berkah fajar | Universitas Diponegoro (Semarang) (original) (raw)

Papers by berkah fajar

Organic Rankine Cycle (ORC) merupakan modifikasi dari siklus Rankine. Pada Rankine Cycle biasanya... more Organic Rankine Cycle (ORC) merupakan modifikasi dari siklus Rankine. Pada Rankine Cycle biasanya menggunakan air bertekanan dan bertemperatur tinggi sebagai fluida kerja. Sedangkan pada ORC, titik didih dari siklus ini lebih rendah sehingga air tidak cocok digunakan sebagai fluida kerja. Oleh karena itu, digunakan fluida kerja R 123, R 134, R 32 dan n-pentane untuk mendesain sebuah sistem ORC dengan data masukkan sebagai berikut; laju aliran massa sebesar 0,515 kg/s, suhu reservoir 70 o C, suhu masuk turbin 60 o C, suhu keluar turbin 45 o C, suhu keluar evaporator 50 o C. Dari keempat fluida kerja sistem tersebut, R 123 dipilih sebagai fluida kerja yang terbaik untuk mendesain alat penukar kalor berupa kondensor, karena memiliki tekanan yang relatif kecil yaitu P 1 = 2 bar, P 2 = 1.1592 bar dan memiliki daya yang relatif tinggi yaitu 2.1 kW. Selain itu, R 123 memiliki biaya lebih murah, pemasangan lebih mudah, ijin lebih mudah, dan mudah didapatkan dibanding ketiga refrigeran terse...

Journal of Mechanical Science and Technology, Oct 1, 2011

Due to the supersonic speed at which propellant gas flows through the gun barrel, a high intensit... more Due to the supersonic speed at which propellant gas flows through the gun barrel, a high intensity impulsive sound pressure is created, which has negative effects in many respects. Therefore, the high pressure waves generated due to muzzle blast flow of tank gun during firing is a critical issue to examine. The purpose of this paper is to study and analyze this high pressure impulsive sound, generated during the blast flow. The large caliber 120 mm K1A1 tank gun has been selected especially for this purpose. An axisymmetric computational domain has been constructed by employing Spalart Allmaras turbulence model to evaluate pressure and sound level in the tank gun using Computation Fluid Dynamics technique. Approximately 90% of pressure and 20 dB of sound level have been attenuated due to use of the three baffle silencer at the muzzle end of the gun barrel in comparison to the tank gun without silencer. Also, the sound pressure level at different points in the ambient region shows the same attenuation in the results. This study will be helpful to understand the blast wave characteristics and also to get a good idea to design silencer for large caliber weapon system.

Journal of Central South University, Oct 1, 2011

Shell-and-tube vaporizers are the most commonly used and dominated types of vaporizers in liquefi... more Shell-and-tube vaporizers are the most commonly used and dominated types of vaporizers in liquefied natural gas (LNG) realm. Due to efficient performance, shell-side flow in this type of vaporizers has received considerable attention and has been investigated extensively. However, the detailed flow structure in the shell needs to be determined for reliable and effective design. Therefore, the objective of this study was to clarify the flow structure in shell by particle image velocimetry (PIV). Experiments were conducted using two types of model; 15% baffle cut having inlet and outlet positions in the direction of 90° to the cut and 30% baffle cut having inlet and outlet positions in the direction of 180° to the cut. Each test section is 169 mm in inner diameter and 344.6 mm in length. The flow features were characterized in different baffle cuts with regards to the velocity vector field and velocity distribution. The results show that the flow characteristics of 15% baffle cut type vaporizer are comparable to those of 30% baffle cut type vaporizer.

