Recent Advances in Renewable Energy Systems

Inhaltsverzeichnis

1. Frontmatter

2. Computational Fluid Dynamics Study of a Steam Reformer Unit Performance to Produce Hydrogen Fuel for PEM Fuel Cell Applications

   Hussein A. Z. AL-bonsrulah, Dhinakaran Veeman, M. V. Reddy

   Abstract

   Electric automobiles get hydrogen nowadays from hydrocarbon reforming fuels. The cost of hydrogen produced by a steam reformer is highly dependent on hydrocarbon fuel prices, and it is currently the cheapest of all hydrogen production technologies. Petroleum consumption and emissions are lower than in gasoline-fueled internal combustion engines. However, even with the upstream phase of processing hydrocarbon hydrogen from hydrocarbon sources, then supplying and conserving it for use in petrol automobiles, the overall greenhouse gas emissions are reduced by more than 90% when compared to existing internal combustion engine vehicles. The computed model will provide a computer-aided method for building and refining the steam reformer at a considerably higher efficiency and lower cost. It runs a parametric analysis of a steam reformer device using a three-dimensional CFD model. The impacts of the reformer are thoroughly investigated and tested under a variety of operating conditions. In this research work, a CFD model involving identification of essential criteria is developed and provided insight into the physical processes that contribute to the performance of a steam reformer under varied operating conditions.

3. Fuel Cell Power Pack with Integrated Metal Hydride Hydrogen Storage for Powering Electric Forklift

   Ivan Tolj, Mykhaylo Lototskyy, Adrian Parsons, Sivakumar Pasupathi

   Abstract

   Compared to battery-powered electric forklifts, fuel cell-powered ones posses higher productivity as they can be refueled in 5 to 10 min, while time to recharge the battery takes 8 h and additional 8 h for cooling down the battery. To ensure 24 h of operation of the battery-powered electric forklift, 2 to 3 battery per forklift is needed. As one battery has volume of ~1 m³, additional space in the warehouse for battery storage should be available. By integrating fuel cell power system onboard electric vehicles, these shortcomings are eliminated; moreover, fuel cell-powered forklifts maintain constant power during their operation as there is no voltage drop as compared to battery. Here, we present fuel cell power pack with integrated metal hydride hydrogen storage for powering 3-ton electric forklift. Liquid-cooled 9SSL PEM fuel cell stack with 75 cells from Ballard was integrated together with air supply, hydrogen storage and supply and liquid stack cooling, and MH heating loop. Developed metal hydride tank has weight of 1200 kg and serves not only for hydrogen storage but also as vehicle ballast. During onboard VDI60 tests, it was observed that power pack has stable operation with energy consumption of 9.564 kWh/h.

4. Testing an In-House CFD Code for Solving Gas–Solid Flow with Different Simulation Parameters

   Is Bunyamin Suryo, Tri Yogi Yuwono, Uwe Schnell

   Abstract

   An In-House Computational Fluid Dynamics (CFD) solver is developed for dealing with the gas–solid flow. The Finite Volume Method (FVM) is the basis of the numerical method utilized by the solver, and the Fortran language is used for building the code. The code relies on the Cartesian coordinate system. In order to analyse the effects of varying the simulation parameters, the developed code is tested to solve gas–solid flow simulation inside a circular riser. The simulation parameters which are employed in this study are three different drag models, two different radial distribution function models, two different coefficient of restitution values, and two different time steps of 0.0001 s and of 0.00015 s. In total, 24 variations of the simulations are calculated up to 6 s and its results are compared with each other. From the simulations, the numerical results can be categorized into several groups. The simulations using time step of 0.00015 s, the radial distribution function of Syamlal model, and coefficient of restitution of 0.70, with three different drag models, Gidaspow, Syamlal, and Wen-Yu, showed the best numerical results which will afterwards be fully simulated up to 40 s.

5. A Numerical Study for the Prediction of Unmanned Aerial Vehicle Aerodynamic Performance Based on Dihedral and Tip-Twist Angles of the Wing

