Papers by Wahyu Haryadi piarah
Protek: Jurnal Ilmiah Teknik Elektro, Sep 3, 2023
WIT transactions on modelling and simulation, Apr 17, 2001
The simulation of unsteady conjugate mass transfer between a spherical droplet and the surroundin... more The simulation of unsteady conjugate mass transfer between a spherical droplet and the surrounding continuous fluid is based on the solution of the balance equations for momentum and mass in both phases. To reduce the effort required various approximations have been introduced. Some authors, for instance, compute the mass transfer in both phases seperately and add the resulting transfer resistances to estimate the rate of the whole process. The reliability of this procedure is discussed in the paper. Even in the case of a simulation of the conjugated problem differences between simulations and experiments are obvious. T h e neglection of instabilities in the phase interface by the model is supposed to be a reason for that. The influence of the Peclet number on the Sherwood number for a given Schmidt number is discussed. An upper and an lower limit of P e can be found where further changes of that value have no influence on the mass transfer.
International Journal on Smart Material and Mechatronics, Oct 30, 2016
To increase agricultural output it is needed a system that can help the environmental conditions ... more To increase agricultural output it is needed a system that can help the environmental conditions for optimum plant growth. Smart greenhouse allows for plants to grow optimally, because the temperature and humidity can be controlled so that no drastic changes. It is necessary for optimal smart greenhouse needed a system to manipulate the environment in accordance with the needs of the plant. In this case the setting temperature and humidity in the greenhouse according to the needs of the plant. So using an automated system for keeping such environmental condition is important. In this study, the authors use fuzzy logic to make the duration of watering the plants more dynamic in accordance with the input temperature and humidity so that the temperature and humidity in the green house plants maintained in accordance to the reference condition. Based on the experimental results using fuzzy logic method is effective to control the duration of watering and to maintain the optimum temperature and humidity inside the greenhouse
International Journal of Heat and Mass Transfer, Jul 1, 2005
The mass transfer between a single droplet and a surrounding fluid can be described mathematicall... more The mass transfer between a single droplet and a surrounding fluid can be described mathematically solving the momentum and mass balances in both phases (conjugate problem). This study of dimensionless parameters can give a deeper inside how the process is influenced by changes in material properties and operating conditions. The influence of the Reynolds number Re on the mass transfer is generally small and vanishes for creeping flows. A sensitivity to the viscosity ratio µ * exists only in a limited range. The influence of the Peclet number P e can be approximated for small P e by considering only the external problem and for high P e by considering only the internal problem.
Chemie Ingenieur Technik, Jun 1, 2001
Chemical Engineering & Technology, Oct 8, 2002
Chemie Ingenieur Technik, Nov 1, 2001
International journal of engineering research and technology, 2016
In diesel engine cycle, 35% of energy losses through the exhaust gases, the heat is an energy pot... more In diesel engine cycle, 35% of energy losses through the exhaust gases, the heat is an energy potential that can still be reused for various purposes. This research aims to design a heat exchanger, based of diesel engine exhaust gases integrated with rice milling unit for drying agricultural products. The exhaust gas is derived from 6D16 diesel engine of 120 kVA as a power generator for rice milling unit at South Sulawesi. Exhaust gas temperature reaches 357C with the mass flow rate of 636 kg/hour at ambient temperatures of 32C and 84% relative humidity. From the calculation, the energy of the exhaust gas is able to dry 2 tons of paddy in the drying air temperature of 53C and drying mass flow rate of 6,600 kg/hour for 8 hours drying time. Used is a compact heat exchanger with 0.3 m long, 0.3 m wide and 0.2 m high, using a plainfin 2.0. Tests carried out using a flat bed drying 174 kg capacity of grain with 24.56% moisture content, using a drying air temperature of 53C and mass flow ...
International journal of engineering research and technology, 2016
The purpose of this paper is to calculate an energy engineering of hybrid dryer based of exhaust ... more The purpose of this paper is to calculate an energy engineering of hybrid dryer based of exhaust gases and LPG, integrated with rice milling unit using a cogeneration system for utilization diesel engine exhaust gas temperature at the power plant of rice milling unit for paddy drying process and LPG burners. The method used is to measure the temperature and mass flow rate of the exhaust gas of a diesel engine and capacity of dryer for calculating heat exchanger design. Results of measurements at 120 kVA diesel engine exhaust gas temperature at 357 °C and the mass flow rate 636 kg/h. From the calculation results, power that can be generated by the exhaust gases are 56 kW and heat required for drying are 24 kW/ton. The total grain can be dried is 2 tons. Selection of LPG burners adjusted to results of the calculation of the energy need for drying capacity of 1 to 2 tons is gas burners wich can operate in the power range 23 kW to 58 kW. The use of LPG burner only when the drying proces...