International Research Journal of Innovations in Engineering and Technology

Onshore Processing Facilities is one of the industries engaged in natural gas processing. The tot... more Onshore Processing Facilities is one of the industries engaged in natural gas processing. The total use of natural gas over the last four years tends to increase. OPF also utilizes electrical energy as secondary energy generated from GEG. Currently the condition of installed equipment such as GEG, air compressor, HVAC, and building lighting is 8 years old, so there are indications of a decrease in efficiency. Then the GEG condition which only generates electricity around 30% of its capacity is also suspected to cause low engine efficiency. Therefore, it is necessary to conduct an energy audit to determine energy use and potential savings that can be made. Based on an audit conducted by the SEC for 2022, 0.8 GJ/TOE is still relatively efficient. The Air Compressor System has an average efficiency of 78.73%, the HVAC unit has a COP value of 3.31, the lighting level of each room in the OPF building does not meet the minimum standard, which is around 125-450 lux, and GEG has an efficiency value of 27.2 %, which is below the design standard. Opportunities for savings that can be made are by reducing the compressor air pressure by 0.7 bar can save Rp. 21,778,565, installing a capacitor bank of 416 micro farads in the HVAC system can increase the value of cos phi to 0.95, replacing building lights with 28 watts installed recess type 69 units to meet lighting standards, and the use of PLN electricity will save electricity costs of IDR 2,367,557,200.

Wind energy is one of the most potential renewable energy sources to be utilized as a source of e... more Wind energy is one of the most potential renewable energy sources to be utilized as a source of electrical energy. Utilization of wind energy for electricity generation does not cause negative impact on the environment. Wind in the atmosphere is in turbulent conditions. Wind in turbulent conditions has a random and uniform velocity. In wind power plants wind speed is a major factor affecting the amount of wind energy input that can be converted into electrical anergy. The main part of wind power is wind turbines. This wind turbine converts wind energy into mechanical energy of shaft rotation and then converted into electrical energy by electric generator. To measure wind speed the wind speed conditions are made uniformly by using wind flow alignment. The wind flow straightening test kit consists of flow alignment, fan, pitot tube meter, and pitot tube holder arm rod. Straight stream flow used in this study is the type of vane tube. In this study, the wind speed measurement was taken before and after passing the flow straighteners. Measurements of wind velocity on the cross section of the wind turbine are performed horizontally, vertically and diagonally. The number of wind speed measurements as much as fifty-two points of gravity with the distance between the point of measurement about two centimeters. Based on the results of measurement and analysis, the average wind speed before passing the straightener is about 4.94 m / s and after passing the flow alignment is about 3.22 m / s. The wind velocity distribution after passing through the vane tube flow alignment is more uniform.

Journal of physics, Nov 1, 2019

Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indo... more Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indonesian population consume rice as staple food. The by-product of paddy processing as to rice is also hush or rice hush. Up until now, in Indonesia, it is widely used as animal feed, fertilizer, mushroom planting media and fuel for making bricks, tiles and others. To increase the benefits of rice husk, the study of the usage of rice husk as an active ingredient in the SDC cooling system was conducted. The research method begins with the making of rice husk test samples and silica gel as a comparison. Rice husk was burned and heated using an oven until all carbons became ash. Then, the rice husk ash was blended and filtered, these applies to silica gel as well. Then these two samples are tested for characteristics with GSA and XRF instruments. From this test it can be concluded that the adsorption / desorption ability of ash is 1/6 time silica gel. If rice husk ash is used as an alternative for desiccant materials, it is necessary to modify the material.

Journal of Physics: Conference Series, 2021

The problem of global warming or called GWP (Global Warming Potential) that occurs in the earth’s... more The problem of global warming or called GWP (Global Warming Potential) that occurs in the earth’s atmosphere, one of which comes from synthetic refrigerants used in household air-conditioning refrigeration machines. R410A is a refrigerant that still contains GWP: 1942. Hydrocarbon refrigerant is a refrigerant that does not contain ODP (Ozone Depleting Potential) and a very small GWP. By using ref prop software, the mixing process can be simulated to obtain refrigerants that have characteristics similar to R410A. Mixing using R32 / R290 ingredients varied with percentage compositions ranging from 50/50, 40/60, 30/70, 20/80, and 10/90. From the simulation results, a mixture approaching R410A with 10/90 composition with COP: 3.85 for R410A and 5.76 for 10/90 mixture was obtained. Compression ratio: R410A: 2.8 and for mixed refrigerants 10/90: 1.8. The refrigerant effect of mixed refrigerants is 10/90: 264,13, R410A: 161,68. By using this refrigerant mixture can reduce the GWP and impro...

