the identification of optimal separator pressure for maximum energy efficiency. Furthermore, the study reveals that increasing the CO2 turbine's inlet pressure adversely impacts the system's efficiency. The study's results contribute significantly to the field of renewable energy, offering practical guidelines for enhancing the performance of geothermal power systems. [ABSTRACT FROM AUTHOR]

Facing the dual challenges of environmental impact and the finite nature of fossil fuels, the shift toward sustainable energy sources is imperative. Geothermal energy, a renewable and underutilized resource, offers a promising alternative. This study ventures into a novel domain, exploring the integration of trans‐critical CO2 (tCO2) cycle with a double‐flash geothermal (DFG) cycle, an area not extensively covered in existing research. This study aims to develop a recovery system that utilizes a tCO2 cycle powered by a DFG cycle. A crucial part of this study involves conducting a sensitivity analysis to evaluate the system's energy and exergy performance. This analysis focuses on understanding the impact of changes in key system design parameters, such as energy efficiency, exergy efficiency, net power output, and total exergy destruction rate, to determine the optimal values for these parameters. The results indicate that the recovery system shows a significant improvement of 22% in energy efficiency over the basic cycle. However, there is a decrease in exergy efficiency in the recovery system, which represents a 5.26% decline. As a result, this study paves the way for innovative approaches in geothermal energy use, suggesting potential breakthroughs in renewable technologies. [ABSTRACT FROM AUTHOR]

The combustion of natural gas consisted of methane CH4, ethane C2H6, and propane C3H8 is theoretically investigated to obtain the optimum adiabatic flame temperature (AFT). The investigation includes the development of combustion equations that take into consideration different compositions of natural gas. The final equation to calculate the AFT is derived and used in the optimization study. The optimization study using genetic algorithm investigates the effect of changing the composition of the gas mixture, the inlet temperature of used air, and the amount of excess air used on the AFT. It is possible to get the required composition of each component, the air inlet temperature, and the excess air by reading the chart to get the required AFT. The heat capacity of all reactants and products is used as a function of temperature. Results showed that the optimum values for CH4,C2H6,C3H8, percentages in the gas mixture, air inlet temperature, and the amount of excess air are 0.478, 0.166, 0.356 mol %, 1.848, 382.104 K, respectively. These optimum values lead to a value of about 1300 K for the AFT. The derived equation shows the AFT at different natural gas compositions along with different process parameters such as the amount of excess air. Thus, the required combustion temperature can be controlled by adjusting the natural gas composition or the combustion temperature can be specified based on the provided composition of the natural gas stream by using either the derived equations or output chart. (R1. 1). [ABSTRACT FROM AUTHOR]

The global utilization of RES, particularly geothermal energy, is rising and the inefficient nature of geothermal cycles necessitates recovering lost heat. This research proposes a combined power generation cycle that simulates integrating a trans-critical CO2 cycle with a single flash geothermal cycle, utilizing the engineering equation solver. The study contrasts the system's performance between two operating states: "Without Economizer" and "With Economizer". The investigation analyzes the impact of an economizer on key output parameters, including energy efficiency, exergy efficiency, and net power output. In the "With Economizer" operating state, the net power output experiences a noticeable increase from 201.5 kW to 204.7 kW, resulting in a 1.58% enhancement in the performance of the "With Economizer" system. The energy efficiency metric demonstrates a corresponding improvement, rising by 1.55% from 3.28% in the "Without Economizer" system to 3.331% in the "With Economizer" system, aligning with the principles of the First law of thermodynamics. Furthermore, the energy efficiency, expressed as a percentage of energy units, shows an increase from 16.3% in the "Without Economizer" system to 16.56% in the "With Economizer" system, representing a 1.595% improvement based on the Second law of thermodynamics or exergy. Regarding cost analysis, the study identifies the optimal separator pressure value for the system without an economizer, equivalent to 23. This configuration achieves a total cost rate of 01 $ per GJ. Conversely, in the system with an economizer, the optimal pressure value for the production cost rate is 322.4 kPa, resulting in a cost rate of 23.57 $ per GJ. [ABSTRACT FROM AUTHOR]