International journal of engineering research and technology, 2015
The purpose of this paper is to calculate a cogeneration system for utilization diesel engine exh... more The purpose of this paper is to calculate a cogeneration system for utilization diesel engine exhaust gas temperature at the power plant of rice milling unit for paddy drying process. The method used is to measure the temperature and mass flow rate of the exhaust gas of a diesel engine as the initial data for calculating heat exchanger design. Results of measurements at 120 kVA diesel engine exhaust gas temperature at 357 °C and the mass flow rate 636 kg/h at 82% relative humidity. From the calculation results have been using cross flow compact heat exchangers, with plate-fin surfaces plain fins 2.0 for air section and 2.0 for exhaust gas, dimensional shape width 0.3 m, high 0.2 m and 0.3 m long, produces drying temperature 53 ° C, can drying 2 (two) tons of paddy grain for 8 hours drying time, use the power of 0.95 kW electric motor fan. This study shows that the exhaust gas of a diesel engine can be applied to the dryer with a cogeneration system.
Nucleation and Atmospheric Aerosols, 2022
Lecture notes in mechanical engineering, Sep 2, 2022
2018 2nd International Conference on Applied Electromagnetic Technology (AEMT)
Variable Step-Size Decremented Window-Size Scanning-based MPPT Algorithms for Thermoelectric Gene... more Variable Step-Size Decremented Window-Size Scanning-based MPPT Algorithms for Thermoelectric Generator Systems are presented in this paper. The proposed MPPT algorithm is simple to implement and can tune automatically the TEG system to operate at its maximum power point effectively. By using different step-size decrements and step-number changes for each scanning-step iteration, four types of DWS-based MPPT algorithms are derived. The performance of the four DWS algorithms are verified through simulations. The optimal or appropriate selection of the variable step-size decrements for each scanning-step iteration can improve the convergence speed of the algorithms to reach the expected maximum power points. The DWS-based MPPT algorithm, which uses for example a 13-4-1 step-size decrement with 1% minimum duty-ratio step-size, can reach the maximum power point after 22 P&O-steps. The need for relatively small number of the required P&O-steps, in addition to the simple computing implementation, is the impressive features of the proposed DWS-based MPPT algorithms for thermoelectric-based energy harvesting applications.
International Journal of Design & Nature and Ecodynamics, 2022
The performance analysis of the biomass briquette stove has been carried out. The research was co... more The performance analysis of the biomass briquette stove has been carried out. The research was conducted with three variations of stove wall materials (clay, steel, and aluminum) and with several variations of shell diameter of the burning chamber (140mm, 150mm, 160mm, 170mm, and 180mm). The fuel used is coconut shell briquettes. The results showed that the maximum fire temperature of clay, steel, and aluminum stoves was obtained, respectively 798℃, 617℃, 508℃ and thermal efficiency of 73.66% for clay followed by a steel stove of 38.98% and the lowest is obtained on an aluminum-based stove, which is only 11.49%. Furthermore, the diameter of the shell optimum is 180 mm for clay, 160 for steel, and 170 for aluminum.
Usage of type alcohol of etanol in gasoline fuel proves a number of machine achievements in terms... more Usage of type alcohol of etanol in gasoline fuel proves a number of machine achievements in terms of parameters, namely actual horsepower, specific fuel consumption, mean effective pressure and thermal efficiency compared to use pure premium fuel. Level of such repair gyrate 73% from maximum energy according to machine specification. In yielding etanol, fermentation process with yeast mixture then destiltaion. Etanol mixed with premium with certain ratio. In this research, variation of mixing of alcohol premium, namely: 95%+5%; 90%+10% and 85%+15% by 3 variation throttle opening: 20%, 40% and 60%. The result indicates that with usage of concentration mixing of premium + etanol, reached actual horsepower by Kijang machine 7k experiencing with maximum value equal to 17,347 kW that happened at condition of opening of throttle 60% at rotation 2100 rpm with usage of mixing 95% premium + 5% etanol. With usage of concentration mixing of premium + etanol, specific fuel consumption also exp...
