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Photovoltaic and Battery Energy Storage System (PV-BESS) is a system for utilizing solar energy. The off-grid PV-BEES design is used for vehicle electric charging stations to ensure the security of the electricity supply and is economically feasible. The HOMER application is used in this study to simulate energetic and economic feasibility. As a result, the offgrid system produces energy of 474,027 kWh/year, consumes energy of 1,957 kWh/year, the excess energy of 471,968 kWh/year, and the value of NPC, COE, ROI is Rp.733,403,300.00, Rp.17,783.04 and -7% respectively. At the same time, the improvised system, by turning it into an on-grid, produces energy, consumed energy, and excess energy of 553,985 kWh/year, 517,790 kWh/year, and 14,410 kWh/year, respectively. For the value of NPC, COE, and ROI, respectively, Rp.934,259,900, Rp.85.63, 46.6%. Finally, it can be said that offgrid PV-BESS is a practical choice for doing more than only lowering emissions by utilizing solar energy. Off-grid PV-BEES has a tremendous excess energy of 471,968 kWh annually. According to energy analysis, it has a high COE value. Propose to Improve an on-grid system. Improvements were made that allow excess energy to be shared with other customers. According to economic analysis, this makes the system more cost-effective, with a potential payback in the second year.

Nowadays, the vibrating fluidized bed dryer is one of the most popular kinds of tea drying equipment available. The water content is lowered to 2.8-3.8 by applying the heat generated by the heater, which stops the enzyme-based oxidation process. The objective is to investigate how vibration affects a vibro-fluidized bed dryer's inherent frequency, structural integrity, and tea mass loading on the device. Tea powder is sprayed onto beds using vibro-fluidized bed dryers, which use an eccentric motor to create vibrations. Hot air flows from tiny holes in the bed into the tea powder that is circulating on it. After leaving the heating furnace, the hot air is directed through air ducts beneath the vibro-fluidized bed drier by the main fan. A cyclone extracts the tea powder and evaporates moisture, which is then released from the vibro-fluidized Bed dryer. Once disturbed, a system is allowed to vibrate on its own without external stimuli, oscillating at its natural frequency. As per the early analysis of the vibro-fluidized Bed Dryer, the dryer structure's normal frequency in the first three modes was 5.8876 Hz, followed by 9.5267 Hz and 10.512 Hz. The vibro-fluidized bed dryer structure's stress is within acceptable bounds when the safety factor for each loading variation is FS>1. The vibro-fluidization frequency of the bed dryer with a tea mass of 695 kg matches to the excitation frequency under real-world conditions. The tea mass supplied to the system increases with the natural frequency of the vibro-fluidized bed dryer. Static structure studies show that the von Misses stress of the vibro-fluid layer drying structure increases with the mass of tea added to the system. The largest von Mises stress was seen at a tea mass of 695 kg. [ABSTRACT FROM AUTHOR]

X company is the oldest of several company units engaged in printing and packaging, supported by other units such as paper making, conversion, holograms, engineering, and an integrated total security system. An offset printing machine is one of the main equipment in the production process which has an important role in printing packages in large quantities and quickly. So on an offset printing machine, there will be factors that cause a decrease in the performance of the offset machine, such as a dirty machine environment, inappropriate roller settings, oil leaks, and worn components. Therefore, it is necessary to carry out preventive maintenance on offset printing machines to maintain machine performance in optimal conditions to produce good quality output and maximum machine lifetime. This research aimed to reduce the wasteful use of oil and to reduce the cost of using oil using preventive maintenance methods. The results of this research indicate that the Heidelberg Speedmaster CD 102 offset machine underwent preventive maintenance by checking adjusting roll, leakage, oil level, and noise every day. By checking this, we get the results that the quality of the output produced is better maintained and the lifetime of the machine increases. This increase in engine lifetime can be seen as a result of decreasing engine oil usage from 1182 liters to 450 liters and decreasing costs incurred for engine maintenance, especially oil. The costs incurred for oil use in August 2022 - January 2023 have decreased from Rp. 82,129,000,-to Rp. 31,275,000,-. [ABSTRACT FROM AUTHOR]

Since the occurrence of the first industrial revolution in the 18th century, machines have become a part of human life. Like humans, machines also need treatment to keep running their activities as described, the treatment carried out on machines is often referred to as maintenance. Maintenance is an activity that can restore the function of a system or a system to the initial function. Machine maintenance can be broadly classified into two types namely unplanned maintenance and planned maintenance; planned maintenance can be further classified as preventive maintenance and predictive maintenance while breakdown maintenance is considered as unplanned maintenance. At PT. XYZ a maintenance has been carried out on the Caterpillar C9 Acert engine, and after the field team carried a diagnosis, it was found that several parts of the engine were damaged, which would result in damage to the Caterpillar C9 Acert engine. This study uses the RCA (root cause analysis) method assisted by 5 whys analysis and fishbone diagrams. The results of the 5 whys analysis show the facts causing the damage in a structured manner, and the results from the fishbone diagram show the factors causing the damage which include human factors, machines, materials, and methods, making it easier to find the basic causal factors. This study aims to identify the cause of the damage so that preventive measures can be taken to minimize the recurrence of this damage in the future. The results of the two methods of analysis can be concluded that the main cause of the damage suffered by the machine is the occurrence of human error on the part of the company that owns the machine, therefore more precise decisions and policies are needed from the company so that the damage does not occur again in the future. [ABSTRACT FROM AUTHOR]

