No abstract

Simulator sistem hidrolik atau yang lebih dikenal dengan hydraulic training unit merupakan alat pembelajaran yang digunakan untuk memahami sistem hidrolik. Pada hydraulic training unit terdapat tiga jenis katup pembatas tekanan yaitu; relief valve, flow control valve dan shut off valve. Tujuan riset ini yakni untuk mendapatkan energi listrik yang optimal pada rangkaian sistem hidrolik dengan mengatur pembukaan katup pembatas tekanan. Metode yang digunakan adalah dengan melakukan pengukuran tegangan, arus dan faktor daya yang terjadi pada masing-masing pembukaan katup pembatas tekanan. Menghitung daya listrik serta menghitung daya mekanik dari rangkaian sistem hidrolik. Melakukan optimalisasi menggunakan linier programming dan di uji menggunakan software Lindo.

Wind turbines are one of the machines that are currently still used to convert wind kinetic energy so that they can be used by humans such as to drive pumps in agriculture and produce electrical energy. Savonius turbine is a vertical axis turbine that is currently widely used as an electrical energy generator, this wind turbine is a type of drag type wind turbine that has a simple design that is in the form of a semicircular curved blade side. Therefore, the author is interested in researching the resulting performance including turbine rotational speed, power generated, and wind turbine efficiency against the variation of the blade radius. The method used is experimental, the stages of this research are in the form of literature studies, making savonius turbines, testing savonius turbines with variations in blade radius as well as data retrieval, data processing, and analysis. Based on the data obtained, the rotating speed of the turbine is influenced by variations in the radius of the blade. The larger the blade radius, the smaller the turbine rotational speed. The maximum turbine rotation speed at blade radius 63 is 173 rpm, while at blade radius, 88 is 118 rpm and at blade radius 113 is 115 rpm. So the highest turbine rotating speed at a radius of 63.

In this work, we propose the use of a low-cost PV monitoring system for providing accurate and comprehensive data required in the development of efficient and reliable solar PV plants. The system is developed based on an open-source Arduino platform with the capability to monitor solar irradiance, and electric outputs and temperature of multiple solar panels, which should enable the accurate assessment of solar energy resource, as well as electrical energy produced by PV plant under real operating conditions. To demonstrate its applicability, the system has been installed at the campus of Politeknik Negeri Pontianak in Pontianak City, and the data collected by the system is used to assess solar energy resource at the location. Data collected by the system from August 2020 to September 2021 shows that the values of solar irradiation are in the range of 2.9–4.1 kWh/m2 per day, and electric energy produced by commercial solar panels are in the range of 0.30–0.46 kWh/m2 per day, correspond to the monthly averaged efficiencies of 8–13%. The values of solar irradiation are 15–40 % lower than those obtained from the space-averaged satellite data which are in the range of 4.1–5.8 kWh/m2 per day. This shows the significant effects of local conditions, and confirms the advantage of assessment using the low-cost monitoring system that directly accounts for the effects of local conditions without the need of simulation using complex model and sophisticated software that required in the assessment using satellite-derived data.

Double acting cylinders in its application are widely used in the industry and are often applied in maintenance or repair instruments. The purpose of this research is to design and make a double acting cylinder so that the movement of the hydraulic cylinder its fluid flow can be seen clearly and easily implemented in the movement process, especially in the learning process. The research employs experimental method by directly design a transparent double acting cylinder. This transparent double acting cylinder will later be applied to the hydraulic trainer. The steps taken were determining the transparent material, making material samples for tensile tests, designing and making hydraulic cylinders, conducting hydraulic cylinder tests using Autodesk Inventor 2019. From the test results of hydraulic cylinders made from acrylic using Autodesk Inventor 2019, the minimum pressure that occurs is 1,456 MPa and the maximum pressure that occurs is 6,573 MPa, in operation, the recommended pressure 1,456 to 5,551 MPa, double acting transparent cylinder which has a transparent hydraulic cylinder length of 250 mm, thickness 11.4 mm, hydraulic cylinder inner diameter 32 mm, hydraulic cylinder locking uses 4 bolts with size M8, design pressure 23 kg/cm².Keywords: hydraulic system, double acting cylinder, transparent.