Papers by Keyword: Efficiency

Abstract: Climate change is progressing rapidly, posing severe risks to the environment and making sustainability and circularity key challenges for future industrial development. Greenhouse gas emissions are largely driven by human activities within industrialized societies, requiring adaptation at individual, societal, and industrial levels. Metal forming technologies can contribute significantly to this transformation by improving material efficiency, process efficiency, product efficiency, and circularity. Material efficiency is particularly important, as material production accounts for the largest share of industrial emissions. Process efficiency offers a high leverage effect, due to the large production volumes in forming process chains, while product efficiency reduces energy consumption during usage and enhances the performance of energy generation systems. Circularity supports sustainability by extending material lifecycles through reuse and recycling, thereby avoiding energy-intensive primary production. This paper presents an overview of exemplary sustainability contributions in metal forming process chains. For open-die forging, it can, for example, be shown, that digital twins, virtual reality–based operator training and real-time assistance systems are measures to improve material and process efficiency. A circularity approach for open-die forging is presented, with a remanufacturing concept for large shafts based on re-forging end-of-life components, in order to heal fatigue-related damage by forming. Increased material, process and product efficiency is demonstrated by a use case study of forging hollow rotor shafts for wind turbines. Whereas, the hollow-forging allows for weight reduction in the rotor component and thus enables higher power density of the generator, thinner tower designs and reduced logistic costs. Additionally, the use of an innovative air-hardening ductile (AHD) steel can eliminate the energy-intensive heat treatment in the process chain.

Abstract: Solar cells are a promising technology for energy production, and they provide a sustainable and environmentally friendly alternative to traditional energy sources based on fossil fuels. This study aims to improve the efficiency (E)of the solar cell using Triglyceride for Oleic Acid. Crystal Triglyceride for Oleic Acid is a compound of two components (Triglyceride and Oleic Acid), Each compound has a structural formula and physical and chemical properties. The prepared samples (1, 1.4, 1.5, 1.6, and 2) mol/l. The required data were collected and analyzed through (a UV/visible spectrophotometer, Spectrofluorometer, and Solar Module Analyzer), The data obtained were wavelength for absorption, wavelength for fluorescence, Stokes shift (the difference between fluorescence and absorption wavelengths), practical and theoretical efficiency, current and voltage values, and power factor. Luminescent solar concentrators were used to test the efficiency of the PV. The results showed that the E improved well, as the efficiency was (21.57) before using the solar concentrator, and after using the concentrator, it became (26.61) at a concentration of 1.5 mol/l.

Abstract: The petroleum production process emphasizes the importance of inspection, analysis, test planning, and providing feedback on rotating equipment. This study discusses the analysis of steam turbine generator overhaul (OH) for efficiency enhancement at the power plant center of refinery unit. The efficiency of steam turbines in power plants is critical for optimizing energy conversion and minimizing operational costs. This study analyzes the impact of a steam turbine generator overhaul on efficiency at a refinery unit power plant. Efficiency was evaluated using Rankine cycle calculations, comparing performance data before and after the overhaul. The findings indicate a 2.63% increase in efficiency, with entropy-temperature analysis revealing energy losses due to scaling buildup and seal strip clearance deterioration. To maintain efficiency and reduce overhaul frequency, demineralized water quality, periodic maintenance, and anti-scaling treatments are recommended. These results highlight the importance of proactive maintenance in sustaining turbine performance and minimizing long-term costs.

Abstract: Corrosion of steel structures in marine environments is a critical issue affecting infrastructure integrity and maintenance costs worldwide. Generally, inhibitors have proven to reduce the corrosion rate to the barest minimum than other methods. The inhibitors are produced using the experimental method which is time consuming and costly. This necessitate the development of models for the quick assessment of the efficiency of the inhibitor. This research focused on the prediction of corrosion inhibitory efficiency of water hyacinth on mild steel in marine environment using multiple linear regression (MLR) method. Various concentrations (5 ml, 10 ml, 15 ml, 20 ml and 25 ml) were added to the samples immersed in seawater and a sample without the addition of the inhibitor was used as the control for a period of 30 days. The study was carried out using weight loss method and the corrosion rate as well as the inhibition efficiency were calculated. Phytochemical analysis and atomic absorption spectroscopic were carried out on the inhibitor while Scanning Electron Microscopy and Energy Display X-ray Spectroscopy were used to analyze the steel sample. The analysis of the result showed that the best inhibition efficiency obtained was 90% and this was achieved with 15% concentration of the inhibitor. Multiple linear regression model was developed to predict the inhibitor’s efficiency. The predicted efficiency with the MLR model was compared with that of the experimentally obtained efficiency and the outcome shows a conformity between the experimental and the predicted value. It would therefore be recommended to rely on multiple linear regression in predicting the efficiency of water hyacinth for corrosion control of mild steel in marine environment based on the closeness of the predicted values to the experimental values.

Abstract: Fossil fuels continue to dominate energy use, despite growing environmental concerns, underscoring the need for renewable energy solutions. Photovoltaic cells convert sunlight but lose efficiency from heat, requiring cooling methods such as photovoltaic thermal systems. Tthis study evaluated a PVT system with three serpentine tubes under varied conditions using computational fluid dynamics simulations. Testing involved water coolant flow rates of 0.001, 0.005, and 0.009 kg/s, radiation intensities of 200, 400, and 600 W/m², and tube diameters of 15 mm and 17 mm. Increasing the mass flow rate significantly reduced temperature and improved thermal efficiency, while electrical efficiency remained stable as the PV panel temperature mainly influenced it. The optimal cooling performance was achieved with a 0.009 kg/s mass flow rate and a 15 mm tube diameter at 600 W/m² radiation intensity. These findings suggest water-based cooling may increase PV system performance and reliability, especially in high solar locations.