   Adi Susanto, Arif Wahjudi

   Abstract

   UAV technology has developed so rapidly to help humans solve problems around them. One of the important criteria in the development of a UAV is its aerodynamic performance. The aerodynamic performance of a UAV is largely determined by the geometry of its wings. This study focuses on variations in wing geometry, especially dihedral and tip-twist to predict the aerodynamic performance of the UAV, each with \(\max \left( {C_L /C_D } \right)\) and \(\left. {C_D } \right|_{\alpha = 0}\). The Artificial Neural Network (ANN) method is used in this study to get predictions of each aerodynamic performance. ANN was chosen because of its superiority in approaching very complex relations between several variables. ANN network structure has up to two hidden layers while each hidden layer has 2 to 10 neurons selected in this research to get the smallest Mean Square Error value. Mean Square Error (MSE) is the difference between the aerodynamic performance target value and the predicted value. Prediction value is obtained from the training results of a network configuration based on predictor and target values as network input and output. Factors analyzed, namely dihedral angle and tip-twist, described their relationship to each of the \(\max \left( {C_L /C_D } \right)\) and \(\left. {C_D } \right|_{\alpha = 0}\) using a network structure of 2-5-7-1 and 2-4-9-1. Both networks yield the smallest MSe \(8.4757 \times 10^{ - 7}\) and \(1.952 \times 10^{ - 8}\) respectfully. The graph of the relationship of factors to changes in the value of \(\max \left( {C_L /C_D } \right)\) and \(\left. {C_D } \right|_{\alpha = 0}\) shows that the tip-twist angle gives a greater contribution than the dihedral. Comparison between prediction and validation simulation shows the relative error smaller than 5%.

6. A Numerical Study for Prediction of Unmanned Aerial Vehicle Aerodynamic Performance Based on Chord Tip and Offset of the Wing

   Firiana Firdaus, Arif Wahjudi, Wawan Aries Widodo

   Abstract

   The development of unmanned aerial vehicle (UAV) is multiplying with its use in various fields, which is marked by the emergence of various models that can be adapted based on the functions and needs of the UAV. A UAV with the Cessna 182 type, which can be easily found, is the research object in this paper. Aerodynamic performance is an essential part of the design of a UAV. Therefore, in this study, the geometry of the chord tip (C_t) and the distance of the sweep-back angel (offset) on the wing, which is set as factor parameters, are varied to predict aerodynamic performance as response parameters in the form of a ratio of lift coefficient to maximum drag coefficient (C_L/C_D max.) and drag coefficient at 0° angle of attack (C_D-0). Simulation using XFLR5 to find the value of aerodynamic performance. Artificial neural network (ANN) is used to predict the performance value and find the relationship between the factor parameters at the input layer and the response parameters at the output layer. By using a network arrangement of a maximum of two hidden layers and a maximum of ten neurons in each hidden layer, an MSE of \(1.8591 \times 10^{ - 7}\) is obtained for the maximum C_L/C_D response and \(3.958 \times 10^{ - 7}\) for the C_D-0 response. Dimensional changes in C_t affect the aerodynamic performance of the UAV than dimensional changes of offset.

7. Potential of a Grid-Tied PV System: A Field Study in Hot and Sunny Climate Region

   I Nyoman Suamir, I Wayan Temaja, I Nengah Ardita

   Abstract

   The paper presents a study on a lab size of a grid-tied PV system installed at Politeknik Negeri Bali southern region of Bali Island, Indonesia. The study includes the potential of renewable energy generation, capacity factor, system efficiencies, and environmental impact reduction. The PV system has a peak capacity of 3.1 kW and is specified for maximum efficiency of 22.96%. Monthly electrical energy generation varied from 300 to 499 kWh with an average of 412 kWh, and annual energy generation can reach 4.95 MWh. The annual utilization potential of the PV system stated as a capacity factor can reach 38.7% on average. PV system efficiencies in a clear and sunny day varied from 11.2% to 19.7%. The efficiency comprises PV cell efficiency which can reach 21.8% and grid-inverter efficiency as high as 93.4%. The study also shows the investigated parameters yearly reach their highest value in August and the lowest in December. The PV system is also found to have a potential contribution to environmental impact reduction of about 4.12 tCO_2e per year due to the replacement of electricity generated from fossil fuel sources.

8. Simulation and Dynamic System Modeling in an Elastically Supported Rigid Cylinder for Vibration Energy Harvesting

   Subekti, Harus Laksana Guntur, Vivien S. Djanali, Achmad Syaifudin

   Abstract

   This paper discusses the dynamic system modeling in an elastically supported rigid cylinder for electrodynamic vibration energy harvesting. In this paper, the fluid flow used is very different from the research that has been done, the fluid that will be used is air. A lot of airflows is generated in tall buildings, especially in the ducting flow. By utilizing airflow, home energy is developed. The harnessed energy used is electrodynamic vibration energy harvesting which arises from the tension of the wire and beam that vibrates due to the turbulence that is formed which produces an external force, causing the cylinder to insulate. The simulation results show that the airflow velocity and diameter greatly affect the amount of power generated. At an airflow rate of 8 m/s, the power generated is 2 × 10⁻¹⁷ watts. At a diameter of 80 m, the power generated is less stable. The phenomenon that occurs due to the placement of electrodynamic vibration energy harvesting, placement at point B has a faster power than the placement at point A.