Journal of Physics: Conference Series, 2018

Mostly, micro-hydro power plant installed in irrigation cannels which flat slope uses waterwheel.... more Mostly, micro-hydro power plant installed in irrigation cannels which flat slope uses waterwheel. The flat slope mean low static head of the flow, thus impacts low rotation speed of the wheel and finally low power output generated. In order to encounter the problem, it is important to developed effective waterwheel for flat slope water channels. The aims of thus work are to design and fabricate a water wheel with jumping water unit and also early analysis of effect of jumping water angle on rotation speed and power output of waterwheel. The waterwheel is installed downstream the jumping water unit, Meanwhile, triangle shaped jumping water unit has variation angle of 10 0 , 20 0 , 30 0 , 40 0 , 50 0. The result shows that the rotation speed and power output increase with increasing angle of jumping water. The maximum rotation speed and power output are 30.86 rpm and 38 Watt at the jumping water angle of 50 0 .

International Journal of Refrigeration, 2018

Machine 2R is necessary in order to avoid the release of refrigerant during the repair of an air ... more Machine 2R is necessary in order to avoid the release of refrigerant during the repair of an air conditioning machine. The main goals of this paper are to determine the rate of exergy transfer, the rate of exergy destruction and the rate of exergy change in the compressor, condenser, oil separator and 2R machine. This study also determines the performance of the 2R machine. Pressure, temperature and mass of the refrigerant were measured every 0.5 minutes for 10 minutes. In conclusion, the results of this analysis show that the rate of destruction exergy in the compressor is 59.98%, and 25.37% in the condenser. The value of the Residual Trapped Refrigerant (RTR) of recycling and recovery machine meets the AHRI standard, that is, 34 grams, and the value of the Refrigerant Loss (RL) complies with the AHRI standard, which is 10 grams, while its performance is 91.2%.

2013 IEEE International Conference ON Emerging Trends in Computing, Communication and Nanotechnology (ICECCN), 2013

ABSTRACT This paper proposes an improved maximum power point tracking (MPPT) method for Wind syst... more ABSTRACT This paper proposes an improved maximum power point tracking (MPPT) method for Wind system using a fuzzy with PLL algorithm. The main advantage of the method is the reduction of the steady state oscillation (to practically zero) once the maximum power point (MPP) is located. Furthermore, the proposed method has the ability to track the MPP for extreme environmental condition, e.g. large fluctuations of isolation and partial shading condition. The algorithm is simple and can be computed very rapidly. To evaluate the effectiveness of the proposed method, MATLAB simulations are carried out under very challenging conditions, namely step changes in irradiance, step changes in load and partial shading of wind array. The proposed method in simulation shows it is efficient than the conventional controllers in terms of achieving maximum wind power generation effectively with steady state output compared to other conventional controllers.

River Basin Management - Under a Changing Climate [Working Title]

River basin management can increase biodiversity conservation, land productivity, ecosystem resto... more River basin management can increase biodiversity conservation, land productivity, ecosystem restoration, rehabilitation, and land reclamation. River basin management cannot be handled by one institution alone but requires cooperation and coordination with various parties. Community involvement in river basin management has a strategic role and is carried out based on the principle of sustainability that combines a balance between productivity and conservation to achieve river basin management goals. Community participation has the power to make decisions autonomously in order to be able to solve the needs and interests of life and improve the standard of living by utilizing the resources that must be owned. In addition, it is also necessary to harmonize structural relationships between institutions in government both at the center and at the local level so that internal factors can be controlled, and programs and activities do not overlap in the management of natural resources and a...

Abstrak Indonesia termasuk negara eksportir furnitur terbesar di dunia. Namun demikian, kualitas ... more Abstrak Indonesia termasuk negara eksportir furnitur terbesar di dunia. Namun demikian, kualitas furnitur Indonesia masih kalah bersaing dengan furnitur dari negara-negara seperti Cina, Kanada, Meksiko, Italia, Vietnam, Malaysia dan Taiwan. Salah satu hal yang menyebabkan kualitas furnitur Indonesia masih rendah adalah kurangnya penguasaan teknologi manufaktur kayu, dalam hal ini proses permesinan, terutama proses bubut, karena merupakan proses yang paling banyak dipakai. Kualitas permukaan dari produk yang terbuat dari kayu adalah satu hal yang sangat penting dalam industri furnitur karena disamping berkaitan dengan masalah estetika juga berpengaruh pada proses manufaktur selanjutnya seperti proses finishing dan kekuatan sambungan adhesifnya. Pada penelitian ini kayu yang digunakan adalah jenis-jenis kayu yang banyak digunakan sebagai bahan baku produk furnitur di Indonesia, terutama di pulau Jawa, seperti kayu jati, nangka, mahoni, dan mangga. Spesimen benda kerja diambil dari bal...