Abstract: Safety, by definition, is a state of protection against hazards, which implies measures for reduction/evasion/exclusion of risks. Safety is relative, depending on the degree of implementation of measures in specific conditions. The concept of security should only be considered as a result of risk management. Modern risk management practice is the basic risk levels and balancing between the need to ensure a certain level of security and the economic feasibility of investment in security measures. In practice, despite the declared safety priorities, industries are balanced between investment in security and an acceptable level of risk, without considering the nature and degree of influence of security measures at the stage of their development. This method of balancing is characterized by the desire of business to formally meet the general standards of risk management in order to minimize costs, minimize social and other types of responsibility, for the sake of maximizing income, which is a common problem. This problem is particularly acute in the context of national and industrial security.

Abstract: Dye-sensitized solar cell (DSSC) is a well-known solar cell device because it can convert electrical energy from solar energy. In addition, DSSC has many benefits to offer humankind such as low cost in production, flexibility and eco-friendliness. However, the efficiency provided for DSSC operation is still low compared to the efficiency offered by semiconductor materials. Thus, four different solvents are used to extract natural dye from mangosteen pericarp in order to increase the efficiency in DSSC: pure ethanol, ethanol containing 20 % distilled water, ethanol containing 1 % hydrochloric acid (HCl) and ethanol containing 1 % acetic acid. Other than that, the dyes are examined to observe the optical properties by using Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectroscopy (UV-Vis). FTIR analysis resulted in the functional group presence in the dyes while UV-Vis shows that absorption activity exists in the mangosteen pericarp dyes. In addition, the efficiency of mangosteen pericarp dyes with pure ethanol, ethanol containing 20 % distilled water, ethanol containing 1 % hydrochloric acid (HCl) and ethanol containing 1 % acetic acid are calculated which are 0.080 x 10^-3 %, 0.554 x 10^-3 %, 0.126 x 10^-3 % and 0.102 x 10^-3 % respectively.

Abstract: Fluid is a substance that can flow and conform to its container. Any substance or material that experiences movement or moves from one place to another will produce energy and this energy is strongly influenced by the physical properties of the fluid which is the source of this energy. Because of the same fluid properties, Savonius can also be applied to water flows. The Savonius waterwheel is a simple water-wheel that works because of the different forces on each blade. The concave blade (concave) facing the direction of the water will catch the water and force the blade to rotate on its axis and the convex blade (convex) which is pushed by the fluid flow also causes the blade to rotate even though there is a load caused by the convex part when pushed by the flow. This study determines to analyze efficiency and power of vertical shaft savonius water wheel with four blades and six blades on discharge variations. The best performance of the vertical shaft savonius water wheel with four blades is on load of 1.5 kg, the highest efficiency 17.16% and the highest water wheel power 1.317 watts with discharge of 0.629 m³/s. For the best performance of the vertical shaft savonius waterwheel with six blades on discharge 1 (0.629 m³/s) produced the highest power of 1.248 watt and the highest efficiency 15.92% at load of 1.5 kg.

Abstract: The Savonius-type rotor is a phenomenal rotor model applied to vertical-axis type hydrokinetic turbines, which use is quite popular even though its performance is considered lower than other rotor types. One of the advantages of the Savonius-type rotor compared to other types of vertical axis hydrokinetic rotors is that it is more effective in extracting hydrokinetic energy from low velocity water flows. This research aims to analyze the performance of the Savonius rotor by modifying the blade model by providing grooves on the concave side. Tests were carried out on a two-blade Savonius rotor without grooves and with blades using 5, 6, 7 and 8 grooves with a width of 15 mm in the direction perpendicular to the shaft with varying input loads and flow rates for several constant rotation levels. The research results indicate that the groove-less blades yielded a maximum tip speed ratio (TSR) of 1.32 and a maximum efficiency (ɳ) of 29.58%. In contrast, grooved blades produced a maximum TSR of 1.40 and a maximum efficiency of 33.71%, indicating an increase in TSR of 0.08 and an efficiency increase of 4.17 %, with the highest increase occurring on eight-groove blades.

Abstract: Steam Power Plant (PLTU) is a type of thermal power plants widely used nowadays due to its high in efficiency. PLTU Moramo is an Independent Power Producer (IPP) that supplies electricity to PT PLN and has two generating units which produce 2 x 50 MW of electricity. The main goal of this research is to investigate effect of the steam power plant’s electricity loads on efficiency of the Subcritical Pulverized Coal (PC) Boiler and to determine values of the boiler’s efficiency based on the three vary loading capacity which are 30 MW net, 40 MW net, and 50 MW net respectively. Method applying to calculate the boiler efficiency in this research is an indirect method or heat loss method of calculation based on the heat loss value for each parameter, then the boiler efficiency is determined. Results obtained in this research showed that by using indirect method or the heat loss method, thermal efficiency of the boiler decreases as the boiler’s loading capacity is increased. Based on this research, thermal efficiency of the boiler is 81.15 % for the loading capacity of 30 MW net and decreasing to 80.20 % and 79.20 % for 40 MW net load and 50 MW net load respectively