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Power Generation Forecasting of Dual-Axis Solar Tracked PV System Based on Averaging and Simple Weighting Ensemble Neural Networks Rohman, Budiman Putra Asmaur; Hilman, Catur; Tridianto, Erik; Ariwibowo, Teguh Hady
EMITTER International Journal of Engineering Technology Vol 6, No 2 (2018)
Publisher : Politeknik Elektronika Negeri Surabaya (PENS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (12.589 KB) | DOI: 10.24003/emitter.v6i2.341

Abstract

Solar power is a renewable energy interest many researchers around the world to be explored for human life beneficial especially for electric power generation. Photovoltaic (PV) is one of technology developed massively to exploit the solar power for this purpose. However, its performance is very sensitive to environmental condition such as solar irradiance, weather, and climatic behavior. Thus, the hybrid power generation systems are developed to solve this output uncertainty problem. To support this such hybrid system, this paper proposes an ensemble neural network based forecaster of the power output of PV systems which will lead an efficient power management. The object of this research is the PV systems equipped with two axes automated solar tracking with peak power 10Wp. The proposed ensemble forecaster model employs four multi-layer perceptron neural networks with two hidden layers as base forecasters while the input number of historical data is varied in order to exploit the forecaster diversity. The final prediction is calculated both by conventional averaging and simple weighting optimized by the least square fitting technique. According to the research results, the both proposed approaches provide low error rate. Moreover, in term of comparison, the ensemble model with averaging combining technique gives the highest accuracy comparing to the other ensemble and conventional neural network structures.
Studi Eksperimen Karakteristik Shell-And-Tube Heat Exchanger Dengan Variasi Jenis Baffle Dan Jarak Antar Baffle Ariwibowo, Teguh Hady; Permatasari, Prima Dewi; Ardhiyangga, Novan; Triyono, Sugit
Jurnal Ilmu Fisika Vol 8, No 2 (2016): JURNAL ILMU FISIKA
Publisher : Jurnal Ilmu Fisika

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2135.355 KB) | DOI: 10.25077/jif.8.2.87-97.2016

Abstract

Shell-and-Tube Heat Exchanger merupakan jenis penukar kalor yang banyak digunakan di pembangkit dan pengolahan minyak. Namun, peningkatan performa penukar kalor ini perlu dilakukan dengan cermat karena alirannya yang kompleks didalam shell. Penelitian ini mengkaji peningkatan performa dalam bentuk koefisien perpindahan panas total dan efektivitas dengan melakukan variasi jenis baffle (single segmental dan triple segmental) dan baffle spacing (5 cm dan 10 cm) menggunakan pendekatan eksperimen dan numerik. Penukar kalor diuji pada laju massa 0,033; 0,066; 0,099; 0,133; dan 0,166 kg/s. Pada variasi jenis baffle, hasil eksperimen menunjukkan single segmental menghasilkan koefisien perpindahan panas total dan efektivitas yang lebih baik dari pada triple segmental dengan nilai koefisien perpindahan panas total maksimal 301 W/m2.K pada 0,166 kg/s dan efektivitas maksimal 0,5 pada 0,033 kg/s. Sedangkan, pada variasi baffle spacing, hasil eksperimen menunjukkan baffle spacing 5 cm menghasilkan koefisien perpindahan panas maksimal 651 W/m2.K saat laju massa 0,166 kg/s sedangkan baffle spacing ini hanya munjukkan performa yang lebih besar dari baffle spacing 10 cm ketika laju massa 0,133 kg/s. Hasil simulasi menunjukkan turbulensi aliran yang besar pada sisi shell mengakibatkan distribusi temperatur merata sehingga mempengaruhi koefisien perpindahan panas total. Kata Kunci : Shell-and-Tube Heat Exchanger , baffle spacing, jenis baffle, koefisien perpindahan panas total, efektivitas, CFD. 
Thermal and Flow Characteristics of Discrete Double Inclined Ribs at Low Curvature Coil for GSHP Application Teguh Hady Ariwibowo; Keishi Kariya; Akio Miyara
EPI International Journal of Engineering Vol 3 No 1 (2020): Volume 3 Number 1, February 2020
Publisher : Center of Techonolgy (COT), Engineering Faculty, Hasanuddin University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25042/epi-ije.022020.02