9. Parameters Analysis of Vortex Formation on Conical Basin of Gravitational Water Vortex Power Plant (GWVPP)

   Erna Septyaningrum, Ridho Hantoro, Sarwono, Ester Carolina

   Abstract

   Gravitational water vortex power plant (GWVPP) is known as a low energy conversion system that can be used in low-head river flows approximately 0.8–2 m. Due to the low-head utilization, the GWVPP does not work in the pressure differences principle, however utilizes eddies, which are called vortexes, to generate mechanical power. Turbine performance is influenced by vortex flow performance, indicated by the value of vortex heigh, tangential velocity, and vortex strength. In addition, the influence of geometric parameters such as outlet to inlet diameter and basin dimension enlargement also affects the tangential velocity and vortex strength. The numerical simulation study was conducted to analyze the influence of basin geometry on vortex formation. The variation of the inlet to outlet diameter and basin enlargement of the conical basin is employed to get the depth information about the geometry effect. In this study, an analysis of a conical basin having an outlet to inlet diameter ratio of 0.2 and 0.3 was carried out. In addition, 1X, 1.1X, and 1.2X enlargement were also carried out. The difference has a significant impact on the vortex height, the smaller the higher the vortex height formed. The vortex formation is also influences by the basin size of basin enlargement; the vortex height gets lower along with the increase of basin size. From the analysis, it was found that the maximum tangential velocity and vortex strength occurred at 0.3 and the enlargement was 1.2X.

10. Solar Canopy with IoT-Based Single-Axis Solar Tracking System as a Solution for Utilizing Urban Open Parking Area

    Radix Kautsar Ramadhan, Hafiz Rayhan Gunawan, Galang Adi Saputro

    Abstract

    Indonesia’s solar energy potential has not been fully utilized due to limited land. Actually, Indonesia can build solar canopy to utilize open parking area, but, without a solar tracking system, the output power of solar canopy is still not worth the investment cost. Although a dual-axis solar tracking system has been developed, the complexity, additional investment costs, and effectiveness are not suitable for use in Indonesia. Because the other studies also state that schedule-based solar tracking system is more efficient than sensor-based solar tracking system, this research is conducted to make a model of solar canopy with IoT-based single-axis solar tracking system. The methodologies of this research are literature study, system planning, design planning, model making, model testing, analysis and evaluation, and report making. Based on this research, it can be concluded that the model can work well according to user’s time and location as well as application commands. Then, the output power of single-axis model is 41% greater than fixed model. Even though the single-axis model has a 6-month BEP difference, it is still superior for some reasons.

11. Investigation of the Four Runner Blade Arrangement Against the Power of Kaplan Turbine

    Sirojuddin, Nadia Sari Dewi, Ragil Sukarno

    Abstract

    A Kaplan turbine is a turbine that utilizes low head and high discharge. Kaplan turbine power and efficiency can be increased by varying the arrangement of the runner blades. This study aims to investigate the arrangement of four runner blades on a Kaplan turbine with variations in the height of the inner blade profile of −5 mm, parallel, +5 mm, +10 mm, and +15 mm from the height of the standard blade profile on power and efficiency when the turbine is in a momentary stop and rotating condition approach. The parameters used are the gross head of 5.25 m and the water discharge of 0.125 m³/s, with theoretical power of 6.131 kW. The runner blade profile was made using Airfoil NACA 2412, and the material used was JIS G3221—SFCM60S. The strength test of the blade profile material used FEA stress analysis software, and the flow test used CFD flow simulation software. The simulation results show that the RB-3 runner blade variant, which is +5 mm, produces the best power and efficiency for the turbine in a momentary stop condition was 5.9899 kW and 97.69%, and rotating condition was 6.0505 kW and 98.68%.

12. Investigation of the Runner Blade Arrangements on a 3-Blade Kaplan Turbine Against Turbine Power

    Sirojuddin, Alya Awanis Zahara, Ragil Sukarno

    Abstract

    Kaplan turbine is one of the power generators in the micro-hydropower (MHP) plant. The power and efficiency of the turbine are influence by the turbine runner construction, the number of blades, the blade’s thickness, the arrangement of the blades, etc. This research aims to find out the best design of the runner blade arrangement on a three-blade of the turbine with variations in the height of the inner blade profile of RB-1 = −5 mm, RB-2 = 0 mm, RB-3 =  +5 mm, and RB-4 =  +10 mm from the height through Y-axis of the outer blade profile against the power efficiency. The gross head was 5.25 m, water discharge 0.125 m³/s with theoretical power of 6.131 kW. The runner blade profile used airfoil NACA-2412, the first step was to optimize the thickness of the blade by calculation and validated by the FEM software, the second step the blade profile optimize by CFD flow simulation software in momentary stop and rotation conditions. From the simulation result, it was found that in a momentary stop condition, the best variant in generating power is RB-1 which is 5955.97 W and turbine efficiency is 97.14%, while in a rotation condition, it is also RB-1 with 5743.89 W power and turbine efficiency 93.68%.