Steam power plant Generation of Tanjung Jati B 3rd unit has a capacity of 660 MW. The power plant operational in 2011, because of the long operation process, there will be a decrease in performance. The plant needs to be researched to analyze the performance and losses that occurs in the power plant. Because this also affects the environment if the efficiency of the power plant is high, it can reduce the use of coal. Because coal becomes air pollution and environmental pollution, which can cause acid rain, water pollution, and global warming. This research is used to analyze energy and exergy on the components of a steam power plant. From the results of this research, the largest of destruction exergy boiler is 881.08 MW and the exergetic efficiency is 48.66%. While the rate of the smallest destruction exergy in LPH 3 is 0.6 MW and the exergetic efficiency is 94.45%. The contribution of the largest Losses energy in the boiler is 231 MW and energetic efficiency is 87.05%. While the contribution of the smallest energy Losses in HPH 6 is 0.74 MW and energetic efficiency is 99.23%.

The Wind turbine is a tool used in Wind Energy Conversion System (WECS). The wind turbine produces electricity by converting wind energy into kinetic energy and spinning to produce electricity. Vertical Axis Wind Turbine (VAWT) is designed to produce electricity from winds at low speeds. Vertical wind turbines have 2 types, they are wind turbine Savonius and Darrieus. This research is to know the effect of addition wind booster to Savonius vertical wind turbine with the variation 2 blades and 3 blades. Calculation the power generated by wind turbine using energy analysis method using the concept of the first law of thermodynamics. The result obtained is the highest value of blade power in Savonius wind turbine without wind booster (16.5 ± 1.9) W at wind speed 7 m/s with a tip speed ratio of 1.00 ± 0.01. While wind turbine Savonius with wind booster has the highest power (26.3 ± 1.6) W when the wind speed of 7 m/s with a tip speed ratio of 1.26 ± 0.01. The average value of vertical wind turbine power increases Savonius after wind booster use of 56%.

Diesel engines are widely used in industry, automotive, power generation due to better reliability and higher efficiency. However, diesel engines produce high smoke emissions. The main problem of diesel engine is actually the use of fossil fuels as a source of energy whose availability is diminishing. Therefore alternative fuels for diesel fuels such as jatropha and butanol are needed to reduce dependence on fossil fuels. In this study, the effect of butanol usage on fuel consumption and smoke emissions of direct injection diesel engine fueled by jatropha oil and diesel fuel with cold EGR system was investigated. The percentage of butanol was in the range of 5 to 15%, jatropha oil was in the range of 10 to 30% and the balance was diesel fuel. Cold EGR was varied through valve openings from 0 to 100% with 25% intervals. The experimental data shows that the BSFC value increases with increasing percentage of butanol. In addition, the use of EGR results in a higher increase of BSFC than that without EGR. While the addition of butanol into a blend of jatropha oil and diesel fuel causes a decrease in smoke emissions. The results also informed that the use of EGR in the same fuel blend led to increased smoke emissions.

Tea processing is basically distinguished into three types which black tea, green tea, and oolong tea. Green tea is processed by heating and drying the leaves. Green tea factories in Indonesia are generally using the process of drying by panning the leaves. It is more recommended to use the fluidization process to speed up the drying process as the quality of the tea can be maintained. Bubbling fluidization is expected to occur in this research. It is a process of bubbles are formed in the fluidization. The effectiveness of the drying process in a fluidized bed dryer machine needs to be improved by using a CFD simulation method to proof that umf < u < ut, where the average velocity value is limited by the minimum and the maximum velocity of the calculation the experimental data. The minimum and the maximum velocity value of the fluidization is 0.96 m/s and 8.2 m/s. The result of the simulation obtained that the average velocity of the upper bed part is 1.81 m/s. From the results obtained, it can be concluded that the calculation and the simulation data is in accordance with the condition of bubbling fluidization in fluidized bed dryer.