Abstract

In this study, the thermal and hydraulic characteristics in low curvature coil with Discrete Double Inclined Ribs (DDIR) were investigated. Water is selected as a working fluid, and flowrate range from 1 to 5 L/min, which is a low flowrate condition. Effect of geometry parameters such as distance between ribs, curvature ribs, and ribs inclination angles was observed. Results obtained by numerical simulations show that the heat transfer in DDIR-coil is 7.7 to 29.11% greater than that in plain coil, while the pressure drop was approximately 12.7 to 89.5% larger than that of plain-coil. A COP improvement factor that is calculated based on energy loss by pressure drop and energy saving by heat transfer enhancement was found to vary between 0.25 and 5.29. Flow visualization shows that there are two vortexes in cross-section at the downstream, and local vortexes arise around the ribs of DDIR-coil, which shows similar pattern and strength to DDIR-straight tube. The vortex makes a long fluid particle path and strengthens the turbulent mixing between the wall and the core flow of the coil. Based on these findings, DDIR-coil is recommended for applications in Slinky Ground Heat Exchangers, especially at low flowrates.
Numerical Study of Shell-And-Tube Heat Exchanger Performance with Various Baffle Spacing Sugit Triyono; Teguh Hady Ariwibowo; Prima Dewi Permatasari
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Seminar Nasional Teknik Kimia Kejuangan

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Abstract

Heat exchanger  is the instrument used to exchange the heat from one system to another that can be used as a heater or cooler. One of those types is shell-and-tube heat exchanger which is mostly used in many factories. Shell-and-tube heat exchanger consist of shell, which there are many tube inside it with baffles arranged along the shell-side. This study examines the effect of baffle spacing towards shell-and-tube heat exchanger performance which geometry have been specified first. This study used a simulation method developed by Heat Transfer Research Inc. (HTRI) to determine heat exchanger performances. Baffle spacing is set to various values: 30 mm, 60 mm, and 90 mm which one of each conditions also vary the mass flow rate to various number: 0.8333 kg/s, 0.1667 kg/s, and 0.25 kg/s. The simulation will generate outlet temperature of each fluid, overall heat transfer coefficient, and pressure drop. Baffle spacing 30 mm generates pressure drop 0.011 kPa while the increase of mass flow rate from 0.1660 kg/s to 0.250 kg/s also increase the value of pressure drop 0.030 kPa to 0.045 kPa. From those three variation of baffle spacing, baffle spacing 60 mm generates a stable value: 0.003 kPa, 0.007 kPa, and 0.015 kPa that is the optimum condition to gain the good performance of shell-and-tube heat exchanger.
Numerical Study of Shell-And-Tube Heat Exchanger Characteristicsin Laminar Flow with Single Segmental Baffle Novan Ardhiyangga; Teguh Hady Ariwibowo; Prima Dewi Permatasari
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Seminar Nasional Teknik Kimia Kejuangan

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Abstract

Shell-and-tube heat exchangers (STHEs) are one of the most popular heat exchanger due its flexibility to allow wide range pressure and temperature. The shell-sideperforms very complex flow which result in the difficult of analysis. This paper examines the characteristic of shell-side which obtained by adjusting vary of mass flow rates to gain laminar flow condition. A certain STHE with single segmental baffle used in this analysis that run by the stream analysis method developed by Heat Transfer Research Inc. (HTRI). The result shows that the increase value of mass flow rate will increase the shell-side heat transfer coefficient, pressure drop, and heat exchanger effectiveness. The increase value of mass flow rate from 0.1065 kg/s to 0.1775 kg/s will increase the shell-side heat transfer coefficient about 37.56% where minimum and maximum values are 1557.58 and 2142.76 W/m2.K. The shell-side pressure drop also increase from 0.325 kPa to 0.898 kPa or up to 176.31% increase. The heat exchanger effectiveness increase with the lower number of 7.02% from 0.276 to 0.295. From this experiment, it can be inferred that the increase value of mass flow rate in shell-side will be good to the heat exchanger performance, but the increase value of pressure drop must be in consideration too.
Experimental Study of Heat Transfer Characteristics in The Hair-Pin Heat Exchanger Aulia Arif Shalihuddin; Teguh Hady Ariwibowo; Prima Dewi Permatasari
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Seminar Nasional Teknik Kimia Kejuangan