This work proposes a new chimney design that allows for the development of a multi‐stage solar updraft tower (SUT). The new design consists of two successive divergent chimneys. A 3D model was established to inspect the air flow behaviour within the SUT in six configurations: four multi‐stage systems with four divergence angles of the second stage were compared to the simple conventional SUT and the simple SUT with a divergent chimney. The new SUT performs better than the conventional one, while the two‐stage solar tower multiplied the system efficiency. Two high‐velocity zones appeared for the two‐stage SUT, whereas one zone occurred for the conventional system. The velocity in the two zones achieved a significant value, like that of the conventional system. In addition, the second stage's divergence angle directly impacts the velocity value inside the two stages. The static pressure distribution varies with the change in chimney design. The depression area occurs twice for the multi‐stage SUT in the inlet of each stage. [ABSTRACT FROM AUTHOR]

At temperatures below 60 °C, the best way to use geothermal sources for heating is to use heat pumps. A heat pump can provide air conditioning for a residential, commercial, etc., all year round by heating in winter and cooling in summer using a low temperature source. Also, a heat pump can be used for water distillation through evaporation. The ground source heat pump with a high COP and low temperature thermal energy sources is one of the best technologies for using RES. In the present study, the effects of changing ambient temperature and soil temperature on a heat pump's overall COP and energy efficiency are investigated using a simulated geothermal heat pump with an economizer. The system's thermodynamic simulation is first performed in the engineering equation solver software for R134a and R513a working fluids. The exergy destruction of different components for both working fluids was calculated and displayed as a figure. The COP of the heat pump for R134a working fluid is equal to 3.916, equal to 3.729 for R513a working fluid, which indicates that R134a fluid has about 5% better performance. The COP of the system for R134a working fluid is equal to 3.662, which is equal to 3.504 for R513a working fluid, which indicates that R134a fluid has about 4.5% better performance. [ABSTRACT FROM AUTHOR]

A new design of solar air heater with triangle cross-section is numerically studied. The thermal performance of solar air heater is studied at various mass-flow rates, inlet air temperatures, and solar irradiation intensities. The CFD model is developed using the software ANSYS FLUENT to study the fluid-flow and heat transfer in the solar air heater. The 3-D discretization is applied to study the thermal performance of solar collector with triangle cross-section. Mesh independence is performed in order to choose the adequate mesh. The discrete ordinate radiation model and the RNG k-e turbulence model are used to study the radiative heat transfer and the turbulent flow inside the solar air heater. Particularly, effects of different internal peak angles (145°,126°, 100°, 80°, and 67.5°) under different solar irradiation intensities (from 620-1081 W/m2) are studied to improve the thermal performance of the solar air heater. The results show a good agreement between the numerical model and the experimental data with an average error of 6%. The maximum outlet air temperature of the solar air heater reached 72 °C for the geometries with 12 and 16 channels (internal peak angles of 80° and 67.5°, respectively) under mass-flow rate of 0.0264 kg/s. The thermal performances of the solar air heater with 16 and 12 channels are 24.2% higher than standard geometry, respectively for solar irradiation intensity of 1081 W/m2. The configuration with internal peak angle of 80° and 12 channels is selected as the optimal with a thermal efficiency of 79%, a low pressure drops compared to geometry with 16 channels and lower costs. [ABSTRACT FROM AUTHOR]

Compared with conventional fossil fuel sources, geothermal energy has several advantages. The produced geothermal energy is safe for the environment and suitable for meeting heating power needs. Because the hot water used in the geothermal process can be recycled and used to generate more steam, this energy is sustainable. Furthermore, the climate change does not affect geothermal power installations. This study suggests a combined power generation cycle replicating using the EES software that combines a single flash cycle with a trans-critical carbon dioxide cycle. The findings demonstrate that, in comparison to the BASIC single flash cycle, the design characteristics of the proposed system are greatly improved. The proposed strategy is then improved using the Nelder–Mead simplex method and Genetic Algorithm. The target parameter is exergy efficiency, and the three assumed variable parameters are separator pressure, steam turbine outlet pressure, and carbon dioxide turbine inlet pressure. The system's exergy efficiency was 32.46% in the default operating mode, rising to 39.21% with the Genetic Algorithm and 36.16% with the Nelder–Mead simplex method. In the final step, the exergy destruction of different system components is calculated and analyzed. Highlights: Designing and simulating a combined single flash geothermal cycle with a trans-critical carbon dioxide cycle in the EES software. Genetic algorithms (GA) and the Nelder–Mead simplex (NMS) method are used to optimize the proposed system to increase the system's exergy efficiency. Examining the system's various components' energy destruction rates. [ABSTRACT FROM AUTHOR]