Refrigerant 22 or called R-22 is still the most widely used for air conditioners. However, since it has a relatively high global warming properties, the use of R-22 should be stopped. Refrigerant 290 briefed as R-290 (propane) is the type of refrigerant recommended by many experts for R-22 replacements because the global warming properties of R290 are much lower than R-22. Therefore, in this study the cooling capacity, flow rate mass, power consumed and COP will be evaluated. The air conditioner engine used in this research has 1 PK capacity which is redesigned by adding separator / ducting on various main components of AC. From the result of the study, there are several conclusions revealed: on the same compressor capacity, R-22 cooling capacity is still greater than R290. Meanwhile, the flow rate of R290 is lower than R-22. For power consumption from R-290, it is smaller than R-22. For the value of COP R-290, the value shows greater ie at R-290 on the variation of Incoming Temperature In Evaporator 20°C = 6.23, 23°C = 6.36, 25°C = 6.86, 29°C = 6.20. While at R-22, it shows 20°C = 5.36, 23°C = 6.02, 25°C = 5.76, 29°C = 6.335

Tea plants in Indonesia are derived from Carmelia sinensis var. assamica which contain catechin in quite high amount compared with other countries tea plant. Green tea is made by inactivating the oxidase / phenolase enzyme that presents in the fresh tea leaf buds from tea garden, by using hot steam to prevent the oxidation of the catechins. Drying process to reduce the moisture of tea, one of the method is by utilizing the dry air from dehumidification process. Liquid desiccant made from 50% concentration of CaCl2, the temperature is lowered to 10 °C and sprayed into the air stream which contains water vapor by using a 0.2 mm spraying nozzle so that mass transfer and latent heat occur in the dehumidifier. The result of air dehumidification process used for drying tea leaves. The air is able to dry the tea leaves from the weight of 58 grams to 47 grams. Then the liquid desiccant dehumidification process will be streamed into the humidifier, where the liquid desiccant regeneration process will have change into the initial concentration. The result of air humidification process has an average absolute humidity rise of 0.07 g/kg. The liquid desiccant regeneration process that happened continuously reaching the saturation point at 280 minutes. It can be concluded that the process of dehumidification-humidification is a fairly effective method for drying the tea leaves.

The cyclone separator has a simple construction design, low operating cost, and the ability to adapt to high pressure and temperature conditions, making it widely used in industry. Cyclone performance can be seen from the efficiency of particle collection and pressure drop. Computational Fluid Dynamic (CFD) methods are widely used in solving complex flow problems. This study examines the outlet diameter and modification of the shape of the vortex finder on the performance of a square cyclone to increase the efficiency of separating a square cyclone. Four different forms of vortex finder, Standard Vortex (SV), Convergent Vortex (CV), Divergent Vortex (DV), and Convergent Divergent Vortex (CDV) will be simulated to assess the impact of gas temperature on the performance of the square cyclone in the velocity flow plane, cyclone performance, temperature distribution, and heat transfer. The RSM turbulence model is used to simulate fluid flow. The Eulerian-Langrangian approach was chosen to predict the phase motion of the particles. The trajectories of particles in the stream are tracked individually using the DPM method. The simulation results show that the use of the Convergent Divergent Vortex (CDV) form increases the efficiency of square cyclone separation while at the same time increasing the pressure drop. Using a Convergent Vortex (CV) shape is useful for reducing the size of the piece by up to 50%. This is because the incoming air flow experiences centrifugal force in the vortex finder area, thereby increasing efficiency and increasing the pressure drop on the square cyclone. [ABSTRACT FROM AUTHOR]

This study focuses on improving heat transfer from the surface of heated tubes to airflow in the channel. Perforated concave delta winglet vortex generators, which have not been used in previous studies, were implemented in this study to increase the heat transfer rate. In this experimental study, the comparison of perforated concave delta winglet and perforated delta winglet was investigated in terms of increased heat transfer from a heated six-tube surface to the flow in a rectangular channel. The experimental results indicated that the use of perforated concave delta winglet vortex generators could increase the heat transfer rate of 46.3% toward the baseline. However, the optimal thermal-hydraulic performance was found in the use of the concave delta winglet at 1.37 with a staggered vortex generators arrangement. The results of this study indicated that the use of perforated vortex generators could reduce the pressure drop with a slight decrease in the heat transfer rate. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has worsened the solid waste management problem in Indonesia. Lockdowns induced by the pandemic have increased waste generation. Meanwhile, the COVID-19 virus continues to spread through droplets and items exposed to such droplets, including solid waste. Therefore, it is necessary to have exceptional municipal waste management systems in place to ensure these contaminants do not negatively impact the environment, society, or waste workers. We reviewed the municipal waste management systems during the COVID-19 pandemic in Indonesia and suggested remediation of several practices. Several problems exist in the current system, such as increase in solid waste generation (especially food and plastic waste), lack of infectious waste management, many workers not using complete personal protective equipment (PPE) while handling waste, and an inequitable distribution of facilities across different cities. Comprehensive recommendations, such as citizen awareness, PPE use by waste workers and waste pickers, and government policies dealing with urban waste amid the COVID-19 pandemic, are discussed. The findings of this study can serve as a reference for municipal waste management under pandemic conditions in developing countries, as well as for future research. [ABSTRACT FROM AUTHOR]