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Abstract

The heat transfer characteristics in the horizontal Hair-pin heat exchanger are investigated experimentally. Heat transfer coefficients were calculated and plotted with the experimental data. The inner and outer diameters of the inner tube are 10.67 and 12.09 mm. The inner tube is made from stainless steel with thickness 0.71 mm and the length of 500 mm with conductivity thernal 14.4 W/m.K. The outer tube is made from PPMA(polymethyl methacrylate) with thickness 2.27 mm and the length of 450 mm. Cold and hot water are used as working fluids in outer tube and inner tube, respectively. Flows in the inner tube and outer tube were counter flow. The mass flow rates were varied of cold water are 0.0167, 0.0194, 0.0222, 0.025 and 0.0278 kg/s. Reynolds number were got between of 1667 and 2776 in laminar flow to turbulent flow. Then, the results data of cold water are heat transfer 139,67 Watt for the lowest flowrate and 348,78 Watt for the highest flowrate. From the experimental results obtained heat transfer characteristics in Hair-pin heat exchanger, can be increased by varied the mass flow rate in cold side
Power Generation Forecasting of Dual-Axis Solar Tracked PV System Based on Averaging and Simple Weighting Ensemble Neural Networks Budiman Putra Asma'ur Rohman; Catur Hilman; Erik Tridianto; Teguh Hady Ariwibowo
EMITTER International Journal of Engineering Technology Vol 6 No 2 (2018)
Publisher : Politeknik Elektronika Negeri Surabaya (PENS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (12.589 KB) | DOI: 10.24003/emitter.v6i2.341

Abstract

Solar power is a renewable energy interest many researchers around the world to be explored for human life beneficial especially for electric power generation. Photovoltaic (PV) is one of technology developed massively to exploit the solar power for this purpose. However, its performance is very sensitive to environmental condition such as solar irradiance, weather, and climatic behavior. Thus, the hybrid power generation systems are developed to solve this output uncertainty problem. To support this such hybrid system, this paper proposes an ensemble neural network based forecaster of the power output of PV systems which will lead an efficient power management. The object of this research is the PV systems equipped with two axes automated solar tracking with peak power 10Wp. The proposed ensemble forecaster model employs four multi-layer perceptron neural networks with two hidden layers as base forecasters while the input number of historical data is varied in order to exploit the forecaster diversity. The final prediction is calculated both by conventional averaging and simple weighting optimized by the least square fitting technique. According to the research results, the both proposed approaches provide low error rate. Moreover, in term of comparison, the ensemble model with averaging combining technique gives the highest accuracy comparing to the other ensemble and conventional neural network structures.
Evaluation of Condensation Friction Pressure Loss Refrigerant 134-a in Internal Horizontal Tube Condenser by CFD Bambang Harjanto; Teguh Hady Ariwibowo; Fifi Hesty Sholihah
Prosiding Seminar Nasional Teknik Kimia "Kejuangan" 2016: Prosiding SNTKK 2016
Publisher : Seminar Nasional Teknik Kimia Kejuangan