13. Analysis Study of Performance and Reliability Impact in Boiler Through Differential Coal Calorific Value (Case Study: Pelabuhan Ratu Coal-Fired Power Plant)

    Hendra Yudisaputro, M. Nur Yuniarto, Yohanes, Agus Wibawa

    Abstract

    This study presents an analysis of coal switching impact by using 3500–4300 kcal/kg of calorific value (plant design more than 4500 kcal/kg) through power plant performance. It aims to investigate changes in thermal efficiency and reliability of main equipment in the boiler and optimize fuel cost by determining the cheapest coal for the power generation process. The research has been done based on a 340 MW subcritical coal-fired power plant model and experimental test with five different types of coal. Furthermore, critical equipment identification and component reliability were analyzed by calculating the boiler system's Asset Criticality Ranking value. At the same time, Reliability Block Diagrams (RBD) were also simulated based on five years of historical failure data. The results show that thermal plant efficiency decreases 0.13% in line with decreased coal calorific value every 97 kcal/kg. The optimum calorific value for the electricity production process is between 4200 and 4300 kcal/kg. The critical component of the boiler equipment is the mill, with an average ACR value of 7.81. The five mill components with the lowest availability values based on RBD analysis are Coal Pipe, Damper, Lub Oil Station, Pyrite Gate and Swing Valve with values of 0.648, 0.74, 0.91, 0.922 and 0.881, respectively. The coal calorific value has a significant influence on the efficiency and reliability of the boiler so that proper maintenance activities are needed to avoid more severe damage.

14. Effect of the Oxide Scale on Tube Boiler Remaining Life of a 600 MW Coal Power Plant

    Diki Purwadi, Suwarno, Vivien S. Djanali

    Abstract

    Boilers are the main system for converting combustion energy from coal into steam energy in power plants. The boiler is mainly composed of tubing in which water steam circulates to absorb heat from the combustion. Superheaters and reheaters are the tubings for increasing the quality of steam before entering the turbine and thus working at high temperatures and generally in the creep regime of the materials. In the present work, a study on the effect of the internal tube oxide layer on the remaining life of the tube is presented by using the secondary superheater tube (SSH) as the model case. The investigation began with analyzing non-destructive testing data, followed by sampling and laboratory analysis. The next step is to simulate the prediction of the remaining life due to the oxide layer. The thickness of the oxide layer grows about 300–900 µm. Tubes that only experience thinning, their life can exceed 200,000 h of operation. Still, if there is a combination of thinning and overheating due to oxide, the tube life will be 93% shorter. The probability of failure will be greater, around 97% if the boiler tube experiences thinning and material degradation. The results obtained can be applied as consideration for decision making in the life cycle boiler area for superheater and can then be used as a guideline for operation and maintenance in the world of power plants in maintaining reliability and controlling the life of the boiler tube.

15. Numerical Study of the Generator Lubricant Cooler Air-Side Flow to Increase the Reliability of GTG#1.3 PLTGU Muara Karang

    Aris Kurniawan, Sutardi

    Abstract

    Generator lubricant cooling system in gas turbine 1.3 by flowing lubricant in the tube and blowing air from the outside of the tube. The lubricant cooling device is called an air-cooled heat exchanger (ACHE) which has been operating for 9 years. ACHE has experienced a decrease in reliability because it causes the unit to trip 5 times, trips to ACHE occur when the ACHE exit lubricant temperature is more than 320 K. Based on analysis using a fishbone diagram, the cause comes from the failure of fan operation. The purposes of the study are (i) to investigate the cooling capacity of Air-Cooled Heat Exchanger for GTG#1.3 generator lubricant existing conditions, (ii) to determine the effect of the modification of the number of fans operating on cooling capacity, outlet pressure and temperature outlet lubricants with parallel and series arrangement of Air-Cooled Heat Exchanger Generator Lubricant GTG#1.3, and (iii) to investigate the optimal operation pattern of the GTG#1.3 Generator Lubricant Air-Cooled Heat Exchanger. This research was conducted by modeling and simulating ACHE using Computational Fluid Dynamic (CFD) software. The simulation was validated using actual operational data. The results showed that the operation of the ACHE series with 4 fans had the highest cooling capacity of 247.57 kW so that the ACHE outlet lubricant temperature was 312.02 K. Therefore, to obtain reliability and optimal operation, the ACHE series operating model with 4 fans were selected.