Journal of Physics: Conference Series, 2019

Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indo... more Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indonesian population consume rice as staple food. The by-product of paddy processing as to rice is also hush or rice hush. Up until now, in Indonesia, it is widely used as animal feed, fertilizer, mushroom planting media and fuel for making bricks, tiles and others. To increase the benefits of rice husk, the study of the usage of rice husk as an active ingredient in the SDC cooling system was conducted. The research method begins with the making of rice husk test samples and silica gel as a comparison. Rice husk was burned and heated using an oven until all carbons became ash. Then, the rice husk ash was blended and filtered, these applies to silica gel as well. Then these two samples are tested for characteristics with GSA and XRF instruments. From this test it can be concluded that the adsorption/desorption ability of ash is 1/6 time silica gel. If rice husk ash is used as an alternative ...

METAL: Jurnal Sistem Mekanik dan Termal

This current investigation was conducted to study the aerodynamic characteristics of Savonius hyd... more This current investigation was conducted to study the aerodynamic characteristics of Savonius hydrokinetics turbine with semicircular blade-sharp leading edge. The influences of blade thickness and freestream velocity were simulated using ANSYS FLUENT with k-w SST model. The results show that the flow structure changes with increasing turbine rotation in which the flow complexity is formed at a larger rotation angle. The coefficient of torque and power for thin blades is higher than for thicker turbine blades and its values increase with the increase in the freestream velocity.

Journal of Sustainable Development of Energy, Water and Environment Systems

Common problem in the operation of breastshot water wheel in Indonesia is discontinuity operation... more Common problem in the operation of breastshot water wheel in Indonesia is discontinuity operation of the wheel due to very low stream velocity in the channel during dry season. In order to minimize the problem, it is important to study the method of maintaining the continuity operation of the wheel during dry season. Thus, the installation of water-jumper at upstream of the wheel is proposed in the present work. The laboratory models of the water channel and breastshot water wheel were fabricated. The water jumper is attached at the upstream whose slope angle can be adjusted. The present work investigates the effect of water-jumper slope on the performance of the breastshot wheel. The slope angles are set at 5°, 10°, 15°, 20°, 25°, 30°, 35°, and 40°and the upstream velocities are 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 m/s. The result reveals that the use of water-jumper can increase the gross head and hydraulic power of very low stream, and hence the torque and the output power of the breastshot wheel are enhanced. The highest efficiency is achieved at the slope angle of 10º for stream velocity of 1.3 m/s. The water-jumper gives significant effect at stream velocity lower than 1.3 m/s. The hydraulic power is influenced by both discharge and gross head where they increase at increasing slope angle of the water-jumper. However, higher momentum losses occurs at the wheel for stream velocity higher than 1.3 m/s, thus output power and efficiency of the breastshot decreases even though hydraulic power increases. The water-jumper can keep continuous operation of the breastshot wheel in the irrigation channel during dry season.

Low temperature heat sources are very abundant in the earth. Changing the low-temperature geother... more Low temperature heat sources are very abundant in the earth. Changing the low-temperature geothermal energy is becoming an effective working is one way to avoid an energy crisis. In Bertani research on the development of geothermal power plants around the world resulted in increased 2GW for 5 years from 2005 to 2010 and if the geothermal power plant low and medium temperature enhanced the capacity of the power plant, geothermal power will increase 8.3% from total world electricity production by 2050. Of these problems has made an Organic Rankine Cycle (ORC) using manual analysis and modeling and validation by software support as Cycle Tempo, REFROP, and HTRI Xchanger Suite. The organic working fluid used is R-123, R-134, R-32 and n-pentane. The results of the analysis of the system Organic Rankine Cycle (ORC) with the data input reservoir temperature of 70 ° C, the mass flow rate of 0.515 kg / s, the turbine inlet temperature 60 ° C, the turbine outlet temperature 45 C, of all the r...

