فهرست مطالب

Energy Equipment and Systems
Volume:12 Issue: 4, Autumn 2024
- تاریخ انتشار: 1403/09/11
- تعداد عناوین: 7
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Pages 285-326With the invention of internal combustion engines in the late 19th century, a tremendous transformation in the field of transportation occurred, paving the way for acceleration in all human endeavors. Consequently, internal combustion engines have continuously advanced, with industry players competing and innovating in this sector. Various industries have shown a noticeable interest in creative approaches to design and improve the quality and performance of these engines. Internal combustion engines can be broadly categorized into gasoline and diesel engines. Marine diesel engines, like gasoline engines, are internal combustion or internal ignition engines that convert chemical energy from fuel into thermal energy inside the cylinder and then convert thermal energy into the mechanical energy required for ignition generation. The importance and necessity of using diesel engines in various industries, especially in maritime applications, are undeniable, as the focus of this research. The field of diesel engines is considered one of the crucial components of a country's industrial and scientific self-reliance and ignition, with the measurement of a nation's capacity and ignition in various sectors, from politics and economics to defense and military, being dependent on the knowledge, analysis, design, and production of equipment and tools that are internationally competitive. Key parameters that play a significant role in selecting engines include size, ignition, and how they perform in various applications. An engine's ignition level and appropriate performance are directly related to optimal design and understanding the forces and stresses applied to the engine components during operation. The primary objective of this project is to perform a mechanical analysis of the piston, connecting rod, and crankshaft in a 150-horse-ignition marine diesel engine, to improve thermal performance and enhance engine efficiency. To achieve this, an in-depth study will be conducted, using available diagrams to analyze these components, and the results obtained will be used to evaluate strategies for reducing thermal stresses and increasing efficiency. Ultimately, based on the research data, it can be concluded that the quenching process on the piston crown with a ceramic material reduces the maximum stress by an average of 40% for the critical element in four phases: compression, combustion, and exhaust. As a result, it increases the reliability coefficient by 23% for the critical element in the ignition phase.Keywords: Stress, Strain, Diesel Engine, Thermal Stress, Coating
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Pages 327-340This research presents an experimental investigation into a double-pass counter-flow solar air heater (DCSAH) incorporating a copper foam absorber plate and PCM heat storage for drying purposes, conducted with a no-load case under Iraq's meteorological conditions in Baghdad (Latitude 33.3⁰N). A total of 36 kilograms of paraffin wax serves as the phase change material, divided equally into two portions and enclosed within separate heat exchangers. The investigation examines the effects of mass flow rate, PCM utilization, and incident solar radiation on various parameters, including outlet air temperature, heat gained, thermal efficiency, benefit factor, and pressure drop across the solar collector. A comparative analysis is performed with a flat plate solar dryer featuring a traditional absorber plate. The findings reveal that, compared to a flat absorber plate, the DCSAH's thermal efficiency improves by (15%, 19%, and 22%) for air mass flow rates of 0.0076, 0.0118, and 0.0136 kg/s, respectively, when equipped with a copper foam absorber plate without PCM. Furthermore, the benefit factor surpasses 1 for an air mass flow rate of 0.0118 kg/s. Comparative analysis with previous studies indicates good agreement between the findings of this study and prior works.Keywords: Solar Dryer, PCM, Copper Foam, Thermal Efficiency, Benefit Factor
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Pages 341-377The use of fossil fuels for energy supply causes air pollution and environmental degradation factors, which itself causes climate change in the world. Therefore, researches are looking for ways to optimize energy consumption in the world. For this purpose, in this study, by optimizing the amount of energy consumption of air conditioning systems (ACS) in a residential building, it helps significantly in reducing the energy consumption of the building. For this purpose, a six residential building in 4 cities of Iran with different climates have been investigated. For this purpose, 5 design variables of summer clothing insulation level (SCIL), winter clothing insulation level (WCIL), ACS (40 different ACS), cooling thermostat temperature (CTT) and heating thermostat temperature (HTT) have been considered. The objective functions in this study are the cost of installing the air conditioning system (CIACS), the annual cost of bills (ACB) and the predicted percentage of dissatisfied (PPD). The effect of design factors on objective functions has been investigated by Morris’s sensitivity analysis. Three Energy Plus, JEPLUS and JEPLUS+EA software is used for optimization. For this purpose, non-dominant sorting genetic algorithm (NSGA-II) - is used for optimization. The optimization results after the calculations showed that Tehran's annual energy consumption has decreased by 81.3%, for Rasht by 63.64%, for Bandar Abbas by 82.66% and for Shahrekord by 77.2%. Also, the PPD for the cities of Tehran, Rasht, Bandar Abbas and Shahrekord improved by 44.42, 50.1, 31.1 and 56.3% respectively.Keywords: PPD, ACS, ACB, CIACS, NSGA-II