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Abstract

Energy crisis stimulates some efforts to empower low heat source. Organic Rankine Cycle is wise way that absorbs low heat gain easily. A device is horizontal condenser where two phase flow of R134a is happening in. Two phase flow is difficult to be solved due to its complexity. An annular flow regime dominates which is plotted as main assumption. It has plotted in Thome Flow Regime Map as variations of mass flux in similar vapor fraction. In CFD solver, flow is analyzed as pseudo, vapor and liquid mixed well, as consequence it will be single phase. It will be solved by SST method as viscous model that needs a multiplier numerical solver to transform from single phase into two phases. A multiplier depends on vapor fraction which is dominated of interfacial shear stress phenomenon as turbulent flow. Muller Steinhagen and Heck’s method is implemented due to its accuration. The value result of pressure loss correlates proportionally to mass flux. In similar mass flux, pressure loss increases as increasing linearly of vapor fraction due to high value of void fraction. The accuracy is within 91 %.      
Studi Eksperimen Karakteristik Shell-And-Tube Heat Exchanger Dengan Variasi Jenis Baffle Dan Jarak Antar Baffle Teguh Hady Ariwibowo; Prima Dewi Permatasari; Novan Ardhiyangga; Sugit Triyono
Jurnal Ilmu Fisika (JIF) Vol 8 No 2 (2016): September 2016
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jif.8.2.87-97.2016

Abstract

Shell-and-Tube Heat Exchanger merupakan jenis penukar kalor yang banyak digunakan di pembangkit dan pengolahan minyak. Namun, peningkatan performa penukar kalor ini perlu dilakukan dengan cermat karena alirannya yang kompleks didalam shell. Penelitian ini mengkaji peningkatan performa dalam bentuk koefisien perpindahan panas total dan efektivitas dengan melakukan variasi jenis baffle (single segmental dan triple segmental) dan baffle spacing (5 cm dan 10 cm) menggunakan pendekatan eksperimen dan numerik. Penukar kalor diuji pada laju massa 0,033; 0,066; 0,099; 0,133; dan 0,166 kg/s. Pada variasi jenis baffle, hasil eksperimen menunjukkan single segmental menghasilkan koefisien perpindahan panas total dan efektivitas yang lebih baik dari pada triple segmental dengan nilai koefisien perpindahan panas total maksimal 301 W/m2.K pada 0,166 kg/s dan efektivitas maksimal 0,5 pada 0,033 kg/s. Sedangkan, pada variasi baffle spacing, hasil eksperimen menunjukkan baffle spacing 5 cm menghasilkan koefisien perpindahan panas maksimal 651 W/m2.K saat laju massa 0,166 kg/s sedangkan baffle spacing ini hanya munjukkan performa yang lebih besar dari baffle spacing 10 cm ketika laju massa 0,133 kg/s. Hasil simulasi menunjukkan turbulensi aliran yang besar pada sisi shell mengakibatkan distribusi temperatur merata sehingga mempengaruhi koefisien perpindahan panas total. Kata Kunci : Shell-and-Tube Heat Exchanger , baffle spacing, jenis baffle, koefisien perpindahan panas total, efektivitas, CFD. 
Evaluasi Pengaruh Kecepatan Rotasi Rotor terhadap Efektifitas Rotary Air Preheater Menggunakan Metode ε-NTU (Halaman 5 s.d. 8) Dewo Sakarum; Teguh Hady Ariwibowo
Jurnal Fisika Indonesia Vol 19, No 56 (2015)
Publisher : Department of Physics Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (560.372 KB) | DOI: 10.22146/jfi.24350

Abstract

Air Preheater (APH) merupakan komponen pendukung dalam PLTU yang berfungsi sebagai pemanasan awal (preheater) pada saat pembakaran di dalam ruang bakar. Salah satu parameter yang mempengaruhi besarnya efektivitas pada rotary air preheater adalah kecepatan rotasi rotor. Untuk mengetahui pengaruh besarnya kecepatan rotasi rotor terhadap performansi rotary air preheater digunakan metode ε-NTU. Variasi dilakukan pada kecepatan rotasi 6 RPM, 9 RPM, 12 RPM, 15 RPM, 18 RPM dan pada C* 0,64 ; 0,78 ; 0,84. Dari lima variasi yang dilakukan menunjukkan bahwa kecepatan rotasi rotor mempengaruhi besarnya efektifitas. Kecepatan tersebut juga mempengaruhi besarnya NTU sehingga efektifitasnya ikut berubah. Efektifitas tertinggi yaitu pada kecepatan 18 RPM  dan C* 0,64 sebesar 0,8750. Pada kecepatan rotasi yang sama efektifitas pada C* 0,64 mempunyai nilai yang lebih besar dari pada C* 0,78 dan 0,84.