Dominicus Danardono Dwi Prija Tjahjana

Bio: Dominicus Danardono Dwi Prija Tjahjana is an academic researcher from Sebelas Maret University. The author has contributed to research in topic(s): Turbine & Wind speed. The author has an hindex of 7, co-authored 65 publication(s) receiving 182 citation(s).

Numerical and Experimental Investigation of Air Cooling for Photovoltaic Panels Using Aluminum Heat Sinks

Abstract: An increase in the operating temperature of photovoltaic (PV) panels caused by high levels of solar irradiation can affect the efficiency and lifespan of PV panels. This study uses numerical and experimental analyses to investigate the reduction in the operating temperature of PV panels with an air-cooled heat sink. The proposed heat sink was designed as an aluminum plate with perforated fins that is attached to the back of the PV panel. A comprehensive computational fluid dynamics (CFD) simulation was conducted using the software ANSYS Fluent to ensure that the heat sink model worked properly. The influence of heat sinks on the heat transfer between a PV panel and the circulating ambient air was investigated. The results showed a substantial decrease in the operating temperature of the PV panel and an increase in its electrical performance. The CFD analysis in the heat sink model with an air flow velocity of 1.5 m/s and temperature of 35°C under a heat flux of 1000 W/m2 showed a decrease in the PV panel’s average temperature from 85.3°C to 72.8°C. As a consequence of decreasing its temperature, the heat sink increased the open-circuit photovoltage ( ) and maximum power point ( ) of the PV panel by 10% and 18.67%, respectively. Therefore, the use of aluminum heat sinks could provide a potential solution to prevent PV panels from overheating and may indirectly lead to a reduction in CO2 emissions due to the increased electricity production from the PV system.

Mini review on the design of axial type eddy current braking technology

Abstract: Eddy Current Brake (ECB) is a type of electric braking that uses eddy current to produce braking forces. This article delivers a solid review of the design of Axial ECB, which is very promising for an alternative braking system. Several types of axial ECB are classified and named as a single disk, double disk, and unipolar model. The classification of axial ECB is based on the design of coil placement, which induces axial area of the disk as well as the electromagnet source. A potential issue for the development of axial ECB is also discussed to explore the braking performance improvement of the axial type ECB. It was highlighted that research on how to change the direction of magnetic field vectors by changing the shape of the pole-shoe on the electromagnetic ECB in axial type has not been widely studied. Therefore, this issue would be interesting for future investigation.

Rancang Bangun Alat Elliptical trainer Outdoor

Abstract: The placement of outdoor fitness equipment at tourist attractions is one of the attractions for tourists. Besides that, it can also be used as a means of health socialization for the community in public places. The elliptical trainer type air walker is a popular fitness tool because it is easy to use and has a small risk of injury. Elliptical trainer has a working principle like a walking person where movement is influenced by the force of the hand and leg movements. The design of an elliptical trainer fitness equipment that will be placed in a public place needs to be done to get a good level of security. This article discusses the design of an elliptical trainer device that is safe to place outdoors. The design process uses the Solidworks 2017a application. The elliptical trainer is divided into 4 parts, namely the main frame, drive shaft, hand handle, and leg handle. The manufacturing process is carried out based on Design Manufacture and Assembly and machinery to reduce the risk of manufacturing failure and make it easier to work on. The result of the elliptical trainer design has dimensions of 2,500 x 1,800 x 1,000 mm. The main frame has a safety factor of 3 with a displacement of 8,524e-7 mm.

Wind energy potential assessment to estimate performance of selected wind turbine in northern coastal region of Semarang-Indonesia

Abstract: The aims of this paper are to investigate the characteristic of the wind speed and wind energy potential in the northern coastal region of Semarang, Central Java, Indonesia. The wind data was gained from Meteorological Station of Semarang, with ten-min average time series wind data for one year period, at the height of 10 m. Weibull distribution has been used to determine the wind power density and wind energy density of the site. It was shown that the value of the two parameters, shape parameter k, and scale parameter c, were 3.37 and 5.61 m/s, respectively. The annual mean wind speed and wind speed carrying the maximum energy were 5.32 m/s and 6.45 m/s, respectively. Further, the annual energy density at the site was found at a value of 103.87 W/m2, and based on Pacific North-west Laboratory (PNL) wind power classification, at the height of 10 m, the value of annual energy density is classified into class 2. The commercial wind turbine is chosen to simulate the wind energy potential of the site. The POL...