Organic Rankine Cycle (ORC) merupakan modifikasi dari siklus Rankine. Pada Rankine Cycle biasanya... more Organic Rankine Cycle (ORC) merupakan modifikasi dari siklus Rankine. Pada Rankine Cycle biasanya menggunakan air bertekanan dan bertemperatur tinggi sebagai fluida kerja. Sedangkan pada ORC, titik didih dari siklus ini lebih rendah sehingga air tidak cocok digunakan sebagai fluida kerja. Oleh karena itu, digunakan fluida kerja R 123, R 134, R 32 dan n-pentane untuk mendesain sebuah sistem ORC dengan data masukkan sebagai berikut; laju aliran massa sebesar 0,515 kg/s, suhu reservoir 70 o C, suhu masuk turbin 60 o C, suhu keluar turbin 45 o C, suhu keluar evaporator 50 o C. Dari keempat fluida kerja sistem tersebut, R 123 dipilih sebagai fluida kerja yang terbaik untuk mendesain alat penukar kalor berupa kondensor, karena memiliki tekanan yang relatif kecil yaitu P 1 = 2 bar, P 2 = 1.1592 bar dan memiliki daya yang relatif tinggi yaitu 2.1 kW. Selain itu, R 123 memiliki biaya lebih murah, pemasangan lebih mudah, ijin lebih mudah, dan mudah didapatkan dibanding ketiga refrigeran terse...

Journal of Mechanical Science and Technology, Oct 1, 2011

Due to the supersonic speed at which propellant gas flows through the gun barrel, a high intensit... more Due to the supersonic speed at which propellant gas flows through the gun barrel, a high intensity impulsive sound pressure is created, which has negative effects in many respects. Therefore, the high pressure waves generated due to muzzle blast flow of tank gun during firing is a critical issue to examine. The purpose of this paper is to study and analyze this high pressure impulsive sound, generated during the blast flow. The large caliber 120 mm K1A1 tank gun has been selected especially for this purpose. An axisymmetric computational domain has been constructed by employing Spalart Allmaras turbulence model to evaluate pressure and sound level in the tank gun using Computation Fluid Dynamics technique. Approximately 90% of pressure and 20 dB of sound level have been attenuated due to use of the three baffle silencer at the muzzle end of the gun barrel in comparison to the tank gun without silencer. Also, the sound pressure level at different points in the ambient region shows the same attenuation in the results. This study will be helpful to understand the blast wave characteristics and also to get a good idea to design silencer for large caliber weapon system.

Journal of Central South University, Oct 1, 2011

Shell-and-tube vaporizers are the most commonly used and dominated types of vaporizers in liquefi... more Shell-and-tube vaporizers are the most commonly used and dominated types of vaporizers in liquefied natural gas (LNG) realm. Due to efficient performance, shell-side flow in this type of vaporizers has received considerable attention and has been investigated extensively. However, the detailed flow structure in the shell needs to be determined for reliable and effective design. Therefore, the objective of this study was to clarify the flow structure in shell by particle image velocimetry (PIV). Experiments were conducted using two types of model; 15% baffle cut having inlet and outlet positions in the direction of 90° to the cut and 30% baffle cut having inlet and outlet positions in the direction of 180° to the cut. Each test section is 169 mm in inner diameter and 344.6 mm in length. The flow features were characterized in different baffle cuts with regards to the velocity vector field and velocity distribution. The results show that the flow characteristics of 15% baffle cut type vaporizer are comparable to those of 30% baffle cut type vaporizer.