16. Optimization of Coal Blending with Backpropagation Neural Networks (BPNN) and Genetic Algorithms (GA) in Tangential In-Furnace Blending Boilers

    Mohamad Kurnadi, Sutikno, M. Khoirul Effendi

    Abstract

    One of Phase 1 Fast Track Program (FTP-1) is a coal-fired power plant with a capacity of 3 × 315 MW and the main fuel is coal. Coal has a very important role in determining combustion characteristics. Coal with good quality will improve the quality of combustion and operation of a power plant. But in reality, often a power plant does not get coal according to specifications, so it is necessary to find a solution to this problem. Coal blending is the process of mixing good quality coal with low-quality coal to obtain medium-quality coal. One method of coal blending is mixing in the furnace whereby only placing one type of coal in each coal burner that is known as furnace blending. The coal blending is done by mixing medium rank coal (MRC) and low-rank coal (LRC) with a composition of 50%:50% which is fed into the boiler through four burners with different elevations. In this research, the optimal search for blending MRC and LRC coal also the composition of the feed on the burner layer is carried out with the backpropagation neural network (BPNN) and genetic algorithm (GA) model in Matlab software. Based on the results obtained in this optimization system, it was found that the coal blending of MRC 1 (BA company), LRC 3 (PLNBB company) and the layer burner composition 1 (composition of MRC in the lower burner layer and LRC in the upper burner layer) produce optimal output (value −0.39402) which is predicted to produce a load of 280 MW, boiler efficiency of 84.15%, flue gas temperature 151.92 ℃, NO_x 21.35 mg/Nm³, SO_x 400.19 mg/Nm³, unburned carbon in fly and bottom ash 4.38 and 3.83%wt.

17. Exergy Analysis in Gas Turbine Power Plant with Different Offline Compressor Washing Methods

    Arif Budianto, D. Bambang Arip

    Abstract

    Compressor performance is one of the important roles in the process of generating electricity in gas turbine. From the literature studies, one of the causes of a decrease in compressor performance is fouling that occurs in the compressor. This research begins by collecting data on the power plant at the same time. The data were taken in two different conditions, after the old method and the new method offline compressor washing. Then the data is processed using thermodynamic equations and using Gate cycle software. The Gate cycle simulation results are validated by comparing the Gate cycle data and the data from manual calculations. After Gate cycle modeling is validated, several operating parameters are varied on the Gate cycle to see the effect of washing on the compressor. Then the data from Gate cycle modeling is analyzed to see the comparison of the old compressor washing method with the new method. The results show that there is an increase in compressor efficiency in the new compressor washing method by 0.27% at 50% loading, 0.6% at 75% loading and 1.21% at 100% loading. This increase in compressor efficiency has an impact on increasing gas turbine efficiency by 0.25% at 50% loading, 0.34% at 75% loading and 1.37% at 100% loading. In addition, the results of the study indicate that increasing inlet temperature of the compressor, the exergy destruction of the compressor, combustion chamber and gas turbine will increase.

18. Swappable Battery Innovation as a Drone Frame Structure with Purpose to Increasing the Flight Time Duration

    Muhammad Haekal Shafi, Valiant Tirta Amarta, Ferdina Ramadhansyah, Puguh Pambudi, Alief Wikarta

    Abstract

    The drone technology development as a mapping tool for the agricultural land resource development, taking some aerial photography, infrastructures monitoring, and air patrols by the authorities (police, army) are growing rapidly. However, in existing drones, there are weaknesses in terms of short flight durations so that they are less efficient and effective in their use. The limited duration of the flight will affect the distance of the drone’s flying range and the drone’s speed performance. Therefore, this study aims to create a drone with a swappable battery innovation that utilizes batteries as a short battery replacement and increases the number of batteries installed on the drone so that the flight time automatically increases. This study considers making the battery as the main-frame structure and combines it with 3D printing the drone’s bodies. The results of the swappable battery innovation in this study is the drone prototype with 236.16 Wh energy and 4s4p configuration. The flight time is calculated by a theoretical and actual method. The theoretical method estimated the flight duration through battery voltage, the thrust required, drone dimensions, and drone speed. From the actual method, it is obtained that the use of swappable battery innovation as a drone frame structure can increase the battery capacity of a drone up to four times and flight duration by 2.4 times.