Performance prediction of serpentine type compact magnetorheological brake prototype

Abstract: A magnetorheological brake (MRB) with serpentine flux type for ankle-foot orthosis (rehabilitation device) was assessed its performance regarding braking torque and dynamic range. This assessment was conducted based on a problem that the MRB did not generate sufficient braking torque for the orthosis device. The braking capability was appraised through analytical approached based on the prototype design. The magnetic circuit of the MRB design was firstly investigated its capability for generating magnetic flux at braking surface area using finite element method magnetic (FEMM) software. Governing equation was derived to determine the braking performance i.e. braking torque and dynamic range as a function of applied current. The main factors influencing the braking performance were magneto-induced shear stress, the clearance between rotor and stator, and braking surface area. Especially for shear stress, this factor was totally influenced by the magnetic flux generated within the braking area. These all fa...

The Design and Analysis of Experiments

Abstract: THE DESIGN AND ANALYSIS OF EXPERIMENTS. By Oscar Kempthorne. New York, John Wiley and Sons, Inc., 1952. 631 pp. $8.50. This book by a teacher of statistics (as well as a consultant for \"experimenters\") is a comprehensive study of the philosophical background for the statistical design of experiment. It is necessary to have some facility with algebraic notation and manipulation to be able to use the volume intelligently. The problems are presented from the theoretical point of view, without such practical examples as would be helpful for those not acquainted with mathematics. The mathematical justification for the techniques is given. As a somewhat advanced treatment of the design and analysis of experiments, this volume will be interesting and helpful for many who approach statistics theoretically as well as practically. With emphasis on the \"why,\" and with description given broadly, the author relates the subject matter to the general theory of statistics and to the general problem of experimental inference. MARGARET J. ROBERTSON

The solutions to electric vehicle air conditioning systems: A review

Abstract: The air conditioning (AC) system provides cool, heating and ventilation in the cabin of the electric vehicles (EVs). It is necessary to control the interior thermal environments of the vehicle and ensure safety in visibility. Because AC systems are electrically powered, vehicle range is reduced drastically when the AC system is operating. EVs present a particular challenge to the development of more efficient AC systems for automotive applications. In this paper, the state of the art for various AC system solutions to EVs was critically reviewed. The investigations of alternative solutions are continuing along many parallel routes, e.g. vapor compression refrigeration-dedicated heater AC systems, reversible vapor compression heat pump AC systems, non-vapor compression AC systems and integrated thermal management system combined AC and battery pack. The characteristics and particular applications of each solution have been extensively discussed. Finally, a comparison listing the various pros and cons of the different available solutions was presented.

Study the influence of using guide vanes blades on the performance of cross-flow wind turbine

Abstract: A cross-flow wind turbine has a high torque coefficient at a low tip speed ratio; therefore, it is a good candidate for a self-starting turbine. This study aims to investigate the best configuration between guide vanes and cross-flow vertical axis wind turbine. The experiment test was carried out to determine the turbine with the highest power coefficient. The cross-flow turbine has 14, 18, and 22 blades with using 6,10 and 14 blades of guide vane (GV) was developed in this study, employing 15°, 25°, 35°, 45°, 55°, 65°, and 75° of tilt angles in fifth different wind speed conditions 4 m/s, 6 m/s, 7.5 m/s, 9.20 m/s, and 11 m/s. The turbine has 22 blades with 14 GV blades at 55° of tilt angle blades producing more remarkable turbine performance improvement than other blades. The highest power coefficient (CP) of cross-flow using 14 GV blades at 55° was 0.0162 at 0.289 TSR, which increased around 59% of the turbine's performance using GV.

Study on Collision Between Two Ships Using Selected Parameters in Collision Simulation

Abstract: 在现在的分析，在数字模拟使用的几个参数在综合研究被调查在这模拟的进程和结果上获得他们的影响。学习的参数是元素明确的表达，磨擦系数，和材料模型。用非线性的有限元素方法的数字模拟被进行为几种碰撞情形生产虚拟试验性的数据。当真实试验性的数据，和这些被用来验证方法，碰撞在一个真实事故案例中引起的模式和尺寸损坏被假定。执行的元素模型学习显示 Belytschko-Tsay 元素明确的表达应该在虚拟实验为使用被推荐。为包含的材料的磨擦系数的真实价值在模拟被使用，这被推荐。为材料模型的学习，有高收益力量的材料的申请在方面壳结构为使用被推荐。

Advanced cooling techniques of P.V. modules: A state of art

Abstract: The efficiency of solar systems, in particular photovoltaic panels, is generally low. The output of the P.V. module is adversely affected by their surface rise in temperature. This increase is associated with the absorbed sunlight that is converted into heat, resulting in reduced power output, energy efficiency, performance and life of the panel. The use of cooling techniques can offer a potential solution to avoid excessive heating of P.V. panels and to reduce cell temperature. This paper presents details of various feasible cooling methods, including novel and advanced solutions for P.V. panels and indicates future trends of research. Different features and capability about each cooling techniques are presented, to provide better insight and valuable guidelines for researchers who intend to study, improve or optimise any type of cooling techniques of P·V. modules.