International Research Journal of Innovations in Engineering and Technology

Onshore Processing Facilities is one of the industries engaged in natural gas processing. The tot... more Onshore Processing Facilities is one of the industries engaged in natural gas processing. The total use of natural gas over the last four years tends to increase. OPF also utilizes electrical energy as secondary energy generated from GEG. Currently the condition of installed equipment such as GEG, air compressor, HVAC, and building lighting is 8 years old, so there are indications of a decrease in efficiency. Then the GEG condition which only generates electricity around 30% of its capacity is also suspected to cause low engine efficiency. Therefore, it is necessary to conduct an energy audit to determine energy use and potential savings that can be made. Based on an audit conducted by the SEC for 2022, 0.8 GJ/TOE is still relatively efficient. The Air Compressor System has an average efficiency of 78.73%, the HVAC unit has a COP value of 3.31, the lighting level of each room in the OPF building does not meet the minimum standard, which is around 125-450 lux, and GEG has an efficiency value of 27.2 %, which is below the design standard. Opportunities for savings that can be made are by reducing the compressor air pressure by 0.7 bar can save Rp. 21,778,565, installing a capacitor bank of 416 micro farads in the HVAC system can increase the value of cos phi to 0.95, replacing building lights with 28 watts installed recess type 69 units to meet lighting standards, and the use of PLN electricity will save electricity costs of IDR 2,367,557,200.

Wind energy is one of the most potential renewable energy sources to be utilized as a source of e... more Wind energy is one of the most potential renewable energy sources to be utilized as a source of electrical energy. Utilization of wind energy for electricity generation does not cause negative impact on the environment. Wind in the atmosphere is in turbulent conditions. Wind in turbulent conditions has a random and uniform velocity. In wind power plants wind speed is a major factor affecting the amount of wind energy input that can be converted into electrical anergy. The main part of wind power is wind turbines. This wind turbine converts wind energy into mechanical energy of shaft rotation and then converted into electrical energy by electric generator. To measure wind speed the wind speed conditions are made uniformly by using wind flow alignment. The wind flow straightening test kit consists of flow alignment, fan, pitot tube meter, and pitot tube holder arm rod. Straight stream flow used in this study is the type of vane tube. In this study, the wind speed measurement was taken before and after passing the flow straighteners. Measurements of wind velocity on the cross section of the wind turbine are performed horizontally, vertically and diagonally. The number of wind speed measurements as much as fifty-two points of gravity with the distance between the point of measurement about two centimeters. Based on the results of measurement and analysis, the average wind speed before passing the straightener is about 4.94 m / s and after passing the flow alignment is about 3.22 m / s. The wind velocity distribution after passing through the vane tube flow alignment is more uniform.

Journal of physics, Nov 1, 2019

Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indo... more Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indonesian population consume rice as staple food. The by-product of paddy processing as to rice is also hush or rice hush. Up until now, in Indonesia, it is widely used as animal feed, fertilizer, mushroom planting media and fuel for making bricks, tiles and others. To increase the benefits of rice husk, the study of the usage of rice husk as an active ingredient in the SDC cooling system was conducted. The research method begins with the making of rice husk test samples and silica gel as a comparison. Rice husk was burned and heated using an oven until all carbons became ash. Then, the rice husk ash was blended and filtered, these applies to silica gel as well. Then these two samples are tested for characteristics with GSA and XRF instruments. From this test it can be concluded that the adsorption / desorption ability of ash is 1/6 time silica gel. If rice husk ash is used as an alternative for desiccant materials, it is necessary to modify the material.

Journal of Physics: Conference Series, 2021

The problem of global warming or called GWP (Global Warming Potential) that occurs in the earth’s... more The problem of global warming or called GWP (Global Warming Potential) that occurs in the earth’s atmosphere, one of which comes from synthetic refrigerants used in household air-conditioning refrigeration machines. R410A is a refrigerant that still contains GWP: 1942. Hydrocarbon refrigerant is a refrigerant that does not contain ODP (Ozone Depleting Potential) and a very small GWP. By using ref prop software, the mixing process can be simulated to obtain refrigerants that have characteristics similar to R410A. Mixing using R32 / R290 ingredients varied with percentage compositions ranging from 50/50, 40/60, 30/70, 20/80, and 10/90. From the simulation results, a mixture approaching R410A with 10/90 composition with COP: 3.85 for R410A and 5.76 for 10/90 mixture was obtained. Compression ratio: R410A: 2.8 and for mixed refrigerants 10/90: 1.8. The refrigerant effect of mixed refrigerants is 10/90: 264,13, R410A: 161,68. By using this refrigerant mixture can reduce the GWP and impro...