IOP Conference Series: Materials Science and Engineering, 2020
Biomass fuel is an alternative energy source used in the form of briquettes using clay stoves. Ut... more Biomass fuel is an alternative energy source used in the form of briquettes using clay stoves. Utilization of clay as a briquette stove often results are not satisfactory as is the use of other fuel stoves, this is because the amount of air in the furnace burning chamber has not been determined and focused properly, so the purpose of this study is to determine the thermal efficiency of the furnace at variations in the diameter of the aluminum sleeve in the furnace burning chamber. The method used is to test 5 variations in diameter of the furnace burning chamber (cylinder). The results showed the best thermal efficiency was obtained at 52.87% at 180 mm slab diameter, boiling time at 9 minutes, with a heat loss of only 2.02 kW.
International Review of Mechanical Engineering (IREME), 2019
In this study, the simulation of Photovoltaic (PV) and Thermoelectric Generator (TEG) hybrid was ... more In this study, the simulation of Photovoltaic (PV) and Thermoelectric Generator (TEG) hybrid was developed using a spectrum splitter. The simulation was carried out by using the AM1.5G solar spectrum as a standard for 1 Sun, with a variation of 0.05, 0.1, 0.25, 0.50, and 0.7 Suns. The light spectrum was concentrated by using a Fresnel lens and then transmitted to a spectrum splitter. Spectrum splitter that was used is a hot and cold mirror with dimensions of 50 × 50 mm, which is positioned at the angle of 45o from the Fresnel lens’s direction. Additionally, PV used is a type amorphous Silicon (a-Si) and TEG types of Bismuth telluride (Bi2Te3). The simulation result shows that by using a cold mirror, its maximum total power is better than a hot mirror. In addition, the Suns and temperature changes have a significant effect on the output power and efficiency of the hybrid. Particularly at 0.7 suns, 25 °C PV temperature, and 55 °C hot-side temperature of TEG, the power obtained was 0.096 W/m2, and the efficiency was 50.37% compared to the hot mirror, which is relatively lower, accounted for 0.094 W/m2 and 48.07%.
International Journal of Biomaterials, 2019
Biochars from bamboo leaves as a potential energy resource were synthesized by annealing in the o... more Biochars from bamboo leaves as a potential energy resource were synthesized by annealing in the oxygen-free environment. Samples were characterized using proximate analysis, Fourier-transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS). Heating temperatures are 250°C, 300°C, and 350°C and for each temperature, the time was varied between 30, 60, and 90 minutes. The heating time for 30 minutes results in FC 30.777% and calorific value 15 MJ/Kg at temperature 250°C and decreased to 4.004% and 6 MJ/Kg at temperature 350°C, respectively. EDS shows the time of heating is an important parameter which shows the carbon and nitrogen contents were decreasing with the increase in the heating time, and silicon and oxygen contents were increasing with increase in the heating time. XRD shows broad (002) reflections between 20° and 30°, which indicated disordered carbon with small domains of coherent and parallel stacking o...
Journal of Physics: Conference Series, 2019
The amount of photon energy becomes a key parameter that determines the release of electron bonds... more The amount of photon energy becomes a key parameter that determines the release of electron bonds which is often called a band-gap in photovoltaic cells (PV) to generate electricity. This paper presents the results of measurements of photon energy from radiation sources of artificial light Halogen, Incandescent and Xenon which aims to adjust the bad gap type of solar cell material. Simulations of measuring 50 watts of bulb radiation were carried out repeatedly with the Spectrometer sensor and the application software Spectragryph 1.2.8 on each electron Volt the bulb light. The incoming radiation form the bulb is concentrated with a Polymethylmetacrylate (PMMA) Fresnel lens with an optimal light transmission capability of 92%. The results of this light transmission will be divided after illuminating at the Cold mirror (CM) spectrum splitterr, partly reflected in the PV module and partially transmitted to the thermoelectric generator (TEG) in the PV-TEG hybrid. The measurement of phot...
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Papers by Wahyu Haryadi piarah