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Pages 379-398Recently, there has been a growing focus on the implementation of integrated energy systems using low-carbon fuels to align with sustainability objectives. This study conducted an investigation into a novel CHP system, which was designed to meet the efficient energy production. This innovative system utilized the ammonia fuel within Brayton cycle, incorporating various interconnected subsystems, including the Kalina cycle, High-Temperature Steam Electrolysis, ultra supercritical steam Rankine cycle as well as ammonia synthesis reactor. The primary aim of this system was to reduce dependence on external resources by establishing local sources for water and fuel, thus enhancing energy sustainability. Using Gaseq and EES software, thermochemistry and thermodynamic models of the integrated system was developed, providing valuable insights into the interactions among system parameters. In-depth investigations involved the examination of different energy system scenarios. The results revealed the superiority of the integrated system with a remarkable thermal efficiency of 47.8% and a net power generation of 2.65 MW, in contrast to the ammonia Brayton cycle with power generation of 1.43 MW and an efficiency of 28.7%. This study also highlighted the environmental benefits of the ammonia Brayton system by zero carbon and under 10 ppm NOx emission, showcasing its significant environmental sustainability.Keywords: Integration, Ammonia Brayton Cycle, EGR, Hydrogen Production, HTSE
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Pages 399-421
The unfavorable heat generation in photovoltaic (PV) panels results in an increased average temperature of PV, followed by decreased electrical performance of the entire system. One can reduce the average temperature of the photovoltaic panel using a phase change material (PCM) at its back which improves the electrical efficiency of the photovoltaic panel. Nonetheless, the low thermal conductivity of the phase change material leads to its poor cooling efficiency. The application of fins can enhance heat transfer through PCM. This investigation conducts a numerical estimation of the geometrical improvement of fins in a phase change material integrated PV system featuring interior fins. The contribution of geometrical characteristics, such as type, fin length, shape, and also disposition angle, to the efficiency of the PCM amalgamated PV module has been investigated. In addition, when the fin length is increased from 0 to 20mm, the efficiency and operating temperature of the photovoltaic panel improved by 3.5% and 2.7%, respectively. To investigate the impact of shape of the fin on its cooling performance, five different fin shapes have been considered. The results show that triple-branched fins exhibited 1.2% and 1.5% augmentation in the mean working temperature of the PV module and performance of the system, respectively, when compared to the traditional rectangular fins. Moreover, comparative results indicate that compared to the conventional rectangular PCM encapsulation, in case of employing non-rectangular PCM encapsulations with higher top to bottom ratio higher cooling performance and melting rate of PCM is achieved.
Keywords: Phase Change Material, Solar Cell, Thermal Management, Fins, Heat Transfer -
Pages 423-453This research utilizes MATLAB and Python coding to optimize the thermal design of an industrial shell and tube steam boiler with an internal superheater. The paper outlines a systematic approach to steam boiler design, including heat transfer dynamics analysis, superheater configuration optimization, and implementation. They take action to enhance the performance of the third pass. The shell and tube steam boiler specifications, including an internal superheater, have been determined, with a steam capacity of 5 tons/hour and operating at a working pressure of 10 bar. According to the results, the opt substantially impacted 71 tubes in the second pass, each with a diameter of 5 cm, and an additional 82 tubes of identical size in the third pass (which includes revisions). To achieve a desired temperature increase of 15 ℃ in the superheater, incorporating the superheater section into the fire tube resulted in a 23.72% increase in the third pass level compared to the scenario without a superheater. For every 5 ℃ temperature increase in the superheater, the steam velocity in the third pass tubes decreases by approximately 1m/s. Adding the superheater to the end of the third pass reduces the temperature of this area from 525 ℃ to 500 ℃. Leveraging machine learning algorithms enabled the identification of parameters influencing the rise in superheater temperature. Linear regression emerged as the best predictor of superheater temperature increase among the eight models considered.Keywords: Heat Transfer, Heat Exchanger Design, Fire Tube Boiler, Superheater, Machine Learning
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Pages 455-477Today, rising concerns about energy shortages and environmental degradation have encouraged innovation in renewable energy sources and cutting-edge technology for capturing their full potential. The adoption of sustainable practices has resulted in the emergence of innovative cogeneration systems that incorporate municipal solid waste as a fuel source. By integrating advanced technologies—including digesters, organic Rankine cycles, multiple effect distillation, methanation, and proton exchange membranes—this system uniquely converts hydrogen and CO2 into methane, enhancing fresh water production through heat recovery in the digestion process. We explore three multiobjective optimization scenarios employing machine learning and Greywolf algorithms to enhance system efficiency. The system has a significant CO2 emission index of 0.1649kg/kWh and total cost products of 12.91$/GJ, with a second-law thermodynamics efficiency of 32.07%. In the second scenario, strategic optimization is centered around the objective of increasing efficiency and net output power, while simultaneously reducing costs. This approach yields significant enhancements, including an exergy efficiency of 39.13% and a net output power of 30366.92 KW. Additionally, the product costs are lowered to 7.2571 $/GJ. These results highlight the system's cost-effectiveness and alignment with sustainability principles, offering meaningful contributions to renewable energy technologies and environmental conservation.Keywords: MED (Multiple Effect Distillation), CO2 Capturing, PEME (Proton Exchange Membrane Electrolyzer), Digester, Methanation, Cogeneration, Multiobjective Optimization, Biogas