Journal of Physics: Conference Series, 2018

Mostly, micro-hydro power plant installed in irrigation cannels which flat slope uses waterwheel.... more Mostly, micro-hydro power plant installed in irrigation cannels which flat slope uses waterwheel. The flat slope mean low static head of the flow, thus impacts low rotation speed of the wheel and finally low power output generated. In order to encounter the problem, it is important to developed effective waterwheel for flat slope water channels. The aims of thus work are to design and fabricate a water wheel with jumping water unit and also early analysis of effect of jumping water angle on rotation speed and power output of waterwheel. The waterwheel is installed downstream the jumping water unit, Meanwhile, triangle shaped jumping water unit has variation angle of 10 0 , 20 0 , 30 0 , 40 0 , 50 0. The result shows that the rotation speed and power output increase with increasing angle of jumping water. The maximum rotation speed and power output are 30.86 rpm and 38 Watt at the jumping water angle of 50 0 .

International Journal of Refrigeration, 2018

Machine 2R is necessary in order to avoid the release of refrigerant during the repair of an air ... more Machine 2R is necessary in order to avoid the release of refrigerant during the repair of an air conditioning machine. The main goals of this paper are to determine the rate of exergy transfer, the rate of exergy destruction and the rate of exergy change in the compressor, condenser, oil separator and 2R machine. This study also determines the performance of the 2R machine. Pressure, temperature and mass of the refrigerant were measured every 0.5 minutes for 10 minutes. In conclusion, the results of this analysis show that the rate of destruction exergy in the compressor is 59.98%, and 25.37% in the condenser. The value of the Residual Trapped Refrigerant (RTR) of recycling and recovery machine meets the AHRI standard, that is, 34 grams, and the value of the Refrigerant Loss (RL) complies with the AHRI standard, which is 10 grams, while its performance is 91.2%.

2013 IEEE International Conference ON Emerging Trends in Computing, Communication and Nanotechnology (ICECCN), 2013

ABSTRACT This paper proposes an improved maximum power point tracking (MPPT) method for Wind syst... more ABSTRACT This paper proposes an improved maximum power point tracking (MPPT) method for Wind system using a fuzzy with PLL algorithm. The main advantage of the method is the reduction of the steady state oscillation (to practically zero) once the maximum power point (MPP) is located. Furthermore, the proposed method has the ability to track the MPP for extreme environmental condition, e.g. large fluctuations of isolation and partial shading condition. The algorithm is simple and can be computed very rapidly. To evaluate the effectiveness of the proposed method, MATLAB simulations are carried out under very challenging conditions, namely step changes in irradiance, step changes in load and partial shading of wind array. The proposed method in simulation shows it is efficient than the conventional controllers in terms of achieving maximum wind power generation effectively with steady state output compared to other conventional controllers.

River Basin Management - Under a Changing Climate [Working Title]

River basin management can increase biodiversity conservation, land productivity, ecosystem resto... more River basin management can increase biodiversity conservation, land productivity, ecosystem restoration, rehabilitation, and land reclamation. River basin management cannot be handled by one institution alone but requires cooperation and coordination with various parties. Community involvement in river basin management has a strategic role and is carried out based on the principle of sustainability that combines a balance between productivity and conservation to achieve river basin management goals. Community participation has the power to make decisions autonomously in order to be able to solve the needs and interests of life and improve the standard of living by utilizing the resources that must be owned. In addition, it is also necessary to harmonize structural relationships between institutions in government both at the center and at the local level so that internal factors can be controlled, and programs and activities do not overlap in the management of natural resources and a...

Abstrak Indonesia termasuk negara eksportir furnitur terbesar di dunia. Namun demikian, kualitas ... more Abstrak Indonesia termasuk negara eksportir furnitur terbesar di dunia. Namun demikian, kualitas furnitur Indonesia masih kalah bersaing dengan furnitur dari negara-negara seperti Cina, Kanada, Meksiko, Italia, Vietnam, Malaysia dan Taiwan. Salah satu hal yang menyebabkan kualitas furnitur Indonesia masih rendah adalah kurangnya penguasaan teknologi manufaktur kayu, dalam hal ini proses permesinan, terutama proses bubut, karena merupakan proses yang paling banyak dipakai. Kualitas permukaan dari produk yang terbuat dari kayu adalah satu hal yang sangat penting dalam industri furnitur karena disamping berkaitan dengan masalah estetika juga berpengaruh pada proses manufaktur selanjutnya seperti proses finishing dan kekuatan sambungan adhesifnya. Pada penelitian ini kayu yang digunakan adalah jenis-jenis kayu yang banyak digunakan sebagai bahan baku produk furnitur di Indonesia, terutama di pulau Jawa, seperti kayu jati, nangka, mahoni, dan mangga. Spesimen benda kerja diambil dari bal...

Journal of Physics: Conference Series, 2019

Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indo... more Indonesia is one of the producers and consumers of paddy or rice due to more than 95% of the Indonesian population consume rice as staple food. The by-product of paddy processing as to rice is also hush or rice hush. Up until now, in Indonesia, it is widely used as animal feed, fertilizer, mushroom planting media and fuel for making bricks, tiles and others. To increase the benefits of rice husk, the study of the usage of rice husk as an active ingredient in the SDC cooling system was conducted. The research method begins with the making of rice husk test samples and silica gel as a comparison. Rice husk was burned and heated using an oven until all carbons became ash. Then, the rice husk ash was blended and filtered, these applies to silica gel as well. Then these two samples are tested for characteristics with GSA and XRF instruments. From this test it can be concluded that the adsorption/desorption ability of ash is 1/6 time silica gel. If rice husk ash is used as an alternative ...

METAL: Jurnal Sistem Mekanik dan Termal

This current investigation was conducted to study the aerodynamic characteristics of Savonius hyd... more This current investigation was conducted to study the aerodynamic characteristics of Savonius hydrokinetics turbine with semicircular blade-sharp leading edge. The influences of blade thickness and freestream velocity were simulated using ANSYS FLUENT with k-w SST model. The results show that the flow structure changes with increasing turbine rotation in which the flow complexity is formed at a larger rotation angle. The coefficient of torque and power for thin blades is higher than for thicker turbine blades and its values increase with the increase in the freestream velocity.

Journal of Sustainable Development of Energy, Water and Environment Systems

Common problem in the operation of breastshot water wheel in Indonesia is discontinuity operation... more Common problem in the operation of breastshot water wheel in Indonesia is discontinuity operation of the wheel due to very low stream velocity in the channel during dry season. In order to minimize the problem, it is important to study the method of maintaining the continuity operation of the wheel during dry season. Thus, the installation of water-jumper at upstream of the wheel is proposed in the present work. The laboratory models of the water channel and breastshot water wheel were fabricated. The water jumper is attached at the upstream whose slope angle can be adjusted. The present work investigates the effect of water-jumper slope on the performance of the breastshot wheel. The slope angles are set at 5°, 10°, 15°, 20°, 25°, 30°, 35°, and 40°and the upstream velocities are 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 m/s. The result reveals that the use of water-jumper can increase the gross head and hydraulic power of very low stream, and hence the torque and the output power of the breastshot wheel are enhanced. The highest efficiency is achieved at the slope angle of 10º for stream velocity of 1.3 m/s. The water-jumper gives significant effect at stream velocity lower than 1.3 m/s. The hydraulic power is influenced by both discharge and gross head where they increase at increasing slope angle of the water-jumper. However, higher momentum losses occurs at the wheel for stream velocity higher than 1.3 m/s, thus output power and efficiency of the breastshot decreases even though hydraulic power increases. The water-jumper can keep continuous operation of the breastshot wheel in the irrigation channel during dry season.

Low temperature heat sources are very abundant in the earth. Changing the low-temperature geother... more Low temperature heat sources are very abundant in the earth. Changing the low-temperature geothermal energy is becoming an effective working is one way to avoid an energy crisis. In Bertani research on the development of geothermal power plants around the world resulted in increased 2GW for 5 years from 2005 to 2010 and if the geothermal power plant low and medium temperature enhanced the capacity of the power plant, geothermal power will increase 8.3% from total world electricity production by 2050. Of these problems has made an Organic Rankine Cycle (ORC) using manual analysis and modeling and validation by software support as Cycle Tempo, REFROP, and HTRI Xchanger Suite. The organic working fluid used is R-123, R-134, R-32 and n-pentane. The results of the analysis of the system Organic Rankine Cycle (ORC) with the data input reservoir temperature of 70 ° C, the mass flow rate of 0.515 kg / s, the turbine inlet temperature 60 ° C, the turbine outlet temperature 45 C, of all the r...